Suppression Methods of 750 kV AC Filter Switching Inrush Surge for Circuit Breakers Having Pre-insertion Resistors

The AC filter is one of the important parts of HVDC transmission system. In order to compensate for reactive power and eliminate harmonics on the AC side, the AC filter needs to be installed. And the A C filter needs to be frequently put in and removed as the DC power changes. When the filter is put into the circuit, because the voltage on the capacitor and the bus voltage are not completely in phase, a closing inrush current will be generated, which will cause an impact on the system. This paper uses EMTDC/PSCAD to establish a simulation model, the effect of pre-insertion resistor, pre-insertion resistor insertion duration and closing target angle on closing inrush current and energy absorption by pre-insertion resistor is calculated. Simulation calculation shows that combining the pre-insertion resistor and the phase selection closing device to accurately control the input time and exit time of the resistor, it can avoid pre-breakdown, and limit the closing inrush current and the energy absorbed by the pre-insertion resistor to the minimum at the same time.