1. Type Test System and StandardsType testing verifies the design rationality and safety of eco-friendly insulated ring main units (RMUs), based on IEC 62271-200 and GB/T 3906, and includes:Insulation Performance: For 12kV RMUs, power frequency withstand voltage is 42kV (1 min) for main circuits and 48kV for breakers. Lightning impulse withstand is 75kV (12kV system) or 125kV (24kV system), with 15 standard impulses (1.2/50μs) per polarity. Partial discharge must be ≤10pC at 1.2× rat

1. Gas System FaultsThe most critical type of fault in environmentally friendly gas-insulated ring main units is related to the gas system, primarily involving gas leakage and pressure anomalies. Gas leakage in nitrogen-insulated ring main units mainly stems from seal material aging and welding process defects. Statistics indicate that approximately 65% of gas leakage faults are related to O-ring aging, while 30% are caused by inadequate welding. Gas leakage not only affects insulation performan

1 Characteristics of Nitrogen-Insulated Ring Main UnitsThe new generation of nitrogen-insulated ring main units has the following main characteristics:Excellent insulation performance. All live components are sealed inside, with external surfaces made of insulating material, effectively blocking current flow and preventing interference from external charged objects.Strong resistance to external environmental conditions. Both the enclosure and internal insulation materials possess high resilience

1. Air-insulated and SF₆ Gas-insulated Ring Main UnitsAir-insulated ring main units primarily integrate load break switches, disconnectors, or a combination of both with grounding capabilities, operated either manually or electrically. These units may also incorporate fuses to control cable input and output lines. Conversely, SF₆ gas-insulated ring main units, commonly referred to as gas-insulated switchgear, utilize SF₆ gas for insulation and arc quenching due to its high dielectric strength, p

This paper takes the primary isolation break of a certain type of 12kV air-insulated ring main unit (RMU) as the research object, analyzing the electric field distribution and uniformity around it, evaluating the insulation performance at this location, and reducing discharge risk while enhancing insulation performance through structural optimization, thereby providing a reference for the insulation design of similar products.1 Structure of the Air-Insulated Ring Main UnitThe three-dimensional s

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