Power Quality Monitoring System Based On Virtual Instrument

With the development of new energy technologies, the power qualityproblems brought by high-power electronic switching devices have become moreprominent than before, the power quality requirements of all walks of life areincreasingly high. Therefore, an in-depth study to achieve comprehensive monitoring,control and management of power quality has an extremely important social andeconomic significance.In view of the current existence of spectral leakage, fences phenomena andother issues when performing harmonic detection, we propose a wavelet-basedcompensation windowed interpolation FFT harmonic analysis algorithm. Thismethod features the use of multi-resolution Mallat algorithm for accurate positioningof the interference signal selectively, while the steady-state harmonic componentextracted, and then using FFT excellent frequency characteristics, identify all theharmonic components, so effectively reduce the computational complexity, andimprove the harmonic detection in real time. As the traditional time-frequencyanalysis methods in dealing with complex fault signal have some limitations, theyhave been unable to meet needs of real-time analysis when the power system failureand complex disturbance occurs. This paper presents a Hilbert-Huang transform(HHT) analysis algorithm for transient power quality disturbance signal detection.This method can accurately detect the disturbance signal timing, frequency andamplitude information after empirical mode decomposition, and Hilbert transform.On this basis, a hardware test platform was built at last, and the design of powerquality monitoring system was completed on the LabVIEW platform. Tests inaccordance with national standards have been made, and the result proved its validityand the detection accuracy. The system reached the Class A requirements for testingequipment.