MPC based coordinated voltage regulation for distribution networks with distributed generation and energy storage system

This paper presents a Model Predictive Control (MPC)-based coordinated voltage control scheme for distribution networks with high penetration of distributed generation (DG) and energy storage. In this scheme, the DG units, energy storage devices and on-load tap changer (OLTC) are optimally coordinated to maintain all bus voltages in the network within a permissable range.

To better coordinate the economical operation and voltage regulation, two control modes are designed according to the operating conditions. In the preventive mode, the DG units operate in the maximum power point tracking (MPPT) mode. State-of-charge (SoC) of energy storage system (ESS) units and power outputs of DG and ESS units are optimized while maintaining the voltages within the feasible range.

In the corrective mode, active power curtailment of DG units is also used as a necessary method to correct the severe voltage deviations. The voltage sensitivity coefficients with respect to the power injections and tap changes are updated in real time using an analytical sensitivity calculation method to improve the computation efficiency.

A test system consisting of two 20kV feeders fed from the same substation based on a real distribution network was used to validate the proposed coordinated voltage control scheme under both normal and large-disturbance conditions.