Microgrids-Based Approach for Voltage Control in Distribution Systems by an Efficient Sensitivity Analysis Method

High levels of renewable energy sources (RESs) in distribution networks have led to complex operational needs. The management of the network in microgrids (MGs) allows the implementation of effective and innovative management strategies. We propose a hybrid control strategy to maintain voltage levels within the operational limits using the RESs reactive and active power outputs. The proposed regulation strategy considers different MGs that are managed by different owners, who contribute to regulating the voltage on the distribution systems. In order to obtain an effective regulation, each MG can collaborate with the others. In the first instance, voltage is regulated inside MG using available distributed generation resources in correspondence of the bus of over/undervoltage is detected (stage 1). Next, more MGs can contribute to alleviating the problem involving other distributed generation resources (stage 2). The control method is based on sensitivity analysis, which allows selecting the appropriate distributed resources: we propose also a new method of calculating the sensitivity coefficients for radial and meshed networks. We demonstrate the effectiveness and the robustness of the proposed voltage control scheme using comparisons and representative studies by extensive simulations on two test networks performed by the proposed methodology. The results demonstrate the effectiveness of the control actions and the used algorithm.