Switchgear

Switchgear encompasses a combination of electrical disconnect switches, circuit breakers, fuses, and protective relays assembled into a unified enclosure. These devices are designed to control, protect, and isolate electrical equipment and circuits within power systems. Voltage classifications include low-voltage (below 1 kV), medium-voltage (1 kV to 52 kV), and high-voltage (above 52 kV). Switchgear configurations include open-type, metal-enclosed, and metal-clad constructions, with insulation media such as air, gas (SF₆), or solid materials. Compliance with IEC 61439 and GB/T 3906 standards governs design and testing. Applications are found in utility substations, industrial facilities, commercial buildings, and power generation plants. Maintenance involves periodic inspection of contact wear, insulation resistance testing, and verification of protective relay settings.