An Adaptive Clustering-Based Distributed Voltage Regulation Scheme for Unbalanced Distribution Systems With Multiple Renewable DGs and OLTCs

In this paper, a real-time adaptive clustering-based distributed voltage regulation scheme is presented for the voltage regulation of unbalanced distribution systems. In the proposed methodology, first, adaptive clusters for the distributed control are formulated based on voltage to injected power sensitivity, and a threshold criterion is designed that limits the size of the clusters to strongly controlled nodes only. Having performed the clustering, a multi-objective optimization problem is solved for power factor optimization within clusters for voltage regulation of all the control zones of the distribution system. Voltage quality factor and voltage unbalance indices are utilized to show the improvements in voltage profile and reduction in voltage unbalance, respectively. Furthermore, for optimally finding the tap positions for multiple OLTCs, another optimization problem is designed. An IEEE 123-node test feeder with multiple wind and solar DGs of varying capacities is used for the simulations, and two test cases with different scenarios are simulated to test the proposed scheme. All the results verify that the proposed scheme effectively regulates the voltage of the unbalanced system without massive remote data requirements and active power curtailment which ensures the stability of the system's voltage profile and prevents OLTC-hunting even in highly dynamic operational scenarios.