利用电压幅值差和测量阻抗特征的风电T接线路保护方案

A Protection Scheme for Teed Lines With Wind Power Based on Voltage Magnitude Difference and Measuring Impedance Characteristics

风电T接线路的保护受风电故障特征、T接线路拓扑等因素影响,整定与配合困难,研究其对系统的安全稳定运行意义重大。利用三侧电压幅值差和测量阻抗特征,提出了一种适用于风电T接线路的纵联保护新方案。首先,研究了传统距离保护在风电T接线路中的适应性,并指出其存在的不足。其次,从T接线路拓扑出发,利用三端正序电压、正序电流关系,提出综合电压幅值差主判据。再次,立足于测量阻抗特征,提出自适应距离辅助判据以消除主判据盲区。该保护方案能够实现全线速动,受风电故障特征和T接线路拓扑影响小、耐过渡电阻能力强、对数据同步性要求低。最后,对所提方案进行仿真建模,仿真结果验证了方案的可靠性和有效性。

For teed lines with wind power, their topology and wind power fault characteristics bring difficulties for relay protection configuration and setting, so it is important to study corresponding protection scheme for safety and stability of teed lines with wind power. In this paper, a protection scheme based on voltage magnitude difference and measuring impedance characteristic is proposed. Adaptability of traditional distance protection is analyzed and its possible limitations are pointed out. From viewpoint of teed lines topology, using relationship between positive-sequence voltage and current at three sides, main criterion based on comprehensive voltage amplitude difference is proposed. Based on measuring impedance characteristic, an adaptive distance auxiliary criterion is proposed to eliminate dead zone of the criterion. The proposed protection scheme can realize whole line high speed performance and possesses a strong ability to resist fault resistance. Influences of wind power fault characteristics and teed lines topology on it are little and strict synchronization of sampled data is not needed. Reliability and effectiveness of the proposed scheme are verified by simulation results.