Novel Modulation Strategy of Stability-Controlling Device After Failure Occurred in HVDC Power Transmission System

Once unexpected failure occurs in high-capacity HVDC power transmission system,it greatly affects both AC power systems located at sending and receiving ends of the HVDC power transmission system,so it is necessary to ensure the stability of whole interconnected power grid by stability-controlling device.Taking an interconnected power grid containing multi HVDC power transmission channels as research object,based on the feature of HVDC system that its power could be rapidly modulated,an action strategy of stability-controlling device after a failure occurred in a single HVDC transmission channel was proposed.In the proposed strategy,the constraints such as critical tie line limitation,power flow,unit output and system stability were taken into account,and the power originally transmitted by the faulty transmission channel was transferred to other HVDC power transmission channels to ensure the minimal power decrease due to power modulation.The effectiveness and practicality of the proposed modulation strategy were verified by simulation results of CEPRI 36-bus system and the results of a computational example of bipolar DC block fault occurred in HVDC transmission system of a certain actual interconnected power grid.