The uptake of variable Mega Watts from Photovoltaic(PV) challenges distribution system operation. The primary problem is significant voltage rise in the feeder that forces existing voltage control devices such as on-load tap changers (OLTCs) and line voltage regulators (VRs) to operate continuously. The consequence is the deterioration their operating life. Also, conventional non-coordinated reactive power control can result in the operation of the line regulator at its control limit (runaway condition). This research proposes an optimal reactive power coordination strategy. The objective is to minimize the number of tap operations and avoid runaway. The proposed objective is achieved by coordinating various reactive power control options in the distribution network while satisfying constraints such as maximum power point tracking of PV and voltage limits of the feeder. The option of voltage support from PV plant is also considered. The problem is formulated as constrained optimization and solved through the interior point technique. The effectiveness of the approach is demonstrated in a realistic distribution network model.
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