Circuit breaker closing control technique for mitigation of LCC HVDC AC filter inrush current and comparitive analysis with pre-insertion resistor

This paper presents the method for mitigating inrush current of AC filter circuits in Line Current Commutated (LCC) HVDC converter stations using circuit breaker closing control with comparative analysis data with Pre-Insertion resistor. Due to the capacitive characteristics of AC filter circuits, high inrush current is inevitable when a circuit breaker is closed. This causes mechanical stress to filter components. The inrush current is depending on several factors such as system’s Short Circuit Level (SCL), application of Pre-Insertion Resistors (PR), tuning frequencies of an AC filter, circuit breaker close timing with respect to phase to ground voltage, and others. To mitigate it, circuit breaker closing controllers that make the closing of main contact at voltage zero can be used. Simulations on inrush current of AC filter circuits are conducted using PSCAD with considering operational conditions in Korea to verify its usefulness using comparative analysis with PR. The illustrations of switchgear configurations to use closing control effectively considering 154kV system in Korea are proposed.