Power flow transfer caused by overloaded tie-lines tripping-off is one of the main reasons leading to cascading failure. However, too strict flow restriction of the tie-lines may inhibit the transmission capacity of the line, resulting in a waste of transmission resources. In order to solve the problem of unnecessary load control caused by the change of the sharp-peak load, it is possible to allow the tie-lines to be overloaded in a short time without affecting the safety of the system. Based on the predicted load curve and the ambient temperature change curve, the load flow-temperature model of the tie-lines is established on account of the dynamic thermal equilibrium process. To solve the model, the BS23 algorithm is proposed. The model can be used to calculate the conductor temperature dynamically and determine the short-time overload capability of the tie-lines to improve the transmission capacity. By way of the simulation of a 16-node system, it shows that the proposed method can retain the peak load and keep the line temperature within the allowable range. As a result, the transmission capability of the section is improved effectively.%断面中的线路过载跳闸引起的潮流转移是导致系统连锁跳闸的重要原因.然而,过于严格的断面潮流限制可能抑制了线路的输送能力,造成了输电资源的浪费.为解决由尖峰负荷变化引起不必要的负荷控制的问题,可在短时间内允许断面一定程度的过载而不影响系统安全.利用预测的负荷曲线和环境温度变化曲线,考虑动态热平衡过程,建立了断面潮流—温度模型,并提出了该模型的BS23求解算法.通过该模型实现断面导线温度的动态计算并确定断面的短时过载能力.通过对某16节点系统进行仿真计算,结果表明所提方法能够保留尖峰负荷而保证导线温度维持在允许范围之内,较为有效地提高了断面的输电能力.
展开▼
