Compensation principle of power capacitor
After the capacitor cabinet cuts off the capacitor, there is still a large amount of charge inside the capacitor. Re-input when the release is not complete, the residual charge will make the peak voltage generated by the capacitor up to twice the rated voltage. Very serious damage to electrical equipment and the capacitor itself. When the capacitor cabinet is designed, a discharge device is installed, and the residual voltage in the capacitor drops to below 50V within 30s of the capacitor being cut off. In principle, a capacitor is equivalent to a generator that generates capacitive reactive current. The principle of reactive power compensation is to connect the device with capacitive power load and the inductive power load in parallel on the same capacitor, and the energy is converted between the two loads.
In this way, the load on the transformers and transmission lines in the power grid is reduced, thereby increasing the output functional power. In the case of outputting a certain active power, the loss of the power supply system is reduced. In comparison, capacitors are the easiest and most economical way to reduce the load on transformers, power supply systems, and industrial distribution. Therefore, it is imperative to use capacitors as reactive power compensation in power systems. At present, it is very common to use shunt capacitors as reactive power compensation devices.
In addition to resistive loads, most of the electrical equipment is inductive electrical loads, such as fluorescent lamps, transformers, motors, etc. These inductive loads change the phase of the power supply voltage, that is, the current lags behind the voltage, so the voltage fluctuates. When the power factor is too low, the output current of the power supply is too large and overload occurs. The capacitor control system in the low-voltage capacitor compensation cabinet can change according to the change of the electrical load. The input of the number of capacitor groups is automatically set for current compensation, thereby reducing a large amount of reactive current, reducing the power loss of the line to a lower level, and providing a high-quality power source.
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