what is gis device

gis equipment refers to "gas insulated metal enclosed switchgear", which consists of circuit breakers, isolating switches, grounding switches, mutual inductors, arresters, busbars, connectors and outlet terminals. GIS is widely used not only in the high-voltage and ultra-high-voltage fields, but also in the ultra-high voltage field. Compared with conventional open substations, GIS has the advantages of compact structure, small footprint, high reliability, flexible configuration, convenient installation, strong safety, strong environmental adaptability, and small maintenance workload.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

GIS (GAS insulated SWITCHGEAR) is the English abbreviation of gas insulated fully enclosed combination electrical appliance. It is a gas insulated metal enclosed switchgear. GIS consists of circuit breakers, isolating switches, grounding switches, transformers, lightning arresters, busbars, connectors and outlet terminals. These equipment or components are all enclosed in a metal grounded shell, which is filled with a certain pressure of SF6 insulating gas. , so it is also called SF6 fully enclosed combined electrical appliances.

Introduction

GIS equipment has been widely used around the world since its practical use in the 1960s. GIS is widely used not only in the high-voltage and ultra-high-voltage fields, but also in the ultra-high voltage field. Compared with conventional open substations, the advantages of GIS are compact structure, small footprint, high reliability, flexible configuration, easy installation, strong safety, strong environmental adaptability, small maintenance workload, and the repair of its main components The interval is not less than 20 years.

There are three types of high-voltage power distribution devices: the first is air-insulated conventional power distribution device, referred to as AIS. The busbar is exposed and in direct contact with the air, and the circuit breaker can be of porcelain column type or tank type. Gezhouba Power Plant adopts this type. The second type is hybrid power distribution device, referred to as H-GIS. The busbar is open type, and the others are sulfur hexafluoride gas insulated switchgear. The third type is sulfur hexafluoride gas insulated fully enclosed power distribution device. Its full English name is GAS—INSTULATED SWITCHGEAR, or GIS for short.

GIS is a high-voltage electrical equipment with high operational reliability, low maintenance workload, and long maintenance cycle. Its failure rate is only 20% to 40% of conventional equipment. However, GIS also has its inherent shortcomings. Due to SF6 gas Leakage, infiltration of external moisture, the presence of conductive impurities, aging of insulators and other factors may cause internal flashover failure of GIS. The fully sealed structure of GIS makes it difficult to locate and repair faults. The maintenance work is complicated. The average power outage maintenance time after an accident is longer than that of conventional equipment. The power outage range is large and often involves many non-faulty components.

The internal flashover failure of GIS equipment usually occurs within one year after installation or overhaul and it is put into operation. According to statistics, the failure rate of equipment operation in the first year is 0.53 times/interval, and in the second year It dropped to 0.06 times/interval and then stabilized. According to operating experience, the failure rate of isolating switches and basin insulators is the highest, 30% and 26.6% respectively; the busbar failure rate is 15%; the voltage transformer failure rate is 11.66%; the circuit breaker failure rate is 10%; other component failures The rate is 6.74%. Therefore, in the first year of operation, operators should strengthen daily inspections, especially inspections of isolation switches. During inspections, they should pay attention to changes in SF6 gas pressure and whether there are any abnormal sounds (changes in sound quality characteristics, continuous time difference), heat and abnormal odor, rust, etc. If there is an abnormality in GIS, the suspected equipment must be detected in time.

Development

The main foreign GIS manufacturers include ABB, Toshiba, Mitsubishi, Hitachi, Siemens, Alstom, etc. The domestic manufacturers include Xikai, Shengao, Pinggao, Taikai, etc. Through technology introduction, digestion and absorption, China has mastered the design and manufacturing technology of 500 kV GIS. The independently developed 1000 kV GIS (including the core components arc extinguishing chamber and operating mechanism) will be completely designed and manufactured independently.

GIS manufacturing technology continues to progress and develop. For more than 40 years, various GIS manufacturers have focused on the two main goals of improving economy and reliability, in terms of component structure, combination form, manufacturing process, and use and maintenance. A lot of research and development have been carried out. With the successful development of large-capacity single-voltage SF6 circuit breakers and the application of zinc oxide arresters, the technical performance and parameters of GIS have surpassed conventional switchgear, and the structure has been greatly simplified and the reliability has been greatly improved, creating opportunities for further miniaturization of GIS. Very favorable conditions.

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