Alternating current sampling circuit and automatic error correction method thereof

Abstract

The invention discloses an alternating current sampling circuit and an automatic error correction method thereof. The alternating current sampling circuit comprises a multiple selector and an AD converter, wherein the multiple selector is provided with more than one signal input channels and more than one control channels, an output end of the multiple selector is connected with an input end of the AD converter; the multiple selector is provided with a standard channel, the signal inside which is totally different from the signal inside the signal input channel. The alternating current sampling circuit according to the invention can automatically correct errors of the input signals. The automatic error correction method according to the invention can accurately correct transmission sequence of the input signals.

Description

technical field [0001] The invention relates to an AC sampling circuit and an automatic error correction method for the AC sampling circuit. Background technique [0002] At present, the pilot operation of a large number of digital substations in China and the digitization of conventional substations have been equipped with process-level digital equipment for on-site sampling of secondary voltage and current to realize on-site digitization of analog signals. In most digital substations, analog digital equipment generally adopts electronic transformers. Electronic transformers are composed of on-site acquisition modules and merging units. The merging unit transmits the analog signals collected by the on-site acquisition modules to Protect measurement and control devices. The merging unit generally provides an Ethernet interface, through which an AC sampling data message conforming to the IEC61850-9-1 or IEC-61850-9-2 standard is provided. The protection measurement and cont...

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Problems solved by technology

[0011] However, in practical applications, various external interference signals will act on the measurement system, causing confusion in the measurement channel, often causing the CPU to think it is an I_A signal, but it may actually be I_C or V_B, causing measurement errors, such as: normal operation In this state, the channel selection signals of ADSW0, ADSW1, and ADSW2 will select the channel according to the logic controlled by the program: 000->001->010->011->100->101. If the current output signal of ADSW0, ADSW1, and ADSW2 is 010, select After the I_C signal, the next one should be 011 to select V_A. At this time, a strong interference signal from the outside makes the output signal of ADSW0, ADSW1, and ADSW2 101, then the data of V_C will be placed in V_A, and then the interference disappears. Then the steps of ADSW0, ADSW1, and ADSW2 are disrupted into 000->001->010->101->000->001->010->011->100->101, in the previous 010->101 part The channel is wrong. After the interference disappears, the output signals of ADSW0, ADSW1, and ADSW2 return to normal, but the data of V_C is stored in V_A, the data of I_A is stored in V_B, the data of I_B is stored in V_C, the data of I_C is stored in I_A, and the data of V_A is stored in I_B Among them, the data of V_B is stored in I_C, and serious signal confusion occurs, especially in harsh working environments, this kind of error often occurs, so it has become necessary to eliminate the occurrence of this error

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