A power-quality index based on multipoint measurements

One of the problems that must be dealt with in a deregulated electricity market is the estimation of the electric power quality of the supply and load. The presence of nonlinear, time-variant, disturbing loads connected to the electric network is responsible for the presence of periodic and nonperiodic disturbances on the line currents and voltages. The availability of indices for the quantification of such disturbances and the assessment of the responsibility for their generation is of utmost importance for the adoption of energy billing policies aimed at discouraging the insertion of uncompensated disturbing loads. This paper analyses a distributed measurement method for the evaluation of a global power quality index for the evaluation of periodic disturbances. The proposed index is validated by means of simulations of the IEEE industrial test system for harmonic modelling and simulation. Some experimental results obtained on a small low-voltage network are also reported.

I. Introduction

Power-quality issues are becoming more and “more relevant in operating the electric power systems, especially in a deregulated electricity market, due to the increasing presence of non-linear, time-variant, disturbing loads connected to the electric network.