1. Statistics on Common Faults of Medium-Voltage Switchgear in the Early Operation StageAs project participants, we found during the early operation of a new metro line: 21 sets of power supply equipment were put into use, with a total of 266 accident phenomena in the first year. Among them, 77 faults occurred in medium-voltage switchgear, accounting for 28.9%—significantly higher than faults in other equipment. Statistical analysis shows that major fault types include: protection device s

Due to the long service life and severe aging of the equipment, the switches in the 6kV working section of Unit 6 of a certain power plant have potential safety hazards such as deformed locating pins, abnormal closing positions of the earthing switches, and malfunctions of the protection devices. These hazards have threatened the stable operation of the unit, making the transformation extremely urgent. Meanwhile, considering the recent cases of electric shock casualties involving medium-voltage

As a professional engaged in power system operations, I recognize that medium-voltage (MV) switchgear plays a pivotal role in power distribution, metering, and protection. Ensuring its operational safety and reliability is critical—any malfunction can severely disrupt the entire power system. To enhance reliability, we must prioritize design-level optimizations, enabling MV switchgear to fulfill its functions and safeguard grid stability.1. Definition of Medium-Voltage SwitchgearIn my prac

Insulation Performance：Air - insulated Circuit Breakers: They use air as the insulating medium. The insulation performance of air is relatively limited. In harsh environments such as high humidity and high pollution, the insulation performance is easily affected. They are suitable for medium - and low - voltage applications.Gas - insulated Circuit Breakers: Commonly, gases such as sulfur hexafluoride (SF6) are used. They have excellent insulation performance and can withstand higher voltages, ma

High-Voltage Conductor SpikesDuring the installation of high-voltage conductors, accidental bumps or scratches can cause metallic spikes on the conductor surface, as shown in Figure 1. Under power-frequency voltage, the ionization effect of high electric fields at the spike tips generates charged particles, which may suppress partial discharge (PD) or breakdown. However, under impulse voltage, the ionization process induced by the strong electric field does not have sufficient time to develop, m

Gas - insulated metal - enclosed switchgear (GIS) is a switching device composed of switching appliances such as circuit breakers (GCB), disconnectors (DS), earthing switches (ES), as well as units like voltage transformers, current transformers, surge arresters, and enclosed busbars. High - potential components are all placed inside a grounded enclosed metal shell, which is filled with SF₆ gas with excellent insulating and arc - extinguishing properties as the insulating medium. GIS features a

Analysis of GIS Equipment Installation ProcessPre - installation Preparations for GIS EquipmentFirst, use a crane to lift the equipment to the entrance. Then, insert a crowbar into the groove of the channel steel to move the equipment along the channel steel into the room. It can be received by a roller or a forklift for transfer. Before the equipment installation after the transfer is completed, sufficient preliminary preparations are required. Firstly, the equipment needs to be comprehensively

Importance of Long - distance Loop Resistance Testing for GISInspecting the Installation Quality of Electrical Equipment and the Integrity of the LoopIn the handover tests of GIS, loop resistance testing plays a crucial role. This test is not only a key step in evaluating the installation quality of electrical equipment but also an important means to ensure the integrity and safety of the entire loop. Through precise testing and analysis, potential problems can be promptly identified and resolve

The 500 kV GIS system of Lianghekou Hydropower Station is composed of circuit breakers, disconnectors, earthing switches, bus - pipes, current transformers (CTs), potential transformers (PTs), arresters, etc. It has a total of 12 circuit - breaker bays, adopting an indoor structure and a "Z" - shaped layout, with 6 incoming lines and 2 outgoing lines, and using 4/3 and 3/2 wiring schemes. To meet the access of the Kela Photovoltaic project in the first - phase hydro - photovoltaic complementary

CIS (Gas Insulated Switchgear) refers to a gas - insulated enclosed switchgear assembly. A busbar is a common pathway to which multiple devices are connected in parallel. In a CIS, the internal space of the busbar is relatively small, yet it operates under high voltage and current. Local discharge, if it occurs, can severely affect the inter - phase insulation and pose a significant threat to the safe and stable operation of the equipment. This article presents an analysis and solution of a loca