Double Integration Method for Power Frequency Measurement

Nowadays, there are a large number of digital methods for measuring frequency. Most of the accurate measurement methods require a long measurement time. A group of fast-acting methods (three-sample and the second-derivative), characterizes low measurement accuracy in the presence of noise and harmonics. To reduce the shortcomings of both groups of methods, a new approach based on double integration of the input signal was proposed. After performing each integration, the constant component of the signal must be removed. The paper discusses ways to solve this problem. The main advantage of the proposed approach compared to the other fast-acting methods is a significantly smaller dependence of the final frequency error on the input noise and nonfundamental spectral components of the input signal. The main sources of an error are considered. The sensitivity of the method measurement error to the input noise and harmonics of the input signal is analyzed.