Protection scheme against turn to turn fault for novel magnetic valve
controllable reactor based on thyristor current distortion
Abstract
Turn to turn short circuit is a common fault of the Magnetic Valve
Controllable Reactor(MVCR), but the current research on the
characteristics of turn to turn faults is not clear. What’s more, the
corresponding protection also has certain limitations. In this paper, a
novel type of MVCR that has been put into operation in engineering is
studied. Firstly, the topology structure of the novel MVCR is
introduced, and the electrical characteristics of its steady-state
operation are analyzed. Based on this, the fault characteristics of the
excitation winding and working winding of the novel MVCR when turn to
turn faults occur are studied. The study shows that when turn to turn
faults occur, the amplitude of DC and AC component in the thyristor
current both increase significantly, resulting in large current
distortion. Due to the fault characteristics, this paper introduces the
current distortion coefficient to quantitatively analyze the different
characteristics of the two components before and after the faults.
Furthermore, a protection scheme against turn to turn fault based on the
thyristor current distortion is proposed. Finally, the feasibility and
effectiveness of the proposed turn to turn protection scheme are
verified by Matlab/Simulink simulation experiments.