Functions of quick grounding mechanism:

More than 90% of the fault rate of EHV lines is single-phase ground fault, while 80% of single-phase ground fault is transient fault. In China, single-phase reclosing is mostly used to eliminate single-phase ground fault in 330kV 550kV lines to improve system stability power supply reliability.

The success of single-phase reclosing depends on the self extinguishing of the secondary arc at the fault point. The secondary arc of the transmission line below 220kV can self extinguish within this time. The secondary arc of the line above 330kV needs to be extinguished by HSGS fast grounding switch.

Secondary arc current: refers to the current supplied to the fault phase by electrostatic coupling electromagnetic coupling between fault phase sound phase possible adjacent lines when circuit breakers at both ends of fault phase trip after single-phase grounding fault occurs.

When opening closing parallel overhead lines, electrostatic induction will produce capacitive current electromagnetic induction will produce inductive current.

The function of HSGS is to reduce the secondary arc current limit the recovery voltage. Its essence is to convert the open arc at the fault point into the compressive arc in the switch. The current flowing through the switch is only several hundred amperes, which is easy to break. It reduces the secondary arc current of the fault point greatly.

Location of HSGS: the outlet disconnector of GIS outlet circuit is close to the line side.

HSGS is to protect the circuit breaker burning explosion caused by its own fault. When the insulator inside the shell creeps the shell internal arcing occurs, the fast grounding switch will quickly ground the main circuit, use the circuit breaker to cut off the fault current.

Operation steps of quick earthing switch: