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

(1) Generator Protection:Generator protection covers: phase-to-phase short circuits in stator windings, stator ground faults, inter-turn short circuits in stator windings, external short circuits, symmetrical overload, stator overvoltage, single- and double-point grounding in the excitation circuit, and loss of excitation. Tripping actions include shutdown, islanding, limiting fault impact, and alarm signaling.(2) Transformer Protection:Power transformer protection includes: phase-to-phase short

Front-panel visible wiring: During manual wiring (not using templates or molds), wiring must be straight, neat, closely attached to the mounting surface, rationally routed, and with secure connections that facilitate maintenance. Wiring channels should be minimized as much as possible. Within the same channel, bottom-layer conductors shall be grouped by main and control circuits, arranged in a single-layer parallel dense layout or bundled, and kept closely attached to the mounting surface. Condu

Common inverter faults mainly include overcurrent, short circuit, ground fault, overvoltage, undervoltage, phase loss, overheating, overload, CPU malfunction, and communication errors. Modern inverters are equipped with comprehensive self-diagnostic, protection, and alarm functions. When any of these faults occurs, the inverter will immediately trigger an alarm or shut down automatically for protection, displaying a fault code or fault type. In most cases, the fault cause can be quickly identifi

Causes of Dielectric Withstand Failure in Vacuum Circuit Breakers: Surface contamination: The product must be thoroughly cleaned before dielectric withstand testing to remove any dirt or contaminants.Dielectric withstand tests for circuit breakers include both power-frequency withstand voltage and lightning impulse withstand voltage. These tests must be performed separately for phase-to-phase and pole-to-pole (across the vacuum interrupter) configurations.Circuit breakers are recommended to be t

There are many taboos and problematic practices in the installation of distribution boards and cabinets that must be noted. Especially in certain areas, improper operations during installation may lead to serious consequences. For cases where the precautions were not followed, some corrective measures are also provided here to remedy previous mistakes. Let’s follow along and take a look at common installation taboos from manufacturers regarding distribution boxes and cabinets!1. Taboo: Lighting

Overhaul Items for Transformer Conservator:1. Ordinary-Type Conservator Remove the end covers on both sides of the conservator, clean rust and oil deposits from inner and outer surfaces, then apply insulating varnish to the inner wall and paint to the outer wall; Clean components such as the dirt collector, oil level gauge, and oil plug; Check that the connecting pipe between the explosion-proof device and the conservator is unobstructed; Replace all sealing gaskets to ensure good sealing with n

Based on years of field statistics on switchgear accidents, combined with analysis focusing on the circuit breaker itself, the main causes have been identified as: failure of operation mechanism; insulation faults; poor breaking and closing performance; and poor conductivity.1.Failure of Operation MechanismFailure of operation mechanism manifests as delayed operation or unintended operation. Since the most basic and important function of a high-voltage circuit breaker is to operate correctly and

1. Induced Lightning OvervoltageInduced lightning overvoltage refers to the transient overvoltage generated on overhead distribution lines due to nearby lightning discharges, even when the line is not directly struck. When a lightning flash occurs in the vicinity, it induces a large amount of charge on the conductors—opposite in polarity to the charge in the thundercloud.Statistical data shows that lightning-related faults caused by induced overvoltages account for approximately 90% of total fau

Air-insulated ring main units (RMUs) are defined in contrast to compact gas-insulated RMUs. Early air-insulated RMUs used vacuum or puffer-type load switches from VEI, as well as gas-generating load switches. Later, with the widespread adoption of the SM6 series, it became the mainstream solution for air-insulated RMUs. Similar to other air-insulated RMUs, the key difference lies in replacing the load switch with an SF6-encapsulated type—where the three-position switch for load and grounding is

1 IntroductionAccording to the provisions of the national standard GB/T 1094.3-2017, the primary purpose of the line terminal AC withstand voltage test (LTAC) for power transformers is to evaluate the AC dielectric strength from the high-voltage winding terminals to ground. It does not serve to assess inter-turn insulation or phase-to-phase insulation.Compared with other insulation tests (such as full lightning impulse LI or switching impulse SI), the LTAC test imposes a relatively more stringen