面向配网电压暂降治理的单相无功电流检测方法研究

当末端配网中有大型负荷投切时,传输线上的无功突变容易引起明显的电压暂降问题,通过在末端配置STATCOM来补偿配网无功突变即可解决此类电压暂降问题。提出了dq坐标系下的单相瞬时无功电流实时检测方法,响应速度快、运算量小、抗噪声/谐波干扰能力强,可实时准确地检测单相配网中的无功电流,可确保STATCOM快速准确地补偿突变的无功,进而削弱无功突变导致的电压暂态问题。该方法通过引入基于三角函数变换的虚拟正交信号构造算法,实现将静止坐标系下的单相电流快速准确地变换至同步旋转坐标系；接着,为了实现在有效抑制干扰的前提下使无功电流检测算法的响应速度最大化,在旋转坐标系下级联了增强型滑动平均滤波器来实现抗噪声/谐波干扰。最后,利用提出的单相无功电流实时检测方法实现了单相链式STATCOM的高性能控制。实验结果表明,提出的检测方法能够快速且准确地跟踪单相配网中的瞬时无功电流变化,同时有效克服噪声/谐波干扰,实现了单相链式STATCOM的高性能控制,验证了所提算法的有效性和先进性。

A Single-phase Reactive Current Detection Algorithm for Restraining Voltage Sag in Distribution Network with Long Feeder

STATCOM can compensate the reactive power change that causes the voltage sag issues of distribution grid with long feeders. In this paper, a novel instantaneous reactive current detection method is developed, overcoming the limitation of conventional methods in detection speed, computation burden and noise/harmonic susceptibility. An improved virtual orthogonal signal generation method based on mathematical deduction is introduced first, remarkably improving the immediacy and precision of detection in dq frame. Then an enhanced moving average filter is utilized in cascade and its design principle is proposed, sufficiently eliminating the effects of noise and harmonics while preserving fast dynamic speed. Finally, high-performance control of single-phase STATCOM is realized utilizing the proposed method. Experiments reveal that the proposed detection scheme is characterized by its fast speed, high precision as well as noise/harmonics immunity.