Study on Power Quality Impacts of Rural Distribution Network with Large-scale Heat Pumps

Abstract

With the advance of the “Coal-to-electricity” program in northern China, heat pump unitsare used more and more widely for rural household heating at a high operating efficiency. When large-scale heat pump units are connected to rural distribution networks, the power quality problems should be considered because of the voltage sag, the current surge, and the harmonics caused by the units. The typical feature, the efficiency index, the operation process and the types of the domestic heat pump units are introduced. The starting characteristics of different heat pump units are compared. Impacts on distribution networkswith heat pumpsare discussed,including the additional load forecast method of heat pump units and the power quality problems. The startup current of the fixed-speed heat pump is too large to cause voltage sag. The variable-speed heat pump may inject the harmonic current into distribution system. A rural distribution network are simulatedwith the actual measurement datain order to analyse the voltage sagsduring the starting process of the heat pump units with different permeability of the units. The corresponding simulation results can be used as the reference for the further implementation of the “Coal-to-electricity” program.