The HV and LV Switchgear Test Bench under UHV Power can help many power workers conduct various power tests more conveniently.

HV and LV Switchgear Test Bench is a very important electrical equipment in the power system. The deterioration of the operating status of switchgear is one of the reasons for power system failures. What are the causes of faults in high-voltage switchgear? Mainly occurs in insulation, conduction, and mechanical aspects.

(1) Inaction or malfunction

This type of fault is the most common fault in high-voltage switchgear, and its causes can be divided into two categories. One type is caused by mechanical faults in the operating mechanism and transmission system, manifested as mechanism jamming, component deformation, displacement or damage, loose and jammed opening and closing iron cores, loose shaft pins, tripping faults, etc. Caused by electrical control and auxiliary circuits, it manifests as poor contact of secondary wiring, loose terminals, wiring errors, mechanism jamming or poor conversion switch, resulting in burnt opening and closing coils, ineffective switching of auxiliary switches, and poor operation. Malfunctions in power supply, closing contactor, micro switch, etc.

(2) Breaking and closing faults

This type of fault is caused by the circuit breaker itself. For low oil level circuit breakers, the main manifestations include fuel injection short circuits, burnt out arc extinguishing chambers, insufficient breaking capacity, and explosions when closing. For vacuum circuit breakers, it is manifested as leakage of the arc extinguishing chamber and corrugated tube, decrease in vacuum degree, reignition of the cut capacitor group, and rupture of the ceramic tube.

(3) Insulation failure

The insulation level is the correct handling of the relationship between various voltages (including working voltage and various overvoltages) acting on insulation, various voltage limiting measures, and insulation strength. Strive to make the product both safe and economical, and achieve the best economic benefits. The main manifestations of insulation faults are external insulation to ground flashover breakdown, internal insulation to ground flashover breakdown, phase to phase insulation flashover breakdown, lightning overvoltage flashover breakdown, porcelain bushing and capacitor bushing. Pollution flashover, breakdown, explosion, suspension rod flashover, CT flashover, breakdown, explosion, porcelain bottle damage, etc.

(4) Current carrying fault

The main cause of live faults at voltage levels of 72-12kV is poor contact of the isolation plug in the switchgear, which leads to contact melting.

(5) External forces and other malfunctions

Including unknown external forces such as foreign object impacts, natural disasters, short circuits in small animals, and unexpected malfunctions. Generally, manufacturers of switchgear production equipment need to conduct a power on test.