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

Characteristics and Detection Devices for Single-Phase Ground Faults1. Characteristics of Single-Phase Ground FaultsCentral Alarm Signals:The warning bell rings, and the indicator lamp labeled “Ground Fault on [X] kV Bus Section [Y]” illuminates. In systems with a Petersen coil (arc suppression coil) grounding the neutral point, the “Petersen Coil Operated” indicator also lights up.Insulation Monitoring Voltmeter Indications:The voltage of the faulted phase decreases (in

The arrangement of neutral point grounding operation modes for 110kV～220kV power grid transformers shall meet the insulation withstand requirements of transformer neutral points, and shall also strive to keep the zero-sequence impedance of substations basically unchanged, while ensuring that the zero-sequence comprehensive impedance at any short-circuit point in the system does not exceed three times the positive-sequence comprehensive impedance.For 220kV and 110kV transformers in new constructi

Why Do Substations Use Stones, Gravel, Pebbles, and Crushed Rock?In substations, equipment such as power and distribution transformers, transmission lines, voltage transformers, current transformers, and disconnect switches all require grounding. Beyond grounding, we will now explore in depth why gravel and crushed stone are commonly used in substations. Though they appear ordinary, these stones play a critical safety and functional role.In substation grounding design—especially when multiple gr

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

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

Design Principles for Pole-Mounted Distribution Transformers(1) Location and Layout PrinciplesPole-mounted transformer platforms should be located near the load center or close to critical loads, following the principle of “small capacity, multiple locations” to facilitate equipment replacement and maintenance. For residential power supply, three-phase transformers may be installed nearby based on current demand and future growth projections.(2) Capacity Selection for Three-Phase Pole-Mounted Tr

1.Noise Mitigation for Ground-Level Independent Transformer RoomsMitigation Strategy:First, conduct a power-off inspection and maintenance of the transformer, including replacing aged insulating oil, checking and tightening all fasteners, and cleaning dust from the unit.Second, reinforce the transformer foundation or install vibration isolation devices—such as rubber pads or spring isolators—selected based on the severity of vibration.Finally, strengthen sound insulation at weak points of the ro

Rockwill Electric Co., Ltd. has successfully passed the real-scenario single-phase-to-ground fault test conducted by the Wenzhou of China Electric Power Research Institute for its DA-F200-302 hood-type feeder terminal and integrated primary-secondary pole-mounted circuit breakers—ZW20-12/T630-20 and ZW68-12/T630-20—receiving an official qualified test report. This achievement marks Rockwill Electric as a leader in single-phase ground fault detection technology within distribution networks.The DA

Common Faults and Causes in Routine Inspection of Distribution TransformersAs the terminal component of power transmission and distribution systems, distribution transformers play a critical role in supplying reliable electricity to end users. However, many users have limited knowledge of power equipment, and routine maintenance is often carried out without professional support. If any of the following conditions are observed during transformer operation, immediate action should be taken: Excess

Analysis of Lightning Protection Measures for Distribution TransformersTo prevent lightning surge intrusion and ensure the safe operation of distribution transformers, this paper presents applicable lightning protection measures that can effectively enhance their lightning withstand capability.1. Lightning Protection Measures for Distribution Transformers1.1 Install surge arresters on the high-voltage (HV) side of the distribution transformer.According to SDJ7–79 Technical Code for Overvol