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

During the operation of high-voltage disconnect switches, arcs may form between the contacts when they separate while current is still flowing. The high temperature of the arc not only damages the switch contacts but can also ignite surrounding flammable materials, leading to safety accidents.Arc formation is influenced by various factors, including the type of current (DC or AC), the inductive and capacitive characteristics of the circuit, and the properties of the contact materials. In DC syst

With the continuous advancement of mechanization in modern society, the demand for electrical energy in daily life has significantly increased. To ensure that power supply meets this growing demand, the power system must operate with greater stability, safety, and real-time responsiveness. This highlights the critical importance of high-voltage disconnector switch quality during manufacturing.Manufacturers must strengthen their awareness of this responsibility to ensure reliable operation of hig

How Residual Current Devices (RCDs) Work and Why They TripA residual current device (RCD), also known as a leakage circuit breaker, trips when it detects a current imbalance of 30mA or more between the live and neutral conductors. In older electrical circuits, or in installations where cables were not run through conduits, it can be extremely difficult to use RCDs effectively. Even if the system works initially, during damp or humid weather, the RCD may trip repeatedly. Identifying the exact cau

In daily life and industrial operations, we often encounter circuit breakers tripping. Common causes include faulty breakers themselves or leakage/short circuits in the load. However, some tripping incidents have unexpected origins.At a mine, an emergency backup power system consisted of a diesel generator (400V), which fed a mining transformer (10,000V–400V) to step up voltage and supply power to the underground shaft. One rainy day, the main grid power failed. To ensure safety underground, the

Classification of Circuit Breakers(1) Air Circuit Breaker (ACB)An air circuit breaker, also known as a molded frame or universal circuit breaker, houses all components within an insulated metal frame. It is typically open-type, allowing installation of various accessories, and facilitates easy replacement of contacts and parts. It is commonly used as the main power supply switch. Overcurrent trip units include electromagnetic, electronic, and intelligent types. The breaker provides four-stage pr

High-Voltage Switchgear Room When the length of a high-voltage switchgear room exceeds 7m, two doors should be provided, preferably located at opposite ends. The access door for handling GG-1A type switchgear should be 1.5m wide and 2.5–2.8m high. Recommended dimensions for operating aisles in front of fixed switchgear: 2m for single-row layout and 2.5m for double-row layout, measured from the front of the panels. When a large number of switchgear units are installed, the aisle width may be appr

What is a Switchgear Room?A switchgear room is an indoor electrical distribution facility that supplies power to low-voltage consumers. It typically includes medium-voltage incoming lines (with limited outgoing lines), distribution transformers, and low-voltage switchgear. Facilities operating at 10kV or below are categorized as either high-voltage or low-voltage switchgear rooms. A high-voltage switchgear room generally refers to a 6kV–10kV high-voltage switch compartment, while a low-voltage s

Maintenance of Main and Control Circuits in Low-Voltage Switchgear (Dust Removal); Inspection and Maintenance of Isolators, Circuit Breakers, Contactors, and RelaysI. Preparation and Standards Before Maintenance Pre-Maintenance Preparations: (1) Working Conditions: Scheduled shutdown and power disconnection. (2) Tools and Instruments:Measuring instruments and tools including: insulation resistance tester (megger), clamp meter, multimeter, combination wrenches, voltage tester, electrician pliers,

High- and Low-Voltage Cable Lines and Cable Trays Inspect cable trays for proper closure and secure rodent-proof sealing. High- and low-voltage cable trays should be intact and undamaged. Address any abnormalities promptly and maintain records. Check for water seepage in cable trays entering switchrooms located in basements or low-lying areas. Inspect cable pits and trenches for standing water or debris, and promptly drain water and remove contaminants if found. Cables and cable terminations wit

Compared with 12kV, 24kV can supply more electrical energy, reduce line losses, and is widely used in overseas markets.SF₆ is a greenhouse gas whose ozone layer depletion potential is over 20,000 times that of CO₂. Its use must be restricted; therefore, medium-voltage switchgear must not use SF₆ as an insulating gas.For switchgear, environmentally friendly gases refer to those that do not contain SF₆ as insulating or arc-extinguishing media. Examples include naturally occurring gases (such as ni