eeefacts

Auto transformer This transformer is used for step up and step down applications. In this primary and secondary are not electrically isolated. An auto transformer has winding common to both primary and secondary, the input and output windings are electrically connected as one continues winding. Its application include starters and interconnection of high voltage lines. Advantage of auto transformer over 2 winding transformer Autotransformer required less volume of core materials. In this no isolation required between primary and secondary winding as it has common winding between input and output circuit. Size and weight are less due to common winding. KVA rating of auto transformer is high as compared to 2 winding transformer. Efficiency of auto transformer will be high as low loss as copper requirement will be less. Analysis of single phase  Autotransformer  A single-phase autotransformer having N1 turns primary with N2 turns tapped for ...

CIRCUIT BREAKER Electrical circuit breaker is a switching device which can be operated automatically or manually for protecting and controlling of electrical power. A circuit breaker can make or break a circuit either manually or automatically under all condition as in no-load, full-load and short-circuit conditions. It is often desirable and necessary to switch on or off the various circuits in power system. In earlier days, this function used to be performed by a switch and a fuse placed in series with the circuit. However, it presents two disadvantages.  Firstly, when a fuse blows out, it takes quite time to replace it and restore supply to the consumer.  Secondly, a fuse cannot successfully interrupt heavy fault currents that result from faults on high-voltage and large capacity circuits. Due to these disadvantages, the use of switches and fuses is limited to low-voltage and small capacity circuits. This necessitates for a more dependable means of c...

S ubstation A Substations generally have switching, protection transformer and control equipments. A substation performs no. of function in electrical systems. Substations transform voltage from high to low level, or the reverse, frequency conversion, PF improvement or perform any of several other important functions.  Between the generating station and consumer, electric power may flow through several substations at different voltage levels. In a large substation, Circuit Breaker are used to interrupt any short circuits or overload currents that may occur on the network. A substation may include transformer to change voltage levels between high transmission voltages and lower distribution voltages, or at the interconnection of two different transmission voltages. Substations may be owned and operated by an electrical utility, or may be owned by a large industrial or commercial customer. Substations may be on the surface in fenced enclosures, underground...