Very Fast and High Accuracy Line Frequency Deviation Meter Design

In the control of HVDC converters, devices are required for obtaining signal proportional to the frequency of the AC side of the converters. For this purpose high accuracy and very fast response is needed. This paper describes a digital method for the accurate measurement of line frequency and its deviation from its nominal value. The method is based on counting a number of high frequency pulses proportional to the line period and then calculating the line frequency deviation by using a high capacity ROM. The design of a prototype with 0.02 Hz resolution and 20 msec response time is introduced in this paper.

Keywords:

frequency deviation , DC transmission , frequency control , microprocessor