What is Switchgear? Definition, Features & Types
Switchgear is the circuits that are used for controlling, protecting and on/off switching of the electrical circuit in the large power system. These days the requirement of electric power has increased much, so to get the continuous supply of electrical power, Power systems must be protected from major faults and provide protection to machinery and devices. In large power systems devices such as generators and motors are switched on and off so many times so this is attained easily by the help of switch gears without any damage. The MCB, switches, isolator, protective relays, fuses, circuit breaker, current, and potential transformer, indicating instrument, control panels and lightning arresters are examples of the switchgear devices.
Fig. Switchgear panel
Essential features of switchgear devices:
• Reliable Operation – switchgear is used in a power system for reliable operation in case fault occurs in the system. Switchgear must isolate the faulty part of the circuit from the remainder circuitry.
• Discrimination Ability – if any fault occurs in a power system then the switchgear circuit must be able to discriminate between the faulty section and the good section.
• Fast operation – In case of fault occurs in a power system then switchgear must be able to act quickly so that no harm occurs to overall circuitry.
• Provision for manual control – switchgear must have manual control capability in case of any electrical or electronic circuit failure.
How it works
Switchgear systems are directly connected to the supply system. It is placed on both the sides(high and low voltage side) of the power transformer. When any fault occurs in the power system, a heavy amount of current flow through the equipment which causes the damage of equipment, and the service also gets interrupted. So to protect the lines, generators, transformers and other electrical equipment from damage, automatic protective devices or switchgear devices are used. The automatic protective switchgear mostly consists of the relay and circuit breaker. When the fault occurs in any part of the system, the relay of that part comes into action and closes the trip circuit of the breaker which detaches the faulty section. The healthy section continuously supplies loads as usual, and thus there is no destruction of equipment and nor complete interruption of supply.
Low voltage switchgear
Electrical switchgear rated up to 1KV rating comes under low voltage switchgear. Low voltage switchgear includes offloading electrical isolators, low voltage circuit breakers, switches, HRC fuses, earth leakage circuit breakers, miniature circuit breakers (MCB) and molded case circuit breakers (MCCB) are all the accessories required to protect the LV system. Low Voltage switchgear mostly used in is LV distribution board. A low-voltage circuitry
Fig.Low voltage switchgear
Medium-voltage circuit breakers
The reason why they are named so is that extremely low voltage environments are not suitable for them to work properly; neither a very high voltage helps them perform their action accurately. So a medium voltage level is required for these circuits to operate on.
Fig. Medium voltage circuit breakers
These devices are rated between 1 and 72 kV. Medium voltage circuit breakers are assembled into metal-enclosed switchgear line UPS for indoor usage, or these can be an individual component installed outdoors in a substation. These are operated by current circuit breakers sensing protective relays operated through current transformers. The characteristics of Medium Voltage breakers are given by international standards such as IEC 62271. Medium-voltage circuit breakers are always used to separate current sensors and protective relays, instead of trusting on built-in thermal or magnetic overcurrent sensors.
High voltage circuit breakers
Electrical power transmission networks are controlled and protected by high-voltage breakers. The definition of high voltage differs, but in power transmission work it is usually thought to be 72.5 kV or higher, according to the latest description by the International Electrotechnical Commission (IEC). High-voltage breakers are always solenoid-operated, with current sensing protective relays operated over current transformers. In substations the protective relay scheme can be complex, protecting equipment and buses from various types of overload or ground/earth fault. High-voltage circuit breakers used in transmission systems, possibly organized to allow a single pole of a three-phase line to trip, instead of tripping all the three poles; for some kind of faults, this improves the system stability and availability.
Fig.High voltage circuit breakers
Gas Insulated Switchgear
Gas protected switchgear gatherings are picking up significance as a result of the intrinsic favorable position of smallness. Dormant, non-combustible SF6 gives three-time more grounded protection than air; consequently utilizing it as a protection medium takes into consideration the intense decrease of size and space for high voltage switchgear congregations. Our GV3 arrangement gas protected switchgear has a fixed tank structure reasonable for dirtied conditions, also it requires the least upkeep. GV3 arrangement switchboards are anything but difficult to introduce and completely extensible at the site.
It is especially required to set up an electrical substation at load focus. Since setting up a substation at load focus is very conservative and productive in numerous viewpoints. As it lessens the length of feeders and because of short length feeders, the nature of voltage guideline improves. Yet, the fundamental deterrent of building up a substation at load focus is space. By and large primary burden focal point of wherever is arranged at the exceptionally blocked spot where adequate land for building up customary electrical substation is not really accessible.
This issue can be tackled by utilizing gas protected switchgear innovation. Right now switchgear, all the vital parts of switchgear can be collected in restricted space. GIS is a sort of metal encased switchgear.
These are introduced at exchanging stations and substations at hand-off focuses for sending power delivered at power plants to customers, (for example, homes and production lines).
Hitachi additionally offers skill as a full lineup of items that bolsters UHV (ultra-high voltage), from 110 kV up to 1,000 kV.
Hitachi participated in the planet’s first business venture for a UHV pilot transmission framework in China, conveying a 1,100 kV GIS (twofold break).
Gas protected segments of substation are for the most part,
Electrical transport bars.
Electrical isolators or disconnectors.
Flood arrestors or lightning arresters.
Single and twofold busbar framework
30% space-sparing over AIS
Plug in kind of link terminations
Brief timeframe circuit rating up to 40 kA for 1 sec.
IEC 62271-200, IEC 62271 – 100, IEC 62271- – 102
Deficiency Making Earthing through VCB up to 100kA
Switchgear Power Systems
Switchgear which is otherwise called a switchgear power framework is shaped by the blend of wires, detach switches and circuit breakers. It is utilized to segregate, disengage and secure diverse electrical gear in that particular force framework. It is additionally utilized so as to slice all wellsprings of power to certain gear so as to permit personals to chip away at it without the danger of being shocked.
At Switchgear Power Systems, we specialist and produce great, custom electrical force appropriation gear with speed, adaptability, and serious estimating. We have confidence in making enduring an incentive over our product offerings, all through our organization, and inside our client connections.
We answer to the extraordinary needs of every client through adaptability and custom design. We endeavor to keep up serious estimating, remarkable quality, and unmatched speed to advertise reaction and conveyance, serving the worldwide electrical commercial center.
At Switchgear Power Systems, we design and produce top-notch, custom electrical force dispersion gear with speed, adaptability, and serious estimating.
We have faith in making enduring an incentive over our product offerings, all through our organization, and inside our client connections.
We answer to the extraordinary needs of every client through adaptability and especially craft.
We endeavor to keep up serious valuing, uncommon quality, and unrivaled speed to advertise reaction and conveyance, serving the worldwide electrical commercial center.
It is likewise used to clear any issues downstream. It is additionally used to switch structures naturally from utilizing the business electric capacity to generator electric force when there is a type of force blackout. This makes the switchgear an exceptionally crucial part that is basic in any force supply framework.