Practical impedance estimation in low-voltage distribution network

Abstract

This paper proposes a method of estimating the impedances between nodes in a low-voltage distribution network. This method works without any information on the phase differences between nodes. It only requires measurements that can be easily obtained and shared from existing devices and communication technologies such as power line communication(PLC). In other words, it is not necessary to carry out synchronized real-time measurement for observing phase differences. From governing equations based on the basic circuit theory, the mathematical optimization problem is formulated to solve them and then obtain the estimates of the impedances among nodes. To find a solution to the nonconvex and nondifferentiable optimization problem, a representative metaheuristic algorithm, called the particle swamp optimization(PSO), is employed with a new biquadratic and linear hybrid cost function that is proper for fast convergence both far away from and near an optimal point.