Discussion on the Common Problem of Anti-Resonance Using 4 PT in the Neutral Node Ungrounded Power System
In the neutral node ungrounded power system,ferroresonance due to the nonlinear excitation inductance of three-phase inductive potential transformer(PT) once happened,has a serious impact on the safe operation of power system.In recent years,connecting single-phase PT to the neutral point of three-phase PT high voltage side is used by most power systems.With the proposed of Smart Grid,the non-normative connection mode of secondary circuits of the anti-resonance PT is urgent to solve,it also affects the judgment of the operators.This paper mainly analyses the common anti-resonance PT of working principles and considerations in operation,offers references for optimization and rectification of the anti-resonance PT.