The paper proposes a stochastic model to analyse the dynamic coupling of the transmission system, the electricity market, and microgrids. The focus is on the impact of microgrids on the transient response of the system and, in particular, on frequency variations. Extensive Monte Carlo simulations are performed on the IEEE 39-bus system, and show that the dynamic response of the transmission system is affected in a nontrivial way by both the number and the size of the microgrids.
