Power-Quality Monitoring Instrument With FPGA Transducer Compensation

In this paper, the design and the prototype implementation of a power-quality (PQ) measuring and monitoring instrument based on an embedded controller with reconfigurable I/O are described. The instrument performs the calculation of main PQ indexes according to the latest standards, and it can be reconfigured for future standard developments. It is properly implemented to operate in stand-alone mode, and it is interfaced with hardware modules to exchange information and data, locally, with RS-232 connection or, remotely, with Transmission Control Protocol/Internet Protocol communication. The design includes enhancing of transducer performances through the correction of systematic errors with digital filters implemented by a field-programmable gate array module. This instance allows better performance without increasing cost. Finally, the whole accuracy of the proposed measurement system is evaluated by experimental tests that were performed in agreement with the specification of a class-A instrument for some of the main PQ indexes. The tests are performed, including the transducers, although that component is not required by the standard, to evaluate the behavior of compensated transducers. The test results are compared with those obtained by a commercial PQ instrument and show a good agreement.