Gis Substation 12256y

Beskudnikovo GIS substation, Russia, 550 kV, 63 kA, 4000 A One of today’s main challenges in power transmission is to bring high voltage levels right into the centers of urban areas. This requires switchgear that features a small footprint, the utmost reliability, and very low noise and electromagnetic emissions. Siemens gas-insulated switchgear (GIS) are ideally suited to meet these requirements. Thanks to their compact design, Siemens GIS need very little space. With more than 45 years of GIS manufacturing experience, the largest installed base of GIS, and a long track record of superior turnkey supply, Siemens is able to provide one-stop GIS substations that also comprise all secondary technology, procurement, installation and commissioning on-site, and operational training. The benefits of Siemens gas-insulated switchgear:   

High reliability, availability, gastightness, and high degree of safety Economic efficiency, long service life, little maintenance requirements, and low life cycle costs Compact design, good accessibility and ergonomics, high degree of adaptability to individual requirements APPLICATION

Siemens supplies high-voltage GIS for rated voltages from 72.5 kV up to 550 kV. The comprehensive product range provides ideal solutions for all indoor and outdoor switching applications up to the highest performance rates. More than 34,500 GIS bays are currently in operation in GIS substations all over the world. Siemens particularly focuses on sophisticated switchgear solutions for installation in challenging locations. High-voltage substations are power grid nodes at which power from different generating sources is pooled, distributed, transformed, and delivered to the load points. Reliability is of the utmost importance and a clear focus in the design and layout of Siemens GIS substation designs and layouts. Typical busbar schemes are the double busbar (2 BB) and the »one circuit-breaker-and-a-half« scheme (1.5 cb). 2 BB The double busbar system ensures flexibility and reliability in the operation of the substation. That’s why the system is used in many network nodes of the power system, especially in distribution and transformer substations. It is possible to control the power flow by using the busbars independently and by switching a feeder from one busbar to the other.

Siemens GIS substation with double-busbar scheme (2 BB) 1.5 cb The »one circuit-breaker-and-a-half« scheme is a compromise between the 2 BB and the double circuit breaker scheme. This scheme improves the reliability and flexibility of the substation because there is no disruption in the power supply of the feeders even in case of a loss of a complete busbar.

Siemens GIS substation with »One-breaker-and-a-half« scheme (1.5 cb)

GIS OR Gas Insulator Switchgear It is very much required to establish an electrical substation at load center. Since, establishing a substation at load center is quite economical and profitable in many aspects. As it reduces length of feeders and due to short length feeders, the quality of voltage regulation improves. But the main obstruction of establishing a substation at load center is space. Generally main load center of any place is situated at very congested place where, sufficient land for establishing conventional electrical substation is very hardly available.

This problem can be solved by using gas insulated switchgear technology. In this type of switchgear, all the necessary components of switchgear can be assembled in very limited space. GIS is a kind of metal enclosed switchgear. That means, all the equipments of the electrical switchgear are enclosed by gas tight metal enclosure and SF6 gas is used as insulation between live parts of the equipments and earthed metal enclosure. This type of switchgear, means, and gas insulated switchgear is available from 12 KV systems to 800 KV system. For establishing electrical substation in very limited place this type of SF6 insulated electrical switchgear plays the major role.

Gas insulated components of substation are generally, 1. 2. 3. 4. 5. 6. 7.

Electrical bus bars. Electrical isolators or disconnectors. Circuit breakers. Current transformers. Voltage transformers. Earth switches. Surge arrestors or lightning arresters.

The substation, assembled by gas insulated switchgear, is popularly known as gas insulated metal enclosed substation (GIMES). GIMES technology is not very recent invention, it is successfully running for over thirty years. In gas insulated medium voltage switchgear, vacuum technology is used as interrupting purpose and SF6 gas is used as insulation material. Although for both interruption and insulation, SF6 gas is used in many medium voltage GIS system. But for such equipments rated SF6 gas pressures are different for interruption and insulation. SF6 gas pressure for insulating purpose is generally kept below 2.5 bar whereas SF6 gas pressure

for interrupting purpose is ranged from 5 bar to 7 bar. As vacuum technology is not available for high voltage, so for GIS or gas insulated switchgear system above 72.5 KV, only SF6 is used both for interruption medium and insulation. There are different types of gas insulated metal enclosed switchgears available depending upon their constructional feature.

Isolated Phase GIS In this configuration, each phase of the bay is assembled separately. That is, for each phase, one pole of circuit breaker, a single pole of electrical isolator, one phase assembly of current transformer are assembled together. This type of GIS requires larger bay width as compared to other gas insulated switchgear system.

Integrated 3 Phase GIS In this configuration all three phase of circuit breaker, 3 phases of disconnectors and three phase current transformer are encapsulated in an individual metal enclosure. The arrangement forms a three phase module for the element. The size of this type of module is one third of the isolated phase GIS.

Hybrid GIS System It is a suitable combination of isolated phase and three phase common elements. Here three phase common bus bar system simplifies the connection from the bus bar. The isolated phase equipment prevents phase to phase faults. This is an optimum design considering, both facts in mind, i.e. space requirement and maintenance facility.

Compact GIS In this GIS or gas insulated switchgear system than one functional element are encapsulate in a single metal enclosure. For example, in some design, a three phase circuit breaker, current transformer, earth switches, even other feeder elements are covered together in a single metal capsule.

Highly Integrated System This design was introduced in the year of 2000, where, total substation equipments are encapsulated together in single enclosure housing. This single unit gas insulated substation has gained appreciation as it is a complete solution for an outdoor substation, in a single unit. As such, only equipment (HIS) is substitute of a total outdoor switch yard.