Research on encoding/decoding method of electric physical information based on LMS-ADPCM algorithm

In order to solve the contradiction between the transmission and storage requirements of massive electric physical information in smart grid and relative shortage of communication resources, this paper puts forward an novel encoding method based on Least Mean Square (LMS) adaptive filtering theory and Adaptive Differential Pulse Code Modulation (ADPCM) system in G.726 international standard proposed by CCITT. The LMS-ADPCM coding method, which combines the adaptive characteristic of Adaptive Pulse Code Modulation (APCM) and the differential characteristic of differential Pulse Code Modulation (DPCM), conducts adaptive quantization coding on the differential values of sample signals using adaptive prediction and adaptive quantization techniques that can improve the quantization and encoding characteristics of the coding system. Moreover, this paper analyzes the coding specification and existing deficiencies of the current power communication protocols, mainly including IEC60870-5 and IEC61850. Based on the LMS-ADPCM coding algorithm and ASN.1´s basic coding rules (BER), the feasible coding scheme for IEC61850 protocol messages is designed to achieve seamless integration communication among different equipments and systems. Results of numerical experiments show that the proposed LMS-ADPCM coding method provides an efficient way for compression coding of electric physical information in smart grid.