Study on Fast Analysis Method Transient Fundamental Frequency Overvoltage of Wind Turbine Generators in Sending System when Serious Power Disturbances Occur in Large-capacity UHVDC

In recent years, with the rapid development of UHV technology and renewble energy generation, when serious power disturbances occur in the large-capacity UHVDCs, the wind turbine generators in sending systems will suffer from serious transient fundamental frequency overvoltage, which may cause many wind turbine generators to trip possibly. Aiming at the problem above, we analyzed the mechanism of the overvoltage throughly, then poposed a fast computational method for the ovevoltage, in which the complete differntial sensitivity formula for node voltage variation caused by load variation were derived. The results are verified with the Jiuquan-Hunan HVDC wind transmission case system. The results show that the proposed method can be adopted to assess the overvoltage of wind turbine generators due to serious power disturbance in UHVDC, the error can be reduced from 21% to 14% compared to the experienced method, which has better engineering applicability.