电网断面热稳定限额计算模型及方法

分析了电网预想开断前后设备组(并联运行的线路或并列运行的主变压器)的有功潮流变化情况。通过剩余/转移系数将预想开断后的设备组有功潮流表示为设备组初始有功潮流的线性函数。依据设备短时、长期运行载流量确定设备组初始有功潮流的约束条件,根据设备组热稳定限额与初始有功潮流的最小比值最大原则,提出了设备组热稳定限额的优化计算模型。运用线性规划单纯形法进行求解,并通过分岛计算提高算法的执行效率。根据用户定义的断面集,对设备组的热稳定限额进行叠加,给出断面热稳定限额。浙江电网的实际算例结果验证了所述模型的正确性和求解方法的有效性。

Calculation Model and Method for Thermal Stability Control Limit to Transmission Interfaces in a Power Grid

The relationships between post-contingency and pre-contingency active power flows for a group of devices(paralleled lines or transformers) are studied.The post-contingency active power flows are formulated as linear functions of pre-contingency active power flows with the concept of transfer/residual coefficients.The constraints on the device group’s active power flow are formulated according to the short-term and long-term thermal stability limit.To maximize the ratio of control limit to the corresponding pre-contingency active power flow,a linear programming model is proposed to optimize the thermal stability control limit for device groups.The proposed linear programming model is solved by simplex method,and is divided into a few islands to improve calculation efficiency.The control limits of user defined transmission interfaces are deemed as the sum of that of related device groups.The practical test results on Zhejiang power grid show the correctness and efficiency of the proposed method.