Sensor Coil for Internal Fault Protection of Shunt Reactors

In shunt reactors of modern day construction the required inductance is realized with coil turns numbering in thousands. When a turn to turn fault develops the conventional relaying schemes and protections are not adequate to sense a fault in its incipient stage until it has progressed through a-major section of the winding. In this paper the authors have described a fault sensing technique for detecting a turn to turn fault instantaneously within a reactor winding. An analytical description of the sensor coil is presented and the performance of the protective system as proven on an EHV shunt reactor is described.