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

Standards for Surge Arresters Used in Cable Auxiliary Equipment GB/T 2900.12-2008 Electrotechnical Terminology – Surge Arresters, Low-Voltage Surge Protective Devices, and ComponentsThis standard defines specialized terminology for surge arresters, low-voltage surge protective devices, and their functional components. It is primarily intended for use in drafting standards, writing technical documents, translating professional manuals, textbooks, journals, and publications. GB/T 11032-2020 Metal-

Transformer Bushings: External Insulation and Current-Carrying ComponentsTransformer bushings are the primary external insulation devices mounted on the transformer tank. The leads from the transformer windings must pass through these insulating bushings, which provide insulation between the leads as well as between the leads and the transformer tank, while also serving to mechanically secure the leads.Depending on the voltage level, transformer bushings are available in several types: porcelain

Comparison of Domestic and International Transformer StandardsAs a core component of power systems, the performance and safety of transformers directly affect grid operation quality. The IEC 60076 series standards established by the International Electrotechnical Commission (IEC) correspond multidimensionally with China’s GB/T 1094 series standards in technical specifications. For example, regarding insulation levels, IEC specifies that power frequency withstand voltage for transformers rated at

The inability to manually operate the local mechanical trip of a 10kV vacuum circuit breaker is a relatively common fault type in power system maintenance work. Based on years of field experience, such issues typically stem from five core areas, each requiring troubleshooting based on specific symptoms.Operating mechanism jamming is the most common cause. The tripping process of a circuit breaker relies on mechanical energy released from spring energy storage; if rust, deformation, or foreign ob

01 PrefaceIn medium-voltage systems, circuit breakers are indispensable primary components. Vacuum circuit breakers dominate the domestic market. Therefore, correct electrical design is inseparable from the proper selection of vacuum circuit breakers. In this section, we will discuss how to correctly select vacuum circuit breakers and common misconceptions in their selection.02 Interrupting Capacity for Short-Circuit Current Need Not Be Excessively HighThe short-circuit interrupting capacity of

Low-Voltage Air Circuit Breakers vs. Vacuum Circuit Breakers: Structure, Performance and ApplicationLow-voltage air circuit breakers, also known as universal or molded frame circuit breakers (MCCBs), are designed for AC voltages of 380/690V and DC voltages up to 1500V, with rated currents ranging from 400A to 6300A or even 7500A. These breakers use air as the arc-quenching medium. The arc is extinguished through arc elongation, splitting, and cooling by an arc chute (arc runner). Such breakers c

Insulation Withstand Voltage Test Standards for Vacuum Circuit BreakersThe main purpose of the insulation withstand voltage test for vacuum circuit breakers is to verify whether the insulation performance of the equipment under high voltage is qualified, and to prevent breakdown or flashover accidents during operation. The test process must be strictly carried out in accordance with power industry standards to ensure equipment safety and power supply reliability.Test ObjectsThe test objects incl

1. IntroductionBuilding electrical engineering is an indispensable component of modern construction projects. The installation of electrical riser lines and distribution boxes is of paramount importance to the integrity and functionality of the entire electrical system. The quality of riser line installation directly impacts the usability, safety, and operational efficiency of the entire building. Therefore, rigorous quality control measures for the construction of electrical riser lines and dis

Common Vacuum Circuit Breaker Faults and On-Site Troubleshooting by Electrical EngineersAs vacuum circuit breakers are widely used in the power industry, performance varies significantly among manufacturers. Some models offer excellent performance, require minimal maintenance, and ensure high power supply reliability. Others suffer from frequent issues, while a few have severe defects that may cause over-level tripping and large-scale blackouts. Let’s explore real-world fault handling by electri

Fault Analysis and Troubleshooting of High-Voltage Vacuum Circuit BreakersIntroduction: Advantages and EvolutionHigh-voltage vacuum circuit breakers (VCBs) offer significant advantages over traditional oil or SF₆-based breakers, including: Oil-free and environmentally friendly design High dielectric strength in vacuum Excellent arc-quenching capability Long electrical and mechanical life Compact size, light weight Suitable for frequent operation Fire-resistant and low maintenanceThese benefits h