In this topic, you study Current Limiting Reactor.
The short circuiting currents under fault conditions are of very high values. These heavy currents suggest to use the C.Bs. of higher capacity which will not be economical. Moreover there is a possibility of damaging the equipment in the power system. This suggests that these fault currents (short-circuiting currents) as they are not controllable by the system and equipment reactances, some additional reactances shall be introduced in the system to limit the short circuiting current to the safe value such that C.Bs. are not overburdened and find capable of sustaining these currents.
The solution is to introduce inductive coils having sufficient number of turns so that their reactance is higher. Such inductive coil located (connected) at proper places in the system are called as “Current Limiting Reactors”. So reactors are high reactance coils with negligibly small resistance. The short-circuit currents induce very high stresses due to the fault forces and it is likely that the coil turns of the reactors may be affected. Due to this reason the reactor coils are mechanically protected and solidly braced.
Advantages of Current Limiting Reactors
- By introducing reactors in the power system the magnitude of Isc is controlled, hence suitable small capacity of C.Bs. can work safely and hence economical.
- Reactors limit the Isc and hence provide protection to the equipment from overheating and avoid failure due to mechanical stresses.
- Introduction of reactors in the system ensures continuity of supply. Troubles are isolated.
Location of Current Limiting Reactors
(a) In series with the generator
(b) In series with the feeder
(c) In bus bars
The reactors are therefore known as :
(1) Generator reactors,
(2) Feeder reactors,
(3) Bus bar reactors (Ring and Tie bar system).
