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GIS (Gas-Insulated Metal-Enclosed Switchgear) contains numerous bolted and screwed connections, and the tightening torque varies depending on bolt material, size, and application. The recommended tightening torque values are listed below for reference:Table 1 Tightening Torque Values for Bolts of Different Materials and Sizes (N·m / kgf·cm) Thread Diameter (mm) Q235 (A3) Cast Insulator 45 Steel Chrome-Molybdenum Steel Stainless Steel M6 5.88/60 3.92/40 12.3/125 19.6/

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-

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

Standard for Loop Resistance of Vacuum Circuit BreakersThe standard for loop resistance of vacuum circuit breakers specifies the required limits for the resistance value in the main current path. During operation, the magnitude of loop resistance directly affects the safety, reliability, and thermal performance of the equipment, making this standard critically important.Below is a detailed overview of the loop resistance standard for vacuum circuit breakers.1. Significance of Loop ResistanceLoop

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

1. Definition of Condition-Based MaintenanceCondition-based maintenance refers to a maintenance method where decisions on whether and how to perform maintenance are determined based on the real-time operating status and health condition of equipment. It has no fixed maintenance methods or schedules. The prerequisite for condition-based maintenance is the establishment of equipment parameters and the comprehensive analysis of various operational information of the equipment, so as to make reasona

IntroductionAs a clean and renewable energy source, wind energy has increasingly attracted the attention of countries around the world. Its reserves are enormous. The total global wind energy resources amount to approximately 2.74×10⁹ MW, of which the exploitable wind energy is 2.0×10⁷ MW. In China, wind energy reserves are large, widely distributed, and the potential for development and utilization is huge. Wind power generation has developed rapidly in recent years, and the

Standards and Classification of Combined Power Distribution DevicesThere is a relatively large variety of combined power distribution devices. Commonly used ones include packaged substations, box - type transformers, pre - assembled substations, combined transformers, European - style box substations, and American - style box substations.Relevant Standards for Combined Power Distribution DevicesThe currently effective relevant standards for combined power distribution devices in China mainly inc

Electrical Principle and Structure of Pad-Mounted SubstationsThe electrical schematic diagram of the pad-mounted substation is shown in Figure 1.Structural Composition:An American-style pad-mounted combined substation is primarily composed of a pad-mounted transformer, structured into front and rear sections: Front Section (Wiring Cabinet): Contains high/low-voltage terminal blocks, a high-voltage load switch, plug-in fuses, a high-voltage tap changer operating handle, a pressure gauge, an oil l