4. Measures

It is important that measurements made by different devices are reproducible, within the limits of their accuracy. This is why the International Electrotechnical Commission (IEC) is working on a standard defining methods for measuring voltage wave parameters: IEC 61000-4-30. In 2002, this standard was approved as a "preliminary draft standard". It will be amended and put to the final vote as an international standard at the end of 2002. It will then be submitted to the European Committee for Standardization (CEN) to become a European standard. Voltage dips are detected by measuring the RMS voltage over one signal period (i.e. 20 ms for 50 Hz). This measurement is refreshed every half-period (i.e. every 10 ms for 50 Hz).