基于过渡电阻倾斜角的风电T接双电源系统自适应距离保护方案

针对风电T型接入高压配电网后传统距离保护可能发生误动、拒动的情况,研究相对应的保护方案意义重大。首先,文章推导了风电T接点上、下游测量阻抗表达式,得出其包含的附加阻抗可能会使传统保护装置不正确动作。鉴于此,提出基于过渡电阻倾斜角的风电T接系统自适应距离保护方案。该方案自适应修正测量阻抗使其能跟踪到短路阻抗,有效消除附加阻抗对距离保护的影响。最后,在MATLAB仿真软件中对方案进行仿真验证,结果表明该方案受故障点位置、过渡电阻、电源相位差及风电运行方式影响较小,可有效解决传统距离保护拒动或者误动的问题,提高电网的安全稳定性。

Adaptive distance protection scheme of wind power T-connected dual power system based on transition resistance inclination angle

In view of the situation that the traditional distance protection may misoperate and refuse to operate after the wind power T-type is connected to the high-voltage distribution network, it is of great significance to study the corresponding protection scheme. First of all, this paper deduces the expressions of measurement impedance of upstream and downstream of wind power t-contact, and concludes that the additional impedance contained in it may make the traditional protection device not operate correctly. In view of this, an adaptive distance protection scheme of wind power T-connection system based on transition resistance inclination angle is proposed. The scheme can adaptively modify the measured impedance so that it can track the short-circuit impedance and effectively eliminate the influence of additional impedance on distance protection. Finally, the scheme is verified by MATLAB simulation software. The results show that the scheme is less affected by the fault location, transition resistance, power phase difference and wind power operation mode, which can effectively solve the problem of refusing to operate or misoperation of traditional distance protection, and improve the security and stability of power grid.