|
|
|
| Adaptive SPIHT Algorithm for Data Compression of Insulator Leakage Currents |
| Zhu Yongli, Zhai Xueming, Jiang Xiaolei |
| North China Electric Power University Baoding 071003 China |
|
|
|
|
Abstract A fault in any one string of insulators may cause a power network accident, so insulator online monitoring is of vital importance. Sampling frequency of leakage currents must be high enough to find abnormalities in insulators, yielding large amount of data, hence the data compression of leakage currents is of great significance. An adaptive version of SPIHT is proposed, which can partition sets of wavelet coefficients according to their significance, thus effectively reduces the number of judgments on whether the coefficients in one set are all 0, making itself well suited for coding signals with high-level noise such as leakage currents. In view of the high noise level and periodic redundancy of the leakage currents, adaptive SPIHT and DPCM are utilized for the coding of wavelet detail and approximation coefficients, respectively. The compression efficiency can be further improved if context-based adaptive binary arithmetic coding is employed. The proposed algorithm is evaluated on testing data of insulator leakage currents, showing compression performance significantly better than SPIHT. Compared with existing two-dimensional algorithms for data compression in power systems, it can do compression after data sampling within just one AC power working cycle, so it is more suitable for the real time or online situations.
|
|
Received: 20 September 2010
Published: 10 March 2014
|
|
|
|
|
|
[1] 黄新波. 输电线路在线监测与故障诊断[M]. 北京: 中国电力出版社, 2008.
[2] Li Jingyan, Sun Caixin, Sima Wenxia, et al. Contamination level prediction of insulators based on the characteristics of leakage current[J]. IEEE Transactions on Power Delivery, 2010, 25(1): 417-424.
[3] Kordkheili H H, Abravesh H, Tabasi M, et al. Determining the probability of flashover occurrence in composite insulators by using leakage current harmonic components[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 2010, 17(2): 502-512.
[4] Suda T. Frequency characteristics of leakage current waveforms of a string of suspension insulators[J]. IEEE Transactions on Power Delivery, 2005, 20(1): 481-487.
[5] 张亚萍, 戴敏. 1000kV交流绝缘子串泄漏电流特性研究[J]. 高电压技术, 2009, 35(2): 242-246.
Zhang Yaping, Dai Min. Research on 1000 kV AC insulator leakage currents characteristic[J]. High Voltage Engineering, 2009, 35(2): 242-246.
[6] Gerek Ö N, Ece D G. Compression of power quality event data using 2D representation[J]. Electric Power Systems Research, 2008, 78(6): 1047-1052.
[7] Ku Cheng Tung, Hung King Chu, Wu Tsung Ching, et al. Wavelet-based ECG data compression system with linear quality control scheme[J]. IEEE Transactions on Biomedical Engineering, 2010, 57(6): 1399-1409.
[8] Lu Zhitao, Dong Youn Kim, Pearlman W A. Wavelet compression of ECG signals by the set partitioning in hierarchical trees algorithm[J]. IEEE Transactions on Biomedical Engineering, 2000, 47(7): 849-856.
[9] Said A, Pearlman W A. A new, fast and efficient image codec based on set partitioning in hierarchical trees [J]. IEEE Transactions on Circuits and Systems for Video Technology, 1996, 6(3): 243-250.
[10] Pearlman W A, Islam A, Nagaraj N, et al. Efficient, low-complexity image coding with a set-partitioning embedded block coder[J]. IEEE Transactions on Circuits and Systems for Video Technology, 2004, 14(11): 1219-1235.
[11] Taubman D. High performance scalable image compression with EBCOT[J]. IEEE Transactions on Image Processing, 2000, 9(7): 1158-1170.
[12] Marpe D, Schwarz H, Wiegand T. Context-based adaptive binary arithmetic coding in the H. 264/AVC video compression standard[J]. IEEE Transactions on Circuits and Systems for Video Technology, 2003, 13(7): 620-636. |
|
|
|
2011, Vol. 26 
