For assuring compatibility of ECT and EVT in the operation of intelligent power distribution equipment

in the design

the imaginary part of impedance in series or parallel admittance of the system and interface shall be equal to the no real solution of zero equation

so to avoid series or parallel resonance of equipment system or interface in the full spectrum range.For meeting normal operation of the equipment during the switching and lightning impulse transient over voltage of the circuit breaker

the influence of parallel capacitance of the secondary output end shall be focused in the design of ECT and the compatibility of the system and interface shall be considered.The capacitance dividing type EVT shall be designed to discharge the transient retention charge way and assure success of reclosing operation.The time constant design of RC type EVT shall meet simultaneously the requirement of reclosing time and insulation to earth.Single phase short circuit earthing keeps ECV

EVT

PT and load etc form complicated series and parallel system.In the design

not only the boundary condition shall be met

but also sufficient allowance shall be maintained.