CN210720561U

CN210720561U - Rogowski coil current signal acquisition system

Info

Publication number: CN210720561U
Application number: CN201921544803.8U
Authority: CN
Inventors: 王宇; 辛明勇; 孟令雯; 高吉普; 徐长宝; 林呈辉; 吕黔苏; 祝健杨; 肖小兵; 刘斌; 汪明媚; 代奇迹
Original assignee: Guizhou Power Grid Co Ltd
Current assignee: Guizhou Power Grid Co Ltd
Priority date: 2019-09-17
Filing date: 2019-09-17
Publication date: 2020-06-09
Anticipated expiration: 2029-09-17

Abstract

The utility model discloses a rogowski coil current signal acquisition system, including passive low pass filter, AD conversion module and FPGA chip, the input of passive low pass filter is connected with rogowski coil differential signal input end, and the passive low pass filter output is connected with AD conversion module input end, and AD conversion module output is connected with FPGA chip input end; the FPGA chip is connected with a Rogowski coil hardware integral signal output end and a current signal output end after software integral reduction. The utility model adopts the front-end sampling system of the passive low-pass filtering and AD conversion module, which ensures that the filtering loop has good high-frequency characteristic while filtering the external interference signal; the high-speed and high-precision AD sampling module can ensure the transmission precision and effectiveness of the original differential signal in the sampling loop so as to improve the reliability of later software algorithm processing.

Description

Rogowski coil current signal acquisition system

Technical Field

The utility model belongs to the power technology smart power grids field especially relates to a luo shi coil current signal acquisition system.

Background

In the application of the electronic current transformer, the rogowski coil has the characteristics of high response speed, almost no phase error, no saturation, real-time measurement of current and the like, so that the electronic current transformer based on the rogowski coil is widely applied to a power system. Because the rogowski coil is a ring coil uniformly wound on a non-ferromagnetic material, the output signal of the rogowski coil is the differential of current to time, and the input current can be really restored only by a circuit for integrating and restoring the output voltage signal.

Currently, an electronic current transformer based on a rogowski coil is generally used for performing integral reduction processing on a WeChat signal through a collecting unit or a merging unit at the rear end of the collecting unit and then outputting a reduced current signal. However, due to the limitation of the sampling frequency, the transmission bandwidth of the higher harmonics is limited during a fault or VFTO (fast transient overvoltage), and the problem of distortion of the current signal after integral recovery is more prominent.

Based on the current application scheme, only one path of current signal after integral reduction is output by the acquisition unit or the merging unit, and a signal for comparison reference is lacked, so that when a problem exists in the integration process, the problem occurring in the integration process cannot be compared and analyzed.

Disclosure of Invention

The to-be-solved technical problem of the utility model is: the Rogowski coil current signal acquisition system is provided to solve the problems that only one path of current signal after integral reduction can be output, and comparison analysis can not be carried out on the problems occurring in the integral link in an acquisition loop in the prior art.

The utility model discloses the technical scheme who takes does: a Rogowski coil current signal acquisition system comprises a passive low-pass filter, an AD conversion module and an FPGA chip, wherein the input end of the passive low-pass filter is connected with the differential signal input end of a Rogowski coil, the output end of the passive low-pass filter is connected with the input end of the AD conversion module, and the output end of the AD conversion module is connected with the input end of the FPGA chip; the FPGA chip is connected with a Rogowski coil hardware integral signal output end and a current signal output end after software integral reduction.

The AD conversion module adopts a high-speed high-precision converter.

The utility model has the advantages that: compared with the prior art, the utility model discloses an effect as follows:

(1) the sampling loop adopts a front-end sampling system of a passive low-pass filtering and AD conversion module, so that external interference signals are filtered, and the filtering loop is ensured to have good high-frequency characteristics; the high-speed and high-precision AD sampling module can ensure the precision and effectiveness of the transmission of the original differential signal in the sampling loop so as to improve the reliability of later software algorithm processing;

(2) the real-time comparison and analysis technology of the hardware integral signal and the current signal of the software integral reduction is that after an original differential signal is input by a collector, a software integral algorithm and the hardware integral signal are simultaneously carried out, and the effectiveness after the signal is integrally reduced is ensured by carrying out real-time comparison and analysis on the current signal of the FPGA after the software integral reduction and the hardware integral signal;

(3) the hardware integration signal and the software integration signal are output to the loop at the same time. The acquisition loop output end is simultaneously provided with a software integral reduction current signal output port and a hardware integral signal output port, and the hardware integral signal is output through internal control, so that the synchronism of the integral reduction signal and the hardware integral signal is ensured, and real-time synchronous comparison data can be provided for a rear-end recording device.

Drawings

FIG. 1 is a hardware schematic diagram of the sampling loop of the present invention;

fig. 2 is a software algorithm flow chart of the present invention.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and specific embodiments.

Example 1: as shown in fig. 1-2, a rogowski coil current signal acquisition system includes a power module 1, a passive low-pass filter 3, an AD conversion module 4 and an FPGA chip 5, where the power module 1 supplies power to the passive low-pass filter 3 and the FPGA chip 5, an input end of the passive low-pass filter 3 is connected to a rogowski coil differential signal input end 2, an output end of the passive low-pass filter 3 is connected to an input end of the AD conversion module 4, and an output end of the AD conversion module 4 is connected to an input end of the FPGA chip 5; the FPGA chip 5 is connected with a Rogowski coil hardware integral signal output end 6 and a current signal output end 7 after software integral reduction.

The AD conversion module 4 employs a high-speed high-precision converter.

The original differential signal output by the Rogowski coil is subjected to hardware filtering processing through a passive low-pass filter, after interference and high-frequency noise are filtered, one path of differential signal is subjected to analog-to-digital conversion through a high-speed high-precision AD conversion module, the original differential signal is converted into digital quantity, and the digital differential signal enters an FPGA chip for processing, including software integration, integral signal comparison and the like of the digital differential signal; and the other path of differential signal is subjected to hardware integration and then is subjected to analog-to-digital conversion through a high-speed high-precision AD conversion module, and the signal subjected to hardware integration is converted into digital quantity and then is accessed to an FPGA chip for processing. And finally, simultaneously outputting two signals by an output end of the FPGA chip: integrating the current signal after reduction by hardware and software of the Rogowski coil; the power module supplies power to the whole acquisition loop.

In the use process of the Rogowski coil mutual inductor, the original differential signal output by the Rogowski coil passes through the acquisition loop, and the differential signal is subjected to integration processing and reduction and then output to the rear end. However, due to the limitation of the sampling frequency, the transmission bandwidth of the higher harmonics is limited during a fault or VFTO (fast transient overvoltage), and the problem of distortion of the current signal after integral recovery is more prominent. Therefore, by improving the acquisition loop, on one hand, the acquisition loop can output two paths of integral signals, and on the other hand, real-time comparison is carried out in the FPGA chip. Compared with the prior art, the utility model discloses an output current signal and the luo shi coil hardware integral signal after the software integral reduction simultaneously to can effectively monitor and judge at trouble or VFTO (fast transient state overvoltage) in-process, the distortion condition after the current signal reduces through the integral can effectively improve the reliability of luo shi coil current transformer in engineering application.

Example 2: as shown in fig. 1-2, an acquisition method of a rogowski coil current signal acquisition system includes: when a digital differential signal sampled by an AD conversion module enters an FPGA chip, firstly, an input sampling value at the current moment is obtained, sampling value software integral data and sampling value hardware integral data are simultaneously calculated, then, the two data are compared, whether the two data are in a normal state or not is judged through error comparison, and if the error is larger than a set threshold value, a calculated integral signal without an error flag bit and a sampling value hardware integral signal are simultaneously output if the error is judged to be consistent; otherwise, if the judgment result is inconsistent, the calculation integral signal with the error flag bit and the hardware integral signal are output.

The above description is only for the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art can easily think of the changes or substitutions within the technical scope of the present invention, and all should be covered within the protection scope of the present invention, therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A Rogowski coil current signal acquisition system is characterized in that: the power supply device comprises a power supply module (1), a passive low-pass filter (3), an AD conversion module (4) and an FPGA chip (5), wherein the input end of the passive low-pass filter (3) is connected with a Rogowski coil differential signal input end (2), the output end of the passive low-pass filter (3) is connected with the input end of the AD conversion module (4), and the output end of the AD conversion module (4) is connected with the input end of the FPGA chip (5); the FPGA chip (5) is connected with a Rogowski coil hardware integral signal output end (6) and a current signal output end (7) after software integral reduction.

2. The rogowski coil current signal acquisition system of claim 1, wherein: the AD conversion module (4) adopts a high-speed high-precision converter.