The rapid development of fluctuating renewable energies puts forward higher requirements on reserve capacity for sustaining the balance of the power system. To address this issue, this paper investigates a distributed control method of massive thermostatically controlled loads (TCLs) as the virtual power plant (VPP) to provide reserve capacity, considering signal noises. Firstly, the VPP model consisting of massive TCLs is derived to participate in the load regulation. Then, a distributed event-triggered control method is designed for TCLs in the VPP, which can realize the same regulation target and response speed while substantially reducing the communication burden compared with conventional time-scheduled distributed control methods. Finally, the VPP model and the proposed control method are verified by numerical studies, which takes the impact of signal noises into consideration.