A Precision High Speed AC Power Monitoring Device for Power Regulation and Control

 Abstract — Precision measurement of AC power at conversion rates comparable to the driving frequency is a challenging task but is a desirable feature in applications involving regulation of power, loaded on a device. Practically, the application assumes significance, typically in developing a test-bench for characterization of a power generation system such as engine (DG set), or to measure and manage the power load in a specified pattern. A good analysis of demands and deliveries of power loads require capturing of transient responses, leading to a need for faster conversion rates in the measurement. Since the AC power measurement involves RMS integration, known to be inherently a slower process, the transient phenomena like a step loading tends to get smudged during measurement and often could lose its identity. It is known that typical conversion rates of commercially available power meters are about 0.5 to 1 Hz. In the approach presented here, a specifically developed analog circuitry, that is built using industrially common analog devices is shown to provide a high definition RMS integration of the AC power (with a typical conversion rate better than 35Hz for a 50 Hz signal source) that is developed, tested and qualified for its functional integrity. The application finds a niche slot, when this module is used as a feedback source, it serves to build a precision power regulator with high reliability and with near- to-practically-fastest realizable conversion speeds. The module when tagged with a power loading panel enables it to load a device to a desired power level with a programmable rate and at high precision. The design allows flexibility in changing its sensitivity by tuning at the field-level making the module versatile and industrially adoptable. The measurement device presented is found to be comparable or lower in cost to build it, as compared to its commercial counterparts, but exceeds in its capability significantly with an enhanced speed and precision of measurement.