CJX8(B) Series AC Contactor in 50/60Hz Circuits

1. Hazards, Causes, and Types of Multi-Point Grounding Faults in Transformer Cores1.1 Hazards of Multi-Point Grounding Faults in the CoreUnder normal operation, a transformer core must be grounded at only one point. During operation, alternating magnetic fields surround the windings. Due to electromagnetic induction, parasitic capacitances exist between the high-voltage and low-voltage windings, between the low-voltage winding and the core, and between the core and the tank. The energized windin

A Brief Discussion on the Selection of Grounding Transformers in Boost StationsThe grounding transformer, commonly referred to as "grounding transformer," operates under the condition of being no-load during normal grid operation and overloaded during short-circuit faults. According to the difference in filling medium, common types can be divided into oil-immersed and dry-type; according to phase number, they can be classified into three-phase and single-phase grounding transformers. The groundi

Impact of DC Bias in Transformers at Renewable Energy Stations Near UHVDC Grounding ElectrodesWhen the grounding electrode of an Ultra-High-Voltage Direct Current (UHVDC) transmission system is located close to a renewable energy power station, the return current flowing through the earth can cause a rise in ground potential around the electrode area. This ground potential rise leads to a shift in the neutral-point potential of nearby power transformers, inducing DC bias (or DC offset) in their

1.Definition and Function1.1 Role of the Generator Circuit BreakerThe Generator Circuit Breaker (GCB) is a controllable disconnect point located between the generator and the step-up transformer, serving as an interface between the generator and the power grid. Its primary functions include isolating generator-side faults and enabling operational control during generator synchronization and grid connection. The operating principle of a GCB is not significantly different from that of a standard c

1.Transformer Maintenance and Inspection Open the low-voltage (LV) circuit breaker of the transformer under maintenance, remove the control power fuse, and hang a “Do Not Close” warning sign on the switch handle. Open the high-voltage (HV) circuit breaker of the transformer under maintenance, close the grounding switch, fully discharge the transformer, lock the HV switchgear, and hang a “Do Not Close” warning sign on the switch handle. For dry-type transformer maintenance: first clean the porcel

In practical work, insulation resistance of distribution transformers is generally measured twice: the insulation resistance between thehigh-voltage (HV) windingand thelow-voltage (LV) winding plus the transformer tank, and the insulation resistance between theLV windingand theHV winding plus the transformer tank.If both measurements yield acceptable values, it indicates that the insulation among the HV winding, LV winding, and transformer tank is qualified. If either measurement fails, pairwise