Switchgear must have provision for manual control. The ground is applied close to the source of potential fault, but is also physically close to the rest of the switchgear undergoing maintenance and … Using the vacuum bottles and contacts from a standard 38kV breaker to form the grounding breaker creates a very robust, fault tolerant system. Low Voltage Switchgear. They include most of the substation equipment such as minimum oil circuit breakers, bulk oil circuit breakers, air magnetic, SF6 gas-insulated, vacuum, and gas-insulated switchgear. The main components, including circuit breakers, disconnectors, earthing switches, and operating mechanisms, are designed for a normal operation of more than 30 years. Today, the circuit breaker switchgear factory will introduce the main components of the high and low voltage switchgear. In an electric power system, switchgear is composed of electrical disconnect switches, fuses or circuit breakers used to control, protect and isolate electrical equipment. 5 . The main reason for using gas, air or vacuum is to quench the arc caused at the time of pulling contacts apart. By admin As can be seen, switchgear is highly complex and needs to be given the fact that switchgear and protection must handle voltages that go as high as 350KV and currents in thousands of amperes. switchgear dealers in ahmedabad, switchgear types, what is switchgear. Ceiling Fan Vs Standing Fan: Which One To Choose From? In addition, it has to perform the function of clearing the fault current for which sensing devices like current transformers, potential transformers and various types of relays, depending on the application, are employed. The primary object of this practice is the definite localization and restriction of any fault to its place of origin. Mainly into trading of Electrical Wires and Cables at that time, Shree R.M.Shah’s vision was to expand into distribution of other Electrical Products. CAUTION BEFORE ENERGIZING THE SWITCHGEAR ASSEMBLY, ENSURE THAT: 6 . Air Insulated or open terminal disconnectors are available in several forms for different applications. When the contacts of a switch are opened, an arc is produced in the air between the contacts. Major components you can spot while looking at HV/EHV GIS (Gas-insulated switchgear) GIS are available internationally, covering the complete voltage range from 11 kV to 800 kV. I think the admin of this web site is really working hard in favor of his web There have been rapid developments in relaying technology during the last two decades. 22 Substation Types Step-up Transmission Substation § The three-phase power enters a transmission substation at the power The switchgear components are; busbars, switches, circuit breakers, current and voltage transformers, surge arresters, grounding switches. Control of the grounding switch is from the front of the switchgear with manual operation, and optionally, can also be motor operated. For voltages beyond 66 kV, we install outdoor switchgear equipment. The circuit breaker MC2 has a constant current source (e.g. A fuse is a short piece of wire or thin strip which melts when excessive current flows through it for sufficient time. If the fault is not cleared quickly, it is likely to spread into healthy parts, thus endangering complete shut down of the system. The line side of the Historically, spark gaps with air insulation were used as surge suppressors. Faulty tripping and switching operation of high voltage circuit breakers are comparatively very rare. Air break switches are used in lower voltage to disconnect on load. Some types of equipment are designed to operate under both normal and abnormal conditions. Part of the role of the ground wire is to force the breaker to trip by supplying a path to ground if a "hot" wire comes in contact with the metal case of the appliance. 2）Connect all the leads that need to be grounded inside the switchgear A switch is a device which is used to open or close an electrical circuit in a convenient way. Circuit Breaker – Operating Principle and Arcing Phenomenon. When a fault occurs the relay contacts are closed and the trip coil of the circuit breaker is energized to open the contacts of the circuit breaker. Switchgear may be purposed for isolation purposes, as load break switches and as grounding switches too in high voltage switchgear, medium voltage and low voltage switchgear. It is so designed that it can be operated manually (or by remote control) under normal conditions and automatically under fault conditions. Enclosures shall completely surround all live parts. This is the perfect webpage for everyone who wants to find out about this topic. wonderful article, you just received a new reader. When a fault occurs on any section of the power system, the switchgear must be able to discriminate between the faulty section and the healthy section. Thanks a lot . Surge Suppressors or Surge Arrestors are very important components of switchgear and substation installations. Easy to understand . The main grounding copper row is found throughout the arrangement for the direct grounding of the components utilized. Read switchgear in the substation for more details. This type of equipment is directly linked to the reliability of the electricity supply. Required fields are marked *, What is Switchgear? The Foundation of Group AR was laid by late Shree R.M. They may metal-enclosed indoor type, metal-enclosed outdoor type, outdoor type without a metal enclosure, etc. The tumbler switch with ordinary fuse is the simplest form of switchgear and was used to control and protect lights and other equipment in homes, offices, etc. It is generally of metal-clad type. The circuit breaker contacts are another switchgear component which are required to carry normal as well as short-circuit current. A circuit breaker is one switchgear which can open or close an electrical circuit under both normal and abnormal conditions. Read in detail about Components of Switchgear. You might find various components in the same row, for instance, a vacuum breaker, an air-insulated bus along with manual switches. Really informative and useful . For instance, medium voltage switchgear operates at around 40000 volts and this high a voltage can cause quite a spark. The figure shows a typical outdoor sub-station with switchgear equipment. Medium voltage switchgear is mainly used for the distribution of electrical energy connected to various electrical networks. There is no room for errors or choice of inferior quality components. NEC High Voltage Gas Insulated Switchgear. fuse in conjunction with a switch may serve the purpose of controlling and protecting the circuit. In the event of an electrical fault which brings dangerous high voltage to the case of an appliance, you want the circuit breaker to trip immediately to remove the hazard. Generally speaking, switchboards are the term one uses to designate low voltage switching whereas switchgear connotes HT usage scenarios. Instrument transformers (current transformer and voltage transformer) are used in switchgear installations for the measurement of electrical parameters for protection and metering purposes. The grounding switch has short-circuit making capacity. these low voltage can be handled by low voltage switchgear. A voltage transformer (VT) is an instrument transformer in which the secondary voltage is substantially proportional to the primary voltage and differs in phase from it by approximately zero degrees. However, HT distribution systems with large circuit breakers and switchgear are usually housed in a building. These equipment are useful for the fast automatic restoration of supply following transient faults in the system. process for grounding switchgear when beginning maintenance can be potentially perilous. In carrying the normal current, it is desirable that the temperature should not rise above the specified limits and that there should be a low voltage drop at the point of contact. we all are know voltage range from 0 to 1000v its called low voltage. The circuit breakers, isolators, transformers, bus-bars, and all other, A fuse is a short piece of wire or thin strip which, An instrument transformer in which the secondary current is substantially proportional to the primary current and differs in phase from it by approximately zero degrees is called a. Switches are used for opening and closing an electric circuit while. It includes switches, fuses, circuit breakers, relays, current transformer, and other equipment. The contacts of the former are opened in the air and that of the latter is opened in oil. At higher voltages, rotating center post, double end rotating post, vertical break, and pantograph type disconnectors are more common. However, a single line may have different devices. The switchgear equipment is essentially concerned with switching and interrupting currents either under normal or abnormal operating conditions. Under abnormal conditions (such as short circuit), the specified abnormal current can be carried within the specified time; but under normal circuit conditions, it is not required to carry current. Depending upon the voltage to be handled, switchgear may be broadly classified into. What is Switchgear? You certainly put a new spin on a subject which has been written about for years. Comments are Off Only the best will do such as genuine L&T switchgear obtained from authorized switchgear dealers in Ahmedabad. Verify that the circuit breaker is in the “Open” position and check the indicator on the front of the circuit breaker. The switchgear devices and their assemblies are used in connection with the generation, transmission, distribution, and conversion of electrical energy. Some equipment is meant for switching and not sensing the fault. When a fault occurs on any part of the power system, the switchgear must operate quickly so that no damage is done to generators, transformers and other equipment by the short-circuit currents. BY OPENING THE BREAKER OR SHORT-CIRCUIT THE SECONDARY OF THE CURRENT TRANSFORMER. The circuit breaker, along with associated devices for protection, metering, and control regulation, is called switchgear. At the lower voltages, single break types are usual with either ‘rocker’ type or single end rotating post types being predominant. When a short circuit or overload occurs, the current through the fuse element increases beyond its rated capacity. This is particularly true for circuits of high voltage and large current capacity. Switchgear covers a wide range of equipment concerned with switching and interrupting currents under both normal and abnormal conditions. Hence high voltage circuit breaker should have special features for safe and reliable operation. So, special care to be taken during designing of high voltage switchgear. Installation of grounding main bus. Components of Switchgear. [For more details, go through  What is a fuse and How it Works? Read in detail How Protective Relays Work? During normal operation, switchgear permits to switch on or off generators, transmission lines, distributors and other electrical equipment. That’s cool! Read Circuit Breaker – Operating Principle and Arcing Phenomenon. It consists of two parts: the cabinet and the circuit breaker. The term ‘switchgear’ is a generic term that includes a wide range of switching devices like circuit breakers, switches, switch fuse units, off-load isolators, HRC fuses, contactors, miniature circuit breakers, ELCBs, GFCIs etc. Switchgear is typically classified into categories like low voltage/low tension switchgear, medium voltage switchgear and high voltage-high tension switchgear. There also has to be provision for metering, controlling and data, wherein innumerable devices are used for achieving the switching function. Switchgear may be classified according to voltage and current rating, by the choice of insulating medium and the interrupting rating or the short circuit current that the device can handle. Thanks for sharing this useful information.. We fabricate all our bus bar components in house, which allows us to accommodate any and all breaker hardware, current transformer mounting, and potential transformer termination. 2. For voltages below 66 kV, switchgear is generally installed indoor because of economic considerations. Low Voltage Circuit Breakers: Miniature Circuit Breaker, Moulded Case Circuit Breaker, Residual Current Circuit Breaker, Ground Fault Circuit Interrupter, High Voltage Circuit Breakers: Vacuum Circuit Breaker, SF6 Circuit Breaker, Oil Circuit Breaker, Air Blast Circuit Breaker. Metal-clad switchgear can be characterized as follows: The primary voltage breakers and switches are mounted on a removable mechanism to allow for movement and proper alignment. i have read it completely. Your email address will not be published. For the latter operation, a relay circuit is used with a circuit breaker. So Circuit Breakers must be reliable enough to ensure safe operation, as when required. 8. Thus switchgear can be taken as a general term covering a wide range of equipment concerned with the switching, protection, and control of various electrical equipment. Various forms of switching and protective devices have been developed. An instrument transformer in which the secondary current is substantially proportional to the primary current and differs in phase from it by approximately zero degrees is called a current transformer (CT). The position of the grounding switch can be seen from the front of the switchgear by … Switchgear may also have multiple sources of supply and automatically switch load in case one source fails. Switchgear for low voltage applications is generally rated up to 1000 V AC and 1500V DC. Thanks a lot , the best article about switchgear on the internet, Your email address will not be published. Breaker Failure Relay (Back-up Protection Relay), 2 Important Distribution Transformer Testing Methods. All of our switchgear bus bars conforms to NEMA and ANSI Standards. We’re versed in NEC requirements for the bus bar. Photo 2 (right) shows a typical MVACB, while Photo 3 shows an MVVCB. (For more details visit working of a circuit breaker and protective relays.). GIS grounding and bonding typical rule: All grounding conductors should be as short as possible. The circuit breakers, isolators, transformers, bus-bars, and all other substation equipment occupy considerable space on account of large electrical clearance associated with high voltages. Historically, spark gaps with air insulation were used as surge suppressors. A circuit breaker is an automatically-operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. Switchgear for medium voltage applications is rated from 3.3 kV to 33 kV class. the low voltage switchgear consists of feeders, incomers, disconnect fuses , protection relays and ON/OFF control switches. The commonly used low voltage devices include oil circuit breakers(OCBs), air circuit breakers (ACBs), switch fuse units (SFUs), off-load isolators, HRC fuses, earth leakage circuit breakers (ELCBs), Residual Current Protective Devices (RCCB & RCBO), miniature circuit breakers (MCB) and moulded case circuit breakers (MCCB) etc i.e. Power conducting components including circuit breakers, switches, lightning arrestors, and These components interrupt or conduct the electrical power flow. | Features, Components and Classification, The term ‘switchgear’ is a generic term that includes a wide range of switching devices like, We all are familiar with low voltage switches and re-wirable fuses in our homes. You know so much its almost tough to argue with you In main grounding, the ground is applied to the line side of the main switch or circuit breaker in switchgear (see Fig. The essential features of switchgear are : With the continued trend of interconnection and the increasing capacity of generating stations, the need for reliable switchgear has become of paramount importance. Grounding & Bonding 2 In our example, the Service Equipment for the home is the 200 Amp Main Breaker Panel. With this vision & his perseverance, the group companies were established later. Most of the time these circuit breakers remain at ON condition and may be operated after a long period of time. 4 SCB Configurations. Residual Current Protective Devices (RCCB & RCBO). These are used to protect the substation equipment from temporary over-voltages, switching impulses, and lightning impulses, and to a certain extent, very fast transient over-voltages. Gas Insulated Switchgear 72.5800kV Gas Insulated Switchgear 72.5800kV short circuit) occurs on any part of the power system, a heavy current flows through the equipment, threatening damage to the equipment and interruption of service to the customers. 38kV breaker in its standard configuration, and a grounding breaker that is a partial 38KV breaker mounted in the back of the cubicle with a high speed closing mechanism on the breaker. Switchgear must have provision for manual control. Hi friend, good piece of writing and an excellent piece of information, I am actually enjoying by these. However, such switchgear cannot be used profitably on a high voltage system (33 kV) for two reasons. fence to the substation grounding grid or to a separate underground ... Oil Circuit Breaker Voltage Regulators Metal-clad Switchgear Control House . High and low voltage switchgear should meet the relevant requirements of GB3906-1991 "3-35 kV AC metal-enclosed switchgear" standard. 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