Impact of distributed generation on voltage regulation by LTC transformer

Distributed Generator (DG) can cause over-voltages as well as under-voltages, depending on several factors including DG size and location, and method of voltage regulation. This paper addresses possible under-voltages when installing a DG on a feeder whose voltage is regulation by a LTC (load-tap changing) transformer with LDC (line drop compensator). Simple analytical expressions of voltage drop on a radial feeder with uniformly distributed load, and containing a DG unit, are derived. The analysis is illustrated by a numerical example that validates the accuracy of the analytical expressions.