FIELD: electricity.
SUBSTANCE: device with earthed neutral protecting capacitor bank against internal faults comprises a microprocessor processing digital values of unbalance current, current measured at input to the capacitor bank, voltage measured at busbars of the substation. The microprocessor perform calculation of valid values for orthogonal components of phase current and voltage, calculation of compensating current and zero-sequence current. Comparing current values with consideration of the preset braking value the microprocessor forms the sign of protection actuation. Switching the sign of protection actuation on and off is made with consideration of the preset resetting coefficient. According to a separate algorithm the microprocessor also forms sign of failure for secondary control voltage circuits and blocks the sign of protection actuation when the sign of failure for secondary control voltage circuits is positive. The microprocessor identifies the modes when burning of sectional fuses is possible; it calculates relative value of imbalance current, increment of the relative imbalance current, and total imbalance current as per diagonal lines with capacitors. Comparing value of the total imbalance current with setting the microprocessor generates a signal specifying available capacitors with burnt sections.
EFFECT: providing protection for a bank of capacitors.
5 dwg, 2 tbl
