The chemical industry is the embodiment of the country's comprehensive national strength, in recent years, the number of chemical enterprises, large scale, strong continuity, high safety requirements, high distribution automation requirements, so the continuity of power supply, safety, reliability put forward higher requirements. According to the demand characteristics of the chemical industry, Mulang Electric put forward the industry-leading solution, through the calculation of various parameters of the system, reasonable selection of distribution protection devices, and the use of microcomputer protection system for comprehensive monitoring and control, to ensure production safety.