单铝层导线输电网电热协调潮流模型及其解法

Electro-thermal Coordinated Power Flow Model for Single-layer Conductor Network and Its Solution

受钢芯磁滞和涡流损耗作用,单铝层导线交流电阻随电流呈明显的非线性变化,但当前电热协调潮流模型忽略了线路电阻与电流的关系,对结果精度造成了影响。为此,文中以LGJ120/25单铝层导线为对象,搭建了相关实验平台,对不同温度和电流条件下的导线交流电阻进行了实测,结合参数估计方法建立了计及电流变化影响的交流电阻修正模型。在此基础上,将线路电流作为电力系统潮流状态量,提出了针对单铝层导线输电网的电热协调潮流模型及其解耦计算方法。算例结果表明,对于含单铝层导线的高压输电网而言,所提模型能得到更为准确的电热协调潮流计算结果,有效避免线路运行温度裕量被高估的现象,减少线路过载风险,为单铝层导线输电网的安全、经济运行提供依据。

Owing to magnetic hysteresis and eddy current losses in the core,the AC resistance of single-layer conductor varies nonlinearly over a substantial range with the carrying current. However,the nonlinear relationship between resistance and carrying current is neglected in the conventional electro-thermal coordinated power flow model,which may cause inaccuracy in the simulation results. Therefore,an experimental platform is set up to measure the resistance values of conductor LGJ120 /25 under different current and temperature conditions. Then a simplified AC resistance model taking the effects of carrying current into account is developed based on the parameter estimation method. On this basis,an electro-thermal coordinated power flow model for single-layer conductor network is proposed by regarding the line current as a state variable of the power system,and a decoupling algorithm for the model is derived.Case study results show that the model is able to provide a more accurate result of electro-thermal coordinated power flow,thus effectively avoiding overrating the allowance of line operating temperature,while reducing overload risks for transmission lines and improving system security for single-layer conductor network.