Abstract: A power monitoring device is disclosed. In at least one embodiment, the power monitoring device includes a power parameter measurement unit for calculating the measurement results of basic power parameters according to acquired digital signals of a voltage and/or a current; and a power quality analysis unit including a field programmable gate array, for obtaining power quality analysis results by executing a wavelet transform algorithm, a fast Fourier transform algorithm, an artificial neural net algorithm or a fuzzy logic algorithm in a parallel mode according to the acquired digital signals of voltage and/or current to perform analysis of stationary and transient power quality disturbances. Since the power monitoring device of at least one embodiment of the present invention employs a field programmable gate array, it can perform power quality analysis, power parameter measurements and other peripheral functions with relatively good performance.

Abstract: At least one embodiment of the present invention proposes a dynamic voltage compensator for compensating voltage fluctuations in a three-phase power supply system. In at least one embodiment, the dynamic voltage compensator includes two dynamic voltage restorers (DVR), and two phases are selected arbitrarily from the three-phase power supply system with each selected power supply phase connected in series with one of said dynamic voltage restorers respectively. The dynamic voltage restorers are each used to monitor the voltage between the power supply phase it is connected to and the power supply phase unselected, and to restore the voltage to a normal level when voltage fluctuation is monitored, and at the same time the phase voltage of the unselected phase can also be restored to its normal level. In this way, it can ensure that the phase voltages of the three phases can be restored to the normal level by using only two sets of single-phase DVRs.

Abstract: At least one embodiment of the present invention provides a method for detecting voltage disturbance. In at least one embodiment the method includes storing the digitized point values of a voltage reference waveform; detecting actual voltage values, and converting the actual voltage values by digitization into point values of the actual voltage which are in one-to-one correspondence with the point values of the reference waveform; comparing the point values of the actual voltage with the corresponding point values of the reference waveform; judging that a voltage disturbance occurs if, for N successive points, the differences between the point values of the actual voltage and the corresponding point values of the reference waveform are all greater than a predetermined disturbance threshold, wherein N is an integer greater than 0. A technical solution of at least one embodiment of the present invention improves the response speed of the detection, and shortens the response time.