基于端电压特征的半波长线路综合保护方案

半波长线路区外故障时,故障相端电压幅值很小;线路中间段故障时,故障相端电压幅值接近额定值。根据这一特征,提出半波长线路端电压特征与贝瑞隆电流差动保护原理相结合的综合保护方案:通过端电压辅助判据与高、低灵敏度不同的贝瑞隆差流判据相结合,保护线路全长并实现故障选相。利用MATLAB/Simulink软件搭建半波长输电线路模型,进行仿真验证。仿真结果表明:该保护方案能够有效区分区外故障与线路中间段故障,可靠保护半波长线路全长,并准确识别故障相。

Comprehensive protection scheme for half-wavelength lines based on terminal voltage characteristics

It was found that in the half-wavelength line, the terminal voltage of the fault phase was low under external fault. While the middle section of the line failed, the terminal voltage of the fault phase was close to the rated value. Based on this feature, a comprehensive protection scheme was proposed, which combined the characteristics of the terminal voltage with Bergeron current differential protection. The terminal voltage auxiliary criterion and the Bergeron differential current criterion with different high and low sensitivity were combined to protect the full length of the line so as to realize the fault phase selection. Then a half-wavelength transmission line model was established based on MATLAB/Simulink platform to carry out simulation verification. The simulation results show that the protection scheme can reliably protect the full length of half-wavelength lines and accurately identify fault phases.