摘要
新能源经柔直送出系统中,新能源电源到柔直整流侧换流器之间的输电线路较为特殊,故障后两侧短路电流均受电力电子设备的控制策略影响,导致传统的差动保护在双侧电流受控的场景下出现灵敏度降低,甚至存在拒动作的风险。因此,该文提出基于矩阵突变特征的交流线路保护新原理。首先,利用Toeplitz矩阵变换能快速放大突变信号占比的特性,将所测得的电流信号构造成Toeplitz矩阵形式。然后,利用矩阵梯度可以精准表征数据突变程度的优势构建保护判据,以实现故障的高速可靠判别,从而解决传统保护因故障电流幅值、相角受控导致的灵敏性降低以及不正确动作的问题。最后,在PSCAD中搭建风电场经柔直送出系统的电磁暂态模型,验证所提保护方法的动作性能。结果表明,所提保护能够短时间内识别区内外不同种类故障,故障识别时间小于5ms,且有最高耐受100Ω的过渡电阻的动作性能,能较好地满足风电场经柔直送出系统对保护灵敏性与可靠性的需求,具有较好的抗过渡电阻和噪声的能力。
The AC transmission line between the new energy source and the MCC of the VSC-HVDC transmission is special.Short circuit current on both sides after fault is controlled by power electronic equipment.The relay protection faces the risk of reduced sensitivity and even the risk of rejection.Therefore,this paper proposes a new principle of AC line protection based on matrix mutation characteristics.First,the Toeplitz matrix transformation can quickly amplify the characteristic of the sudden change in the proportion of the signal.The measured current signal is constructed into the Toeplitz matrix form.Then the protection criterion is constructed by using the advantage that the matrix gradient can accurately characterize the degree of mutation in the data,so as to solve the problem of reduced sensitivity and incorrect operation of conventional protection caused by the fault current amplitude and phase angle controlled.Finally,an electromagnetic transient model of a wind farm via a VSC-HVDC transmission system is built in PSCAD and the action performance of the proposed protection method is verified.The results indicate that the proposed scheme can better meet the demand of the wind farms integrated with VSC-HVDC system protection for the sensitivity and reliability,with fault identification time less than 5ms,and good resistance to transition resistance and noise.
作者
余越
王聪博
沙兆义
杨国生
詹荣荣
阮思烨
YU Yue;WANG Congbo;SHA Zhaoyi;YANG Guosheng;ZHAN Rongrong;RUAN Siye(State Key Laboratory for Security and Energy Saving(China Electrical Power Research Institute),Haidian District,Beijing 100192,China;State Grid Corporation of China,Xicheng District,Beijing 100031,China)
出处
《中国电机工程学报》
EI
CSCD
北大核心
2023年第14期5441-5449,共9页
Proceedings of the CSEE
基金
国家重点研发计划项目(2021YFB2401000)。
