保留二阶项的连续潮流法

将保留二阶项的普通潮流算法融入电压稳定性分析的连续潮流计算，构成了保留二阶项的连续潮流计算，并分析讨论了算式的具体特点。节点电压采用直角坐标形式，节点功率的二阶表达接近于完整，每个负荷水平下的二阶状态估计值也相当接近其准确值；由于雅可比矩阵恒定，可充分利用稀疏技术。所得算法对IEEE30节点和IEEE57节点系统进行计算，结果表明：就一次计算而言，保留二阶项法的所需时间为常规一阶法的1／2—2／3，如反复进行连续计算，可大大减少计算量，提高运算速度。

Continuation power flow with the second order terms retained

By using the second order power flow equations in voltage stability analysis, an algorithm of the second order continuation power flow is formulated. Because nodal voltages are used in the rectangular form, nodal power equations can be completely expanded with the second order terms retained. It is possible to fully use the advantage of the second order technique. Based on the investigation for the second order representation, the estimation and correction for the initial point in each load level are effectively established. Therefore, the constant Jacobian matrix and corresponding factor-table technique can be employed, which largely reduces the computational requirement. The presented approach is studied on the IEEE30-bus and IEEE57-bus testing systems.The results indicate that, for one time computation, the needed time for QCPF is about 1/2 - 2/3 of that for the constant continuation power flow. When continuous computation is made times without number,the computational requirement will be greatly reduced and the speed will be improved.