A novel non-unit transient based boundary protection for HVDC transmission lines using synchrosqueezing wavelet transform
A novel non-unit transient based boundary protection for HVDC transmission lines using synchrosqueezing wavelet transform
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DOI：
10.1016/j.ijepes.2019.105478
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发表时间：
2020-02
影响因子：
5.2
通讯作者：
Duan Jiandong-;Hao Li;Y. Lei;Lihao Tuo
中科院分区：
文献类型：
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作者：
Duan Jiandong-;Hao Li;Y. Lei;Lihao Tuo
高压直流输电系统在协调电网异步互联和能源综合利用方面具有重要的意义，因此，可靠、快速的故障切除是保证电力系统安全稳定运行的重要环节。在分析高压直流输电边界特征的基础上，提出了一种新型的基于非单元暂态的边界保护作为高压直流输电线路的主保护，并采用新型同步压缩小波变换（SWT）进行时频（T-F）表示。SWT通过对连续小波变换（CWT）的T-F谱进行同步压缩和重新分配，可以获得高分辨率的T-F谱，从而提高保护的可靠性。基于调谐电压和低频电压通过边界的传输差异，提出了基于SWT的非单位暂态边界保护算法，并利用正负电压微增量的比值来选择故障线路。利用PSCAD对±800 kV高压直流输电工程进行了仿真，并结合现场数据对所提出的保护方案进行了验证。实验结果表明，与基于连续小波变换的边界保护相比，该方法在各种故障类型下均能快速、可靠地执行保护动作，特别是对换相失败具有免疫能力，对切换操作和距离线路最接近的故障具有良好的保护性能，且具有较高的选择性和灵敏度。
Since high voltage direct current (HVDC) transmission system takes on significant tasks in coordinating the power grids asynchronous interconnection and the comprehensive utilization of energy resources, the reliable and fast faults clearance to guarantee the safety and stability of the power system should be attached great attention. This paper, based on the analysis of the HVDC boundary characteristics, proposes a novel non-unit transient based boundary protection as the main protection for HVDC transmission lines, and uses the novel synchrosqueezing wavelet transform (SWT) for time-frequency (T-F) representation. By synchrosqueezing and reassigning the T-F spectrum of the continuous wavelet transform (CWT), SWT can obtain a high resolution T-F spectrum, which brings higher reliability to protection. Based on the transmission differences between tuning voltage and low-frequency voltage by the boundary, this paper proposes the SWT-based non-unit transient boundary protection algorithm, and the ratio of the positive and negative voltage micro-increment is used to select the faulty line. Extensive PSCAD simulations of ±800 kV HVDC project and some field data are used to test the proposed protection scheme. Compared with the CWT-based boundary protection, experimental results verified the proposed method could perform rapidly and reliably in various types of fault, especially can be immune to commutation failure and shows good performance for switching operation as well as fault closer to the very begging of the line, and with high selectivity and sensitivity.