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Improving power quality is important for grid security, economic operation and reducing energy consumption and is directly related to the overall effectiveness of the national economy. Real-time monitoring of power quality has a positive impact to effectively identify and analyze the phenomenon of power quality disturbances, and to improve the quality of power supply system. Traditional detection system has been unable to meet network, intelligence, standardization, real-time and other testing requirements.Therefore, this paper proposed and designed the general power quality analysis platform based on virtual instrument, which can monitor voltage, current, power, frequency, sags, harmonics and other power quality parameters and indicators, and has some analytical ability. The main works are as follows:1 The definitions of common power quality and indices, including voltage deviation, frequency deviation, grid harmonics, three-phase unbalance and voltage fluctuation and flicker, are summarized.2 GST is introduced to analyze the typical PQDs, and extracts a set of useful characteristics. Then various disturbance training samples are employed to construct the characteristics sets which are applied to train a multi-lay SVMs classifier. Finally, 400 testing PQDs samples are identified using the SVMs classifier, in which N kinds of PQDs are classified by N-1 turns.3 The overall framework of the general power quality analysis system based on virtual instrument with modular design method is presented. Then the structures and functions of the system are determined. The common power quality indices are programmed by LabVIEW, in which voltage sag and grid harmonics are the main issues. Finally, the system implements the alarm, record wave, storage, query and other functions.
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