Power capacitors are divided into series capacitors and shunt capacitors, which improve the voltage quality of power systems and improve the transmission capacity of transmission lines, power system is an important device.
1. The role of power capacitors
Series capacitors in the line, its role is as follows: Thermoelectric Technology Alliance. The series capacitor in series, the role of the following: thermoelectric technology alliance.
(1) to improve the line end voltage. Capacitor connected in the line, the use of its capacitive reactance xc compensation circuit inductance xl, so that the voltage drop of the line to reduce, so as to improve the end of the line (receiving end) voltage, the line voltage can generally be the maximum increase of 10% To 20%. | Power plant boiler, steam turbine, electrical, water treatment and other thermoelectric industry technical exchanges)
(2) reduce the power-side voltage fluctuations. The series capacitor eliminates voltage fluctuations when there is a large impact load (such as an electric arc furnace, welding machine, electrical rail, etc.) that is subject to line termination. This is because the series capacitor in the line voltage drop compensation effect is with the load through the capacitor changes, with the load changes with the instantaneous adjustment of performance, can automatically maintain the load side (receiving end) voltage.
(3) to improve line transmission capacity. As the line into the capacitor compensation reactor xc, the line voltage drop and power loss reduction, the corresponding increase in the transmission capacity of the line.
(4) to improve the system power flow distribution. Some of the lines in the closed network in series capacitor, in part to change the line reactance, the current flow by the specified line to achieve the purpose of economic power distribution.
(5) to improve the stability of the system. Line into the capacitor, the improved transmission capacity of the line, which in itself improves the static stability of the system. When the line fault is partially removed (such as the double loop is cut back, but the circuit single-phase ground to remove a phase), the system equivalent reactance increased dramatically, this time, the series capacitor forcibly compensated, that is forced to change the capacitor string , The number of parallel, temporary increase in capacitance xc, the system reduces the total equivalent reactance to improve the transmission of the limit power, thereby enhancing the system''''''''s dynamic stability.
2. The role of parallel capacitors
The parallel capacitor is connected in parallel to the bus of the system. It is similar to a capacitive load on the system bus. It absorbs the capacitive reactive power of the system. This is equivalent to the parallel capacitor sending inductive reactive power to the system. Therefore, the shunt capacitor can provide inductive reactive power to the system, the power factor of the system operation, improve the voltage level of the busbar at the receiving end. At the same time, it reduces the transmission of inductive reactive power on the line, thus reducing the voltage and power loss. The transmission capacity of the line.
The normal operation state of the capacitor means that under the rated condition, the capacitor can run continuously within the permissible range of the rated parameter, and the normal operation state of the capacitor can be continued without any operation of the capacitor. Any abnormalities. BASIC REQUIREMENTS FOR THE OPERATION OF CAPACITOR COMPENSATION DEVICES. 化 AUTOMATION IN PETRO - CHEMICAL INDUSTRY.
(1) three-phase capacitor phase capacity should be equal;
(2) capacitors should be rated voltage and rated current operation, the change should be allowed within the scope of; Thermoelectric Technology Alliance
(3) the capacitor room should be kept well ventilated, the operating temperature does not exceed the allowable value;
(4) capacitors can not be charged with residual charge, such as in the operation of the gate, the gate or closing a not, must be fully discharged before closing; for a discharge voltage transformer capacitor can be broken Open 5min after closing. Switching capacitor group in the running time interval of 15min, shunt capacitor device should be rated voltage operation, generally not more than 1.05 times the rated voltage, the maximum operating voltage does not exceed 1.1 times the rated voltage.
