The earliest central power stations used simple open knife switches, mounted on insulating panels of marble or asbestos. Metal-Enclosed Switchgear: This is an earthed metallic enclosure, made of supreme quality sheet steel that houses different types of circuit breakers. To overcome this, a switchgear device is used because of its different features and functions. There are various voltage levels and hence various fault levels between the generating stations and load centres. Electrical switchgear refers to a centralized collection of circuit breakers, fuses and switches (circuit protection devices) that function to protect, control and isolate electrical equipment. These components are connected in a definite sequence such that a circuit can be switched off during normal operation by manual command and also automatically during abnormal conditions such as short-circuit. Open air substations contain separately mounted and interconnected switching equipment and components, like current transformers (CTs), voltage transformers (VTs), busbar support insulators, cable sealing ends, etc., where atmospheric air provides the main insulation path to earth. Switchgear (Figure 6) is a general term covering primary switching and interrupting devices together with its control and regulating equipment. This device de-energizes for clearing the fault, testing & maintaining. Types of Switchgears. Electrical switches are binary devices, they can be either completely off or completely on. The single-line diagram should be shared with the architect with an explanation from the electrical engineer describing the types of large equipment, space needed and how the equipment is interconnected. , (German) Allgemeine Elektricitäts-Gesellschaft (ed). Switchgear power systems can vary, depending on several factors, such as power need, location of system and necessary security. The metal-enclosed form is a relatively recent innovation made possible by the use of SF 6 gas and is now widely employed, it is generally referred to as âgas-insulated switchgearâ.  The technology has been improved over time and can now be used with voltages up to 1,100 kV. The main functions of this equipment include the following. As a result, during the designing of this equipment, special care has to be taken. This switch has two contacts one is input and other output. A short circuit at the end of a long transmission line appears similar to a normal load, because the impedance of the transmission line limits the fault current. If you have any additonal questions on ATS or switchgear requiremnts for your backup power system contact us today. Switches are essentially binary devices: they are either completely on (closed) or completely off (open). Ratings, design, specifications and details of switchgear are set by a multitude of standards. A network switch (also called switching hub, bridging hub, and, by the IEEE, MAC bridge) is networking hardware that connects devices on a computer network by using packet switching to receive and forward data to the destination device.. A network switch is a multiport network bridge that uses MAC addresses to forward data at the data link layer (layer 2) of the OSI model. Additionally, the type of transformer, switchgear or UPS specified will also impact the physical size and working space required around the equipment as required by the NEC. Vacuum circuit breakers are frequently used in modern medium-voltage switchgear to 40,500 volts. Types of Switchgear HV: High Voltage Switchgear. There are various types of switchgear and protection devices in power system. To see a good example of the various types of components found in medium voltage switchgear watch the illutrated video below on Siemens NXAir product. A. Switchgears . Circuit breakers can open and close on fault currents, Load-break/Load-make switches can switch normal system load currents, Isolators are off load disconnectors which are to be operated after Circuit Breakers, or else if the load current is very small, Medium voltage (1 kV AC through to approximately 75 kV AC), Extra high voltage, ultra high voltage (more than 230 kV), Draw-out elements (removable without many tools). However they cannot sense other critical faults, such as unbalanced currents—for example, when a transformer winding contacts ground. A collection of one or more of these structures is called a switchgear line-up or assembly. Near zero current the arc is not hot enough to maintain a plasma, and current ceases; the gap can then withstand the rise of voltage. A distance relay detects a fault by comparing the voltage and current on the transmission line. Working Principle of Circuit Breaker. SWITCHGEAR AND PROTECTIVE DEVICES (3-1-0) MODULE-I (10 HOURS) Protective Devices: Philosophy of protection, Nature, Causes and consequences of faults, Zone of protection, Requirements of a protective scheme, Basic terminology components of protection scheme. This article will highlight some important things about switchgear. IEEE Std C37.20.2-1999. At present, the demand for electrical power is growing rapidly, and this can be fulfilled by the power generating substations. A collection of one or more of these structures is called a switchgear line-up or assembly. This device gives isolation to the circuits from power supplies. HV type is used for motors & electrical equipment which operate with above 1000V AC whereas LV type is used to run electrical devices that operate with below 1,000 volts AC. From 3 KV to 36 KV switchgear system is categorized as medium voltage switchgear or MV switchgear.These switchgears are of many types. The main features of this include the following. Once a fault happens this device detects the fault & detaches the damaged part in the power system. This button is used in many electronics circuits and can handle a small amount of current. TYPES OF SWITCHGEAR It is mainly classified into two types the outdoor type and the indoor type if the voltage is above 66kv the output switchgear is used below 66kv indoor type is used the indoor type is of metal clad and is compact because of the compactness the area used is reduced 3. In modern power systems, this is an essential device to protect the equipment from overload or short circuits. The electrical power system has a fuse and circuit breaker as an electrical disconnect switch. The current through both ends should be identical. Switches: A switch is a static device, which is use to open or close an electrical circuit in a convenient way. To understand where each fits, we will have a look at their functions and differences. 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