Compressing method for high density time sequence data in WAMS (Wide Area Measurement System) of power system
A technology of wide-area measurement system and processing method, which is applied in the field of compression processing of high-density time series data, can solve problems such as occupying large disk space, and achieve the effect of improving speed, compression rate and compression efficiency
Active Publication Date: 2010-08-04
BEIJING SIFANG JIBAO AUTOMATION +1
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[0003] Because the dynamic data of WAMS has the characteristics of high speed, high density, and high precision, each monitoring point transmits 50 frames or even 100 frames of dynamic data per second on average. For large power grids, the generated data is massive. These data If stored directly, it will take up a lot of disk space
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[0035] After floating-point numbers are calculated and converted, there will be calculation errors and random residual values at the last decimal place. Therefore, floating-point numbers are usually not equal. In mathematical calculations, the difference is often less than a small value to judge the equality of floating-point numbers. This feature is defined here as the poor similarity of floating-point numbers, which has a great impact on the lossless compression algorithm. Taking dictionary compression algorithms such as LZW as an example, when the data similarity is poor, the compression processing will multiply the statistics and the number of cycles, thereby reducing the compression rate and compression efficiency. The acquisition of WAMS data has the highest precision requirements for the data. For example, the frequency accuracy is ±0.001Hz. The frequency value in the fourth digit after the decimal point is actually not within the range of accuracy requirements and can...
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The invention relates to a preprocessing method for high density time sequence data in WAMS (Wide Area Measurement System) of a power system before compressed by a dictionary algorithm and a sparse processing method for high density curve data. The preprocessing method means the fixed point and increased processing of floating point data to be compressed, and comprises the following steps of defining conversion coefficients of each measure according to the precision requirement of WAMS data, and forming an integer fixed point data sequence after multiplying all the floating point data with the conversion coefficients; making subtraction to adjacent points of the fixed point data sequence to obtain an increased data sequence; and compressing the increased data sequence with an LZW (Lempel Ziv Welch ) algorithm, and reversely processing in order during decompression to obtained an original curve.
Description
technical field [0001] The invention belongs to the field of power system scheduling automation, in particular to a method for compressing high-density time series data in a dynamic safety monitoring process. Background technique [0002] The power system wide area measurement system (hereinafter referred to as WAMS) is a set of dispatching automation system composed of the PMU and the monitoring master station of the dispatching center. The system can provide dispatchers and operation analysts with the dynamic process of grid operation. With the popularization and practical construction of WAMS application, WAMS data has become necessary information for power grid event analysis. Expired data is required to be completely stored, and event data is even required to be stored for a long time for post-event analysis and research. [0003] Since the dynamic data of WAMS has the characteristics of high speed, high density and high precision, each monitoring point transmits 50 fr...
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IPC IPC(8): H03M7/30G06F7/57
Inventor 杨东许君德吴京涛
Owner BEIJING SIFANG JIBAO AUTOMATION