The impact of distributed generation on voltage control in distribution systems

Voltage control is a major factor in the design of distribution system, so much so that it is a statutory requirement [1] in many countries that customers receive a voltage that remains within stated parameters. In addition to its magnitude, other factors such as continuity and freedom from harmonics are also important. Each of these parameters has cost implications for the utility. This paper concentrates primarily on the impact of distributed generation on voltage control. Traditionally, voltage control in distribution systems consisted principally of onload tap changers in bulk supply point stations. When necessary, these were augmented by booster transformers and possibly capacitors to increase the voltage where it dropped to too low a level. Distributed generation has a tendency to increase the voltage at its terminals. Where possible, this effect should be harnessed to contribute to voltage control. Where the generator cannot assist with voltage control, its impact has to be managed to ensure an acceptable voltage appears at the busbars of all customers.