Influence on the unbalance of three-phase voltage of bus brought by multi-tap arc suppression coil system

However, in practical use, the unbalance of the three-phase voltage of the 10 (20) kV bus is too large due to the unreasonable gear of the grounding transformer and unreasonable design of damp resistance. Alarming signal is even mistakenly sent. In the grid system with insulated neutral points, the neutral-point-to-ground offset voltage is generated due to the unequal phase-to-ground capacitance (caused by the arrangement of the lines). IN this paper we think that adjusting the tap changer of the grounding transformer can decrease the offset voltage caused by the incomplete conductor transposition. The validity of this method is proved through real cases.