Introduction to GIS (Gas Insulated Switchgear)equipment

What is GIS equipment

GIS is the English abbreviation of Gas Insulated Switchgear. It is generally translated as gas insulated fully enclosed combined electrical appliances. SF6 gas is usually used as the insulating medium, including circuit breakers (CB), isolating switches (DS), grounding switches (ES, FES), busbars ( BUS), current transformer (CT), voltage transformer (VT), lightning arrester (LA) and other high-voltage components. At present, GIS equipment products cover the voltage level range of 72.5 kV to 1200 kV.

Figure 1 Typical structural composition of GIS equipment

Characteristics of GIS equipment

Since SF6 gas has excellent insulation properties, arc extinguishing properties and stability, GIS equipment has the advantages of small footprint, strong arc extinguishing capability, and high reliability. However, the insulation capability of SF6 gas is greatly affected by the uniformity of the electric field. When GIS Insulation abnormalities are likely to occur when sharp points or foreign objects are present inside.

GIS equipment adopts a fully enclosed structure, which brings the advantages of internal components not being disturbed by the environment, long maintenance cycle, less maintenance workload, and low electromagnetic interference. At the same time, it also has problems such as complicated single maintenance work and relatively poor detection methods. When the closed structure is eroded and damaged by the external environment, it will further cause a series of problems such as water intrusion and air leakage.

Figure 2 GIS equipment adopts a fully enclosed structure

Internal structure of GIS equipment

The GIS conductive circuit is composed of several components. According to the working method, it can generally be divided into: fixed contact (electrical contact fastened with fasteners such as screws is called fixed contact. Fixed contact has no relative movement during the working process. Such as the connection between the contact and the basin, etc.), contact Contact (electrical contact that can be separated during the working process is also called separable contact), sliding and rolling contact (during the working process, the contacts can slide or roll with each other, but the electrical contact that cannot be separated is called sliding and rolling contact .The middle contact of the switching appliance uses this kind of electrical contact).

Figure 3 Contacts of GIS equipment

GIS substation

No.1

GIS concept

Sulfur hexafluoride enclosed combined electrical appliances, internationally known as “Gas Insulated Switchgear” ( GIS for short), include primary equipment in a substation other than transformers, including circuit breakers, isolating switches, grounding switches, voltage Transformers, current transformers, arresters, busbars, cable terminals, incoming and outgoing line bushings, etc. are organically combined into a whole through optimized design.

In addition to GIS, there is also HGIS, which is designed for harsher environments. Compared with GIS, there are fewer busbars, busbar voltage transformers, arresters and other equipment, especially busbars, so it is more flexible to use.

No.2

GIS features

(1) Miniaturization: Using SF6 gas with excellent insulation properties as insulation and arc extinguishing medium, the size of the substation can be greatly reduced.

(2) High reliability: All live parts are sealed in inert SF6 gas, which improves the reliability of the substation.

(3) Good safety: The live parts are sealed in a grounded metal shell, so there is no risk of electric shock. SF6 gas is a non-combustible gas, so there is no fire hazard.

(4) Eliminate adverse effects on the outside: The live parts are enclosed with a metal shell to shield electromagnetic and static electricity, with low noise and strong anti-radio interference ability.

(5) Short installation cycle: The realization of miniaturization allows the complete machine to be assembled and tested in the factory and then delivered to the site in the form of units or intervals. Therefore, the on-site installation period can be shortened and reliability can be improved.

(6) Easy maintenance and short maintenance time: Because of its reasonable structural layout and advanced arc extinguishing system, the service life of the product is greatly improved, so the maintenance cycle is long and the maintenance workload is small. Moreover, due to its miniaturization and low height from the ground, it is easy to use daily. Easy to maintain.

No.3

GIS classification

GIS can be divided into two types: outdoor type and indoor type according to the installation location.

outdoor

Indoor

GIS can generally be divided into two forms: single-phase single-cylinder type and three-phase common-cylinder type. The 110kV voltage level and busbar can be made into a three-phase common cylinder type, and the 220kV and above adopt a single-phase single-cylinder type.

Single phase common cylinder type

Three-phase common cylinder type

No.4

Basic principles of operation

(1) Under normal circumstances, GIS equipment circuit breakers and isolating switches are mainly operated remotely. The “remote/local” switch of circuit breakers and isolating switches switches to the “remote” position.

(2) The GIS equipment grounding knife gate can only be operated on site. During operation, turn the “remote/local” switch of the partition knife /ground knife to “local”.

(3) Under any circumstances, only program operations can be performed. The ” interlock release switch” on the HSBC cabinet must be in the ” interlock ” position, and its unlocking key is sealed together with the microcomputer anti-mistake locking key and used according to the same regulations.

No.5

Basic requirements for operation

(1) Indoor SF6 equipment rooms frequently entered by operating personnel: Ventilate at least once per shift for 15 minutes. The air exchange volume should be greater than 3-5 times the air volume. The exhaust outlet should be installed in the lower part of the room; operating personnel do not frequently enter. Access equipment areas: Ventilate for 15 minutes before entering.

(2) Under normal circumstances, the induced voltage on the shell and structure of the GIS during operation should not exceed 36V for parts that are easily accessible to operation and maintenance personnel.

Temperature rise: The parts that are easily accessible to operators should not exceed 30K; the parts that are easily accessible to operators but not accessible during operation should not exceed 40K; the individual parts that are not easily accessible to operators should not exceed 65K.

(3) SF6 switching equipment is inspected and inspected at least once a day, and unmanned substations are inspected in accordance with regulations. During the inspection, we mainly conduct visual inspections to see if there are any abnormalities in the equipment and keep records.

#CompositeInsulator#TransmissionLine#linepostinsulator#PinTypeInsulator #CrossArmInsulator#RubberInsulator#ElectricProduction #InsulationProduction #PowerStationProductions#lightingarrester #surgearrester #dropoutfusecutout #dropoutfuse #outdoorisolatingswitch #highvoltagefuse #polymerinsulator #porcelaininsulator #glassinsulator #highvoltagevacuumcircuitbreaker #vacuumcircuitbreaker #pininsulator #postinsulator #crossarminsulator#electricpower#МФЭС#VDNKh#ВДНХ#МЕЖДУНАРОДНЫЙФОРУМ#ЭЛЕКТРИЧЕСКИЕСЕТИ

#sf6 #loadbreakswitch #loadswitch #35kv #ringmainunit #RMU #electrical #switchgear #transformer #manufacturing #design #protection #supply #power #threeworkstations #earth #electricalequipment