In many applications, modern current-using equipment utilizes power electronic converters to control the consumed power and to adjust the motor speed. Such equipment is used both in industrial and domestic installations. A characteristic feature of the converters is producing distorted earth fault currents, which contain a wide spectrum of harmonics, including high-order harmonics. Nowadays, protection against electric shock in low-voltage power systems is commonly performed with the use of residual current devices (RCDs). In the presence of harmonics, the RCDs may have a tripping current significantly different from that provided for the nominal sinusoidal waveform. Thus, in some cases, protection against electric shock may not be effective. The aim of this paper is to present the result of a wide-range laboratory test of the sensitivity of A-type RCDs in the presence of harmonics. This test has shown that the behavior of RCDs in the presence of harmonics can be varied, including the cases in which the RCD does not react to the distorted earth fault current, as well as cases in which the sensitivity of the RCD is increased. The properties of the main elements of RCDs, including the current sensor, for high-frequency current components are discussed as well.

中文翻译：

---

使用谐波测试A型剩余电流设备对接地故障电流的灵敏度。

在许多应用中，现代用电设备利用功率电子转换器来控制消耗的功率并调节电动机速度。此类设备可用于工业和家庭安装。转换器的一个特征是产生失真的接地故障电流，该故障电流包含多种谐波，包括高次谐波。如今，低压电源系统中的电击防护通常是通过使用剩余电流设备（RCD）来实现的。在存在谐波的情况下，RCD的跳闸电流可能与为正弦波形提供的跳闸电流明显不同。因此，在某些情况下，防触电保护可能无效。本文的目的是介绍在谐波存在下对A型RCD灵敏度进行的广泛实验室测试的结果。该测试表明，在存在谐波的情况下，RCD的行为可以改变，包括RCD对失真的接地故障电流不反应的情况以及RCD的灵敏度提高的情况。还讨论了RCD的主要元件（包括电流传感器）的高频电流分量的特性。