WPGJ reactive power compensation capacitor
I. General
Most of the loads in electric power system are inductive which lead a low power factor. As an enterprise, for the requirement of the electricity, the lower of the power factor, the more capacity of the supply transformer in the condition of the same active power. This will increase the supply investment, and reduce the use factor of the equipments, as well as increase the network circuit lost which impairs the quality of the voltage. Thus, to improve the power factor is an important project for enterprises to save energy and to improve the quality of the electric network. Enterprises shall take some corresponding methods to improve the power factor.
Reactive power compensation is necessary for the improvement of the power factor. The basic principle is to parallel connect the unit of capacitive power load to the inductive power load. While the capacitive load is releasing energy, the inductive load is absorbing it; while the inductive load is releasing energy, the capacitive load is absorbing it. That is, the energy is transformed in between the two loads and thus the reactive power received by the capacitive load is compensated by the reactive power released by the inductive load to reduce the absorption of the reactive power from the electric network.
There are many methods of the reactive power compensation, mainly as follows:
- To use over-excitation synchronous motor. This method is of complex equipments and high cost, which is only workable when it is large power device drive.
- To use the phase adjuster as the power supply of the reactive power. This device is of good performance which can improve the stability of the electric power system, but it is of high cost, large investment, high consumption for about 1.8% to 5.5% power consumption per kilovar and complex operation technique.
- To use static advancer to change the performance of the single motor, to reduce the reactive power and the temperature rise, to increase the output power, to improve the efficiency and to save the energy. But it only applies to wound-rotor motor.
- To synchronize the asynchronous motor. This method has a certain effect but it is with large self consumption for about 4% to 19% of the reactive power per kilovar, which is generally not adopted.
- To use the power capacitor for compensating. This method is with convenient installation, short construction period, low cost, easy operation and maintenance and low self consumption for about 0.3% to 0.4% or below of the consumption per kilovar.
There are two methods of the power capacitor as a compensating device:
- Serial connecting compensation: that is, serially connect the power capacitor to the high voltage electric transmission line to improve the parameter of the electric transmission line, to lower the voltage lost, to increase the output capacity and to reduce the consumption of the circuit. This method is applicable to high voltage remote electric transmission and it is seldom adopted by the electricity enterprises.
- Parallel connecting compensating: that is, parallel connect the capacitor and the compensating equipments to one circuit to improve the power factor. This compensation method is adopted by all the electricity enterprises.
The main functions of the parallel connecting capacitor compensating the reactive power are:
- To compensate the reactive power and improve the power factor.
- To increase the output capacity of the equipment.
- To lower the energy consumption and the energy lost.
- To improve the voltage quality.
For improving the electric network quality and other aspects of the enterprise, our company produced WPGJ low voltage reactive power automatic compensating parallel connecting capacitor complete equipment which can improve the power factor of the electric network automatically and increase the voltage quality of the network as well as lower the consumption of the power distribution system and the transformer.
III. Performance characteristic
- Adopting self-healing capacitor whose performance is far better than oil medium power capacitor. The medium and the poles of the self-healing capacitor have self-healing performance. It is with high density of field, low consumption of the medium, small volume and large capacity.
- An automatic controller of reactive power compensation has been set which can circulate automatically and switch the capacitor by steps. The switching time interval can be adjusted to keep the reactive power consumption of the electric network at the lowest level, in order to improve the quality of the network voltage efficiently and reduce the consumption of the power distribution system and the transformer.
- Multiple protections:
1). Single fuse protection
2). Over current protection
3). Over voltage protection
4). Under voltage protection
5). Inrush current and higher harmonic suppression
4. The power factor can be improved to 0.92 or above if the proper capacity is adopted.
VI. Applications
- The power factor in the enterprise is low and often fined by the supply apartment. The power factor needs to be improved.
- The voltage of the enterprise substation is low. The voltage of the electric network needs to be increased.
- The wire lost of the enterprise is too much and it needs to be reduced.
- Electricity equipments put into use lately.
- The old capacitors need to be replaced.
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VI. Use condition
- Indoor use with good ventilation.
- Height above sea level shall not exceed 1000m. If exceeds, high-altitude capacitor and other equipments shall be adopted after agreement.
- Around air temperature is ±40℃, and the relative humidity is 80%.
- Installation inclination pitch shall not exceed 5°.
- No rain on the installation site, any erosive gas or mass dust.
- No explosion, strong impact or shake.
