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Protection System in Power System This portion of our website covers almost everything related to  protection system in power system  including standard lead and device numbers, mode of connections at terminal strips, color codes in multi-core cables, Dos and Don’ts in execution. It also covers principles of various power system protection relays and schemes including special  power system protection  schemes like differential relays, restricted earth fault protection, directional relays and distance relays etc. The details of transformer protection, generator protection, transmission line protection and protection of capacitor banks are also given. It covers almost everything about  protection of power system . The switchgear testing, instrument transformers like current transformer testing voltage or potential transformer testing and associated protection...

CHOPPER CIRCUIT In power electronics  chopper circuits , unidirectional power semiconductors are used.  If these semiconductor devices are arranged appropriately, a chopper can work in any of the four quadrants. we can classify chopper circuits according to their working in any of these four quadrants  as  type  A, type B, type C, type D and type E. Let us now take a look of these classifications and the characteristics of various classifications. Type A Chopper or First–Quadrant Chopper This type of chopper is shown in the figure. It is known as first-quadrant chopper or type A chopper. When the chopper is on, v 0 =  V S  as a result and the current flows in the direction of the load. But when the chopper is off v 0    is zero but I 0   continues to flow in the same direction through the freewheeling diode FD, thus average value of voltage and current  say V 0   and I 0   will be always ...