Surge Arrester and Control System for GIS

Surge Arrester: Zinc oxide surge arrester elements suitable for immersion in SF6 are supported by an insulating cylinder inside a GIS enclosure section to make a surge arrester for overvoltage. Because the GIS conductors are inside in a grounded metal enclosure, the only way for lightning impulse voltages to enter is through the connections of the GIS to the rest of the electrical system. Cable and direct transformer connections are not subject to lightning strikes, so only at SF6-to-air bushing Read More …

Bus and Air, Cable, Direct Transformer Connection For GIS

Bus: To connect GIS modules that are not directly connected to each other, an SF6 bus consisting of an inner conductor and outer enclosure is used. Support insulators, sliding electrical contacts, and flanged enclosure joints are usually the same as for the GIS modules. Air Connection: SF6-to-air bushings are made by attaching a hollow insulating cylinder to a flange on the end of a GIS enclosure. The insulating cylinder contains pressurized SF6 on the inside and is suitable for exposure Read More …

Circuit Breaker, Current And Voltage Transformers, Disconnect And Ground Switches For GIS

Circuit Breaker: GIS uses essentially the same dead tank SF6 puffer circuit breakers used in AIS. Instead of SF6 -to-air as connections into the substation as a whole, the nozzles on the circuit breaker enclosure are directly connected to the adjacent GIS module. Current Transformers: CTs are inductive ring types installed either inside the GIS enclosure or outside the GIS enclosure. The GIS conductor is the single turn primary for the CT. CTs inside the enclosure must be shielded from Read More …

Construction and Service Life of GIS Substation

GIS is assembled of standard equipment modules (circuit breaker, current transformers, voltage transformers, disconnect and ground switches, interconnecting bus, surge arresters, and connections to the rest of the electric power system) to match the electrical one-line diagram of the substation. A cross-section view of a 242-kV GIS shows the construction and typical dimensions. Construction of GIS Substation: The modules are joined using bolted flanges with an “O” ring seal system for the enclosure and a sliding plug-in contact for the Read More …

GIS – Gas Insulated Substations

A gas-insulated substation (GIS) uses a superior dielectric gas, SF6, at moderate pressure for phase-to-phase and phase-to ground insulation. The high voltage conductors, circuit breaker interrupters, switches, current transformers, and voltage transformers are in SF6 gas inside grounded metal enclosures. The atmospheric air insulation used in a conventional, air-insulated substation (AIS) requires meters of air insulation to do what SF6 can do in centimeters. GIS can therefore be smaller than AIS by up to a factor of 10. A GIS Read More …