The characteristics of a power quality disturbance generator for microgrid is described. The generator is used to test the performance of a microgrid including STS. The proposed generator has good features of high reliability, low cost, simple structure, high efficiency, and reduced voltage drop. The main switching device is SCR thyristor, and all the thyristors have natural commutation characteristic, which provides reliable system. The circuit analysis and operating principle of the proposed scheme are described in each mode of voltage sag and outage. The dynamic characteristics of the voltage and current in case of voltage sag and outage is analyzed through simulation.