基于特定频带能量比的高压直流输电线路保护

High-voltage DC Transmission Line Protection Based on Energy Ratio of Specific Frequency Band

随着大规模交直流混联电网的发展,交流侧和直流侧之间的联系更加紧密。考虑换流器交直流侧的谐波映射关系,提出一种基于换流站交直流侧特定频带能量比识别直流故障的保护方案。换流器交流侧和直流侧在特定频带内的故障电压、电流谐波存在联系,利用故障电压、电流关系计算特定频带能量比,根据此特定频带能量比识别直流故障。该方案考虑了交流侧和直流侧的耦合作用,融合了换流站交流和直流侧的信息,提高了保护的可靠性。仿真测试结果验证了所提保护方案能够可靠、快速地识别直流输电线路故障,抗干扰能力较强。

With the development of large-scale AC/DC hybrid power grids,the connection between the AC side and DC side has become tighter.Considering the harmonic mapping relationship between the AC and DC sides of the converter,a protection scheme is proposed to identify DC faults based on the energy ratio of specific frequency band of the AC and DC sides.There is a relation between the fault voltage and current within the specific frequency band of the AC and DC sides of the converter.The relationship of fault voltage and current is used to calculate the energy ratio of specific frequency band,and the DC fault is identified based on the energy ratio of specific frequency band.The proposed scheme considers the coupling between AC and DC sides,integrates the information on the AC and DC sides of the converter station,and improves the reliability of the protection.The simulation test results verify that the proposed protection scheme can reliably and quickly identify the faults in DC transmission lines,and has a strong anti-interference ability.