Free Expert Guides on Power Systems, Circuit Design & Electrical Troubleshooting

The windings and core of a transformer are the primary components responsible for transmitting and transforming electromagnetic energy. Ensuring their reliable operation is a major concern. Statistical data shows that core-related issues account for the third-highest cause of transformer failures. Manufacturers have paid increasing attention to core defects and have implemented technical improvements regarding reliable core grounding, core ground monitoring, and ensuring single-point grounding.

The grounding disconnect switch of a pad-mounted transformer is a switching device used to isolate the pad-mounted transformer from the grounding cable. It is an essential component of pad-mounted transformer equipment and plays a critical role in protecting the safety of the transformer equipment. The grounding disconnect switch of a pad-mounted transformer serves important functions in grounding down leads, grounding switching, auxiliary grounding, and lightning protection.Its functions includ

Grounding transformers, commonly referred to as "grounding transformers" or simply "grounding units," operate under no-load conditions during normal grid operation and experience overload during short-circuit faults. Based on the filling medium, they are commonly categorized into oil-immersed and dry-type types; based on phase count, they can be either three-phase or single-phase grounding transformers.A grounding transformer artificially creates a neutral point for connecting a grounding resist

The main hazard points in transformer operation are: Switching overvoltages that may occur during the energizing or de-energizing of no-load transformers, endangering transformer insulation; No-load voltage rise in transformers, which may damage transformer insulation.1. Preventive Measures Against Switching Overvoltages During No-Load Transformer SwitchingGrounding the transformer neutral point is primarily aimed at preventing switching overvoltages. In 110 kV and higher large-current grounding

What is a Grounding Transformer?A grounding transformer, abbreviated as "grounding transformer," can be classified into oil-immersed and dry-type according to the filling medium; and into three-phase and single-phase grounding transformers according to the number of phases.Difference Between Grounding Transformers and Conventional TransformersThe purpose of a grounding transformer is to create an artificial neutral point for connecting an arc suppression coil or resistor when the system is conne

In China's power system, the 6 kV, 10 kV, and 35 kV grids generally adopt a neutral-point ungrounded operation mode. The distribution voltage side of main transformers in the grid is usually connected in delta configuration, which provides no neutral point for connecting grounding resistors. When a single-phase ground fault occurs in a neutral-point ungrounded system, the line-to-line voltage triangle remains symmetrical, causing minimal disruption to user operations. Moreover, when the capaciti

In power systems, transformers, as core equipment, are critical to the safe operation of the entire grid. However, due to various reasons, transformers are often exposed to multiple threats. In such cases, the importance of grounding resistor cabinets becomes evident, as they provide indispensable protection for transformers.Firstly, grounding resistor cabinets can effectively protect transformers from lightning strikes. The instantaneous high voltage caused by lightning can severely damage tran

Problems with Zero-Sequence Protection of 110 kV TransformersIn an effectively grounded system, the neutral-to-ground displacement voltage of a transformer is limited to a certain level, and the neutral-point gap protection does not operate. The purpose of installing gap protection is to prevent damage to transformer insulation caused by elevated zero-sequence voltage in non-effectively grounded systems. The discharge gap only operates when a single-phase ground fault occurs, all directly ground

In China's power system, the 6 kV, 10 kV, and 35 kV grids generally adopt a neutral-point ungrounded operation mode. The distribution voltage side of the main transformer in the grid is usually connected in delta configuration, which provides no neutral point for connecting a grounding resistor.When a single-phase ground fault occurs in a neutral-point ungrounded system, the line-to-line voltage triangle remains symmetrical, causing minimal impact on user operations. Moreover, when the capacitiv

When the capacitive current of a generator is slightly large, a resistor must be added at the generator neutral point to avoid power-frequency overvoltage that could damage the motor insulation during a ground fault. The damping effect of this resistor reduces the overvoltage and limits the ground fault current. During a single-phase ground fault of the generator, the neutral-to-ground voltage equals the phase voltage, typically several kilovolts or even above 10 kV. Therefore, this resistor mus