风火打捆交直流外送系统区域间输电能力评估

Assessment on the Total Transfer Capability of AC/DC System for Integrated Wind-Thermal Power

风火打捆交直流外送是一种重要的输电形式,风电出力的波动性以及交直流混联的输电方式对其区域间输电能力的计算提出了新的要求。首先建立了风火打捆经交直流输电通道送往同一受端区域的系统模型;考虑到系统无功充裕度问题,建立了基于改进连续潮流算法的最大输电能力(TTC)计算模型,完成了对其单一样板值的快速求取;在此基础上,综合考虑风电固有的波动特性以及系统内各种不确定因素,采用非序贯蒙特卡洛仿真法对区域间输电能力进行概率评估,并通过实际算例进行验证,发现交直流混联的输电形式可以提高系统的区域输电能力,在合理范围内通过增加风火打捆比例可以提高区域间输电能力,但是当风火打捆比例较高时,只有对现有网架结构进行改造升级,提高线路的输电容量,才能进一步提高系统的TTC水平。

AC/DC delivery of integrated wind-thermal power will be an important form of transmission in the future in China.The volatility of wind power output and the AC/DC hybrid transmission mode bring a new challenge to the calculation of the interregional total transfer capacity(TTC).Firstly,a system model is established for delivery of the integrated wind-thermal power into the same receiving-end area through the AC/DC transmission channel.Considering the problem of system reactive power adequacy,a TTC calculation model is established based on the improved continuous power flow algorithm,and the single sample value is quickly acquired.Then,considering the inherent volatility of wind power and various uncertain factors in the system,the nonsequential Monte Carlo simulation method is used to evaluate the inter-regional TTC,and the result is verified by case study.It is found that the AC/DC hybrid transmission mode can improve the regional TTC of the system,and the inter-regional TTC can be improved by increasing the proportion of integrated wind-thermal power within a reasonable range.However,when the proportion of wind-thermal power is too high,only the existing grid structure is upgraded and the transmission capacity of the transmission lines is improved,can the system's TTC level be further increased.