Study And Implementation Of Power System Data Compression And Transmission

With electric energy measuring technology and power quality monitoring technology developing rapidly in power system, the tremendous amounts of electric energy data and power quality data collected need to be sent to management center through communication network, which brings great difficulties to data transmission and storage. The most effective method to resolve this problem is to compress the monitoring data. The wavelet transform has good time-frequency localization features, so in recent years it has been widely applied in power system data compression. However, traditional single wavelet can't have orthogonality, symmetry, short support and high order vanishing moment simultaneously, which are the key factors in improving compression effect, thus the compression performance is limited to some extent. Considering multiwavelet can have the mentioned properties simultaneously, this paper deeply researched and experimented on electric energy data and power quality data compression with multiwavelet transform, and implemented remote data transmission.The main tasks are below:1,Some basic theories such as definition and classification about data compression, estimation standard of compression performance etc. were discussed. Several communication technologies in current power system were elaborated in detail and compared in feateres. The GPRS technology was analyzed in detail.2,One-dimensional algorithm of threshold compression based on multiwavelet was designed, The electric energy signal compression was completed with CL4 multiwavelet based on balancing pre-processing. Compression performace with traditional DB4 wavelet was analyzed and compared. At the same compression ratio, The results demonstrate that CL4 multiwavelet compression algorithm have smaller mean square error than DB4 wavelet compression algorithm.3,One-dimensional implementation of SPIHT was researched, and its codec program was designed.According to the features of multiwavelet transform coefficients, compression algorithm combining multiwavelet transform with SPIHT was proposed and applied to compress one-dimensional data in power system. Electric energy signal and power quality disturbance signals were compressed with the algorithm and the compression performance was analyzed in detail, The results illustrate that the algorithm not only can control the compression ratio freely but also can gain better compression performance.4,For the characteristics of GPRS wireless communication network, The terminal communication scheme of remote electric energy data and power quality data transmission system based on GPRS was designed and demonstrated in detail from network access,transmission protocol, the way of data transmission and the selection of GPRS module.Based on the above, the application level data transmission protocol was designed and the necessity of using heartbeat mechanism was discussed.5,The software and hardware development platform of electric energy data and power quality data remote transmission system based on GPRS was built, Based on the above, Monitoring Terminal software was designed and implemented, the remote communication between monitoring terminal and control center was implemented.Mass of network transmission testing result confirms the reliability and stability of the transmission system.