What is the capacitor cabinet used for? What is the role of adding capacitor cabinet? Usage of the capacitor cabinet

Low voltage capacitor compensation cabinet is often used in the distribution system of industrial and manufacturing factories. Generally, low-voltage capacitor compensation cabinet is composed of power capacitor, reactor, arrester, circuit breaker, power factor automatic compensation control device, isolation switch, thermal relay, disk instrument and other components. Low voltage capacitor compensation cabinet in the power system, mainly use low voltage capacitor to play the role of reactive power compensation, so as to improve the power factor, improve the power quality environment. The role of compensation cabinet is: current 90 degrees ahead of the voltage, using the parallel capacitor to enhance the line voltage, reduce reactive power loss. As an electrician should have learned, the coil is separated from the traffic straight, when the coil gives power, there is a current to establish a magnetic field, when the power is cut, the coil will generate electricity. It's like giving the power back. In the motor, you have coils like this, and you do alternating currents 100 times a second. Active power measures the amount of power you use, which is used and returned, which is reactive power.

1. Capacitance compensation is reactive power compensation or power factor compensation. Electrical equipment in the power system will generate inductive reactive power in the process of use, which will lead to the reduction of the capacity efficiency of the power supply.

2. The role of capacitor compensation: the parallel capacitor generates capacitor current to offset inductance current, and reduces the so-called reactive current that does no work to a certain range, so as to maintain reactive power balance in the power system.

3. The specific selection needs to be based on the capacity of the transformer to choose, most of the general compensation for the transformer capacity of about one-third.

What is reactive power?

Reactive power means that in an inductive or capacitive AC circuit, the inductor (or capacitor) stores the energy of the AC power source in the form of magnetic field or electric field energy for half the time of a cycle, and sends the stored magnetic field or electric field energy back to the power source for the other half of the cycle. At this point, they only exchange energy with the AC power supply, and actually do not consume energy, but only exchange electric and magnetic fields in the AC circuit, and use the electrical power to establish and maintain the magnetic field in the electrical equipment. The maximum rate of energy exchange between inductive or capacitive and AC power is called reactive power. Its biggest characteristic is that it does not work externally, but transforms into other forms of energy. Denoted by the letter symbol Q, the unit is Var or Kar.

To put it simply, all electrical equipment with electromagnetic coils must consume reactive power to establish a magnetic field. The mathematical expression of reactive power is Q=UIsin.

Opening of capacitor cabinet: when opening, check whether the switches and circuit breakers are closed first, then close the cabinet door and twist the door knob in the closed position, confirm no error, and close the knife switch. The stopping sequence is: set the reactive power controller to manual operation, use the manual down key to exit the capacitor sequence, and then pull the knife switch open. It is forbidden to pull the knife switch with load to prevent arc accidents. The lower end of the circuit breaker in the capacitor cabinet can not be connected for other purposes. The capacitor cabinet is to improve the power factor and can not be loaded. Capacitive compensation cabinet uses capacitive reactance to compensate inductive reactance of inductive load. Reduce reactive current, enhance line voltage, reduce reactive loss, achieve the effect of energy saving. Observe the number of switching capacitors by using a power factor meter. When the power factor reaches or approaches 1, the capacitor cabinet works normally. The capacitor compensation cabinet is full of compensation capacitors and contactors, that is to say, it adopts the principle of capacitor phase shift to compensate the reactive power loss generated by the equipment. General power failure or power supply without operation, it can be opened and closed with the total power supply parallel operation. Generally, as long as you pay attention to check the capacitor at any time there is no leakage or abnormal sound and other abnormal conditions can be.

The ambient temperature of power capacitor should not be too high. If the ambient temperature is too high, the heat generated when the capacitor works can not be dispersed; If the environment is too low, the technical conditions of the capacitor, the operating temperature of the capacitor is generally 40℃ as the upper limit. Temperatures are below that in most parts of the country, so cooling facilities are not usually necessary. If there is some kind of heat source near the capacitor, which may make the room temperature rise to more than 40℃, ventilation and cooling measures should be taken, otherwise the capacitor should be removed immediately. The ambient temperature and lower limit of the capacitor shall be determined according to the type and nature of the capacitor mediator. When the power capacitor is working, the temperature of its internal medium should be less than 65℃, not more than 70℃C, otherwise it will cause thermal breakdown, or cause belly bulge phenomenon. The temperature of the capacitor shell is between the medium temperature and the ambient temperature, generally 50~60℃, shall not exceed 60℃.