To analyse the impacts of the overvoltage of energizing no-load cable to a microgrid， the simulation model of the microgrid based on PSCAD/EMTDC is designed. This simulation model includes three types of micro-sources， small synchronous generators， wind turbine generators based on asynchronous generators and micro-sources based on inverters. This paper studies the overvoltage level under three kinds of conditions， different cable length， different micro-source types and different system operation models. The results shows that the overvoltage of energizing no-load cable exceeds 4 p.u. when the cable length is less than 1 km， which endangers the insulation of electrified equipments. In addition， the micro-source types， system parameters and operation models have certain influence on the overvoltage.