Research on Operating Modes of 750 kV Northwest China Power Grid Electro-Magnetically Coupled with 330 kV Power Grid

Along with the completion and put into service of 750 kV Northwest China power grid, the original 330 kV network will electro-magnetically coupled with the newly built 750 kV power grid. The authors research the influence of operation modes of electro-magnetically coupled 750/330 kV power grid on system security and stability when Northwest China 750 kV main network is preliminarily completed at the end of 2008. The results of static security and stability analysis show that before a strong 750 kV network is built up, the operation mode of electro-magnetically coupled power grid, i.e., the close-loop operation mode, is available to enhance the transmission capacity and stability level of Northwest China power grid than open loop operation mode. For the potential problems such as system oscillation and restricted power transmission that may occur under close-loop operation, some suggestions are put forward, including reinforcing the configuration of security and stability control devices, developing circuit breakers with higher interrupting capacity, optimizing operating modes and network structure, etc., to ensure stable operation of Northwest China power grid.