Electrical Engineering Department, Escuela Politécnica Superior, Universidad de Sevilla, c/Virgen de África 9, 41011 Sevilla, Spain.
Sensors (Basel). 2021 Feb 14;21(4):1348. doi: 10.3390/s21041348.
The stability of power systems is very sensitive to voltage or current variations caused by the discontinuous supply of renewable power feeders. Moreover, the impact of these anomalies varies depending on the sensitivity/resilience of customer and transmission system equipment to those deviations. From any of these points of view, an instantaneous characterization of power quality (PQ) aspects becomes an important task. For this purpose, a wavelet-based power quality indices (PQIs) are introduced in this paper. An instantaneous disturbance index (ITD(t)) and a Global Disturbance Ratio index (GDR) are defined to integrally reflect the PQ level in Power Distribution Networks (PDN) under steady-state and/or transient conditions. With only these two indices it is possible to quantify the effects of non-stationary disturbances with high resolution and precision. These PQIs offer an advantage over other similar because of the suitable choice of mother wavelet function that permits to minimize leakage errors between wavelet levels. The wavelet-based algorithms which give rise to these PQIs can be implemented in smart sensors and used for monitoring purposes in PDN. The applicability of the proposed indices is validated by using a real-time experimental platform. In this emulated power system, signals are generated and real-time data are analyzed by a specifically designed software. The effectiveness of this method of detection and identification of disturbances has been proven by comparing the proposed PQIs with classical indices. The results confirm that the proposed method efficiently extracts the characteristics of each component from the multi-event test signals and thus clearly indicates the combined effect of these events through an accurate estimation of the PQIs.
电力系统的稳定性对可再生电源馈线中断供电引起的电压或电流变化非常敏感。此外，这些异常的影响因客户和传输系统设备对这些偏差的敏感程度/弹性而异。从任何这些角度来看，对电能质量（PQ）方面进行瞬时特征化成为一项重要任务。为此，本文引入了基于小波的电能质量指标（PQI）。定义了瞬时扰动指数（ITD(t)）和全局扰动比指数（GDR），以综合反映稳态和/或暂态条件下配电网络（PDN）中的PQ 水平。仅使用这两个指标就可以高精度、高分辨率地量化非平稳干扰的影响。这些 PQI 比其他类似的 PQI 具有优势，因为选择了合适的母小波函数，可以最小化小波之间的泄漏误差。产生这些 PQI 的基于小波的算法可以在智能传感器中实现，并用于 PDN 的监测目的。通过使用实时实验平台验证了所提出的指标的适用性。在这个模拟电力系统中，通过专门设计的软件生成信号并实时分析数据。通过将所提出的 PQI 与经典指标进行比较，证明了这种检测和识别干扰的方法的有效性。结果证实，该方法能够有效地从多事件测试信号中提取每个分量的特征，并通过准确估计 PQI 清楚地指示这些事件的综合影响。
