Development of group control method of heat pump water heaters for PV generation and consumption in local area

Abstract

To lower the burden on the global environment, renewable energy resources are increasingly being integrated to power systems, in particular, a great deal of photovoltaics (PVs) in Japan are expected to be installed on the roof-top of residential houses. However, this will make the supply-demand balance control and the voltage control of a power system difficult. A measure to reduce this impact is consuming excess power in local area where PVs are located. We have developed a control algorithm for adjusting the operating pattern of multiple heat pump water heaters as a group to maximize the consumption of excess power of PVs in local area. The problem was formulated as a combinatorial optimization problem, and the tabu search method was applied as a meta-heuristics solution. The result of a case study for group control of six consumers that used the same low-voltage transformer showed an operating pattern that has the following features. First, the consumption of excess PV power was maximized. Second, the consumption of commercial electric power was minimized. We also compared the result by controlling a group of six consumers with the result by controlling of six consumers that had been controlled individually, and showed that the consumption of PV excess power was increased by 46% at the same level of commercial electric power consumption. © 2013 The Institute of Electrical Engineers of Japan.