Signal sampling device and method

Abstract

The invention relates to a signal sampling device and a method. The signal sampling device comprises a central processing unit, an input interface module and an output interface module. The input interface module and the output interface module are respectively connected with the central processing unit; the input interface module comprises a first signal input circuit and a second signal input circuit, the first signal input circuit is used for inputting original signals into the central processing unit, the second signal input circuit is used for amplifying the original signals and inputting amplified signals to the central processing unit; and the central processing unit is used for respectively sampling the original signals and the amplified signals and outputting results of sampling of the original signals through the output interface module when the current value of the original signals is higher than the preset threshold value, or outputting results of sampling of the amplified signals through the output interface module when the current value of the original signals is lower than the preset threshold value. When the original signals are large signals or small signals, the authenticity of sampled signals can be better ensured, that is, the signal sampling accuracy is improved within a wider range.

Description

technical field [0001] The present invention relates to electric power systems or other technical fields requiring signal sampling processing, and in particular to a signal sampling device and method. Background technique [0002] In the power system, the maximum protection current of the power relay protection equipment is at least 20 times the rated current of the protected equipment, and the sampling signal current input to the power relay protection equipment in the actual power system may vary within the range of 0-20 times. Power relay protection equipment usually calculates the working current in the circuit according to the sampling signal, and determines whether to carry out relay protection according to the calculation result. It can be seen that the authenticity of the sampling signal will directly affect the calculation results of the relay protection; if the sampling signal is distorted, it will cause the power relay protection equipment to malfunction or refuse...

AI Technical Summary

Problems solved by technology

If the original signal input to the power relay protection product is a large signal, the signal-to-noise ratio of the original signal is large, the authenticity of the sampling signal is better, and the sampling accuracy of the signal is higher; on the contrary, if the input signal of the power relay protection product If the original signal is a small signal, the signal-to-noise ratio of the original signal is small, and the authenticity of the sampled signal is poor

When the original signal input to the power relay protection product is a small signal, the existing technology usually uses a software algorithm to filter out the noise in the original signal, but the sampling software algorithm also filters out the useful signal while filtering out the noise, reducing the small signal input. Sampling accuracy of time signal

[0004] Through the above analysis, it can be seen that although the existing technology can better guarantee the sampling accuracy of large signals, the sampling accuracy of small signals is poor, so it is impossible to improve the sampling accuracy of signals in a wide range

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