Research on Series-wound Reactor Protection Against Inter-turn Fault in Power Traction System

Shunt capacitor compensation (SCC) is important equipment of power traction system in electrified railway. The protections at present prevent the SCC from damage by fault. However, the reactor series-wound with the compensator is short of necessary protection against inter-turn fault. The voltage ratio of the capacitor and reactor will change when the fault occurs. Together with the characteristic of power traction system in electrified railway, a new protection against inter-turn fault of reactor based on the voltage ratio was proposed. The simulation by ATP shows that the voltage ratio protection against inter-turn fault of reactor can make correct judgement to this kind of fault rapidly. The protection is applied at a substation in a railway and has been running well for several years.