Free Expert Guides on Power Systems, Circuit Design & Electrical Troubleshooting

From 3 KV to 36 KV switchgear system is categorized as medium voltage switchgear or MV switchgear. These switchgears are of many types. They may metal enclosed indoor type switchgear, metal enclosed outdoor type switchgear, outdoor type switchgear without metal enclosure, etc. The interruption medium of this switchgear may be insulating oil, SF6 gas or vacuum. The main requirement of power network is to interrupt current during faulty condition irrespective of what type of CB is used in the MV s

Definition of SwitchgearA switchgear is a generic term which includes all the switching devices associated with power system protection. It also includes all devices associated with control, metering and regulating of electrical power systems. Assembly of such devices in a logical manner forms switchgear. In other words systems used for switching, controlling and protecting the electrical power circuits and different types of electrical equipment are known as switchgear. This is very basic defin

Generally electrical switchgear rated upto 1KV is termed as low voltage switchgear. The term LV Switchgear includes low voltage circuit breakers, switches, off load electrical isolators, HRC fuses, earth leakage circuit breaker, miniature circuit breakers (MCB) and molded case circuit breakers (MCCB) etc i.e. all the accessories required to protect the LV system. The most common use of LV switchgear is in LV distribution board. This system has the following partsIncomerThe incomer feeds incoming

Conductor is a physical medium to carry electrical energy form one place to other. It is an important component of overhead and underground electrical transmission and distribution systems. The choice of conductor depends on the cost and efficiency. An ideal conductor has following features. It has maximumelectrical conductivity. It has high tensile strength so that it can withstand mechanical stresses. It has least specific gravity i.e. weight/unit volume. It has least cost without sacrificing

This test is used to determine the DC resistance of copper or aluminum conductors. Resistance of a conductor tells us how easily a conductor allows the flow of current through it. Higher the resistance, lesser the current will flow though the conductor. Resistance of a conductor is influenced by conductor dimension and construction, conditions like, temperature and resistivity. It is normally expressed as ohms per km.This test will make use of either Kelvin Double Bridge with accuracy of 0.2 per

This test is done on aluminum wire used as conductor in power cables to determine its ductility. Ductility of a conductor is nothing but the property of how easily it can be wound and twisted. Higher the ductility, easily the material can be wound and twisted without its breaking. This property plays the significant role during manufacturing and installation process where the cable is subjected to torsion due to axial twist and might break. Hence, this wrapping test ensures suitability of alumin

This test covers the technique to confirm the thickness of insulation and sheath of electric power cables. Adequate thickness of insulation and sheath is provided to power cable meet up the voltage stresses and mechanical stresses imposed on the cable during its service life. The measurement of such thickness is necessary to verify whether it is as per specified limit or not. These dimensions ensure safe and reliable performance of the cable.Apparatus required to test for thickness of insulation

This test is performed only to confirm tensile strength of aluminum wires used for conductor in electric power cables. This test is significantly performed on conductor material to judge the strength of this material. A cable conductor is often subjected to pull from one end during laying, installing and manufacturing hence it should be strong enough to tolerate the pulling force as well. Hence it becomes necessary to ensure that the conductor material has sufficient tensile strength.Apparatus r

This test is normally carried on annealed copper wires, aluminum wires for welding cables and solid conductors of electric power cables. The current carrier conductors of power cable is subjected to twist and bend during laying and installation hence it should be flexible enough to take any desired bending and twisting without breaking and cracking. Annealing test for wires and conductors is performed to confirm the durability of conductor during twisting and bending.Process of annealing test fo

The following tests are the type test ofelectrical powercable.Physical tests for insulation and sheath Tensile strength and elongation at break Aging in an air oven Aging in air bomb Aging in an oxygen bomb Hot set Oil resistance Tear resistance Insulation resistance High voltage (water immersion) test Flammability test (only for SE-3, SE-4) Water abortion test (for insulation) Persulphate test (for copper ) Annealing test(for copper) Tensile test(for Aluminium) Wrapping test(