Distributed secondary voltage controller for droop-controlled microgrids to improve power quality in power distribution networks

A distributed secondary voltage controller is designed for droop-controlled microgrids in power distribution networks to improve power quality. Microgrids are typically managed by the droop control mechanism that ensures stability but does not guarantee power quality of voltage magnitude. To solve this power quality problem, the proposed distributed secondary voltage controller maintains a constant voltage at a microgrid's point of common coupling (PCC) using only local measurements. With the voltage regulation capability, a microgrid can be used to improve power quality so that greatly promote the microgrid's value to power system daily operations. The improved voltage regulation in a power network is demonstrated through simulation tests of a modified IEEE 37-node test feeder. Furthermore, this secondary voltage controller is compatible with existing voltage control devices, such as tap-changing transformers that automatically regulate voltage.