Вдосконалення методу захисту від однофазних замикань на землю обмотки статора синхронного генератора, що працює в блоці з трансформатором

Abstract

The given paper describes the solution of actual, scientific and applied tasks of improving a method and means of defense from single-phase ground fault of the stator winding of synchronous generator which works in a block with a transformer, which appears in consideration of terminal significances and which consequently have effect on importance of current in a place of single-phase ground fault. This research investigates the main features and processes which have effect on changing of technical condition of insolation of the stator winding of the synchronous generator during its exploitation. As a parameter of operation of protection from single-phase ground fault of the stator winding of synchronous generator which works in a block with a transformer, effective value of current of single-phase ground fault is proposed to use. This work presents a method and guard devices from single-phase ground fault of the stator winding of synchronous generator which works in a block with a transformer. Their work is based on the calculation of the current in a place of a single-phase ground fault, by using the combined principle of imposing a direct current, using a current of discharge of pre-charged capacitor, measuring of voltage of zero-sequence and taking into account a capacitance of insulation of the stator winding of synchronous generator which works in a block with a transformer. This suggested protection react on the signal during symmetrical lowering of resistance isolation of the stator winding and also it reacts on the disconnection of generator from network in case of detection of emergency conditions with current of locking on the ground. Also, the important research of qualities and characteristics of proffering method and guard devices is carried out. An algorithm of searching the faults in a gear of relay protection is developed.