Abstract: To better guide the construction and application of joint frequency regulation project of energy storage and thermal power and to promote the development of the auxiliary frequency regulation market in South China, the construction and operation of joint frequency regulation project of China Southern Power Grid are introduced. The benefits from frequency regulation of energy storage system and its influences on power grid are especially analyzed, and the main conclusions include: the energy storage system basically has no influence on torsional vibration mode, power system stabilizer function and primary frequency regulation of the unit; the harmonic of energy storage ratio can be restrained less than 1% through resonance rejection technologies such as the repetitive control technology. Moreover, the performance index and mileage of comprehensive frequency regulation can be well improved, which remarkably increases the frequency regulation compensation revenue and economic benefits.