Electric Power System
Electrical power system refers to remove power and electric parts of the part, It includes substation, power station and distribution. The role of the power grid is connected power plants and urs and with the minimum transmission and distribution network disturbance through transport power, with the highest efficiency and possibility will voltage and frequency of the power transmission to the ur fixed .网球的好处Grid can be divided into veral levels bad on the operating voltage transmission system, substructure, transmission system and distribution system, the highest level of voltage transmission system is ZhuWangJia or considered the high power grids. From the two aspects of function and operation, power can be roughly divided into two parts, the transmission system and substation. The farthest from the maximum output power and the power of the highest voltage grade usually through line to load. Secondary transmission usually refers to the transmission and distribution system is that part of the middle. If a plant is located in or near the load, it might have no power. It will be direct access to condary transmission and distribution system. Secondary transmission system voltage grade transmission and distrib
ution system between voltage level. Some systems only single cond transmission voltage, but usually more than one. Distribution system is part of the power system and its retail rvice to urs, commercial urs and residents of some small industrial urs. It is to maintain and in the correct voltage power to urs responsible. In most of the system, Distribution system accounts for 35% of the total investment system President to 45%, and total loss of system of the half .
More than 220kv voltage are usually referred to as Ultra high pressure, over 800kv called high pressure, ultra high voltage and high pressure have important advantages, For example, each route high capacity, reduce the power needed for the number of transmission. In as high voltage to transmission in order to save a conductor material em desirable, however, must be aware that high voltage transmission can lead to transformer, switch equipment and other instruments of spending increas, so, for the voltage transmission to have certain restriction, allows it to specific circumstances in economic u. Although at prent, power transmission most is through the exchange of HVDC transmission, and the growing interest in, mercury arc rectifier and brake flow pipe
圆凿into the ac power generation and distribution that change for the high voltage dc transmission possible.
Compared with the high-voltage dc high-voltage ac transmission has the following some advantages: (1) the communication with high energy; (2) substation of simple maintenance and communication cost is low;看书 (3) ac voltage can easily and effectively rai or lower, it makes the power transmission and high pressure With safety voltage distribution
HVDC transmission and high-voltage ac transmission has the following advantages: (1) it only need two pha conductors and ac transmission to three-pha conductors; (2) in the dc transmission impedance, no RongKang, pha shift and impact overvoltage大白兔; (3) due to the same load impedance, no dc voltage, and transfer of the transmission line voltage drop less communication lines, and for this reason dc transmission line voltage regulator has better properties; (4) in dc system without skin effect. Therefore, the entire ction of route conductors are using; (5) for the same work, dc voltage potential stress t
关于植物的句子
气功八段锦han insulation. Therefore dc Wire need less insulation; (6) dc transmission line loss, corona to little interference lines of communication; (7) HVDC transmission without loss of dielectric, especially in cable transmission; (8) in dc system without stability and synchronization of trouble.年终终结
A transmission and the cond transmission lines terminated in substation or distribution substations, the substation and distribution substations, the equipment including power and instrument transformer and lightning arrester, with circuit breaker, isolating switch, capacitor t, bus and a substation control equipment, with relays for the control room of the equipment. Some of the equipment may include more transformer substations and some less, depending on their role in the operation. Some of the substation is manual and other is automatic. Power distribution system through the distribution substations. Some of them by many large capacity transformer feeders, large area to other minor power transformer capacity, only a near load control, sometimes only a doubly-fed wire feeders (single single variable substation)
Now for economic concerns, three-pha three-wire type communication network is widely ud, however, the power distribution, four lines using three-pha ac networks.
Coal-fired power means of main power generating drive generators, if coal energy is ud to produce is pushing the impeller, then generate steam force is called the fire. U coal produces steam to promote the rotating impeller machine plant called coal-fired power plants. In the combustion process, the energy stored in the coal to heat relead, then the energy can be transformed into the form within vapor. Steam into the impeller machine work transformed into electrical energy.
Coal-fired power plants could fuel coal, oil and natural gas is. In coal-fired power plant, coal and coal into small pieces first through the break fast, and then put out. The coal conveyer from coal unloader point to crush, then break from coal, coal room to pile and thence to power. In most installations, according to the needs of coal is, Smash the coal storage place, no coal is through the adjustable coal to supply coal, the broken pieces of coal is according to the load changes to control needs. Through the broken into the chamber, the coal dust was in the cond wind need enough air to ensure coal burning.
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