Phase loss alarm circuit 2

The negative sequence voltage filter is composed of capacitor Cl and resistor Ri-R3 .     The resistance and capacitance must meet the following requirements:     Ri =Rz =Ra—5.5/C1 (kn)     In the formula, the unit of Cl is F. The numerical relationship between resistance and capacitance is arbitrary.     When selecting the capacitor, the current required by the relay KA should be considered, which can be calculated according to the following formula:     C - where the current required by the relay KA, A;     - reliability coefficient, takes - 2.5 to 3;     U. ——The rated voltage of the capacitor, v;     f-power frequency, the power frequency is 50Hz.