Download Citation on ResearchGate | Transmission-line reference book. specific recommendations are made for insulator configurations from to kV. Transmission Line Reference Book KV and Above [Electric Research Council] on aracer.mobi *FREE* shipping on qualifying offers. Transmission Line Reference Book Kv and Above [J. J. LaForest] on site .com. *FREE* shipping on qualifying offers. load growth and transmission.
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Transmission Line. Reference Book. kV and Above/Second Edition. Prepared by. Project UHV. Technical Resource Operation. Large Transformer Division. EPRI Perspective The EPRI report, Transmission Line Reference Book, kV and Above (ELR1), was originally printed with a red cover and quickly. Transmission Line Reference Book - Kv and Above Epri - Ebook download as PDF File .pdf) or read book online.
Westinghouse alternating current polyphase generators on display at the World's Fair in Chicago , part of their "Tesla Poly-phase System". Such polyphase innovations revolutionized transmission The first transmission of single-phase alternating current using high voltage took place in Oregon in when power was delivered from a hydroelectric plant at Willamette Falls to the city of Portland 14 miles downriver. By , fifty-five transmission systems each operating at more than 70 kV were in service.
The highest voltage then used was kV. The most efficient available plants could be used to supply the varying loads during the day. Reliability was improved and capital investment cost was reduced, since stand-by generating capacity could be shared over many more customers and a wider geographic area.
Remote and low-cost sources of energy, such as hydroelectric power or mine-mouth coal, could be exploited to lower energy production cost. The interconnection of local generation plants and small distribution networks was greatly spurred by the requirements of World War I , with large electrical generating plants built by governments to provide power to munitions factories.
Later these generating plants were connected to supply civil loads through long-distance transmission. It also reroutes power to other transmission lines that serve local markets. This is the PacifiCorp Hale Substation, Orem, Utah , USA Engineers design transmission networks to transport the energy as efficiently as feasible, while at the same time taking into account economic factors, network safety and redundancy.
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 greatly improved by devices that increase the voltage and thereby proportionately reduce the current , in the line conductors, thus allowing power to be transmitted with acceptable losses. The reduced current flowing through the line reduces the heating losses in the conductors.
According to Joule's Law , energy losses are directly proportional to the square of the current.
Thus, reducing the current by a factor of two will lower 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 the size is at its optimum when the annual cost of energy wasted in the resistance is equal to the annual capital charges of providing the conductor.
At times of lower interest rates, Kelvin's law indicates that thicker wires are optimal; while, when metals are expensive, thinner conductors are indicated: however, power lines are designed for long-term use, so Kelvin's law has to be used in conjunction with long-term estimates of the price of copper and aluminum as well as interest rates for capital.
The increase in voltage is achieved in AC circuits by using a step-up transformer. HVDC systems require relatively costly conversion equipment which may be economically justified for particular projects such as submarine cables and longer distance high capacity point-to-point transmission. HVDC is necessary for the import and export of energy between grid systems that are not synchronized with each other.
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.
Higher order phase systems require more than three wires, but deliver little or no benefit. The synchronous grids of the European Union The price of electric power station capacity is high, and electric demand is variable, so it is often cheaper to import some portion of the needed power than to generate it locally.
Because loads are often regionally correlated hot weather in the Southwest portion of the US might cause many people to use air conditioners , electric power often comes from distant sources. Because of the economic benefits of load sharing between regions, wide area transmission grids now span countries and even continents. The web of interconnections between power producers and consumers should enable power to flow, even if some links are inoperative. The unvarying or slowly varying over many hours portion of the electric demand is known as the base load and is generally served by large facilities which are more efficient due to economies of scale with fixed costs for fuel and operation.
Such facilities are nuclear, coal-fired or hydroelectric, while other energy sources such as concentrated solar thermal and geothermal power have the potential to provide base load power. Renewable energy sources, such as solar photovoltaics, wind, wave, and tidal, are, due to their intermittency, not considered as supplying "base load" but will still add power to the grid. 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 fueled by natural gas.
Hydro and wind sources cannot be moved closer to populous cities, and solar costs are lowest in remote areas where local power needs are minimal. Connection costs alone can determine whether any particular renewable alternative is economically sensible.
Costs can be prohibitive for transmission lines, but various proposals for massive infrastructure investment in high capacity, very long distance super grid transmission networks could be recovered with modest usage fees.
Grid input[ edit ] At the power stations , the power is produced at a relatively low voltage between about 2. Determine the size of the ground conductor from typical values used.
Use a deg C as ambient temperature. Calculate the resistance, inductance, and capacitance per mi. Use the hyperbolic equations and compute the ABCD line parameters and the pi-equivalent circuit for the entire line. What is the charging MVar of the line when it is supplied by rated voltage? What is the receiving end voltage, if the sending end voltage is kV and the load at the receiving end is disconnected?
The insulation leakage distance and the switching impulse insulation level govern the design of the insulation. A short duration power frequency withstand voltage of 1.
Mechanical design The basic mechanical design data for the kV transmission line is shown in Table 2. Phase conductors and earthwires The clamp component of the conductor and earthwire tensile stress should not exceed the permitted maximum tensile stress, calculated for a safety factor of 2.
The dimensions of the vibration dampers and spacer dampers were selected to assure a year life expectancy of conductors and earthwires. While normal SRAC cable with a greased galvanised steel core was selected for the largest portion of the line, alumoweld core wires of the same size were used in the salt polluted area near the Salar del Rincon — a distance of approximately 40 km.
Insulators Cap and pin disc type toughened glass insulators were used for the project. The suspension towers are equipped with V-strings on the middle phase and I-strings on the outer phases.
For increased safety, double strings were used at various crossings. The tension towers were generally equipped with double tension strings utilising two different connection points. A safety factor of 2. The electric design required 26 insulator units with mm spacing. Tension insulator strings were equipped with 2 additional insulators in order to provide sufficient electric safety margin in the case of damage to individual discs. All insulator strings were equipped with life-end guard rings.
Earth-end grading rings were mounted onto all insulator strings within a distance of 1.
Towers The tower geometry selection was based on the following criteria: cost of the materials needed for the structures and weight of structures per component ; foundation types and costs; ease of transport of structural elements; reliability under severe meteorological conditions; ease of maintenance and replacement of components; performance under cascade failures; performance when subject to lateral rain or snow conditions; resilience to stone or snow avalanches; ease and stability of erection on steeply sloping ground; performance when subject to differential earth movement; electrical parameters, joule and corona losses area of tower base line corridor; lightning performance; and environmental impact.
Taking all these into account, either self-supporting or guyed towers were chosen, with a horizontal conductor arrangement and two earthwires at the top of the structures. Self-supporting structures were used in mountainous regions and at locations with high mechanical loading. Guyed towers were used in flat or hilly regions with easy access.