Reactive power optimization for distribution network based on serial and parallel iterative modes of alternating direction method of multipliers

We formulate the control of reactive power generation by reactive compensation capacitors in power distribution network (DN) as a constrained optimization problem that aims to minimize power losses and improve voltage profiles subject to finite capacitor capacity and upper and lower bus voltage limits. The objective function is separable enabling a distributed online implementation with node-local computations using only local measurements augmented with limited information from the neighboring buses communicated over cyber channels. A distributed approach based on the alternating direction method of multipliers (ADMM) is developed to realize the distributed reactive power optimization among capacitors. A serial iterative mode of ADMM based on Gauss-Seidel and a parallel iterative mode of ADMM based on Proximal Jacobian are applied respectively and the differences between the two modes in communication efficiency are discussed. Simulation studies with the modified IEEE 69-bus distribution system demonstrate the effectiveness and superiority of the proposed optimization solution.