Gas-insulated substation components (GIS) consist of several key parts that work together to facilitate the transmission and distribution of electrical power. Here are the main components typically found in a gas-insulated substation:
Circuit Breakers:
GIS circuit breakers are used to interrupt or isolate the flow of electrical current in the event of a fault or during switching operations. They use SF6 gas as the arc-quenching and insulating medium. Circuit breakers in GIS can be of various types, such as spring-operated, hydraulic-operated, or pneumatic-operated.
Disconnectors (Isolators):
Disconnectors, also known as isolators, used for the isolation of electrical equipment and sections of the substation. They provide mechanical isolation for maintenance and safety purposes. Disconnectors in GIS designed to handle the high voltage levels and equipped with SF6 gas as insulation.
Current Transformers (CTs):
Current transformers used to measure and step down the current flowing through the conductors. They provide accurate current readings for monitoring, metering, and protection purposes. CTs in GIS typically installed within the busbars or circuit breaker compartments.
Voltage Transformers (VTs):
Voltage transformers, also known as potential transformers (PTs), are used to step down high voltages to lower levels suitable for metering and protection purposes. They provide accurate voltage measurements for monitoring and control. VTs in GIS usually installed within the busbars or circuit breaker compartments.
Busbars:
Busbars are conductors that carry electrical power within the substation. They provide a path for the flow of current between different components, such as circuit breakers, disconnectors, transformers, and other equipment. Busbars in GIS typically made of copper or aluminum and enclosed within the GIS modules.
Transformers:
Transformers used to step up or step down voltage levels for transmission or distribution purposes. In GIS, transformers commonly used to step down high voltages to lower levels suitable for distribution. They usually oil-immersed or dry-type transformers, depending on the specific application.
Surge Arresters:
Surge arresters, known as lightning arresters, used to protect the GIS equipment from high voltage surges caused by lightning or switching operations. They divert the excess voltage to the ground, preventing damage to the sensitive components.
Control and Protection Systems:
GIS substations equipped with control and protection systems that monitor and control the operation of various components. These systems include protection relays, control panels, human-machine interfaces (HMIs), and communication equipment for remote operation and monitoring.