Electric container security operation
During the operation of the capacitor, the current should not exceed 1.3 times the rated current of the capacitor for a long time, and the voltage should not exceed 1.1 times the rated voltage of the capacitor for a long time. The ambient temperature at which the capacitors are used must not exceed the limits listed in Table 6---11. The temperature of the capacitor case must not exceed the manufacturer's specified value (usually 60 or 65). Each contact of the capacitor should be kept well, and there should be no signs of loosening or overheating; The casing should be clean and there should be no traces of discharge; The shell should not have obvious deformation and should not have traces of oil leakage. The switchgear, protective appliances and discharge devices of the capacitor should be kept intact.
Under normal circumstances, the shunt capacitor should be input or exit according to the power factor on the line and the high and low voltage of the line. When the power factor is lower than 0.9 and the voltage is low, the capacitor bank should be put in; When the power factor is close to 1 and there is a leading trend, the voltage is high, and the capacitor bank should be withdrawn.
When the operating parameters are abnormal and exceed the working conditions of the capacitor, the capacitor bank should be withdrawn. If the capacitor's three-phase current is significantly unbalanced, it should also be withdrawn from operation.
When it is found that the capacitor connection point is seriously overheated or even melted, the porcelain sleeve is seriously flashover discharged, the shell is seriously expanded and deformed, the capacitor or its discharge device emits a serious abnormal sound, the capacitor bursts or fires and smokes, it should urgently exit the operation.
The following points should be noted when performing capacitor operation:
(1) Under normal circumstances, when the whole station is powered off, first pull the switch of the capacitor, and then pull the switch of each way; Under normal circumstances, when the power transmission of the whole station resumes, the switch of each outlet line is closed first, and then the switch of the capacitor line is closed.
(2) After the power outage of the whole station accident, the switch of the capacitor should be opened.
(3) The capacitor circuit breaker shall not be forcibly transmitted after tripping; After the fuse is blown off, the fuse must not be replaced until the cause is ascertained.
(4) Neither high-voltage capacitors nor low-voltage capacitors are allowed to brake when there is a residual charge. Otherwise, a large current surge may occur. Before the capacitor is reclosed, it should be discharged for at least 3 minutes.
(5) In order to meet the needs of inspection and repair, after the capacitor is disconnected from the power supply, whether the capacitor is equipped with a discharge device or not, it must be manually discharged with a special discharge load that can be carried, regardless of whether the capacitor is equipped with a discharge device.
When the total capacity of the high-voltage capacitor bank does not exceed 100kvar, it can be protected and controlled by the fuse during the start period; When the total capacity is 100~300kvar, load switch protection and control should be adopted; When the total capacity is 300kvar or less, vacuum circuit breakers or other circuit breakers should be used for protection and control.
When the total capacity of the low-voltage capacitor bank does not exceed 100kvar, it can be protected and controlled by AC contactor, knife switch, fuse or knife fusion switch; When the total capacity is more than 100kvar, low-voltage circuit breaker protection and control should be adopted.