Simulation of Power Quality in Residencial Electricity Networks

Abstract

The prevalent engineering practice (PEP) for demand estimation in Low Voltage electricity networks is based on an After Diversity Maximum Demand (ADMD) modified by a Diversity Factor. This method predicts the maximum likely voltage drop, accounting for diversity. However, it is inconsistent with both the nature of demand, which can be represented as a stochastic process, and with the wording of power quality standards such as BS EN 50160. This paper develops a numerical method that is then applied to a case study. A programme is undertaken to meter residential electricity demand. Using this data a generalised mathematical model is developed. The model is applied in a Monte Carlo simulation of the three-phase Low Voltage network. A house that was the subject of a power quality complaint, which resulted in network reparation, is chosen for the case study. A retrospective analysis is performed to hindcast the power quality received before the reparation, using both the Monte Carlo method and PEP; this is compared with a voltage trace recorded at the time of the complaint. The analysis is then used to model the power quality for the present network design and compared with measurements. The model is also used to examine phase unbalance, and the effect of sampling interval on measured demand.