Four-Wire Delta Service Sinusoidal Operation and Compensation Simulator

Abstract

An off-line simulator based on Excel used to evaluate the operation of four-wire delta (4WD) services as well as the effects of reactive and imbalance compensators in sinusoidal steady-state conditions is described in this paper. Voltages, currents and powers in the primary and secondary windings of the transformer as well as in the high voltage (HV) and low voltage (LV) lines and in the loads are calculated through that simulator. The apparent powers in the mains, transformer and loads are determined applying Buchholz¿s and unified power measurement (UPM) formulations in both scalar and vector notations. The effects of the neutral current are especially examined, in order to minimize them, and the optimal wye load distribution is determined by the simulator. The simulator provides the necessary elements of passive reactive and unbalanced compensators that optimize the 4WD transformer operation too. Those compensators are determined for each load, and they can be separately selected and included in the simulation process or not. An application example is finally used to step by step explain how the simulator runs.