Reactive Power Support from Converter Connected Renewables in Active Distribution Network

Network operators have been increasingly concerned with procuring reactive power sources as more synchronous generators are planned to be decommissioned and number of distributed generation is on the rise. Reactive power is necessary in the evolving grid with distributed generation to support the additional power flow and avoid expensive grid reinforcements. Converter connected renewable generators can be a solution both to provide the much needed reactive power support in distribution grids and the voltage regulation support to the transmission network via altering the reactive power feed-in. This research explores the reactive power capabilities of a mutli-voltage active distribution network. A semidefinite programming based optimal power flow is implemented to find the maximum reactive power support from converter connected generation having two different objectives, namely loss minimization in the distribution network and following a reactive power reference from the transmission network. Changes in voltage profiles in correlation to altering reactive power flow in the distribution network is also analyzed.