The reasonable transmission efficiency of power grid considering to the security constraint

The reasonable transmission efficiency of power grid was analyzed considering to N-1 and power outrage risk constraint respectively in this paper. The representative index of security and efficiency had been selected to reflect the condition of power grid. In the aspect of security, the N-1 Pass ratio represented the determinacy index and the power outage risks represented a non-determinacy index were used to evaluate the security of grid, the transformer and power line load ratio was used to assess the efficiency of power grid. The relation between security and efficiency of power grid with unchanging framework was studied. The efficiency of considering to N-1 constraint was obtained through the optimal growth load. The variation ratio are defined to seek the rapidly increase point of security relative to efficiency, and the reasonable transmission efficiency of power grid considering to the power risk outrage constraint was found out by the variation ratio.