What principles should be followed to select the switchgear of the capacitor bank
(1) A circuit breaker that cuts off the capacitive current and does not reignite should be used.
(2) The rated current of the circuit breaker should be at least 1.43 times the rated current of the capacitor bank (1.3 times should be selected among the questions of the low-voltage electrician certificate examination).
(3) The rated breaking current of the circuit breaker should not be less than the effective value of the three-phase short-circuit current periodic component within the actual breaking time of the circuit breaker (the sum of the relay protection action time and the inherent opening time of the circuit breaker).
(4) The peak value of the rated closing current of the circuit breaker shall not be less than the maximum value of the short-circuit current, and not less than the peak value of the charging inrush current when the capacitor bank is put into operation.
(5) Indoor low-voltage capacitor banks below 50 kvar should be controlled by iron shell switches; low-voltage capacitor banks above 50 kvar can be operated with automatic air switches or AC contactors according to specific conditions.
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