In GIS(GasInsulatedSubstation), most electrical equipment is directly or indirectly sealed in a pipe tree composed of metal pipes and sleeves, and no switches, lines and terminals can be seen from the outside. SF6 gas is used as insulation medium in the pipeline tree, and all high-voltage electrical components are sealed in the grounded metal cylinder.
Extended data:
Matters needing attention in GIS substation:
1, the flexibility of capacity expansion and troubleshooting should be fully considered in the main wiring design and gas chamber division.
When designing GIS equipment, it is generally divided into several sections, with complete functions such as power supply and transmission (control, measurement, protection, etc. ) Press the main wiring. Each compartment can be subdivided into several air chambers or compartments. After being divided into air compartments, it can also prevent the accident scope from expanding, which is convenient for individual maintenance and equipment replacement of each component.
2, indoor ventilation device design should prevent suffocation accidents caused by gas leakage.
The density of gas in GIS substation is about 5 times that of air. When leaking, it will be deposited in low-lying places such as cable trench. If the concentration is too high, people will choke. In the indoor sulfur hexafluoride equipment place, sulfur hexafluoride concentration meter and oxygen meter should be equipped, and the control switch of GIS indoor ventilation facilities should be designed outside GIS.
3. The quick earthing switch shall be designed and configured.
Different from conventional equipment, GIS needs to be equipped with two different grounding switches: maintenance grounding switch and quick grounding switch. The former is arranged next to the disconnectors on both sides of the circuit breaker, which only plays the role of grounding on both sides when the circuit breaker is overhauled; The quick earthing switch is installed on the line side of the outlet disconnector of the outlet circuit, which has two functions:
Turn on and off capacitive current generated by electrostatic induction and inductive current generated by electromagnetic induction of parallel overhead lines;
When the basin insulator in the cabinet creeps up and develops into arc in the cabinet, the quick grounding switch can quickly ground the main circuit, and use the circuit breaker to cut off the fault current to protect the cabinet of GIS from burning through.
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