Research On Integrated Detection And Recorded Data Compression Of Power Quality

There are new trends in the grid and load structure of modern power system, leading to various power quality problems which have aroused great attention of power departments and users. Power quality monitoring is a prerequisite for supervising and improving power quality, and a guarantee for power system's safe and economic operation and users'security. Thus, it's significant in both theory and practice. The operation of modern power system and the development of smart grid put forward higher requirement for power quality monitoring technology. Traditional instruments limited to steady-state power quality detection no longer meet the requirements, since dynamic quality detection becomes more and more concerned and more intuitive real-time information about power quality is necessary. How to solve the problem of saving and transmitting vast amounts of measurement data is urgent in the development process of power quality monitoring technology. To address problems existing in present power quality monitoring technology, researches are conducted in this paper.Steady-state power quality detection algorithms are discussed in this paper, the accuracy of which is verified by measuring various power quality indices. Taking advantage of good real-time performance of mathematical morphology and according to waveform characteristics of various transient disturbances, an algorithm based on mathematical morphology is presented in this paper, the feasibility of which is verified by detecting usual dynamic quality disturbances. Power quality detection results function as data recording criterion and analysis basis in power quality monitoring system.To handle the problem of storing and transmitting a large number of measurement data, a data compression method based on two-dimension discrete wavelet transform (2-D DWT) in lifting format, set partitioning in hierarchical tree (SPIHT) coding with arithmetical coding is presented in this paper. The high compression performance of which is verified by compressing several kinds of frequent power quality disturbance data. And the compression ratio can be regulated by changing the bit-rate, thus the amount of data can be adjusted to the network environment.Based on the above power quality detection algorithms and data compression method, the power quality integrated detection and data management system is designed in this paper, and the design and implementation process are presented in detail. With LabVIEW as a development platform, the system has achieved functions of integrated detection of steady-state and dynamic quality, recorded data compression, network, database access and etc, and provided image and intuitive detection and analysis results. It's significant both in theory and practice respects.