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

Transformer Core Inspection and Assembly Requirements The iron core should be flat with intact insulation coating, tightly stacked laminations, and no curling or waviness at the edges of silicon steel sheets. All core surfaces must be free of oil, dirt, and impurities. There should be no short circuits or bridging between laminations, and joint gaps must meet specifications. Good insulation must be maintained between the core and upper/lower clamping plates, square iron pieces, pressure plates,

1. Regarding GIS, how should the requirement in Clause 14.1.1.4 of the State Grid’s "Eighteen Anti-Accident Measures" (2018 Edition) be understood?14.1.1.4: The neutral point of a transformer shall be connected to two different sides of the main mesh of the grounding grid via two grounding down conductors, and each grounding down conductor shall meet the thermal stability verification requirements. Main equipment and equipment structures shall each have two grounding down conductors connected to

Recently, three IEC standards on insulators, led by China for the first time, have been officially published. These standards primarily address the coupling markings, dimensions, and tests of insulator end fittings, specifically including IEC 60120:2020, IEC 60372:2020, and IEC 60471:2020. These three standards were jointly completed under the leadership and coordination of numerous experts from the National Technical Committee on Insulators of China (SAC/TC80). The publication of these standard

1.Working Principle and Structural Features of GW4-126 DisconnectorThe GW4-126 disconnector is suitable for AC 50/60 Hz power lines with a rated voltage of 110 kV. It is used to disconnect or connect high-voltage circuits under no-load conditions, enabling circuit switching, operational mode changes, and safe electrical isolation of busbars, circuit breakers, and other high-voltage equipment during maintenance. Disconnectors typically feature a clearly visible open point to ensure safe current i

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

Core Standards for Calibration of Online Power Quality Monitoring DevicesThe calibration of online power quality monitoring devices follows a comprehensive standard system, encompassing mandatory national standards, industry technical specifications, international guidelines, and requirements for calibration methods and equipment. The following provides a structured overview with practical recommendations for real-world applications.I. Core Domestic Standards1. DL/T 1228-2023 – Technical Require

IntroductionSF6 gas is widely used as an insulating and arc-quenching medium in high-voltage and extra-high-voltage electrical equipment due to its excellent insulation, arc-extinguishing properties, and chemical stability. The insulation strength and arc-quenching capability of electrical equipment depend on the density of SF6 gas. A decrease in SF6 gas density can lead to two main hazards: Reduced dielectric strength of the equipment; Decreased interrupting capacity of circuit breakers.Additio

Combined Instrument Transformers: Technical Requirements and Testing Standards Explained with DataA combined instrument transformer integrates a voltage transformer (VT) and a current transformer (CT) into a single unit. Its design and performance are governed by comprehensive standards covering technical specifications, testing procedures, and operational reliability.1. Technical RequirementsRated Voltage:The primary rated voltages include 3kV, 6kV, 10kV, and 35kV, among others. The secondary v

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-

Differences Between Vacuum Circuit Breakers Complying with IEEE C37.04 and IEC/GB StandardsVacuum circuit breakers designed to meet the North American IEEE C37.04 standard exhibit several key design and functional differences compared to those conforming to IEC/GB standards. These differences primarily stem from safety, serviceability, and system integration requirements in North American switchgear practices.1. Trip-Free Mechanism (Anti-Pumping Function)The "trip-free" mechanism—functionally eq