A line voltage acquisition device with elbow structure

Abstract

The utility model relates to a kind of line voltage acquisition devices of elbow type structure, including acquisition unit and output unit, the acquisition unit includes cable rear T type joint and voltage sensor body, the cable rear T type joint is connected with voltage sensor body to form elbow type structure, the voltage sensor body includes resistance-capacitance voltage divider and pole, the resistance-capacitance voltage divider is built-in in pole, the resistance-capacitance voltage divider is in series by high-voltage arm and low-voltage arm, the high-voltage arm includes high-voltage resistance and high-voltage capacitor, the low-voltage arm includes voltage dividing resistance;The output unit includes voltage stabilizing filter circuit and integration circuit, the voltage dividing resistance of the low-voltage arm is connected voltage stabilizing filter circuit of output unit by wire, and voltage signal is exported by integration circuit.The device is small in size, high in acquisition accuracy, and widely used.

Description

Technical Field

[0001] This utility model relates to the field of voltage acquisition technology, specifically to a line voltage acquisition device with an elbow-shaped structure. Background Technology

[0002] In the digital upgrade and transformation of distribution network ring main units, it is necessary to collect incoming line voltage for automatic transfer switches (ATS). While electromagnetic PTs offer high measurement accuracy, their large size makes them difficult to install in space-constrained ring main units. Live-line display devices collect line voltage signals through capacitive voltage division, but their accuracy is low, easily leading to misjudgments by ATS, and have been banned in several regions as a criterion for determining line voltage. Therefore, for ring main units without line PTs and with limited space, a voltage acquisition solution that balances installation convenience and measurement stability is urgently needed. Utility Model Content

[0003] The purpose of this invention is to provide a line voltage acquisition device with an elbow-shaped structure, which is small in size, has high acquisition accuracy, and has a wide range of applications.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows: an elbow-shaped line voltage acquisition device, comprising an acquisition unit and an output unit. The acquisition unit includes a cable T-joint and a voltage sensor body. The cable T-joint and the voltage sensor body are connected to form an elbow structure. The voltage sensor body includes a resistive-capacitive voltage divider and a terminal. The resistive-capacitive voltage divider is built into the terminal and consists of a high-voltage arm and a low-voltage arm connected in series. The high-voltage arm includes a high-voltage resistor and a high-voltage capacitor, and the low-voltage arm includes a voltage-dividing resistor. The output unit includes a voltage-stabilizing filter circuit and an integrating circuit. The voltage-dividing resistor of the low-voltage arm is connected to the voltage-stabilizing filter circuit of the output unit through a wire, and the voltage signal is output through the integrating circuit.

[0005] Furthermore, the cable rear T-joint includes three connection ends: the front end is connected to the T-joint in the ring network box, the rear end is sealed by a plug, and the lower end is connected to the voltage sensor body.

[0006] Furthermore, a shielded grounding point is provided on the rear T-joint of the cable.

[0007] Furthermore, the high-voltage resistor is connected in series with the high-voltage capacitor, one end of the voltage divider resistor is connected to the high-voltage capacitor and the other end is grounded, and the two ends of the voltage divider resistor are connected to wires. The wires are led out of the voltage sensor body in the form of twisted pairs and connected to the voltage stabilizing filter circuit. The voltage stabilizing filter circuit is connected to the integrating circuit, which is used to restore the differential signal output by the RC voltage divider into a voltage signal proportional to the primary side voltage and output it.

[0008] Furthermore, a protection module is connected in parallel across the voltage divider resistor.

[0009] Furthermore, the resistive-capacitive voltage divider is built into the terminal post and integrally cast with the terminal post to form an insulating structure. The wires and grounding wires of the resistive-capacitive voltage divider are led out from the terminal post.

[0010] Furthermore, the withstand voltage and creepage distance of the electrode insulation structure meet the insulation requirements for a 10kV voltage level.

[0011] Furthermore, the resistance value of the high-voltage arm is in the MΩ range, the resistance value of the low-voltage arm is in the KΩ range, and the rated operating current of the RC divider is in the microampere range.

[0012] Furthermore, the integrating circuit adopts an active analog integrating circuit.

[0013] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a line voltage acquisition device with an elbow structure, which solves the problems of excessive size of electromagnetic PT and insufficient acquisition accuracy of live display device in the prior art. The device can be directly installed on the T-joint after the cable, while meeting the requirements of installation space and acquisition accuracy. It can be applied to the digital transformation of ring network boxes and has strong practicality and broad application prospects. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the acquisition unit in the elbow-shaped line voltage acquisition device provided in this embodiment of the utility model;

[0015] Figure 2 This is a schematic diagram of the cable T-joint in the elbow-shaped line voltage acquisition device provided in this embodiment of the utility model;

[0016] Figure 3 This is a schematic diagram of the voltage sensor body in the elbow-shaped line voltage acquisition device provided in this embodiment of the utility model;

[0017] Figure 4 This is a circuit diagram of the elbow-shaped line voltage acquisition device provided in this embodiment of the utility model;

[0018] Figure 5 This is a schematic diagram of the external connection of the acquisition unit in the elbow-shaped line voltage acquisition device provided in this embodiment of the utility model.

[0019] In the diagram: 1-Cable rear T-connector; 2-Voltage sensor body; 3-High voltage arm; 4-Low voltage arm; 5-High voltage resistor; 6-High voltage capacitor; 7-Voltage divider resistor; 8-Output unit; 9-Voltage stabilizing and filtering circuit; 10-Integrating circuit; 11-Wire; 12-T-front connector; 13-End cap; 14-Shielding grounding point; 15-Protection module; 16-Grounding wire; 17-Standard cable conduit. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0022] 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 application. 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.

[0023] like Figure 1-4 As shown, this embodiment provides an elbow-shaped line voltage acquisition device, including an acquisition unit and an output unit 8. The acquisition unit includes a cable T-joint 1 and a voltage sensor body 2. The cable T-joint 1 and the voltage sensor body 2 are connected to form an elbow structure. The voltage sensor body 2 includes a resistive-capacitive voltage divider and a terminal. The resistive-capacitive voltage divider is built into the terminal and is composed of a high-voltage arm 3 and a low-voltage arm 4 connected in series. The high-voltage arm 3 includes a high-voltage resistor 5 and a high-voltage capacitor 6, and the low-voltage arm 4 includes a voltage-dividing resistor 7. The output unit 8 includes a voltage-stabilizing filter circuit 9 and an integrating circuit 10. The voltage-dividing resistor 7 of the low-voltage arm 4 is connected to the voltage-stabilizing filter circuit 9 of the output unit 8 through a wire 11, and outputs a voltage signal through the integrating circuit 10.

[0024] like Figure 5 As shown, the cable rear T-joint 1 includes three connection ends: the front end connects to the T-joint 12 inside the ring network box, the rear end is sealed by a plug 13, and the lower end connects to the voltage sensor body 2. Furthermore, the cable rear T-joint 1 is equipped with a shielded grounding point 14.

[0025] like Figure 4As shown, the circuit connection principle of the line voltage acquisition device is as follows: the high-voltage resistor 5 is connected in series with the high-voltage capacitor 6, one end of the voltage divider resistor 7 is connected to the high-voltage capacitor 6, and the other end is grounded. A protection module 15 is connected in parallel across the voltage divider resistor 7. Furthermore, wires 11 are connected to both ends of the voltage divider resistor 7. These wires 11 are led out of the voltage sensor body 2 via twisted-pair cables and connected to the voltage stabilizing filter circuit 9. The voltage stabilizing filter circuit 9 is connected to an integrating circuit 10, used to restore the differential signal output by the RC voltage divider to a voltage signal proportional to the primary side voltage and output it. The resistance value of the high-voltage arm is in the MΩ range, the resistance value of the low-voltage arm is in the KΩ range, and the rated operating current of the RC voltage divider is in the microampere range.

[0026] The power rating of the resistors should be determined based on the rated operating voltage and resistance value of the device, with a certain margin. In this device, the high-voltage resistor 5 in the high-voltage arm has a resistance in the MΩ range, and the voltage divider resistor 7 in the low-voltage arm has a resistance in the KΩ range. The temperature coefficient is -25ppm / ℃, the voltage coefficient is -0.2ppm / V, and the power rating is 5W.

[0027] When selecting capacitors, consider the resistor-capacitor combination model and choose resistors and capacitors with different temperature change relationships to compensate for errors caused by temperature changes.

[0028] In addition, high-voltage resistors and capacitors with similar temperature coefficients but opposite signs are selected to effectively reduce transmission errors caused by parameter changes due to temperature variations.

[0029] The purpose of setting up a voltage regulation and filtering circuit is to improve the measurement accuracy by passing the input signal being measured through a low-pass anti-aliasing filter to remove the influence of noise. The three most commonly used low-pass filters are the Bessel filter, the Butterworth filter, and the Chebyshev filter. In this device, the filter selection must meet certain bandwidth characteristics and ensure that its phase offset value is within the accuracy range that meets the measurement error. The Butterworth filter has the maximum flatness of amplitude-frequency response within the passband, therefore it is chosen as the second-order low-pass filter in this device.

[0030] The secondary voltage signal of a resistor-capacitor voltage divider is the derivative of the primary voltage signal; therefore, an integrating circuit is needed to reconstruct the output voltage signal of the divider. This device uses an active analog integrating circuit to achieve the integration function.

[0031] This device requires not only small size but also good insulation performance. Therefore, a resistive-capacitive voltage divider is embedded in the terminal post and integrally cast with it to form the terminal post insulation structure. In this embodiment, epoxy resin vacuum casting is used. During the casting process to form the terminal post, the conductor 11 and grounding wire 16 of the resistive-capacitive voltage divider need to be led out from the terminal post. The withstand voltage and creepage distance of the terminal post insulation structure meet the insulation requirements of a 10kV voltage level.

[0032] The elbow-shaped line voltage acquisition device provided by this utility model adopts a resistive-capacitive voltage divider. By reasonably selecting high-voltage resistors and high-voltage capacitors (with similar temperature coefficients but opposite signs), the transmission error caused by parameter changes due to temperature variations can be effectively reduced. The secondary voltage signal of the resistive-capacitive voltage divider is the derivative of the primary voltage signal, and the voltage acquisition waveform is restored in the output unit through an integrating circuit. In addition, this device uses an acquisition unit composed of a cable T-joint and a voltage sensor body, with the resistive-capacitive voltage divider built into the pole and integrally cast with the pole, which can well adapt to the installation and operation conditions of ring main units.

[0033] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model in any other way. Any person skilled in the art may make changes or modifications to the disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this utility model without departing from its scope of protection shall still fall within the protection scope of this utility model.

Claims

1. A line voltage acquisition device with an elbow-shaped structure, characterized in that, The system includes a data acquisition unit and an output unit. The data acquisition unit comprises a rear T-connector of a cable and a voltage sensor body. The rear T-connector of the cable is connected to the voltage sensor body to form an elbow-shaped structure. The voltage sensor body includes a resistive-capacitive voltage divider and terminals. The resistive-capacitive voltage divider is built into the terminals and consists of a high-voltage arm and a low-voltage arm connected in series. The high-voltage arm includes a high-voltage resistor and a high-voltage capacitor, and the low-voltage arm includes a voltage-dividing resistor. The output unit includes a voltage stabilizing filter circuit and an integrating circuit. The voltage-dividing resistor of the low-voltage arm is connected to the voltage stabilizing filter circuit of the output unit through a wire, and the voltage signal is output through the integrating circuit.

2. The elbow-shaped line voltage acquisition device according to claim 1, characterized in that, The cable rear T-joint includes three connection ends: the front end connects to the T-joint in the ring network box, the rear end is sealed by a plug, and the lower end connects to the voltage sensor body.

3. The elbow-shaped line voltage acquisition device according to claim 1, characterized in that, The cable has a shielded grounding point on the rear T-joint.

4. The elbow-shaped line voltage acquisition device according to claim 1, characterized in that, The high-voltage resistor is connected in series with the high-voltage capacitor. One end of the voltage divider resistor is connected to the high-voltage capacitor, and the other end is grounded. Both ends of the voltage divider resistor are connected to wires. The wires are led out of the voltage sensor body in the form of twisted pairs and connected to the voltage stabilizing filter circuit. The voltage stabilizing filter circuit is connected to the integrating circuit, which is used to restore the differential signal output by the RC voltage divider into a voltage signal proportional to the primary voltage and output it.

5. The elbow-shaped line voltage acquisition device according to claim 4, characterized in that, The voltage divider resistor is connected in parallel with a protection module.

6. The elbow-shaped line voltage acquisition device according to claim 4, characterized in that, The resistive-capacitive voltage divider is built into the terminal post and is integrally cast with the terminal post to form an insulating structure. The wires and grounding wires of the resistive-capacitive voltage divider are led out from the terminal post.

7. The elbow-shaped line voltage acquisition device according to claim 6, characterized in that, The withstand voltage and creepage distance of the pole insulation structure meet the insulation requirements for a 10kV voltage level.

8. The elbow-type line voltage acquisition device according to claim 1, characterized in that, The resistance of the high-voltage arm is in the MΩ range, the resistance of the low-voltage arm is in the KΩ range, and the rated operating current of the RC divider is in the microampere range.

9. The elbow-shaped line voltage acquisition device according to claim 1, characterized in that, The integrator circuit is an active analog integrator circuit.

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