When the SF6 circuit breaker and other high voltage electrical components (except the main transformer) are installed in a metal shell filled with SF6 gas with a certain pressure according to the required electrical main wiring, a set of substation equipment is called gas insulated switchgear or closed combination. Electrical appliances, referred to as GIS.
Composition: Gas-insulated metal-enclosed switchgear, consisting of electrical components such as circuit breakers, isolating switches, grounding switches, transformers, arresters, bus bars, connecting pipes and transition elements (SF6 cable heads, SF6 bushings), and the metal cylinder is the shell. The conductive rods and insulating parts are enclosed inside and filled with a certain pressure of SF6 gas.
Features: 1. Small footprint; 2. Components in the SF6 sealed body, not affected by the external environment, high operational reliability, long maintenance cycle; 3. Small operation and maintenance workload; 4. The price is more expensive, and the use of SF6 gas Many, inconvenient maintenance.
Structure
Overall structure: GIS is generally composed of units that realize various functions, called intervals, which mainly include incoming (outgoing) line interval, mother denominator (parent denominator) interval, metering protection interval (pressure change), etc. The gas system of GIS can be divided into several gas chambers. Generally, circuit breakers have high pressure in the air chamber, and current transformers are installed in the air chamber; the main bus, voltage transformer, and arrester are separate air chambers, and other components are determined according to the project. The gas pressure of each gas chamber is detected by the corresponding density controller.