Signal acquisition method compatible with Rogowski coil sensor and acquisition terminal

Abstract

The invention relates to the technical field of current signal acquisition equipment, in particular to a signal acquisition method compatible with a Rogowski coil sensor and an acquisition terminal. The Rogowski coil channel is used for coping with large current, measurement distortion caused by CT saturation during fault is fundamentally avoided, the reliability of protection control is improved, the problem of magnetic saturation is solved, the high-precision measurement advantage of the CT under normal small current and the linear measurement advantage of the Rogowski coil in a wide dynamic range are fused, and the measurement accuracy of the Rogowski coil is improved. High-quality data is provided for a power grid, the integration level and adaptability of equipment are improved, and an optimization strategy of a CT for normal metering and a Rogowski coil for fault recording is realized.

Description

Technical Field

[0001] This application relates to the field of current signal acquisition equipment technology, and in particular to a signal acquisition method and acquisition terminal compatible with Rogowski coil sensors. Background Technology

[0002] The statements in this section are merely background information related to this application and do not necessarily constitute prior art.

[0003] Currently, in the field of smart distribution networks, there is a trend of integrating the functions of electricity information acquisition terminals and control and protection equipment (such as distribution automation terminals) into the same hardware product. However, both commonly use traditional electromagnetic current transformers for the basic function of current acquisition. Their current measurement modules are also based on electromagnetic transformers. Electromagnetic transformers are based on the principle of induction by changes in the magnetic flux of the iron core, and the technology is mature and stable under normal operating conditions. However, their inherent defect is that the magnetic circuit of the iron core has saturation characteristics. When a fault such as a short circuit occurs in the power grid, the fault current can reach tens of times the normal current, which can easily lead to iron core saturation, causing severe distortion (flat-top wave) in the output current waveform of the secondary side of the transformer, making it impossible to accurately reflect the fault current on the primary side. The main drawbacks of the aforementioned existing technologies are: First, they have a narrow dynamic range and are prone to saturation. The linear measurement range of electromagnetic transformers is limited, making it impossible to simultaneously meet the high-precision metering requirements for small currents during normal operation and the accurate capture requirements for large currents during faults. Once saturated, protection devices may fail to operate or malfunction due to measurement distortion, affecting grid safety. Second, they are unsuitable for the needs of new power grids. With the integration of intermittent power sources such as distributed photovoltaics and wind power, as well as impact loads such as electric arc furnaces and rolling mills, the dynamic range of grid current is larger and changes faster, making the limitations of electromagnetic transformers more prominent. The root cause of these problems lies in the inherent defects of electromagnetic transformers based on the physical principle of ferromagnetic materials. A difficulty encountered in solving this problem is that although Rogowski coils have advantages such as no magnetic saturation, wide measurement range, and fast response speed, their output signal is a voltage signal proportional to the current derivative (di / dt), which is completely different from the standard current / voltage signal format output by electromagnetic transformers, making it impossible to directly connect to existing acquisition or protection devices designed for the latter. Therefore, it is necessary to provide a signal acquisition method and acquisition terminal compatible with Rogowski coil sensors to solve the above-mentioned technical problems. Summary of the Invention

[0004] Based on this, and in response to the aforementioned technical problems, this application provides a signal acquisition method and acquisition terminal compatible with Rogowski coil sensors.

[0005] The technical solution adopted in this application to solve the problems existing in the prior art is: This application proposes a signal acquisition method compatible with Rogowski coil sensors, the acquisition method comprising the following steps: S1: The multi-functional power metering unit continuously analyzes the current data it collects; if the current data is within the set threshold range, proceed to step S2; otherwise, proceed to step S3. S2: Determine if there is a manual switching command. If a manual switching command is received, proceed to step S3. S3: The multi-functional power metering unit switches the current acquisition channel.

[0006] Preferably, The following steps are included before step S1: S0: Connect the Rogowski coil sensor and the CT current sensor, which collect the same current signal, to the multi-functional energy metering unit; and set the current signal route of the multi-functional energy metering unit to the CT current sensor signal channel.

[0007] Preferably, The multi-functional energy metering unit continuously analyzes the current data it collects, including: Calculate the rate of change of the current data, di / dt; Monitor current amplitude; Compare the rate of change of the current data di / dt with a first threshold. The current amplitude is compared with a second threshold.

[0008] Preferably, In step S2, the manual switching command includes remote commands and local commands; In step S3, under the manual switching command mode, the main control module controls the analog switch switching channel in the multi-functional energy metering unit through its own GPIO port.

[0009] Preferably, In step S3, if the current data is not within the set threshold range and is not in manual switching command mode, the multi-functional energy metering unit controls the analog switch switching channel within the multi-functional energy metering unit through its own GPIO port.

[0010] Preferably, In step S3: The multi-functional energy metering unit switches the current acquisition channel by changing the current signal routing path of the multi-functional energy metering unit from the CT current sensor channel to the Rogowski coil sensor channel.

[0011] Preferably, it further includes: Step S4: When the manual switching command ends, or the current data returns to the set threshold range, return to step S1.

[0012] A signal acquisition terminal compatible with Rogowski coil sensors includes: The Rogowski coil signal conditioning module has its input side connected to the Rogowski coil sensor and its output side connected to the channel switching module. It is used to process the current signal collected by the Rogowski coil sensor and then send it to the multi-functional energy metering unit through the channel switching module. The CT current signal conditioning module is connected to the CT current transformer on the input side and to the channel switching module on the output side; it is used to process the current signal collected by the CT current transformer and then send it to the multi-functional energy metering unit through the channel switching module. The channel switching module is electrically connected to the multi-functional energy metering unit and the main control module. It is used to select, under the control of the multi-functional energy metering unit and the main control module, to input the current signal output by the Rogowski coil signal conditioning module or the current output by the CT current signal conditioning module into the multi-functional energy metering unit. A multi-functional power metering unit is used to analyze the current data it collects. The main control module, when it receives a manual switching command, controls the channel switching module to input the current output by the Rogowski coil signal conditioning module into the multi-functional energy metering unit.

[0013] Preferably, The multi-functional energy metering unit has GPIO ports.

[0014] Preferably, The CT current signal conditioning module includes a bidirectional diode limiting circuit connected in parallel between the two output signal lines of the CT current sensor. The bidirectional diode limiting circuit includes two sets of diode combination circuits connected in reverse parallel; the diode combination circuit includes multiple diodes connected in series.

[0015] Compared with the prior art, the beneficial effects of this application are as follows: 1. Solved the magnetic saturation problem: By using the Rogowski coil channel to handle large currents, the measurement distortion caused by CT saturation during faults is fundamentally avoided, thus improving the reliability of protection control. 2. Achieved high-precision measurement across the entire range: It combines the high-precision measurement advantages of CT under normal low current and the linear measurement advantages of Rogowski coil under wide dynamic range, providing higher quality data for the power grid. 3. Improved equipment integration and adaptability: One terminal can be adapted to two types of sensors, reducing system complexity and cost, and is especially suitable for special fields with high requirements for current measurement range. 4. A dynamic signal source intelligent switching method based on real-time current monitoring results was proposed, realizing the optimization strategy of "using CT for normal measurement and Rogowski coil for fault recording". Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0017] Figure 1 This is a control flowchart of a signal acquisition method compatible with Rogowski coil sensors according to this application; Figure 2 This is a block diagram of a signal acquisition terminal compatible with a Rogowski coil sensor according to this application; Figure 3 This is a schematic diagram of a conditioning module for one phase output signal of a Rogowski coil current signal. Figure 4 Schematic diagram of the conditioning module for one phase output signal of the CT current transformer; Figure 5 This is the circuit schematic of the channel switching module. Detailed Implementation

[0018] The present application will be further described below with reference to the accompanying drawings and embodiments.

[0019] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this disclosure. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms “comprising” and / or “including” are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0020] In this disclosure, terms such as "upper," "lower," "left," "right," "front," "back," "vertical," "horizontal," "side," and "bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are merely relational terms determined for the convenience of describing the structural relationship of the various components or elements in this disclosure, and do not specifically refer to any component or element in this disclosure, nor should they be construed as limiting this disclosure.

[0021] refer to Figure 1 This application discloses a signal acquisition method compatible with Rogowski coil sensors, comprising the following steps: S1: The multi-functional power metering unit continuously analyzes the current data it collects; if the current data is within the set threshold range, proceed to step S2; otherwise, proceed to step S3. S2: Determine if there is a manual switching command. If a manual switching command is received, proceed to step S3. S3: The multi-functional power metering unit switches the current acquisition channel.

[0022] In some embodiments, the following steps are included before step S1: S0: Connect the Rogowski coil sensor and the CT current sensor, which collect the same current signal, to the multi-functional energy metering unit; and set the current signal route of the multi-functional energy metering unit to the CT current sensor signal channel.

[0023] It should be noted that in practical applications, there can be multiple sets of Rogowski coil sensors and CT current sensors, each set can measure the current of one phase.

[0024] In some embodiments, the multifunctional energy metering unit continuously performs data analysis on the current data it collects, including: Calculate the rate of change of the current data, di / dt; Monitor current amplitude; Compare the rate of change of the current data di / dt with a first threshold. The current amplitude is compared with a second threshold.

[0025] In practical use, the first threshold and the second threshold can be set according to actual needs. This is a common technique used by those skilled in the art and will not be elaborated here.

[0026] In some embodiments, in step S2, the manual switching command includes remote commands and local commands; in step S3, in manual switching command mode, the main control module controls the analog switch switching channel in the multi-functional energy metering unit through its own GPIO port.

[0027] In step S3, if the current data is not within the set threshold range and is not in manual switching command mode, the multi-functional energy metering unit controls the analog switch switching channel within the multi-functional energy metering unit through its own GPIO port.

[0028] In step S3: The multi-functional energy metering unit switches its current acquisition channel by changing the current signal routing path from the CT current sensor channel to the Rogowski coil sensor channel. During this stage, leveraging the advantages of the Rogowski coil—no magnetic saturation and wide bandwidth—the full waveform of the fault current is accurately captured for precise protection judgment and fault recording. The system continuously makes judgments during fault data processing. In some embodiments, a signal acquisition method compatible with Rogowski coil sensors according to this application further includes step S4: When the manual switching command ends, or the current data returns to the set threshold range, return to step S1. Once it is confirmed that the system has returned to normal (e.g., the current value drops and stabilizes), the device will automatically or manually switch the signal path back to the CT signal channel according to a preset strategy, and return to step S2 to start a new cycle of monitoring. This process achieves the intelligent dynamic optimization goal of "accurate CT measurement under normal operating conditions and high-fidelity recording of Rogowski coils under abnormal operating conditions," which is the core innovation of this invention.

[0029] This application provides a signal acquisition terminal compatible with Rogowski coil sensors, including: Rogowski coil signal conditioning module, reference Figure 3 The input side is connected to the Rogowski coil sensor, and the output side is connected to the channel switching module; it is used to process the current signal collected by the Rogowski coil sensor and then enter the multi-functional energy metering unit through the channel switching module. CT current signal conditioning module, reference Figure 4 The input side is connected to the CT current transformer, and the output side is connected to the channel switching module; it is used to process the current signal collected by the CT current transformer and then enter the multi-functional power metering unit through the channel switching module. Channel switching module, see reference Figure 2 It is electrically connected to the multi-functional energy metering unit and the main control module, and is used to select the current signal output by the Rogowski coil signal conditioning module or the current output by the CT current signal conditioning module to be input into the multi-functional energy metering unit under the control of the multi-functional energy metering unit and the main control module. A multi-functional energy metering unit is used to analyze the current data it collects; in some embodiments, the multi-functional energy metering unit is an HT7132 integrated circuit chip.

[0030] Main control module, reference Figure 2 When it receives a manual switching command, the control channel switching module inputs the current output by the Rogowski coil signal conditioning module into the multi-functional energy metering unit.

[0031] The multi-functional energy metering unit has a GPIO port to send signals to the channel switching module through its GPIO port. In some embodiments, reference Figure 4 The CT current signal conditioning module includes a bidirectional diode limiting circuit connected in parallel between the two output signal lines of the CT current sensor. The bidirectional diode limiting circuit includes two sets of diode combination circuits connected in reverse parallel. The diode combination circuit includes multiple diodes connected in series.

[0032] This application proposes and designs a hardware architecture that combines a "dual-channel current signal conditioning module" and a "channel switching module," achieving native compatibility between two sensors based on different principles.

[0033] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

[0034] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0035] While the specific embodiments of this application have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of this application. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of this application are still within the scope of protection of this application.

Claims

1. A signal acquisition method compatible with Rogowski coil sensors, characterized in that: The data acquisition method includes the following steps: S1: The multi-functional power metering unit continuously analyzes the current data it collects; if the current data is within the set threshold range, proceed to step S2; otherwise, proceed to step S3. S2: Determine if there is a manual switching command. If a manual switching command is received, proceed to step S3. S3: The multi-functional power metering unit switches the current acquisition channel.

2. The signal acquisition method compatible with Rogowski coil sensors according to claim 1, characterized in that: The following steps are included before step S1: S0: Connect the Rogowski coil sensor and the CT current sensor, which collect the same current signal, to the multi-functional energy metering unit; and set the current signal route of the multi-functional energy metering unit to the CT current sensor signal channel.

3. The signal acquisition method compatible with Rogowski coil sensors according to claim 1, characterized in that: In step S1, the multi-functional energy metering unit continuously analyzes the current data it collects, including: Calculate the rate of change of the current data, di / dt; Monitor current amplitude; Compare the rate of change of the current data di / dt with a first threshold. The current amplitude is compared with a second threshold.

4. The signal acquisition method compatible with Rogowski coil sensors according to claim 1, characterized in that: In step S2, the manual switching command includes remote commands and local commands; In step S3, under the manual switching command mode, the main control module controls the analog switch switching channel in the multi-functional energy metering unit through its own GPIO port.

5. The signal acquisition method compatible with Rogowski coil sensors according to claim 1, characterized in that: In step S3, if the current data is not within the set threshold range and is not in manual switching command mode, the multi-functional energy metering unit controls the analog switch switching channel within the multi-functional energy metering unit through its own GPIO port.

6. The signal acquisition method compatible with Rogowski coil sensors according to claim 2, characterized in that: In step S3: The multi-functional energy metering unit switches the current acquisition channel by changing the current signal routing path of the multi-functional energy metering unit from the CT current sensor channel to the Rogowski coil sensor channel.

7. The signal acquisition method compatible with Rogowski coil sensors according to claim 1, characterized in that: Also includes: Step S4: When the manual switching command ends, or the current data returns to the set threshold range, return to step S1.

8. A signal acquisition terminal compatible with Rogowski coil sensors, characterized in that: include: The Rogowski coil signal conditioning module has its input side connected to the Rogowski coil sensor and its output side connected to the channel switching module. It is used to process the current signal collected by the Rogowski coil sensor and then send it to the multi-functional energy metering unit through the channel switching module. The CT current signal conditioning module is connected to the CT current transformer on the input side and to the channel switching module on the output side; it is used to process the current signal collected by the CT current transformer and then send it to the multi-functional energy metering unit through the channel switching module. The channel switching module is electrically connected to the multi-functional energy metering unit and the main control module. It is used to select, under the control of the multi-functional energy metering unit and the main control module, to input the current signal output by the Rogowski coil signal conditioning module or the current output by the CT current signal conditioning module into the multi-functional energy metering unit. A multi-functional power metering unit is used to analyze the current data it collects. The main control module, when it receives a manual switching command, controls the channel switching module to input the current output by the Rogowski coil signal conditioning module into the multi-functional energy metering unit.

9. A signal acquisition terminal compatible with Rogowski coil sensors according to claim 8, characterized in that: The multi-functional energy metering unit has GPIO ports.

10. A signal acquisition terminal compatible with Rogowski coil sensors according to claim 8, characterized in that: The CT current signal conditioning module includes a bidirectional diode limiting circuit connected in parallel between the two output signal lines of the CT current sensor. The bidirectional diode limiting circuit includes two sets of diode combination circuits connected in reverse parallel; the diode combination circuit includes multiple diodes connected in series.

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