The classification and main application of power capacitor

The classification and main application of power capacitor
Power capacitor is a capacitor for power system and electrical equipment. Feature is the large power, high voltage, low frequency, so the huge volume. In 1926 the power capacitor start factory production, and the formal application in electric power system. With the establishment of large power plants and long distance transmission system, the development of new science and technology, the power capacitor varieties and capacity has been rapid development. In the early 50 century, shunt capacitor of the largest single capacity of 25kvar-kvar, to 1978 the largest single production capacity has reached 6667kvar, 80 time has reached a single capacity of 1 thousands spent. At present, power capacitors are moving higher capacity towards.
A lot of power capacitor types, according to the installation can be divided into indoor and outdoor type two; according to the operation of the rated voltage can be divided into low and high pressure two categories; according to the number of phases can be divided into single-phase and three-phase two, except for low voltage shunt capacitor, the rest are single-phase; according to its shell material the material can be divided into the metal shell, shell, shell porcelain insulation bakelite cylinder; according to their use can be divided into the following 8.
(1) parallel capacitor: originally called phase-shift capacitor. Mainly used for inductive load reactive power compensation in power system, in order to improve the power factor, improve the quality of voltage, reduce the loss of line. A single-phase shunt capacitor is mainly composed of a core shell structure, and the outgoing line consists of several. With metal foil (as a plate) winding with insulating paper or plastic film stack up, consists of several components, insulation parts and fasteners after pressing and constitute the capacitance core, and impregnating insulating oil. Lead capacitance plate by the outgoing connection piece on parallel, led to the outlet at the lower end of the porcelain bushing. The metal casing capacitor filled with insulating medium oil.
(2) the series capacitor on power frequency voltage transmission: series, distribution line, to distribution inductive reactance compensation circuit, the static, improving system dynamic stability, improvement of voltage quality line, extended power transmitting distance and increase transport capacity. The basic structure and parallel capacitor similar.
(3) the coupling capacitor: mainly used in high voltage electric power line HF communication, measurement, control, protection and components used in the device is powered by extraction. High end coupling capacitor connected to the transmission line, the low pressure end through the coupling coil grounding, the high frequency carrier wave device is coupled with the high-voltage line in low voltage. Coupling capacitor shell comprises a porcelain sleeve and the steel base and a cover. Housing is provided with a dilator is made of thin steel sheet, to compensate for impregnating agent volume change with temperature.
(4) circuit breaker capacitors: originally called equalizing capacitor. Mainly used in parallel has a pressure equalizing effect in the fracture of ultra high voltage circuit breaker, evens the voltages among in the breaking process and disconnected, arc resistance and improve the circuit breaker, improving the breaking capacity. Structure and coupling capacitor circuit breaker capacitors used similar. With the development of high voltage ceramic capacitor, ceramic capacitor have been adopted as the capacitor element, and then into the porcelain sleeve and the steel casing made of circuit breaker capacitor.
(5) the electric capacitor for electric equipment system: frequency of 40Hz - 24000Hz, in order to improve the power factor, improve the circuit voltage or frequency. Electric capacitor because of higher heat, must ensure the good heat, usually adopts water cooling plate. Electric capacitor applies to more than 4000Hz, the shell with brass plate welded.
(6) pulse capacitor: mainly from the energy storage function, charging the power from the power is not in a long time, and then the oscillation or non oscillatory discharge in a short period of time, can receive a lot of impact power. Pulse capacitor is widely used, such as impulse voltage generator, the impact of current generator, circuit breaker test using oscillation circuit and other basic (storage) element.
(7) and DC filter capacitors: for high voltage DC unit and a high voltage rectifier and filter device. AC filter capacitor is used to filter the harmonic component in the AC current.
(8): power frequency high voltage standard capacitor for measuring dielectric loss of circuit, as the standard capacitance or capacitance is used for the measurement of high voltage divider device. Standard capacitor requirements capacitance value is accurate and stable, so often used gas and double shielded coaxial cylindrical and concentric spherical plate system.