Abstract: The frequent power failure caused by the engineering operation in the substation area has influenced greatly on the production and life of residents. In order to improve the reliability of power supply, the use of low-voltage generator cars for power protection is an important means in common use. At present, the average time for the on-site electricity preservation preparation of the low-voltage generator car is 20.6 minutes, which does not meet the requirements of the company's high-quality production target of 15 minutes. The QC team shortened the time for the preparation of the electricity conservation site to 9.9 minutes by finding the crux of the problem and the main cause, and formulated corresponding countermeasures, achieving the goal while improving the electricity conservation rate.