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Electrical transmission and distribution reference book. byWestinghouse Electric Westinghouse electric & manufacturing company. Get this from a library! Electrical transmission and distribution reference book. [ Westinghouse Electric Corporation.]. Results 1 - 26 of 26 Electrical Transmission and Distribution Reference Book. The Central Station Engineers Of Westinghouse. Published by Westinghouse.
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. The Losses[ edit ] Transmitting electricity at high voltage reduces the fraction of energy lost to resistance , which varies depending on the specific conductors, the current flowing, and the length of the transmission line.
Measures to reduce corona losses include conductors having larger diameters; often hollow to save weight,  or bundles of two or more conductors.
Factors that affect the resistance, and thus loss, of conductors used in transmission and distribution lines include temperature, spiraling, and the skin effect. The resistance of a conductor increases with its temperature. Temperature changes in electric power lines can have a significant effect on power losses in the line. 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 of a conductor to increase at higher alternating current frequencies. Corona and resistive losses can be estimated using a mathematical model. As of , the longest cost-effective distance for direct-current transmission was determined to be 7, kilometres 4, miles.
For alternating current it was 4, kilometres 2, miles , though all transmission lines in use today are substantially shorter than this.
These reactive currents, however, are very real and cause extra heating losses in the transmission circuit. 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, the reactive power increases and the 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-shifting transformers ; 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[ edit ] 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 mutual inductance of the conductors is partially dependent on the physical orientation of the lines with respect to each other.
Three-phase power transmission lines are conventionally strung with phases separated on different vertical levels. The mutual inductance seen by a conductor of the phase in the middle of the other two phases will be different than the inductance seen by the conductors on the top or bottom.
An imbalanced inductance among the three conductors is problematic because it may result in the middle line carrying a disproportionate amount of the total power transmitted.
Similarly, an imbalanced load may occur if one line is consistently closest to the ground and operating at a lower impedance. Because of this phenomenon, conductors must be periodically transposed along the length of the transmission line so that each phase sees equal time in each relative position to balance out the mutual inductance seen by all three phases.
Out of all of the books on my shelf, this is my go-to book. I agree with the positive reviews from others. I don't know how they made it hand tooled or with a press or??
Our professor had worked for Westinghouse as a consultant and has pretty good connections with them. For a good book it doesn't seem so bad! That was paid by a poor student not by my company.
So I recommend anybody to download them. If anybody have seen the new versions of this books, I would like to know if they have upgraded them, since the only problem is that they are a little bit outdated. What I would like to see in a new version are the following: Modern excitation systems and power system stabilizers.
FACTS devices and applications. Digital relays and modern protection philosophies. SCADA systems. System operations, dispatch, wide area controls.