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

1. Characteristics of Fully Insulated SF₆ Switchgear1.1 OverviewFully insulated SF₆ switchgear comprises functional units such as load switches, load switch-fuse combinations, disconnectors-circuit breakers, etc., all sealed within stainless steel gas boxes filled with low-pressure SF₆ gas. This gas serves both as the arc-quenching and insulating medium. The switchgear employs electric or manual spring-operated mechanisms. Each cabinet is an independent gas box, allowing for expansion through bu

1 Ring Network Power Supply and Ring Main UnitsWith the advancement of urbanization, the demand for higher reliability in power distribution continues to grow, and an increasing number of users require two or more power supply sources. The traditional "radial power supply" method faces challenges such as difficulties in cable installation, complicated fault detection, and inflexibility in grid upgrades and expansions. In contrast, "ring network power supply" enables dual or multiple power source

1 Live Testing AnalysisDetection of Issues through Live TestingIn October of a certain year, during live partial discharge (PD) testing on 10kV ring main units (RMUs) under our jurisdiction, the maintenance and testing team observed significantly elevated signal amplitudes in several units (Transient Earth Voltage (TEV) readings around 18 dB, and ultrasonic readings around 20 dB). Most of these units were from the same manufacturer. Consequently, a unified test was conducted on 15 RMUs from this

1. Introduction to 10kV SF6 Ring Main Units (RMUs)A 10kV SF6 ring main unit typically consists of three main parts: the gas compartment (tank), the operating mechanism compartment, and the cable connection compartment. The gas compartment is the core component of the RMU. It is filled with SF6 gas and houses critical elements such as the load switch, busbars, and switch shaft. The load switch features a three-position design—comprising closing, opening, and grounding functions&mdas

SF6 Fully Insulated Gas-Insulated Ring Main Units (hereinafter referred to as RMUs) primarily consist of load switch units and high-voltage AC load switch-fuse combination appliances (hereinafter referred to as combination appliances). Depending on user requirements, they can be configured as either common-tank or unitized structures.In practical engineering applications, electrical connections are typically established using either top-mounted solid-insulated busbars or side-mounted plug-in bus

Current Power Supply Method Using SF6 Ring Main UnitsTo enhance grid performance, the design of traditional SF6 ring main units (RMUs) has been further optimized. A key feature of second-generation SF6 RMUs is the use of a grounded, enclosed epoxy resin housing, with SF6 gas as the insulating medium. Two three-position load switches and one three-position arc-rotating circuit breaker are integrated into a single sealed unit, equipped with a pressure relief safety valve. In the event of arc-quenc