Multi-Stage Coordination Volt/VAR Control with CVR in Active Distribution Network in presence of Inverter-Based DG Units and Soft Open Points

The increasing penetration of renewable energy sources (RES) exacerbates the problems such as voltage rise, higher energy losses and energy consumption. The VAR support provided by inverter based distributed generators (IDG) and soft open points (SOP) devices is emerge as a potential solution for aforementioned problems. Therefore, a multi-stage coordination Volt/VAR control (VVC) with conservation voltage reduction (CVR) methodology incorporating IDG and SOP devices has been proposed in this paper. The proposed methodology includes three different stages namely; day-ahead scheduling stage, inner- day control stage, and real-time dispatch stage. In the day-ahead scheduling stage, a coordination optimisation model considering traditional VVC devices, IDG and SOP has been established; in the inner day control stage, a rolling optimisation control model based on model predictive control (MPC) is built, to reduce the influence of the predicted RES forecasted deviations; in the real-time dispatch stage, voltage violations occurred due to sudden change in generation/load are mitigated by regulating the reactive powers of IDG and SOP. To validate the developed scheme, a real time co-simulation framework using real time digital simulator (RTDS) and MATLAB-GAMS interface has been built. The proposed scheme has been tested and validated on a well-known 33 bus distribution system. The test results demonstrate the significance of the proposed scheme on volt/VAR control problems.