 To offset the capacitive effect of the transmission line and to regulate the voltage and reactive power of the power system, reactors are connected either at line terminals or at the middle, thereby improving the voltage profile of transmission line.In large systems with many generators connected in parallel, it may be necessary to use a series reactor to prevent excessively large current flow during a short-circuit; this protects transmission line conductors and switching apparatus from damage due to high currents and forces produced during a short-circuit.A shunt reactor is connected in parallel with a transmission line or other load.