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

1. Integrated Operation and Maintenance Strategy for Medium-Voltage Distribution EquipmentTo effectively prevent discharge faults in distribution equipment, it is essential to establish a corresponding operation and maintenance (O&M) strategy. This strategy should focus on air-insulated ring main units (RMUs) as the primary subject, utilizing live-line detection as a key method and aiming for closed-loop defect elimination. This approach establishes a scientific and effective closed-loop man

1 Insulation Materials and DesignBased on cost statistics for medium-voltage solid-insulated ring main units (RMUs), the insulation structure accounts for over 40% of the total cost. Therefore, selecting appropriate insulation materials, designing rational insulation structures, and determining the correct insulation method are crucial to the value of medium-voltage RMUs. Since the first synthesis of epoxy resin in 1930, various additives have been continuously explored to improve its properties

1.Permanent Magnet Mechanism DesignDue to the high demand for miniaturization in solid-insulated ring main units (RMUs), traditional single permanent magnet mechanisms with three-phase interlocking cannot meet the overall miniaturization requirements of the equipment. Therefore, the permanent magnet mechanism designed in this context adopts a three-phase independent direct-acting structure. Each phase's arc extinguishing chamber unit is integrally cast with the casting body of the RMU and connec

Development Status at Home and AbroadToshiba Corporation of Japan developed high-performance epoxy resin materials and casting technology in 1999, and subsequently launched a 24 kV solid-insulated ring main unit (RMU) in 2002. The product line has since been expanded, and the company is now advancing toward higher voltage levels of 72 kV and 84 kV. Holec, originally a European pioneer with advanced design concepts and environmentally friendly manufacturing processes that produce no pollution, wa

1.Current Application Status of Solid-Insulated Ring Main Units in Medium-Voltage Distribution Networks1.1 Widespread Application in Urban Residential AreasThe core components of medium-voltage ring main units (RMUs) primarily consist of load switches and fuses. These units offer several advantages, including a simple structure, compact size, and relatively low cost. Additionally, they effectively improve power quality and enhance the reliability and safety of power supply. Observations indicate

Current Application Status of Solid-Insulated Ring Main Units in Medium-Voltage Distribution Networks(1) Solid-insulated ring main units (RMUs) have been widely applied in urban residential areas and other medium-voltage distribution applications. The core components of medium-voltage RMUs mainly include the load switch and the fuse. These units offer advantages such as a simple structure, compact size, and low cost, while effectively improving power supply parameters and enhancing operational s

Selection of Vacuum Interrupter Mounting Method in Solid Insulation DesignThe key issue in designing solid insulation components is whether to use direct encapsulation or subsequent potting for the vacuum interrupter. If direct encapsulation is adopted, there may be a certain scrap rate due to APG process issues or vacuum interrupter quality problems. Additionally, direct encapsulation results in poorer heat dissipation for the main conductive circuit and demands higher material performance, mak

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