There are mainly two types of circuit breakers used for any substations. Circuit Breaker The circuit breakers are used to break the circuit if any fault occurs in any of the instrument.
In its most basic form the device consists of three parts: Proper operation of over-current protection relays requires that current transformers provide a predictable transformation ratio even during a short circuit. There may be double line in the bus so that if any fault occurs in the one the other can Substation and equipment surge protection engineering essay have the current and the supply will not stop.
The care should be taken to protect the fins of radiators while unloading and storage to avoid further oil leakages. This is so that one can work at a time and the other works only if the first is having any fault. The main use of this transformer is to measure the voltage through the bus.
Protective Relaying Protective relays are used to detect defective lines or apparatus and to initiate the operation of circuit interrupting devices to isolate the defective equipment. The gas is put inside the circuit breaker by force i. Substations transform voltage from high to low, or the reverse, or perform any of several other important functions.
All protective, indicating and control elements are mounted on the front panel for ease of operation and control. The use of SF6 circuit breaker is mainly in the substations which are having high input kv input, say above kv and more. CVTs are typically single-phase devices used for measuring voltages in excess of one hundred kilovolts where the use of voltage transformers would be uneconomical.
Even the instruments are very costly, so to prevent any damage lightening arrestors are used. The spring type is used for step down side of kv to 33kv also in 33kv to 11kv and so on. Thus an isolator is used after the bus also for protection.
Oil is received in sealed oil barrels. Test methodologies and data supporting these guidelines are also presented. This is only done automatically by the circuit breaker.
This in essence means that the voltage transformer has to be as close as possible to the ideal transformer. In practice the first capacitor, C1, is often replaced by a stack of capacitors connected in series.
The isolator isolates the extra voltage to the ground and thus any extra voltage cannot enter the line. These may be hydro, thermal, atomic etc. Bus bars may be enclosed in a metal housing, in the form of bus duct or bus way, segregated-phase bus, or isolated-phase bus.
C V T A capacitor voltage transformer CVT is a transformer used in power systems to step-down extra high voltage signals and provide low voltage signals either for measurement or to operate a protective relay. The function of this trap is that it traps the unwanted waves.
Control and Relay Panel The control and relay panel is of cubical construction suitable for floor mounting. For cable entry provision is made both from top and bottom.
Bus bars are protected from accidental contact either by a metal enclosure or by elevation out of normal reach. The spring type of circuit breakers is used for small kv stations. Provision is made for terminating incoming cables at the bottom of the panels by providing separate line-up terminal blocks.
It is connected to the main incoming feeder so that it can trap the waves which may be dangerous to the instruments here in the substation.
A hollow section has higher stiffness than a solid rod of equivalent current carrying capacity, which allows a greater span between bus bar supports in outdoor switchyards.
The transformers are received on site with loose accessories hence the materials should be checked as per bills of materials.
There being more of fragile material, care should be taken while handling them. Isolator The use of this isolator is to protect the transformer and the other instrument in the line.
In case of a KV or more KV line station auto transformers are used. During their live time protection relays operate seldom or never.
These are further classified into two types which are discussed below.Siemens Energy Sector t Power Engineering Guide t Edition 6 Protection, Substation Automation, Power Quality and Measurement Protection Systems Introduction Siemens is one of the world’s leading suppliers of protection.
Introduction Substation Protection system Power System-Protection is a branch of electrical power engineering that deals with the protection of electrical power systems from faults through the isolation of faulty parts.
Protecting Distribution Substation Assets – Modern Protection Schemes With Microprocessor-Based Relays Protecting Distribution Substation Assets – sensitivity and personnel and equipment protection when a feeder relay has failed.
Substation equipment and its Function This high voltage is very dangerous to the instruments used in the substation. Even the instruments are very costly, so to prevent any damage lightening arrestors are used.
The lightening arrestors do not let the lightening to fall on the station. Surge Protection 30 March at Substation safety awareness has been gaining prominence, have a read through this in-depth look into several aspects of substation safety, primarily focusing on personal protective equipment (PPE) essentials, risks, danger.
The successful candidate will be responsible for the relay protection and control engineering associated with high voltage substation and transmission projects.Download