| Popis: |
With the continuous increasing load and construction of UHV, A plurality of EHV / UHV AC and DC transmission lines centralize in the load center. In order to analyze the interactive effects of AC or DC system when fault occurs, a hybrid simulation model on electromechanical and electromagnetic transient process of AC and DC is established for regional power grid. The electromagnetic transient model covers the EHV / UHV AC and DC transmission lines, EHV / UHV transformer and lots of generators. Various faults are simulated in four network partitions, including all kinds of AC and DC transmission faults. On the basis of simulation, the characteristics and interactive effects of AC and DC system is studied. Research results suggest that for load center with both DC and AC, AC system faults will cause multiple HVDC commutation failure, thereby affecting the performance of AC relay protection. For the power grid closely connected, the DC system blocking will not cause any problem on system stability. |
