A low cost automated scheme to avoid load shedding during simultaneous start-up of single and three-phase aplit air-conditioning units

There is a very large number of split air conditioners without inverter in operation in Mauritius and despite the various advantages that inverter-equipped air conditioners offer, traditional air conditioners are still being widely installed in the country because there is no legislation regarding the use of energy efficient equipment at present. In this paper, we design a low cost automated scheme to avoid load shedding during simultaneous start-up of single and three phase split air-conditioning units. The main idea is to give customers the flexibility of extending their plant's load without bothering too much about load-shedding when starting all their equipment at a time. The design strategy is based on a PLC which interfaces the indoor with the outdoor unit of every split air conditioner. Furthermore, the possibility of reducing the maximum kilovolt-ampere (KVA) demand with this strategy is also possible. Finally, the design is tested and implemented on a sample of three such single phase units based in Mauritius. Analysis of the results of this scheme clearly shows its superiority compared to the simultaneous start-up of three units normally in terms of the peak apparent power consumption.