Electric power transmission

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https://en.wikipedia.org/wiki/Electric_power_transmission

Five-hundred kilovolt (500 kV) Three-phase electric power Transmission Lines at Grand Coulee Dam. Four circuits are shown. Two additional circuits are obscured by trees on the far right. The entire 7079 MW nameplate generation capacity of the dam is accommodated by these six circuits.

Electric power transmission is the bulk movement of electrical energy from a generating site, such as a power plant, to an electrical substation. The interconnected lines that facilitate this movement form a transmission network. This is distinct from the local wiring between high-voltage substations and customers, which is typically referred to as electric power distribution. The combined transmission and distribution network is part of electricity delivery, known as the electrical grid.

Efficient long-distance transmission of electric power requires high voltages. This reduces the losses produced by strong currents. Transmission lines use either alternating current (AC) or direct current (DC). The voltage level is changed with transformers. The voltage is stepped up for transmission, then reduced for local distribution.

A wide area synchronous grid, known as an "interconnection" in North America, directly connects generators delivering AC power with the same relative frequency to many consumers. North America has four major interconnections: Western, Eastern, Quebec and Texas. One grid connects most of continental Europe.

Historically, transmission and distribution lines were often owned by the same company, but starting in the 1990s, many countries liberalized the regulation of the electricity market in ways that led to separate companies handling transmission and distribution.

System

A diagram of an electric power system. The transmission system is in blue.

Most North American transmission lines are high-voltage three-phase AC, although single phase AC is sometimes used in railway electrification systems. DC technology is used for greater efficiency over longer distances, typically hundreds of miles. High-voltage direct current (HVDC) technology is also used in submarine power cables (typically longer than 30 miles (50 km)), and in the interchange of power between grids that are not mutually synchronized. HVDC links stabilize power distribution networks where sudden new loads, or blackouts, in one part of a network might otherwise result in synchronization problems and cascading failures.

Electricity is transmitted at high voltages to reduce the energy loss due to resistance that occurs over long distances. Power is usually transmitted through overhead power lines. Underground power transmission has a significantly higher installation cost and greater operational limitations, but lowers maintenance costs. Underground transmission is more common in urban areas or environmentally sensitive locations.

Electrical energy must typically be generated at the same rate at which it is consumed. A sophisticated control system is required to ensure that power generation closely matches demand. If demand exceeds supply, the imbalance can cause generation plant(s) and transmission equipment to automatically disconnect or shut down to prevent damage. In the worst case, this may lead to a cascading series of shutdowns and a major regional blackout.

The US Northeast faced blackouts in 1965, 1977, 2003, and major blackouts in other US regions in 1996 and 2011. Electric transmission networks are interconnected into regional, national, and even continent-wide networks to reduce the risk of such a failure by providing multiple redundant, alternative routes for power to flow should such shutdowns occur. Transmission companies determine the maximum reliable capacity of each line (ordinarily less than its physical or thermal limit) to ensure that spare capacity is available in the event of a failure in another part of the network.

Overhead

Main article: Overhead power line

 

A four-circuit, two-voltage power transmission line; "Bundled" 2-ways

 

A typical ACSR. The conductor consists of seven strands of steel surrounded by four layers of aluminium.

High-voltage overhead conductors are not covered by insulation. The conductor material is nearly always an aluminum alloy, formed of several strands and possibly reinforced with steel strands. Copper was sometimes used for overhead transmission, but aluminum is lighter, reduces yields only marginally and costs much less. Overhead conductors are supplied by several companies. Conductor material and shapes are regularly improved to increase capacity.

Conductor sizes range from 12 mm² (#6 American wire gauge) to 750 mm² (1,590,000 circular mils area), with varying resistance and current-carrying capacity. For large conductors (more than a few centimetres in diameter), much of the current flow is concentrated near the surface due to the skin effect. The center of the conductor carries little current but contributes weight and cost. Thus, multiple parallel cables (called bundle conductors) are used for higher capacity. Bundle conductors are used at high voltages to reduce energy loss caused by corona discharge.

Today, transmission-level voltages are usually 110 kV and above. Lower voltages, such as 66 kV and 33 kV, are usually considered subtransmission voltages, but are occasionally used on long lines with light loads. Voltages less than 33 kV are usually used for distribution. Voltages above 765 kV are considered extra high voltage and require different designs.

Overhead transmission wires depend on air for insulation, requiring that lines maintain minimum clearances. Adverse weather conditions, such as high winds and low temperatures, interrupt transmission. Wind speeds as low as 23 knots (43 km/h) can permit conductors to encroach operating clearances, resulting in a flashover and loss of supply. Oscillatory motion of the physical line is termed conductor gallop or flutter depending on the frequency and amplitude of oscillation.

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  A five-hundred kilovolt (500 kV) three-phase transmission tower in Washington State, the line is "Bundled" 3-ways

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  Three abreast Electrical Pylons in Webster, Texas

Underground

Main article: Undergrounding

Electric power can be transmitted by underground power cables. Underground cables take up no right-of-way, have lower visibility, and are less affected by weather. However, cables must be insulated. Cable and excavation costs are much higher than overhead construction. Faults in buried transmission lines take longer to locate and repair.

In some metropolitan areas, cables are enclosed by metal pipe and insulated with dielectric fluid (usually an oil) that is either static or circulated via pumps. If an electric fault damages the pipe and leaks dielectric, liquid nitrogen is used to freeze portions of the pipe to enable draining and repair. This extends the repair period and increases costs. The temperature of the pipe and surroundings are monitored throughout the repair period.

Underground lines are limited by their thermal capacity, which permits less overload or re-rating lines. Long underground AC cables have significant capacitance, which reduces their ability to provide useful power beyond 50 miles (80 kilometres). DC cables are not limited in length by their capacitance.

History

Main article: History of electric power transmission

New York City streets in 1890. Besides telegraph lines, multiple electric lines were required for each class of device requiring different voltages.

Commercial electric power was initially transmitted at the same voltage used by lighting and mechanical loads. This restricted the distance between generating plant and loads. In 1882, DC voltage could not easily be increased for long-distance transmission. Different classes of loads (for example, lighting, fixed motors, and traction/railway systems) required different voltages, and so used different generators and circuits.

Thus, generators were sited near their loads, a practice that later became known as distributed generation using large numbers of small generators.

Transmission of alternating current (AC) became possible after Lucien Gaulard and John Dixon Gibbs built what they called the secondary generator, an early transformer provided with 1:1 turn ratio and open magnetic circuit, in 1881.

The first long distance AC line was 34 kilometres (21 miles) long, built for the 1884 International Exhibition of Electricity in Turin, Italy. It was powered by a 2 kV, 130 Hz Siemens & Halske alternator and featured several Gaulard transformers with primary windings connected in series, which fed incandescent lamps. The system proved the feasibility of AC electric power transmission over long distances.

The first commercial AC distribution system entered service in 1885 in via dei Cerchi, Rome, Italy, for public lighting. It was powered by two Siemens & Halske alternators rated 30 hp (22 kW), 2 kV at 120 Hz and used 19 km of cables and 200 parallel-connected 2 kV to 20 V step-down transformers provided with a closed magnetic circuit, one for each lamp. A few months later it was followed by the first British AC system, serving Grosvenor Gallery. It also featured Siemens alternators and 2.4 kV to 100 V step-down transformers – one per user – with shunt-connected primaries.

Working to improve what he considered an impractical Gaulard-Gibbs design, electrical engineer William Stanley, Jr. developed the first practical series AC transformer in 1885. Working with the support of George Westinghouse, in 1886 he demonstrated a transformer-based AC lighting system in Great Barrington, Massachusetts. It was powered by a steam engine-driven 500 V Siemens generator. Voltage was stepped down to 100 volts using the Stanley transformer to power incandescent lamps at 23 businesses over 4,000 feet (1,200 m). This practical demonstration of a transformer and alternating current lighting system led Westinghouse to begin installing AC systems later that year.

In 1888 the first designs for an AC motor appeared. These were induction motors running on polyphase current, independently invented by Galileo Ferraris and Nikola Tesla. Westinghouse licensed Tesla's design. Practical three-phase motors were designed by Mikhail Dolivo-Dobrovolsky and Charles Eugene Lancelot Brown. Widespread use of such motors were delayed many years by development problems and the scarcity of polyphase power systems needed to power them.

Westinghouse alternating current polyphase generators on display at the 1893 World's Fair in Chicago, part of their "Tesla Poly-phase System". Such polyphase innovations revolutionized transmission.

In the late 1880s and early 1890s smaller electric companies merged into larger corporations such as Ganz and AEG in Europe and General Electric and Westinghouse Electric in the US. These companies developed AC systems, but the technical difference between direct and alternating current systems required a much longer technical merger. Alternating current's economies of scale with large generating plants and long-distance transmission slowly added the ability to link all the loads. These included single phase AC systems, poly-phase AC systems, low voltage incandescent lighting, high-voltage arc lighting, and existing DC motors in factories and street cars. In what became a universal system, these technological differences were temporarily bridged via the rotary converters and motor-generators that allowed the legacy systems to connect to the AC grid. These stopgaps were slowly replaced as older systems were retired or upgraded.

The first transmission of single-phase alternating current using high voltage came in Oregon in 1890 when power was delivered from a hydroelectric plant at Willamette Falls to the city of Portland 14 miles (23 km) down river. The first three-phase alternating current using high voltage took place in 1891 during the international electricity exhibition in Frankfurt. A 15 kV transmission line, approximately 175 km long, connected Lauffen on the Neckar and Frankfurt.

Transmission voltages increased throughout the 20th century. By 1914, fifty-five transmission systems operating at more than 70 kV were in service. The highest voltage then used was 150 kV. Interconnecting multiple generating plants over a wide area reduced costs. The most efficient plants could be used to supply varying loads during the day. Reliability was improved and capital costs were reduced, because stand-by generating capacity could be shared over many more customers and a wider area. Remote and low-cost sources of energy, such as hydroelectric power or mine-mouth coal, could be exploited to further lower costs.

The 20th century's rapid industrialization made electrical transmission lines and grids critical infrastructure. Interconnection of local generation plants and small distribution networks was spurred by World War I, when large electrical generating plants were built by governments to power munitions factories.

Bulk transmission

A transmission substation decreases the voltage of incoming electricity, allowing it to connect from long-distance high-voltage transmission, to local lower voltage distribution. It also reroutes power to other transmission lines that serve local markets. This is the PacifiCorp Hale Substation, Orem, Utah, US.

These networks use components such as power lines, cables, circuit breakers, switches and transformers. The transmission network is usually administered on a regional basis by an entity such as a regional transmission organization or transmission system operator.

Transmission efficiency is improved at higher voltage and lower current. The reduced current reduces heating losses. Joule's first law states that energy losses are proportional to the square of the current. Thus, reducing the current by a factor of two lowers the energy lost to conductor resistance by a factor of four for any given size of conductor.

The optimum size of a conductor for a given voltage and current can be estimated by Kelvin's law for conductor size, which states that size is optimal when the annual cost of energy wasted in resistance is equal to the annual capital charges of providing the conductor. At times of lower interest rates and low commodity costs, Kelvin's law indicates that thicker wires are optimal. Otherwise, thinner conductors are indicated. Since power lines are designed for long-term use, Kelvin's law is used in conjunction with long-term estimates of the price of copper and aluminum as well as interest rates.

Higher voltage is achieved in AC circuits by using a step-up transformer. High-voltage direct current (HVDC) systems require relatively costly conversion equipment that may be economically justified for particular projects such as submarine cables and longer distance high capacity point-to-point transmission. HVDC is necessary for sending energy between unsynchronized grids.

A transmission grid is a network of power stations, transmission lines, and substations. Energy is usually transmitted within a grid with three-phase AC. Single-phase AC is used only for distribution to end users since it is not usable for large polyphase induction motors. In the 19th century, two-phase transmission was used but required either four wires or three wires with unequal currents. Higher order phase systems require more than three wires, but deliver little or no benefit.

The synchronous grids of Europe

While the price of generating capacity is high, energy demand is variable, making it often cheaper to import needed power than to generate it locally. Because loads often rise and fall together across large areas, power often comes from distant sources. Because of the economic benefits of load sharing, wide area transmission grids may span countries and even continents. Interconnections between producers and consumers enables power to flow even if some links are inoperative.

The slowly varying portion of demand is known as the base load and is generally served by large facilities with constant operating costs, termed firm power. Such facilities are nuclear, coal or hydroelectric, while other energy sources such as concentrated solar thermal and geothermal power have the potential to provide firm power. Renewable energy sources, such as solar photovoltaics, wind, wave, and tidal, are, due to their intermittency, not considered to be firm. The remaining or "peak" power demand, is supplied by peaking power plants, which are typically smaller, faster-responding, and higher cost sources, such as combined cycle or combustion turbine plants typically fueled by natural gas.

Long-distance transmission (hundreds of kilometers) is cheap and efficient, with costs of US$0.005–0.02 per kWh (compared to annual averaged large producer costs of US$0.01–0.025 per kWh, retail rates upwards of US$0.10 per kWh, and multiples of retail for instantaneous suppliers at unpredicted high demand moments. New York often buys over 1000 MW of low-cost hydropower from Canada. Local sources (even if more expensive and infrequently used) can protect the power supply from weather and other disasters that can disconnect distant suppliers.

A high-power electrical transmission tower, 230 kV, double-circuit, also double-bundled

Hydro and wind sources cannot be moved closer to big cities, and solar costs are lowest in remote areas where local power needs are nominal. Connection costs can determine whether any particular renewable alternative is economically realistic. Costs can be prohibitive for transmission lines, but high capacity, long distance super grid transmission network costs could be recovered with modest usage fees.

Grid input

At power stations, power is produced at a relatively low voltage between about 2.3 kV and 30 kV, depending on the size of the unit. The voltage is then stepped up by the power station transformer to a higher voltage (115 kV to 765 kV AC) for transmission.

In the United States, power transmission is, variously, 230 kV to 500 kV, with less than 230 kV or more than 500 kV as exceptions.

The Western Interconnection has two primary interchange voltages: 500 kV AC at 60 Hz, and ±500 kV (1,000 kV net) DC from North to South (Columbia River to Southern California) and Northeast to Southwest (Utah to Southern California). The 287.5 kV (Hoover Dam to Los Angeles line, via Victorville) and 345 kV (Arizona Public Service (APS) line) are local standards, both of which were implemented before 500 kV became practical.

Losses

Transmitting electricity at high voltage reduces the fraction of energy lost to Joule heating, which varies by conductor type, the current, and the transmission distance. For example, a 100 mi (160 km) span at 765 kV carrying 1000 MW of power can have losses of 0.5% to 1.1%. A 345 kV line carrying the same load across the same distance has losses of 4.2%. For a given amount of power, a higher voltage reduces the current and thus the resistive losses. For example, raising the voltage by a factor of 10 reduces the current by a corresponding factor of 10 and therefore the ${\displaystyle I^{2}R}$ losses by a factor of 100, provided the same sized conductors are used in both cases. Even if the conductor size (cross-sectional area) is decreased ten-fold to match the lower current, the ${\displaystyle I^{2}R}$ losses are still reduced ten-fold using the higher voltage.

While power loss can also be reduced by increasing the wire's conductance (by increasing its cross-sectional area), larger conductors are heavier and more expensive. And since conductance is proportional to cross-sectional area, resistive power loss is only reduced proportionally with increasing cross-sectional area, providing a much smaller benefit than the squared reduction provided by multiplying the voltage.

Long-distance transmission is typically done with overhead lines at voltages of 115 to 1,200 kV. At higher voltages, where more than 2,000 kV exists between conductor and ground, corona discharge losses are so large that they can offset the lower resistive losses in the line conductors. Measures to reduce corona losses include larger conductor diameter, hollow cores or conductor bundles.

Factors that affect resistance and thus loss include temperature, spiraling, and the skin effect. Resistance increases with temperature. Spiraling, which refers to the way stranded conductors spiral about the center, also contributes to increases in conductor resistance. The skin effect causes the effective resistance to increase at higher AC frequencies. Corona and resistive losses can be estimated using a mathematical model.

US transmission and distribution losses were estimated at 6.6% in 1997, 6.5% in 2007 and 5% from 2013 to 2019. In general, losses are estimated from the discrepancy between power produced (as reported by power plants) and power sold; the difference constitutes transmission and distribution losses, assuming no utility theft occurs.

As of 1980, the longest cost-effective distance for DC transmission was 7,000 kilometres (4,300 miles). For AC it was 4,000 kilometres (2,500 miles), though US transmission lines are substantially shorter.

In any AC line, conductor inductance and capacitance can be significant. Currents that flow solely in reaction to these properties, (which together with the resistance define the impedance) constitute reactive power flow, which transmits no power to the load. These reactive currents, however, cause extra heating losses. The ratio of real power transmitted to the load to apparent power (the product of a circuit's voltage and current, without reference to phase angle) is the power factor. As reactive current increases, reactive power increases and power factor decreases.

For transmission systems with low power factor, losses are higher than for systems with high power factor. Utilities add capacitor banks, reactors and other components (such as phase-shifters; static VAR compensators; and flexible AC transmission systems, FACTS) throughout the system help to compensate for the reactive power flow, reduce the losses in power transmission and stabilize system voltages. These measures are collectively called 'reactive support'.

Transposition

Current flowing through transmission lines induces a magnetic field that surrounds the lines of each phase and affects the inductance of the surrounding conductors of other phases. The conductors' mutual inductance is partially dependent on the physical orientation of the lines with respect to each other. Three-phase lines are conventionally strung with phases separated vertically. The mutual inductance seen by a conductor of the phase in the middle of the other two phases is different from the inductance seen on the top/bottom.

Unbalanced inductance among the three conductors is problematic because it may force the middle line to carry a disproportionate amount of the total power transmitted. Similarly, an unbalanced load may occur if one line is consistently closest to the ground and operates at a lower impedance. Because of this phenomenon, conductors must be periodically transposed along the line so that each phase sees equal time in each relative position to balance out the mutual inductance seen by all three phases. To accomplish this, line position is swapped at specially designed transposition towers at regular intervals along the line using various transposition schemes.

Subtransmission

A 115 kV subtransmission line in the Philippines, along with 20 kV distribution lines and a street light, all mounted on a wood subtransmission pole

115 kV H-frame transmission tower

Subtransmission runs at relatively lower voltages. It is uneconomical to connect all distribution substations to the high main transmission voltage, because that equipment is larger and more expensive. Typically, only larger substations connect with this high voltage. Voltage is stepped down before the current is sent to smaller substations. Subtransmission circuits are usually arranged in loops so that a single line failure does not stop service to many customers for more than a short time.

Loops can be "normally closed", where loss of one circuit should result in no interruption, or "normally open" where substations can switch to a backup supply. While subtransmission circuits are usually carried on overhead lines, in urban areas buried cable may be used. The lower-voltage subtransmission lines use less right-of-way and simpler structures; undergrounding is less difficult.

No fixed cutoff separates subtransmission and transmission, or subtransmission and distribution. Their voltage ranges overlap. Voltages of 69 kV, 115 kV, and 138 kV are often used for subtransmission in North America. As power systems evolved, voltages formerly used for transmission were used for subtransmission, and subtransmission voltages became distribution voltages. Like transmission, subtransmission moves relatively large amounts of power, and like distribution, subtransmission covers an area instead of just point-to-point.

Transmission grid exit

Substation transformers reduce the voltage to a lower level for distribution to loads. This distribution is accomplished with a combination of sub-transmission (33 to 132 kV) and distribution (3.3 to 25 kV). Finally, at the point of use, the energy is transformed to low voltage.

Advantage of high-voltage transmission

See also: Ideal transformer

High-voltage power transmission allows for lesser resistive losses over long distances. This efficiency delivers a larger proportion of the generated power to the loads.

Electrical grid without a transformer

Electrical grid with a transformer

In a simplified model, the grid delivers electricity from an ideal voltage source with voltage ${\displaystyle V}$, delivering a power ${\displaystyle P_V}$) to a single point of consumption, modelled by a resistance ${\displaystyle R}$, when the wires are long enough to have a significant resistance ${\displaystyle R_C}$.

If the resistances are in series with no intervening transformer, the circuit acts as a voltage divider, because the same current ${\displaystyle I=\frac{V}{R+R_C}}$ runs through the wire resistance and the powered device. As a consequence, the useful power (at the point of consumption) is:

${\displaystyle P_R=V_2\times I=V\frac{R}{R+R_C}\times \frac{V}{R+R_C}=\frac{R}{R+R_C}\times \frac{V^2}{R+R_C}=\frac{R}{R+R_C}{P}_V}$

Should an ideal transformer convert high-voltage, low-current electricity into low-voltage, high-current electricity with a voltage ratio of ${\displaystyle a}$ (i.e., the voltage is divided by ${\displaystyle a}$ and the current is multiplied by ${\displaystyle a}$ in the secondary branch, compared to the primary branch), then the circuit is again equivalent to a voltage divider, but the wires now have apparent resistance of only ${\displaystyle R_C/a^2}$. The useful power is then:

${\displaystyle P_R=V_2\times I_2=\frac{a^{2}R\times V^2}{(a^{2}R+R_C{)}^2}=\frac{a^{2}R}{a^{2}R+R_C}{P}_V=\frac{R}{R+R_C/a^2}{P}_V}$

For ${\displaystyle a>1}$ (i.e. conversion of high voltage to low voltage near the consumption point), a larger fraction of the generator's power is transmitted to the consumption point and a lesser fraction is lost to Joule heating.

Modeling

Main article: Performance and modelling of AC transmission

"Black box" model for transmission line

The terminal characteristics of the transmission line are the voltage and current at the sending (S) and receiving (R) ends. The transmission line can be modeled as a "black box" and a 2 by 2 transmission matrix is used to model its behavior, as follows:

${\displaystyle \left[\begin{array}{c}{V}_{\mathrm{S}}\\ I_{\mathrm{S}}\end{array}\right]=\left[\begin{array}{cc}A& B\\ C& D\end{array}\right]\left[\begin{array}{c}{V}_{\mathrm{R}}\\ I_{\mathrm{R}}\end{array}\right]}$

The line is assumed to be a reciprocal, symmetrical network, meaning that the receiving and sending labels can be switched with no consequence. The transmission matrix T has the properties:

• ${\displaystyle det(T)=AD-BC=1}$
• ${\displaystyle A=D}$

The parameters A, B, C, and D differ depending on how the desired model handles the line's resistance (R), inductance (L), capacitance (C), and shunt (parallel, leak) conductance G.

The four main models are the short line approximation, the medium line approximation, the long line approximation (with distributed parameters), and the lossless line. In such models, a capital letter such as R refers to the total quantity summed over the line and a lowercase letter such as c refers to the per-unit-length quantity.

Lossless line

The lossless line approximation is the least accurate; it is typically used on short lines where the inductance is much greater than the resistance. For this approximation, the voltage and current are identical at the sending and receiving ends.

Voltage on sending and receiving ends for lossless line

The characteristic impedance is pure real, which means resistive for that impedance, and it is often called surge impedance. When a lossless line is terminated by surge impedance, the voltage does not drop. Though the phase angles of voltage and current are rotated, the magnitudes of voltage and current remain constant along the line. For load > SIL, the voltage drops from sending end and the line "consumes" VARs. For load < SIL, the voltage increases from the sending end, and the line "generates" VARs.

Short line

The short line approximation is normally used for lines shorter than 80 km (50 mi). There, only a series impedance Z is considered, while C and G are ignored. The final result is that A = D = 1 per unit, B = Z Ohms, and C = 0. The associated transition matrix for this approximation is therefore:

${\displaystyle \left[\begin{array}{c}{V}_{\mathrm{S}}\\ I_{\mathrm{S}}\end{array}\right]=\left[\begin{array}{cc}1& Z\\ 0& 1\end{array}\right]\left[\begin{array}{c}{V}_{\mathrm{R}}\\ I_{\mathrm{R}}\end{array}\right]}$

Medium line

The medium line approximation is used for lines running between 80 and 250 km (50 and 155 mi). The series impedance and the shunt (current leak) conductance are considered, placing half of the shunt conductance at each end of the line. This circuit is often referred to as a "nominal π (pi)" circuit because of the shape (π) that is taken on when leak conductance is placed on both sides of the circuit diagram. The analysis of the medium line produces:

${\displaystyle \begin{array}{rl}A& =D=1+\frac{GZ}{2}\text{ per unit}\\ B& =Z\mathrm{\Omega }\\ C& =G(1+\frac{GZ}{4})S\end{array}}$

Counterintuitive behaviors of medium-length transmission lines:

• voltage rise at no load or small current (Ferranti effect)
• receiving-end current can exceed sending-end current

Long line

The long line model is used when a higher degree of accuracy is needed or when the line under consideration is more than 250 km (160 mi) long. Series resistance and shunt conductance are considered to be distributed parameters, such that each differential length of the line has a corresponding differential series impedance and shunt admittance. The following result can be applied at any point along the transmission line, where ${\displaystyle \gamma }$ is the propagation constant.

${\displaystyle \begin{array}{rl}A& =D=\cosh (\gamma x)\text{ per unit}\\ B& =Z_c\sinh (\gamma x)\mathrm{\Omega }\\ C& =\frac{1}{Z_c}\sinh (\gamma x)S\end{array}}$

To find the voltage and current at the end of the long line, ${\displaystyle x}$ should be replaced with ${\displaystyle l}$ (the line length) in all parameters of the transmission matrix. This model applies the Telegrapher's equations.

High-voltage direct current

Main article: High-voltage direct current

High-voltage direct current (HVDC) is used to transmit large amounts of power over long distances or for interconnections between asynchronous grids. When electrical energy is transmitted over very long distances, the power lost in AC transmission becomes appreciable and it is less expensive to use direct current instead. For a long transmission line, these lower losses (and reduced construction cost of a DC line) can offset the cost of the required converter stations at each end.

HVDC is used for long submarine cables where AC cannot be used because of cable capacitance. In these cases special high-voltage cables are used. Submarine HVDC systems are often used to interconnect the electricity grids of islands, for example, between Great Britain and continental Europe, between Great Britain and Ireland, between Tasmania and the Australian mainland, between the North and South Islands of New Zealand, between New Jersey and New York City, and between New Jersey and Long Island. Submarine connections up to 600 kilometres (370 mi) in length have been deployed.

HVDC links can be used to control grid problems. The power transmitted by an AC line increases as the phase angle between source end voltage and destination ends increases, but too large a phase angle allows the systems at either end to fall out of step. Since the power flow in a DC link is controlled independently of the phases of the AC networks that it connects, this phase angle limit does not exist, and a DC link is always able to transfer its full rated power. A DC link therefore stabilizes the AC grid at either end, since power flow and phase angle can then be controlled independently.

As an example, to adjust the flow of AC power on a hypothetical line between Seattle and Boston would require adjustment of the relative phase of the two regional electrical grids. This is an everyday occurrence in AC systems, but one that can become disrupted when AC system components fail and place unexpected loads on the grid. With an HVDC line instead, such an interconnection would:

• Convert AC in Seattle into HVDC;
• Use HVDC for the 3,000 miles (4,800 km) of cross-country transmission; and
• Convert the HVDC to locally synchronized AC in Boston,

(and possibly in other cooperating cities along the transmission route). Such a system could be less prone to failure if parts of it were suddenly shut down. One example of a long DC transmission line is the Pacific DC Intertie located in the Western United States.

Capacity

The amount of power that can be sent over a transmission line varies with the length of the line. The heating of short line conductors due to line losses sets a thermal limit. If too much current is drawn, conductors may sag too close to the ground, or conductors and equipment may overheat. For intermediate-length lines on the order of 100 kilometres (62 miles), the limit is set by the voltage drop in the line. For longer AC lines, system stability becomes the limiting factor. Approximately, the power flowing over an AC line is proportional to the cosine of the phase angle of the voltage and current at the ends.

This angle varies depending on system loading. It is undesirable for the angle to approach 90 degrees, as the power flowing decreases while resistive losses remain. The product of line length and maximum load is approximately proportional to the square of the system voltage. Series capacitors or phase-shifting transformers are used on long lines to improve stability. HVDC lines are restricted only by thermal and voltage drop limits, since the phase angle is not material.

Understanding the temperature distribution along the cable route became possible with the introduction of distributed temperature sensing (DTS) systems that measure temperatures all along the cable. Without them maximum current was typically set as a compromise between understanding of operation conditions and risk minimization. This monitoring solution uses passive optical fibers as temperature sensors, either inside a high-voltage cable or externally mounted on the cable insulation.

For overhead cables the fiber is integrated into the core of a phase wire. The integrated Dynamic Cable Rating (DCR)/Real Time Thermal Rating (RTTR) solution makes it possible to run the network to its maximum. It allows the operator to predict the behavior of the transmission system to reflect major changes to its initial operating conditions.

Control

To ensure safe and predictable operation, system components are controlled with generators, switches, circuit breakers and loads. The voltage, power, frequency, load factor, and reliability capabilities of the transmission system are designed to provide cost effective performance.

Load balancing

The transmission system provides for base load and peak load capability, with margins for safety and fault tolerance. Peak load times vary by region largely due to the industry mix. In hot and cold climates home air conditioning and heating loads affect the overall load. They are typically highest in the late afternoon in the hottest part of the year and in mid-mornings and mid-evenings in the coldest part of the year. Power requirements vary by season and time of day. Distribution system designs always take the base load and the peak load into consideration.

The transmission system usually does not have a large buffering capability to match loads with generation. Thus generation has to be kept matched to the load, to prevent overloading generation equipment.

Multiple sources and loads can be connected to the transmission system and they must be controlled to provide orderly transfer of power. In centralized power generation, only local control of generation is necessary. This involves synchronization of the generation units.

In distributed power generation the generators are geographically distributed and the process to bring them online and offline must be carefully controlled. The load control signals can either be sent on separate lines or on the power lines themselves. Voltage and frequency can be used as signaling mechanisms to balance the loads.

In voltage signaling, voltage is varied to increase generation. The power added by any system increases as the line voltage decreases. This arrangement is stable in principle. Voltage-based regulation is complex to use in mesh networks, since the individual components and setpoints would need to be reconfigured every time a new generator is added to the mesh.

In frequency signaling, the generating units match the frequency of the power transmission system. In droop speed control, if the frequency decreases, the power is increased. (The drop in line frequency is an indication that the increased load is causing the generators to slow down.)

Wind turbines, vehicle-to-grid, virtual power plants, and other locally distributed storage and generation systems can interact with the grid to improve system operation. Internationally, a slow move from a centralized to decentralized power system has taken place. The main draw of locally distributed generation systems is that they reduce transmission losses by leading to consumption of electricity closer to where it was produced.

Failure protection

Under excess load conditions, the system can be designed to fail incrementally rather than all at once. Brownouts occur when power supplied drops below the demand. Blackouts occur when the grid fails completely.

Rolling blackouts (also called load shedding) are intentionally engineered electrical power outages, used to distribute insufficient power to various loads in turn.

Communications

Grid operators require reliable communications to manage the grid and associated generation and distribution facilities. Fault-sensing protective relays at each end of the line must communicate to monitor the flow of power so that faulted conductors or equipment can be quickly de-energized and the balance of the system restored. Protection of the transmission line from short circuits and other faults is usually so critical that common carrier telecommunications are insufficiently reliable, while in some remote areas no common carrier is available. Communication systems associated with a transmission project may use:

• Microwaves
• Power-line communication
• Optical fibers

Rarely, and for short distances, pilot-wires are strung along the transmission line path. Leased circuits from common carriers are not preferred since availability is not under control of the operator.

Transmission lines can be used to carry data: this is called power-line carrier, or power-line communication (PLC). PLC signals can be easily received with a radio in the long wave range.

High-voltage pylons carrying additional optical fibre cable in Kenya

Optical fibers can be included in the stranded conductors of a transmission line, in the overhead shield wires. These cables are known as optical ground wire (OPGW). Sometimes a standalone cable is used, all-dielectric self-supporting (ADSS) cable, attached to the transmission line cross arms.

Some jurisdictions, such as Minnesota, prohibit energy transmission companies from selling surplus communication bandwidth or acting as a telecommunications common carrier. Where the regulatory structure permits, the utility can sell capacity in extra dark fibers to a common carrier.

Market structure

Main article: Electricity market

Electricity transmission is generally considered to be a natural monopoly, but one that is not inherently linked to generation. Many countries regulate transmission separately from generation.

Spain was the first country to establish a regional transmission organization. In that country, transmission operations and electricity markets are separate. The transmission system operator is Red Eléctrica de España (REE) and the wholesale electricity market operator is Operador del Mercado Ibérico de Energía – Polo Español, S.A. (OMEL) OMEL Holding | Omel Holding. Spain's transmission system is interconnected with those of France, Portugal, and Morocco.

The establishment of RTOs in the United States was spurred by the FERC's Order 888, Promoting Wholesale Competition Through Open Access Non-discriminatory Transmission Services by Public Utilities; Recovery of Stranded Costs by Public Utilities and Transmitting Utilities, issued in 1996. In the United States and parts of Canada, electric transmission companies operate independently of generation companies, but in the Southern United States vertical integration is intact. In regions of separation, transmission owners and generation owners continue to interact with each other as market participants with voting rights within their RTO. RTOs in the United States are regulated by the Federal Energy Regulatory Commission.

Merchant transmission projects in the United States include the Cross Sound Cable from Shoreham, New York to New Haven, Connecticut, Neptune RTS Transmission Line from Sayreville, New Jersey, to New Bridge, New York, and Path 15 in California. Additional projects are in development or have been proposed throughout the United States, including the Lake Erie Connector, an underwater transmission line proposed by ITC Holdings Corp., connecting Ontario to load serving entities in the PJM Interconnection region.

Australia has one unregulated or market interconnector - Basslink - between Tasmania and Victoria. Two DC links originally implemented as market interconnectors, Directlink and Murraylink, were converted to regulated interconnectors.

A major barrier to wider adoption of merchant transmission is the difficulty in identifying who benefits from the facility so that the beneficiaries pay the toll. Also, it is difficult for a merchant transmission line to compete when the alternative transmission lines are subsidized by utilities with a monopolized and regulated rate base. In the United States, the FERC's Order 1000, issued in 2010, attempted to reduce barriers to third party investment and creation of merchant transmission lines where a public policy need is found.

Transmission costs

The cost of high voltage transmission is comparatively low, compared to all other costs constituting consumer electricity bills. In the UK, transmission costs are about 0.2 p per kWh compared to a delivered domestic price of around 10 p per kWh.

The level of capital expenditure in the electric power T&D equipment market was estimated to be $128.9 bn in 2011.

Health concerns

Main article: Electromagnetic radiation and health

Mainstream scientific evidence suggests that low-power, low-frequency, electromagnetic radiation associated with household currents and high transmission power lines does not constitute a short- or long-term health hazard.

Some studies failed to find any link between living near power lines and developing any sickness or diseases, such as cancer. A 1997 study reported no increased risk of cancer or illness from living near a transmission line. Other studies, however, reported statistical correlations between various diseases and living or working near power lines. No adverse health effects have been substantiated for people not living close to power lines.

The New York State Public Service Commission conducted a study to evaluate potential health effects of electric fields. The study measured the electric field strength at the edge of an existing right-of-way on a 765 kV transmission line. The field strength was 1.6 kV/m, and became the interim maximum strength standard for new transmission lines in New York State. The opinion also limited the voltage of new transmission lines built in New York to 345 kV. On September 11, 1990, after a similar study of magnetic field strengths, the NYSPSC issued their Interim Policy Statement on Magnetic Fields. This policy established a magnetic field standard of 200 mG at the edge of the right-of-way using the winter-normal conductor rating. As a comparison with everyday items, a hair dryer or electric blanket produces a 100 mG – 500 mG magnetic field.

Applications for a new transmission line typically include an analysis of electric and magnetic field levels at the edge of rights-of-way. Public utility commissions typically do not comment on health impacts.

Biological effects have been established for acute high level exposure to magnetic fields above 100 µT (1 G) (1,000 mG). In a residential setting, one study reported "limited evidence of carcinogenicity in humans and less than sufficient evidence for carcinogenicity in experimental animals", in particular, childhood leukemia, associated with average exposure to residential power-frequency magnetic field above 0.3 µT (3 mG) to 0.4 µT (4 mG). These levels exceed average residential power-frequency magnetic fields in homes, which are about 0.07 µT (0.7 mG) in Europe and 0.11 µT (1.1 mG) in North America.

The Earth's natural geomagnetic field strength varies over the surface of the planet between 0.035 mT and 0.07 mT (35 µT – 70 µT or 350 mG – 700 mG) while the international standard for continuous exposure is set at 40 mT (400,000 mG or 400 G) for the general public.

Tree growth regulators and herbicides may be used in transmission line right of ways, which may have health effects.

Policy by country

United States

The Federal Energy Regulatory Commission (FERC) is the primary regulatory agency of electric power transmission and wholesale electricity sales within the United States. FERC was originally established by Congress in 1920 as the Federal Power Commission and has since undergone multiple name and responsibility modifications. Electric power distribution and the retail sale of power is under state jurisdiction.

Order No. 888

Order No. 888 was adopted by FERC on April 24, 1996. It was "designed to remove impediments to competition in the wholesale bulk power marketplace and to bring more efficient, lower cost power to the Nation's electricity consumers. The legal and policy cornerstone of these rules is to remedy undue discrimination in access to the monopoly owned transmission wires that control whether and to whom electricity can be transported in interstate commerce." The Order required all public utilities that own, control, or operate facilities used for transmitting electric energy in interstate commerce, to have open access, non-discriminatory transmission tariffs. These tariffs allow any electricity generator to utilize existing power lines to transmit the power that they generate. The Order also permits public utilities to recover the costs associated with providing their power lines as an open access service.

Energy Policy Act of 2005

The Energy Policy Act of 2005 (EPAct) expanded federal authority to regulate power transmission. EPAct gave FERC significant new responsibilities, including enforcement of electric transmission reliability standards and the establishment of rate incentives to encourage investment in electricity transmission.

Historically, local governments exercised authority over the grid and maintained significant disincentives to actions that would benefit states other than their own. Localities with cheap electricity have a disincentive to encourage making interstate commerce in electricity trading easier, since other regions would be able to compete for that energy and drive up rates. For example, some regulators in Maine refused to address congestion problems because the congestion protects Maine rates.

Local constituencies can block or slow permitting by pointing to visual impacts, environmental, and health concerns. In the US, generation is growing four times faster than transmission, but transmission upgrades require the coordination of multiple jurisdictions, complex permitting, and cooperation between a significant portion of the many companies that collectively own the grid. The US national security interest in improving transmission was reflected in the EPAct which gave the Department of Energy the authority to approve transmission if states refused to act.

Specialized transmission

Grids for railways

Main article: Traction power network

In some countries where electric locomotives or electric multiple units run on low frequency AC power, separate single phase traction power networks are operated by the railways. Prime examples are countries such as Austria, Germany and Switzerland that utilize AC technology based on 16 ²/₃ Hz. Norway and Sweden also use this frequency but use conversion from the 50 Hz public supply; Sweden has a 16 ²/₃ Hz traction grid but only for part of the system.

Superconducting cables

High-temperature superconductors (HTS) promise to revolutionize power distribution by providing lossless transmission. The development of superconductors with transition temperatures higher than the boiling point of liquid nitrogen has made the concept of superconducting power lines commercially feasible, at least for high-load applications. It has been estimated that waste would be halved using this method, since the necessary refrigeration equipment would consume about half the power saved by the elimination of resistive losses. Companies such as Consolidated Edison and American Superconductor began commercial production of such systems in 2007.

Superconducting cables are particularly suited to high load density areas such as the business district of large cities, where purchase of an easement for cables is costly.

HTS transmission lines

Location	Length (km)	Voltage (kV)	Capacity (GW)	Date
Carrollton, Georgia				2000
Albany, New York	0.35	34.5	0.048	2006
Holbrook, Long Island	0.6	138	0.574	2008
Tres Amigas			5	Proposed 2013
Manhattan: Project Hydra				Proposed 2014
Essen, Germany	1	10	0.04	2014

Single-wire earth return

Main article: Single-wire earth return

Single-wire earth return (SWER) or single-wire ground return is a single-wire transmission line for supplying single-phase electrical power to remote areas at low cost. It is principally used for rural electrification, but also finds use for larger isolated loads such as water pumps. Single-wire earth return is also used for HVDC over submarine power cables.

Wireless power transmission

Main article: Wireless power transfer

Both Nikola Tesla and Hidetsugu Yagi attempted to devise systems for large scale wireless power transmission in the late 1800s and early 1900s, without commercial success.

In November 2009, LaserMotive won the NASA 2009 Power Beaming Challenge by powering a cable climber 1 km vertically using a ground-based laser transmitter. The system produced up to 1 kW of power at the receiver end. In August 2010, NASA contracted with private companies to pursue the design of laser power beaming systems to power low earth orbit satellites and to launch rockets using laser power beams.

Wireless power transmission has been studied for transmission of power from solar power satellites to the earth. A high power array of microwave or laser transmitters would beam power to a rectenna. Major engineering and economic challenges face any solar power satellite project.

Security

The Federal government of the United States stated that the power grid is susceptible to cyber-warfare.^[64][65] The United States Department of Homeland Security works with industry to identify vulnerabilities and to help industry enhance the security of control system networks.

In June 2019, Russia conceded that it was "possible" its electrical grid is under cyber-attack by the United States. The New York Times reported that American hackers from the United States Cyber Command planted malware potentially capable of disrupting the Russian electrical grid.

Records

• Highest capacity system: 12 GW Zhundong–Wannan（准东-皖南）±1100 kV HVDC.
• Highest transmission voltage (AC):
  • planned: 1.20 MV (Ultra-High Voltage) on Wardha-Aurangabad line (India) – under construction. Initially will operate at 400 kV.
  • worldwide: 1.15 MV (Ultra-High Voltage) on Ekibastuz-Kokshetau line (Kazakhstan)
• Largest double-circuit transmission, Kita-Iwaki Powerline (Japan).
• Highest towers: Yangtze River Crossing (China) (height: 345 m or 1,132 ft)
• Longest power line: Inga-Shaba (Democratic Republic of Congo) (length: 1,700 kilometres or 1,056 miles)
• Longest span of power line: 5,376 m (17,638 ft) at Ameralik Span (Greenland, Denmark)
• Longest submarine cables:
  • North Sea Link, (Norway/United Kingdom) – (length of submarine cable: 720 kilometres or 447 miles)
  • NorNed, North Sea (Norway/Netherlands) – (length of submarine cable: 580 kilometres or 360 miles)
  • Basslink, Bass Strait, (Australia) – (length of submarine cable: 290 kilometres or 180 miles, total length: 370.1 kilometres or 230 miles)
  • Baltic Cable, Baltic Sea (Germany/Sweden) – (length of submarine cable: 238 kilometres or 148 miles, HVDC length: 250 kilometres or 155 miles, total length: 262 kilometres or 163 miles)
• Longest underground cables:
  • Murraylink, Riverland/Sunraysia (Australia) – (length of underground cable: 170 kilometres or 106 miles)

Type A and Type B personality theory

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Type_A_and_Type_B_personality_theory

Type A and Type B personality hypothesis describes two contrasting personality types. In this hypothesis, personalities that are more competitive, highly organized, ambitious, impatient, highly aware of time management, or aggressive are labeled Type A, while more relaxed, "receptive", less "neurotic" and "frantic" personalities are labeled Type B.

The two cardiologists, Meyer Friedman and Ray Rosenman, who developed this theory came to believe that Type A personalities had a greater chance of developing coronary heart disease. Following the results of further studies and considerable controversy about the role of the tobacco industry funding of early research in this area, some reject, either partially or completely, the link between Type A personality and coronary disease. Nevertheless, this research had a significant effect on the development of the health psychology field, in which psychologists look at how an individual's mental state affects physical health.

History

Type A personality behavior was first described as a potential risk factor for heart disease in the 1950s by cardiologists Meyer Friedman and Ray Rosenman. They credit their insight to an upholsterer who called to their attention the peculiar fact that the chairs in their waiting rooms were only worn out on the front edge of the seat. After an eight-and-a-half-year-long study of healthy men between the ages of 35 and 59, Friedman and Rosenman estimated that Type A behavior more than doubled the risk of coronary heart disease in otherwise healthy individuals. The individuals enrolled in this study were followed well beyond the original time frame of the study. Participants were asked to fill out a questionnaire, that asked questions like "Do you feel guilty if you use spare time to relax?" and "Do you generally move, walk, and eat rapidly?" Subsequent analysis indicated that although Type A personality is associated with the incidence of coronary heart disease, it does not seem to be a risk factor for mortality. It was originally called 'Type A Personality' by Friedman and Roseman, it has now been conceptualized as the Type A behavior pattern.

The types

Type A

The hypothesis describes Type A individuals as outgoing, ambitious, rigidly organized, highly status-conscious, impatient, anxious, proactive, and concerned with time management. People with Type A personalities are often high-achieving "workaholics". They push themselves with deadlines, and hate both delays and ambivalence. People with Type A personalities experience more job-related stress and less job satisfaction. They tend to set high expectations for themselves, and may believe others have these same high expectations of them as well. Interestingly, those with Type A personalities do not always outperform those with Type B personalities. Depending on the task and the individual's sense of time urgency and control, it can lead to poor results when there are complex decisions to be made. However, research has shown that Type A individuals are in general associated with higher performance and productivity. Moreover, Type A students tend to earn higher grades than Type B students, and Type-A faculty members were shown to be more productive than their Type B behavior counterparts (Taylor, Locke, Lee, & Gist, 1984).

In his 1996 book dealing with extreme Type A behavior, Type A Behavior: Its Diagnosis and Treatment, Friedman suggests that dangerous Type A behavior is expressed through three major symptoms: (1) free-floating hostility, which can be triggered by even minor incidents; (2) time urgency and impatience, which causes irritation and exasperation usually described as being "short-fused"; and (3) a competitive drive, which causes stress and an achievement-driven mentality. The first of these symptoms is believed to be covert and therefore less observable, while the other two are more overt.

Type A people were said to be hasty, impatient, impulsive, hyperalert, potentially hostile, and angry. Research has also shown that Type A personalities may be used to deal with reality or avoiding difficult realizations. Therefore, those with Type A may use certain defenses or ways of dealing with reality to avoid difficult realizations. For example, one study found that the those with Type A personality are more likely to show higher levels of denial, than Type B, in stressful situations. However, Type A personality are also known to be more capable of multitasking, being competitive, having ambition, and being more focused on their goals than Type B.

There are two main methods to assessing Type A behavior, the first being the SI and the second being the Jenkins Activity Survey (JAS). The SI assessment involves an interviewer measuring a person's emotional, nonverbal and verbal responses (expressive style). The JAS involves a self-questionnaire with three main categories: Speed and Impatience, Job Involvement, and Hard-Driving Competitiveness.

Individuals with Type A personalities have often been linked to higher rates of coronary heart disease, higher morbidity rates, and other undesirable physical outcomes.

Type B

Type B is a behavior pattern that is lacking in Type A behaviors. A-B personality is a continuum where one either leans to be more Type A or Non Type A (Type B).

The hypothesis describes Type B individuals as a contrast to those of Type A. Type B personalities, by definition, are noted to live at lower stress levels. They typically work steadily and may enjoy achievement, although they have a greater tendency to disregard physical or mental stress when they do not achieve. When faced with competition, they may focus less on winning or losing than their Type A counterparts, and more on enjoying the game regardless of winning or losing. Type B individuals are also more likely to have a poorer sense of time.

Type B personality types are more tolerant than individuals in the Type A category. This can be evident through their relationship style that members of upper management prefer. Type B individuals can "...see things from a global perspective, encourage teamwork, and exercise patience in decision making..."

Interactions between Type A and Type B

Type A individuals' proclivity for competition and aggression is illustrated in their interactions with other Type As and Type Bs. When playing a modified Prisoner's Dilemma game, Type A individuals elicited more competitiveness and angry feelings from both Type A and Type B opponents than did the Type B individuals. Type A individuals punished their Type A counterparts more than their Type B counterparts, and more than Type Bs punished other Type Bs. The rivalry between Type A individuals was shown by more aggressive behavior in their interactions, including initial antisocial responses, refusal to cooperate, verbal threats, and behavioral challenges.

A common misconception is that having a Type A personality is better than having a Type B personality. This largely comes into play in the workforce because people with Type A personalities are often viewed as very hardworking, highly motivated, and competitive, while Type B personalities often don't feel a sense of urgency to get projects completed and are more relaxed and easy-going. In reality, both personality types are required and bring their own set of strengths to the workplace.

Criticism

Friedman et al. (1986) conducted a randomized controlled trial on 862 male and female post-myocardial infarction patients, ruling out (by probabilistic equivalence) diet and other confounds. Subjects in the control group received group cardiac counseling, and subjects in the treatment group received cardiac counseling plus Type-A counseling, and a comparison group received no group counseling of any kind. The recurrence rate was 21% in the control group and 13% in the treatment group, a strong and statistically significant (p < .005) finding, whereas the comparison group experienced a 28% recurrence rate. The investigative studies following Friedman and Rosenman's discovery compared Type A behavior to independent coronary risk factors such as hypertension and smoking; in contrast, the results here suggest that the negative effects on cardiovascular health associated with Type A personality can be mitigated by modifying Type A behavior patterns.

Funding by tobacco companies

Further discrediting the so-called Type A Behavior Pattern (TABP), a study from 2012 – based on searching the Legacy Tobacco Documents Library – suggests the phenomenon of initially promising results followed by negative findings to be partly explained by the tobacco industry's involvement in TABP research to undermine the scientific evidence on smoking and health. Documents indicate that around 1959, the tobacco industry first became interested in the TABP when the Tobacco Institute Research Committee received an application for funding from New York University in order to investigate the relationship between smoking and personality. The industry's interest in TABP lasted at least four decades until the late 1990s, involving substantial funding to key researchers encouraged to prove smoking to simply correlate with a personality type prone to coronary heart disease (CHD) and cancer. Hence, until the early 1980s, the industry's strategy consisted of suggesting the risks of smoking to be caused by psychological characteristics of individual smokers rather than tobacco products by deeming the causes of cancer to be multifactorial with stress as a key contributing factor. Philip Morris (today Altria) and RJ Reynolds helped generate substantial evidence to support these claims by funding workshops and research aiming to educate about and alter TABP to reduce risks of CHD and cancer. Moreover, Philip Morris primarily funded the Meyer Friedman Institute, e.g. conducting the "crown-jewel" trial on the effectiveness of reducing TABP whose expected findings could discredit studies associating smoking with CHD and cancer but failing to control for Type A behavior.

In 1994, Friedman wrote to the US Occupational Safety and Health Administration criticising restrictions on indoor smoking to reduce CHD, claiming the evidence remained unreliable since it did not account for the significant confounder of Type A behavior, although by then, TABP had proven to be significant in only three of twelve studies. Though apparently unpaid for, this letter was approved by and blind-copied to Philip Morris, and Friedman (falsely) claimed to receive funding largely from the National Heart, Lung and Blood Institute.

When TABP finally became untenable, Philip Morris supported research on its hostility component, allowing Vice President Jetson Lincoln to explain passive smoking lethality by the stress exerted on a non-smoking spouse through media claiming the smoking spouse to be slowly killing themselves. When examining the most recent review on TABP and CHD in this light, the close relationship to the tobacco industry becomes evident: of thirteen etiologic studies in the review, only four reported positive findings, three of which had a direct or indirect link to the industry. Also on the whole most TABP studies had no relationship to the tobacco lobby but the majority of those with positive findings did. Furthermore, TABP was used as a litigation defence, similar to psychosocial stress. Hence, Petticrew et al. proved the tobacco industry to have substantially helped generate the scientific controversy on TABP, contributing to the (in lay circles) enduring popularity and prejudice for Type A personality even though it has been scientifically disproven.

Other issues

Some scholars argue that Type A behavior is not a good predictor of coronary heart disease. According to research by Redford Williams of Duke University, the hostility component of Type A personality is the only significant risk factor. Thus, it is a high level of expressed anger and hostility, not the other elements of Type A behavior, that constitutes the problem. Research done by Hecker et al. (1988) showed that the ‘hostility’ component of the Type A description was predictive of cardiac disease. As time continued, more research was conducted which focused on different components of type A behavior such as hostility, depression, and anxiety predicting cardiac disease.

The initial study that pointed to the association of Type A personality and heart attacks had a massive number of questions under consideration. When there are a lot of questions there is a high probability of a false positive. A study undertaken by the U.S. National Institute of Aging, Sardinian and Italian researchers, as well as bio-statisticians from the University of Michigan, had specifically tested for a direct relationship between coronary heart disease and Type A personalities, and the results had indicated that no such relation exists. A simple explanation is that the initial finding was chance due to multiple questions being under consideration. Those considerations may have changed.

Other studies

A study (that later was questioned for nonplausible results and considered unsafe publication) was performed that tested the effect of psychosocial variables, in particular personality and stress, as risk factors for cancer and coronary heart disease (CHD). In this study, four personality types were recorded. Type 1 personality is cancer-prone, Type 2 is CHD-prone, Type 3 is alternating between behaviors characteristic of Types 1 and 2, and Type 4 is a healthy, autonomous type hypothesized to survive best. The data suggest that the Type 1 probands die mainly from cancer, type 2 from CHD, whereas Type 3 and especially Type 4 probands show a much lower death rate. Two additional types of personalities were measured Type 5 and Type 6. Type 5 is a rational anti-emotional type, which shows characteristics common to Type 1 and Type 2. Type 6 personality shows psychopathic tendencies and is prone to drug addiction and AIDS.

While most studies attempt to show the correlation between personality types and coronary heart disease, studies (that also later were questioned for non plausible results and were considered unsafe) suggested that mental attitudes constitute an important prognostic factor for cancer and that as a method of treatment for cancer-prone patients, behavior therapy should be used. The patient is taught to express his/her emotions more freely, in a socially acceptable manner, to become autonomous and be able to stand up for his/her rights. Behavior therapy would also teach them how to cope with stress-producing situations more successfully. The effectiveness of therapy in preventing death in cancer and CHD is evident. The statistical data associated with higher death rates is impressive. Other measures of therapy have been attempted, such as group therapy. The effects were not as dramatic as behavior therapy, but still showed improvement in preventing death among cancer and CHD patients.

From the study above, several conclusions have been made. A relationship between personality and cancer exists, along with a relationship between personality and coronary heart disease. Personality type acts as a risk factor for diseases and interacts synergistically with other risk factors, such as smoking and heredity. It has been statistically proven that behavior therapy can significantly reduce the likelihood of cancer or coronary heart disease mortality. Studies suggest that both body and mental disease arise from each other. Mental disorders arise from physical causes, and likewise, physical disorders arise from mental causes. While Type A personality did not show a strong direct relationship between its attributes and the cause of coronary heart disease, other types of personalities have shown strong influences on both cancer-prone patients and those prone to coronary heart disease.

A study conducted by the International Journal of Behavioral Medicine re-examined the association between the Type A concept with cardiovascular (CVD) and non-cardiovascular (non-CVD) mortality by using a long follow-up (on average 20.6 years) of a large population-based sample of elderly males (N = 2,682), by applying multiple Type A measures at baseline, and looking separately at early and later follow-up years. The study sample was the participants of the Kuopio Ischemic Heart Disease Risk Factor Study, (KIHD), which includes a randomly selected representative sample of Eastern Finnish men, aged 42–60 years at baseline in the 1980s. They were followed up until the end of 2011 through linkage with the National Death Registry. Four self-administered scales, Bortner Short Rating Scale, Framingham Type A Behavior Pattern Scale, Jenkins Activity Survey, and Finnish Type A Scale, were used for Type A assessment at the start of follow-up. Type A measures were inconsistently associated with cardiovascular mortality, and most associations were non-significant. Some scales suggested a slightly decreased, rather than increased, risk of CVD death during the follow-up. Associations with non-cardiovascular deaths were even weaker. The study's findings further suggest that there is no evidence to support the Type A as a risk factor for CVD and non-CVD mortality.

Substance use disorder

In a 1998 study done by Ball et al., they looked at differences in Type A and Type B personalities based on substance use. Their results showed that Type B personalities had more severe issues with substance use disorders than Type A personalities. Another discovery in their research was more Type B personalities had been diagnosed with a personality disorder than users who had Type A personalities. Type B personalities were rated higher than Type A personalities on symptoms of all DSM-IV personality disorders, with the exception of schizoid personality disorder.

The research conducted in the experiment was tested on 370 outpatients and inpatients who used alcohol, cocaine, and opiates. The personality types and distinctions were replicated. Additionally within the personality dimensions Type A and Type B exhibited different results. Type A personality portrayed higher levels of agreeableness, conscientiousness, cooperativeness, and self-directedness. In contrast, Type B personality showed higher levels of neuroticism, novelty seeking, and harm avoidance. These dimensions can have high correlational levels with mental illness or substance use disorders. Furthermore, even after antisocial personality and psychiatric symptoms, these effects remained.

Cultural conservatism

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Cultural_conservatism

Cultural conservatism is described as the protection of the cultural heritage of a nation state, or of a culture not defined by state boundaries. It is usually associated with criticism of multiculturalism, and opposition to illegal immigration. Cultural conservatism is sometimes concerned with the preservation of a language, such as French in Quebec, and other times with the preservation of an ethnic group's culture such as Native Americans.

In the United States, cultural conservatism may imply a conservative position in the culture wars. Because cultural conservatism (according to the compass theory) expresses the social dimension of conservatism, it is sometimes referred to as social conservatism. However, social conservatism describes conservative moral and social values or stances on socio-cultural issues such as abortion and same-sex marriage in opposition to cultural liberalism (in USA, social liberalism). Nationalism, meanwhile, also differs from cultural conservatism as it does not always develop in a particular culture.

Arguments

In favor

Proponents argue that cultural conservatism preserves the cultural identity of a country. They often promote assimilation into the dominant culture, believing that monoculturalism is more constructive to national unity. They claim that assimilation facilitates the integration of immigrants and ethnic minorities into broader society, framing cultural conservatism as a solution to ethnic strife. Researchers note that the more culturally homogeneous a community is, the more people trust each other. Trust was shown to decrease in more culturally diverse areas.

Proponents of cultural conservatism have criticized multiculturalism, believing that cultural pluralism is detrimental to a unified national identity. They argue that cultural diversity only serves to marginalize immigrants by othering them as outsiders in society. In some countries multiculturalism is believed to create de facto racial segregation in the form of ethnic enclaves. Opposition to immigration is also a common stance among proponents. Immigrants often bring the cultures, religions, and languages of their home countries with them, sometimes influencing and changing the cultures of their host countries. Proponents of cultural conservatism argue that some of these imported cultural practices, such as hijabs, polygamy, child marriage, and female genital mutilation, are in direct conflict with the values of the dominant culture.

Against

Opponents argue that cultural conservatism is detrimental to cultural diversity. They criticize cultural conservatism for promoting cultural intolerance, creating narrow ethnocentric mindsets, and stifling self-expression. Opponents cite numerous historical atrocities that originated from extreme forms of cultural conservatism, such as racism, genocide, ethnic cleansing, colonialism, and racial segregation. They claim that cultural assimilation leads to the marginalization of minorities who do not conform to the dominant culture.

Opponents have supported multiculturalism, believing it creates a more diverse and tolerant society. They claim it helps people of the ethnic majority to learn more about other cultures, adapt better to social change, and be more tolerant of diversity. They also believe multiculturalism brings more attention to the historical accomplishments of other ethnic groups, which had been neglected in past times. Support for immigration is also a common stance among opponents of cultural conservatism, who argue that it enriches society by contributing diverse new ideas. In some cases the art, music, food, or clothing of the immigrants are adopted by the dominant culture.

By country

Australia

In 2006 the Australian Government proposed to introduce a compulsory citizenship test which would assess English skills and knowledge of Australian values. This sparked a debate over cultural conservatism in Australia. Andrew Robb told a conference that some Australians worried that interest groups had transformed multiculturalism into a philosophy that put "allegiances to original culture ahead of national loyalty, a philosophy which fosters separate development, a federation of ethnic cultures, not one community."

The One Nation Party is a conservative political party that opposes multiculturalism, calling it "a threat to the very basis of the Australian culture, identity and shared values."

Canada

Main articles: Canadian cultural protectionism and Culture of Canada

Unlike the United States, Canada has always been a culturally divided country, though to varying degrees. Since the premiership of Pierre Trudeau, Canadian identity has been viewed as a cultural mosaic. Trudeau Sr. once stated that there is "no such thing as a model or ideal Canadian," and that to desire one is a "disastrous" pursuit. His son Justin Trudeau, likewise Prime Minister, has continued to spread this spirit in declaring Canada "the first post-national state" due to its lack of a core identity and mainstream. The fifth wave of immigration to Canada which followed Trudeau Sr.'s premiership and continues to this day is the largest manifestation of this change. For example, the city of Richmond, British Columbia is majority Chinese, and nearly half of Torontonians are foreign-born, the city which now bears the motto "Diversity Our Strength." Canadian cultural conservatism as a reaction to the multiculturalism of Pierre Trudeau (and subsequently of Brian Mulroney) reached its peak with the Reform Party and waned over time. Its decline has been marked by the electoral failure of the People's Party of Canada, which formed partly as a response to the Conservative Party's perceived weakness on the issue.

Quebec

See also: Quebec sovereignty movement and French in Canada

Quebec is unique in Canada for its cultural conservatism. Though not a socially conservative province, nor religiously conservative (not since the aftermath of the Grande Noirceur), Quebecois culture has always maintained a certain suspicion and reluctance towards unity with the rest of Canada. Language protectionism (reflected in laws such as Bill 101) is a central concern of Quebec cultural conservatives. Quebec has held two referendums on separation and has never ratified the Constitution Act of 1982. The Bloc Québécois formed in reaction to the Mulroney premiership (like the Reform Party) to advocate for Quebecois interests in the federal parliament. It once held the office of Official Opposition, which was followed by a decline, but the party has seen a surge in popularity as of late, currently holding 32 of Quebec's 78 seats in the House of Commons.

China

Central to the ideas of the Cultural Revolution was the elimination of the Four Olds, which were elements of Chinese culture that at the time were seen to oppose the goals of Communism in China. However, the Chinese Communist Party (CCP) at the time protected some of the most important Chinese historical monuments, including some archaeological discoveries such as the Terracotta Army. CCP general secretary Xi Jinping has overseen a revival in popularity of historical Chinese cultural figures such as Confucius and has placed more emphasis on the value of Chinese culture than his predecessors. He also includes culture in his "comprehensive" political goals.

France

French political theorist Alain de Benoist argues that democracy itself must inherently be a government of a national culture, and that liberal pluralism is therefore not democratic.

Germany

In Germany, parallel societies established by some immigrant communities have been criticized by cultural conservatives, giving rise to the concept of the Leitkultur. Conservative Chancellor Angela Merkel of the Christian Democratic Union described attempts to build a multicultural German society to have "failed, utterly failed". Many Germans have expressed alarm over the large number of Muslim immigrants in their country, many of whom have failed to integrate into German society.

Italy

Italy is a very culturally conservative society. Recent surveys show that the vast majority of Italians want fewer immigrants to be allowed into the country, while few want to keep the current level or increase immigration.

Japan

Japan has been a culturally conservative society. Being monocultural, it has traditionally refused to recognize ethnic differences in Japan. Taro Aso has called Japan a "one race" nation.

Netherlands

Paul Cliteur attacked multiculturalism, political correctness, cultural relativism, and non-Western cultural values. He argued that cultural relativism would lead to acceptance of outdated practices brought to the Western World by immigrants such as sexism, homophobia, and antisemitism.

Paul Scheffer believes that cultural conservatism and integration are necessary for a society, but the presence of immigrants undermines this. He cites failure to assimilate, de facto segregation, unemployment, crime, and Muslim opposition to secularism as the main problems resulting from immigration.

Russia

In Russia, Russian culture has been defended by cultural conservatives on the grounds that the destruction of traditional values is undemocratic.

United Kingdom

In the 20th century, immigration to the United Kingdom gave rise to multicultural policies. However, ever since the beginning of the 21st century, the UK government has moved towards cultural conservatism and the assimilation of minority communities. Opposition has grown to multicultural government policies, with some viewing it as a costly failure. After the 7 July 2005 London bombings, Conservative David Davis called such policies "outdated".

Ed West argues that the British establishment had blindly embraced multiculturalism without proper consideration of the downsides of ethnic diversity. According to cultural conservatives, while minority cultures are allowed to remain distinct, traditional British culture is abhorred for being exclusive and adapts to accommodate minorities, often without the consent of the local population.

United States

Main article: Social conservatism in the United States

A prominent criticism by cultural conservatives in the United States is that multiculturalism undermines national unity, hinders social integration, and leads to the fragmentation of society. Samuel P. Huntington described multiculturalism as an anti-Western ideology that attacked the United States' inclusion in Western civilization, denied the existence of a common American culture, and promoted ethnic identities over national ones.

Discussions to do with the conservation of American culture often involve definitional disputes. Some consider the United States as a nation of immigrants or "melting pot," others (such as David Hackett Fischer) argue that British immigrant cultures are responsible for the development of modern American culture and values. American cultural conservatives often claim that the culture is at risk due primarily to demographic change from immigration, as well as the influence of academia, which has produced increasingly left-wing alumni over time. Dinesh D'Souza argues that multiculturalism in American universities undermines the moral universalism that education once stood for. In particular, he criticized the growth of ethnic studies programs.