Because of the bulk transmission capacity of ultra-high voltage direct current(UHVDC)

there will be a serious power unbalance in the receiving-end power grid once the blocking fault takes place. On occasion

normal dispatch schemes

such as increasing generation output and shedding load

are not sufficient for secure operation of the power system. If the frequency is lower than the threshold

fast demand response(DR)can switch the devices or adjust the setpoint to maintain frequency stability. Meanwhile

by appropriately lowering the bus voltage

power consumption of conserved voltage reduction(CVR)can be adjusted down according to electrical devices' static PV characteristic. So

fast DR and CVR are both able to contribute to low frequency disturbances. By referring to prior assessment and post statistics of fast DR and CVR

and cooperation between fast DR

CVR and direct load control(DLC)

load shedding can be reduced during fault. Thus

the frequency stability of receiving-end power grid can be greatly enhanced by coordination between generation and demand side resources. The effectiveness of the control strategies is proved by simulation. This work is supported by State Grid Corporation of China.