Based on the risk of frequency security of the northwest sending-end power grid

a test method for the frequency characteristics of the northwest sending-end power grid is presented. The frequency ramp disturbance is generated by gradually increasing and decreasing the output of the hydropower generating units in the network. Through the analysis of the frequency response of the power grid

the whole frequency static characteristics of the northwest sending-end power grid are measured. At the same time

the actual frequency large-step disturbance is made by the trip of two large-scale hydropower units in the network. The dynamic characteristics of the whole northwest network are measured and the performance of the primary frequency regulation of the conventional power unit is tested. The practical application shows the feasibility of the proposed method.