Relation of Frequency to Power Flow In Tie-Line of Northeast Power Gird in China

The control strategy for frequency in northeast power grid in China and power flow in tie line between northeast and north China power grid are described. Based on statistical analysis of frequency control in Liaoning power grid in 2001 and 2002, this paper analyzed and summarized the causes of the frequency over limit. Combining the real-time records of the frequency and tie-line power flow during the several trips of some major generating units in this area in 2002, the load flow variations in the regions in the northeast power grid are investigated and the natural frequency characteristic coefficients of Liaoning power network and Heilongjiang power network are calculated. The calculation results show that the natural frequency characteristic coefficient continuously varies with different operating modes during the power system operation. It is proved that the regional frequency characteristic coefficient should be set larger than its natural to make the regulation of the deviation of frequency in whole power grid and the power flows in regional tie-lines more favorable