A protection system for an artificial lift device including but not limited to electrical submersible pump and an electrical submersible progressing cavity pup. The temperature of an aqueous solution contained in a freezer which includes a heat exchanger for cooling is measured with a thermometer, and as the liquid temperature drops with the progress of freezing, melted water is replenished into the freezer from a melted water tank by means of a pump to keep almost constant the temperature of freezing performed by the heat exchanger for cooling. The result is a system that operates at nearly constant voltage without the need for an expensive power conditioning system.