Online Voltage Control for Unbalanced Distribution Networks Using Projected Newton Method

This paper proposes an online voltage control strategy of distributed energy resources (DERs), based on the projected Newton method (PNM), for unbalanced distribution networks. The optimal Volt/VAr (VVC) problem is formulated as optimization program, with goal maintaining profile across network by coordinating VAr outputs DERs. To overcome slow convergence rate conventional gradient-based methods, a PNM-based solution algorithm developed to solve this VVC problem. It utilizes non-diagonal symmetric positive definite matrix, from Hessian matrix objective, scale gradient, and thus fast performance can be expected in Newton-like algorithm. Moreover, taking advantage instantaneous feedback measurements, implementation further designed deal system variations. In scheme, each bus agent communicates measurements central agent, output commands DERs back agent. PNM results stronger capability track variations real time. Finally, numerical case studies are performed validate effectiveness, superiority, scalability proposed method.