新疆与西北联网750kV交流联络线功率波动峰值计算分析研究

Calculation and Analysis of the Power Fluctuation Peak Value on the 750 kV AC Tie-Line with Xinjiang Grid Interconnected with Northwest China Grid

2010年,新疆电网通过750 kV哈密—安西(哈敦)双回线与西北主网联网运行。为保障联网后电网的安全运行,分析了哈敦联络线在各种方式下的功率波动情况。联网后的电网通过等值和简化,在扰动后的特定时间段内,联络线功率波动曲线为二阶系统阶跃响应曲线;功率波动峰值大小,取决于功率缺额的数值、两大区交流电网的惯性常数比和区域振荡模式的阻尼比。最后,对新疆送西北1000 MW、新疆受西北500 MW 2种极限方式下的功率波动幅值进行了估算,并通过哈敦线的PMU实测数据、以及中国电科院PSASP程序仿真结果验证了等值、估算的正确性和有效性;同时,该结果表明,在目前的方式下,对设定的扰动仍留有较大的功角稳定裕度。该研究方法有助于掌握两大区互联系统联络线功率波动的动态特性,并提供了扰动校验的简便方法,有利于运行方式的安排和控制措施的制定。

In 2010, Xinjiang grid was interconnected with Northwest China Grid through the 750 kV Hami-Anxi （Hadun） double-circuit line. To ensure the safe operation after the interconneetion, researchers analyzed power fluctuations of the tie-line in several cases. Through network equivalence and simplification, the tie-line power fluctuation curve after the disturbance within a certain time period can be considered as a second-order system step response. The peak value of the power fluctuation depends on the value of power disturbance, inertial constant ratio of two interconnected AC grids and damping ratio of the regional oscillation mode. Finally, the tie- line power fluctuation of two limited cases, namely Xinjiang sending 1 000 MW and Xinjiang receiving 500 MW, are calculated. Through measured data of the 750 kV Hadun line by PMU, and PSASP simulation, the correctness and effectiveness of the calculation is validated. The results show that after these disturbances, angle stability still leaves a large margin. This research helps to master dynamic characteristics of power fluctuations in two interconnected grids, and provides a simple way to check power disturbance, resulting in benefits for the operation mode planning and control measure making.