The EW-trending strain variation along the western margin is the maximum and it is characterized by the alternatively positive and negative variations from the west to the east;
东西向应变西边缘变化最大。 此外，由西向东还具有正负交替的变化特征；
2
By using the voltage stability analysis with uncertain factors of load variation considered in computation, more information about the critical point and the minimal power margin will be offered.
By the solid example, reasons that measuring errors, because of minimal variation of cross-coupling matrix, are cleared, and methods for calculating the upper limit of error margin are described.