提出了一种多机电力系统稳定器( PSS) 参数协调优化的共轭梯度法．该方法以系统动态组合泛函作为评价PSS 阻尼效果的性能指标，通过变分法处理组合泛函指标中的积分项，提出了采用轨迹逆积分技术计算该指标对PSS 参数向量梯度的新方法．该方法以上述组合泛函指标最小作为PSS 参数优化模型中的目标函数．由于目标函数考虑了电力系统大扰动的非线性特征，因此优化后的PSS 可提高系统的小扰动稳定性，并对大扰动引起的功率振荡提供充分的阻尼．通过在IEEE 四机双区域和十机新英格兰测试系统上的算例验证了该方法的可行性和有效性．

Proposed in this paper is a new conjugate gradient approach for the coordination of the power system stabilizer ( PSS) parameter optimization of multi-machine power system. In this approach,combination functional index is introduced as a performance index to evaluate the damping effect of PSS,the integral term of the index is dealt with by means of the variational method,and a backward trajectory integration approach is put forward to calculate the gradient of the index to the PSS parameter vector. Moreover,minimizing the index is taken as the objective function of the optimization model of the PSS parameter,and the objective function considers the nonlinear features of big disturbance of the power system,so that the optimized PSS can improve the small-disturbance stability of the power system and efficiently damp the power oscillation caused by large disturbances. In addition,the practicality and effectiveness of the proposed method are verified on IEEE 4-generator 2-area and IEEE 10-generator New England test systems.