Electric field sensor circuit of overhead line comprehensive detection device

Abstract

The utility model discloses an electric field sensor circuit of an overhead line comprehensive detection device, which comprises a high-impedance input module, a signal conditioning module and an output module, and is characterized in that the high-impedance input module is used for converting an induction signal into a voltage signal, and the input end of the high-impedance input module is connected with an induction signal port; the output end of the high-impedance input module is connected with the input end of the signal conditioning module; the output end of the signal conditioning module is connected with the output module; the high-impedance input module comprises a sixth resistor, a fifteenth capacitor, a sixteenth capacitor, an eighteenth capacitor, a fourth resistor, a fourteenth capacitor, a seventeenth capacitor, a seventh resistor, a fifth resistor and an operational amplifier. According to the utility model, the small-sized modularization of the electric field sensor can be realized. The sensor can be widely applied to the technical field of sensors.

Description

Technical Field

[0001] This utility model relates to the field of sensor technology, and in particular to an electric field sensor circuit for an overhead line integrated detection device. Background Technology

[0002] The overhead line online integrated monitoring device is an intelligent device used to monitor the operating status of transmission lines in real time, aiming to improve power grid safety, prevent faults, and optimize operation and maintenance efficiency. The device relies on voltage sensors mounted on it to detect the line's voltage signal in real time. However, voltage sensors typically use high-voltage dividing capacitors for voltage division, and these capacitors are in direct contact with the high-voltage signal. If the high-voltage divider fails or breaks down during use, both the connected voltage sensor and the online integrated monitoring device are easily damaged under high-voltage conditions.

[0003] Therefore, there is a need for integrated overhead line monitoring devices that use electric field sensors to detect the voltage signal of the line in real time, avoiding direct contact with high-voltage electrical signals. However, existing electric field sensors rely on junction field-effect transistors or specially manufactured operational amplifiers for their high-impedance input stages, resulting in large PCB area requirements, making circuit integration difficult and costly. Furthermore, the signal conditioning circuits rely on passive components for multi-stage filtering and extensive amplification, leading to bulky electric field sensor modules. Therefore, existing electric field sensors cannot meet the non-contact, small-scale, modular requirements of integrated overhead line monitoring devices for high-voltage power grid monitoring. Utility Model Content

[0004] To address the aforementioned technical problems, the objective of this utility model is to provide an electric field sensor circuit for an overhead line integrated detection device, which enables the electric field sensor to be miniaturized and modularized.

[0005] The technical solution adopted in this utility model is: an electric field sensor circuit for an overhead line integrated detection device, comprising a high-impedance input module, a signal conditioning module, an output module, a data acquisition and processing unit, a power supply module, and a communication module, wherein:

[0006] The high-impedance input module is used to convert the induced signal into a voltage signal, and its input terminal is connected to the induced signal port. The output terminal of the high-impedance input module is connected to the input terminal of the signal conditioning module. The output terminal of the signal conditioning module is connected to the input terminal of the output module. The output terminal of the output module is connected to the input terminal of the data acquisition and processing unit, which is used to acquire analog voltage signals and perform analysis and processing. The output terminal of the data acquisition and processing unit is connected to the input terminal of the communication module.

[0007] The high-impedance input module includes a sixth resistor, a fifteenth capacitor, a sixteenth capacitor, an eighteenth capacitor, a fourth resistor, a fourteenth capacitor, a seventeenth capacitor, a seventh resistor, a fifth resistor, and an operational amplifier. The first terminal of the sixth resistor is connected to the sensing signal port; the second terminal of the sixth resistor is connected to the first terminals of the fifteenth and sixteenth capacitors and the input terminal of the operational amplifier module; the second terminals of the fifteenth and sixteenth capacitors are grounded; the negative input gain adjustment pin of the operational amplifier is connected to the first terminal of the fourth resistor; the positive input gain adjustment pin of the operational amplifier is connected to the second terminal of the fourth resistor; and the differential input negative pin of the operational amplifier is connected to the fifth resistor. The second terminal of the resistor is connected; the first terminal of the fifth resistor is grounded; the differential input positive pin of the operational amplifier is connected to the second terminal of the sixth resistor; the negative power supply pin of the operational amplifier is connected to the second terminal of the eighteenth capacitor and the negative terminal of the power supply module; the first terminal of the eighteenth capacitor is grounded; the positive power supply pin of the operational amplifier is connected to the first terminal of the fourteenth capacitor and the positive terminal of the power supply module; the second terminal of the fourteenth capacitor is grounded; the reference voltage input pin of the operational amplifier is connected to the first terminal of the seventeenth capacitor and the first terminal of the seventh resistor; the second terminals of the seventeenth capacitor and the second terminal of the seventh resistor are grounded; the output pin of the operational amplifier is connected to the first terminal of the eighth resistor.

[0008] The signal conditioning module includes an eighth resistor, a ninth resistor, and a nineteenth capacitor. The first end of the eighth resistor is connected to the output terminal of the operational amplifier. The second end of the eighth resistor is connected to the first end of the ninth resistor, the first end of the nineteenth capacitor, and the signal output interface of the output module. The second end of the ninth resistor and the second end of the nineteenth capacitor are grounded.

[0009] Furthermore, the sixth resistor, the fifteenth capacitor, and the sixteenth capacitor constitute a π-type RC low-pass filter network to suppress high-frequency noise and power supply ripple in the induced signal and improve DC stability.

[0010] Furthermore, the fourth resistor and the fifth resistor constitute the feedback resistor network of the inverting input of the operational amplifier, which is used to set the closed-loop gain of the operational amplifier and adjust the signal amplification factor and bandwidth.

[0011] Furthermore, the seventh resistor and the seventeenth capacitor form a static bias resistor network to provide a midpoint voltage for the differential input stage, ensuring that the operational amplifier operates in the linear region.

[0012] Furthermore, the ninth resistor and the nineteenth capacitor constitute an output stage RC compensation network, which is used to match the output impedance and correct high-frequency phase shift, thereby avoiding self-excited oscillation.

[0013] Furthermore, the eighth resistor and the ninth resistor constitute an output stage voltage divider feedback network, which is used to adjust the output voltage swing, match the load requirements of the subsequent stage, and avoid signal clipping.

[0014] Furthermore, the fourteenth capacitor is a positive power rail decoupling capacitor, used to suppress voltage fluctuations caused by transient currents and reduce power supply coupling crosstalk.

[0015] Furthermore, the eighteenth capacitor is a negative power rail decoupling capacitor, used to filter out low-frequency power frequency interference and high-frequency switching noise, and optimize power integrity.

[0016] The beneficial effects of this utility model are as follows: This utility model proposes an electric field sensor circuit for an overhead line integrated testing device. It utilizes the principle of charge induction to sense high-voltage input signals and obtain a weak induced signal, avoiding direct contact between the electric field sensor and the high-voltage test signal, which could cause component breakdown. The π-type RC low-pass filter network in the high-impedance input module is connected to the induced signal to suppress high-frequency noise and power supply ripple in the induced signal, thereby improving DC stability. The operational amplifier in the high-impedance input module converts the induced signal to obtain an output voltage signal. The signal conditioning module performs high-frequency phase shift correction and output impedance matching on the voltage output module, avoiding self-excited oscillation and signal clipping, ultimately achieving the monitoring of high-voltage input signals. Using this electric field sensor circuit, the number of passive components required is greatly reduced, enabling the electric field sensor to be miniaturized and modularized, saving a significant amount of materials, and being environmentally friendly and low-carbon. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the electric field sensor circuit of an overhead line integrated detection device according to this utility model;

[0018] Figure 2 This is a schematic diagram of the structure of an overhead line online integrated monitoring device, which is a voltage sensor circuit of an overhead line online integrated monitoring device according to this utility model.

[0019] Figure description: R4, fourth resistor; R5, fifth resistor; R6, sixth resistor; R7, seventh resistor; R8, eighth resistor; R9, ninth resistor; C15, fifteenth capacitor; C16, sixteenth capacitor; C17, seventeenth capacitor; C18, eighteenth capacitor; C19, nineteenth capacitor; U5, operational amplifier; CN1, output module; 1, voltage sensor. Detailed Implementation

[0020] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the embodiments of the present invention, and should not be construed as limiting the present invention.

[0021] In the description of the embodiments of this utility model, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the embodiments of this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0023] In this embodiment of the invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment of the invention according to the specific circumstances.

[0024] Reference Figure 1 An electric field sensor circuit for an overhead line integrated detection device includes a high-impedance input module, a signal conditioning module, an output module, a data acquisition and processing unit, a power supply module, and a communication module, wherein:

[0025] The high-impedance input module includes a filtering module and an operational amplifier module. The input of the filtering module is connected to the inductive signal port to filter out noise and AC components from the inductive signal. The output of the filtering module is connected to the input of the operational amplifier module to amplify and convert the filtered inductive signal, outputting a voltage signal for observation. The output of the operational amplifier module is connected to the input of the signal conditioning module to determine the output impedance of the circuit and calibrate the phase difference of the operational amplifier output signal. The output of the signal conditioning module is connected to the input of the output module. The output of the output module is connected to the input of the data acquisition and processing unit, which acquires and analyzes the analog voltage signal. The output of the data acquisition and processing unit is connected to the input of the communication module to transmit the processed digital voltage signal to the communication module, which then sends the processed digital voltage signal to the operator's terminal device or cloud platform.

[0026] In a preferred embodiment, a small capacitive sensing capacitor is used to sense changes in the electric field of the electrode metal plate. A weak charge flows between the positive and negative terminals of the sensing capacitor, forming an induction signal.

[0027] In a preferred embodiment, the filtering module includes a sixth resistor R6, a fifteenth capacitor C15, and a sixteenth capacitor C16, wherein:

[0028] The first terminal of the sixth resistor R6 is connected to the second terminal of capacitor C; the second terminal of the sixth resistor R6 is connected to the first terminal of the fifteenth capacitor C15, the first terminal of the sixteenth capacitor C16, and the input terminal of the operational amplifier module; the second terminals of the fifteenth capacitor C15 and the sixteenth capacitor C16 are grounded. The sixth resistor R6 reduces current noise and common-mode noise, and also improves the stability and reliability of the circuit; the sixth resistor R6, the fifteenth capacitor C15, and the sixteenth capacitor C16 together form a π-type RC low-pass filter network, which is used to suppress high-frequency noise and power supply ripple in the induced signal and improve DC stability. Based on the target frequency, appropriate resistance and capacitance values ​​can be selected for the sixth resistor R6, the fifteenth capacitor C15, and the sixteenth capacitor C16. When the capacitance values ​​of the fifteenth capacitor C15 and the sixteenth capacitor C16 are both C, due to the mutual influence between the first-stage RC (sixth resistor R6 and fifteenth capacitor C15) and the second-stage RC (sixth resistor R6 and sixteenth capacitor C16), accurate calculation requires solving the transfer function. Therefore, in this specific embodiment of the invention, the expression for calculating the cutoff frequency is approximately in the following form:

[0029]

[0030] Among them, f cR represents the cutoff frequency; R represents the resistance value of the sixth resistor R6; C represents the capacitance values ​​of the fifteenth capacitor C15 and the sixteenth capacitor C16.

[0031] In a preferred embodiment, the operational amplifier module includes an eighteenth capacitor C18, a fourth resistor R4, a fourteenth capacitor C14, a seventeenth capacitor C17, a seventh resistor R7, a fifth resistor R5, and an operational amplifier U5, wherein:

[0032] The negative input gain adjustment pin RG- of operational amplifier U5 is connected to the first terminal of the fourth resistor R4; the positive input gain adjustment pin RG+ of operational amplifier U5 is connected to the second terminal of the fourth resistor R4; the negative differential input pin IN- of operational amplifier U5 is connected to the second terminal of the fifth resistor R5; the first terminal of the fifth resistor R5 is grounded; the positive differential input pin IN+ of operational amplifier U5 is connected to the second terminal of the sixth resistor R6; the negative power supply pin VS- of operational amplifier U5 is connected to the second terminal of the eighteenth capacitor C18 and the negative terminal VEE of the power supply module; the first terminal of the eighteenth capacitor C18 is grounded; the positive power supply pin VS+ of operational amplifier U5 is connected to the first terminal of the fourteenth capacitor C14 and the positive terminal VCC of the power supply module; the second terminal of the fourteenth capacitor C14 is grounded; the reference voltage input pin REF of operational amplifier U5 is connected to the first terminal of the seventeenth capacitor C17 and the first terminal of the seventh resistor R7; the second terminals of the seventeenth capacitor C17 and the second terminal of the seventh resistor R7 are grounded; the output pin OUT of operational amplifier U5 is connected to the first terminal of the eighth resistor R8.

[0033] The fourth resistor R4 and the fifth resistor R5 form the feedback resistor network of the operational amplifier's inverting input, used to set the closed-loop gain of the operational amplifier, and adjust the signal amplification factor and bandwidth. The expression for calculating the closed-loop gain is as follows:

[0034]

[0035] Where A represents the closed-loop gain; R4 represents the resistance value of the fourth resistor R4; and R5 represents the resistance value of the fifth resistor R5.

[0036] The seventh resistor R7 and the seventeenth capacitor C17 together form a static bias resistor network, which is used to provide a midpoint voltage for the differential input stage and ensure that the op-amp operates in the linear region.

[0037] The fourteenth capacitor, C14, is a positive power rail decoupling capacitor. It is an X7R multilayer ceramic capacitor used to suppress voltage fluctuations caused by transient currents and reduce power supply coupling crosstalk.

[0038] The eighteenth capacitor, C18, is a negative power rail decoupling capacitor. It is a multilayer ceramic capacitor made of X7R material, used to filter out low-frequency power frequency interference and high-frequency switching noise, and optimize power integrity.

[0039] In a preferred embodiment, the signal conditioning module includes an eighth resistor R8, a ninth resistor R9, and a nineteenth capacitor C19, wherein:

[0040] The first terminal of the eighth resistor R8 is connected to the output terminal of operational amplifier U5; the second terminal of the eighth resistor R8 is connected to the first terminal of the ninth resistor R9, the first terminal of the nineteenth capacitor C19, and the signal output interface of the output module; the second terminals of the ninth resistor R9 and the nineteenth capacitor C19 are grounded. The ninth resistor R9 and the nineteenth capacitor C19 together form the output stage RC compensation network, used to match the output impedance and correct high-frequency phase shift, avoiding self-oscillation. When correcting high-frequency phase shift, stability needs to be optimized in conjunction with the op-amp open-loop gain curve to avoid loop oscillation. The eighth resistor R8 and the ninth resistor R9 form the output stage voltage divider feedback network, used to adjust the output voltage swing, match the load requirements of the subsequent stage, and avoid signal clipping.

[0041] As a preferred embodiment, the output module also includes a power port VCC and a ground port GND. In a specific embodiment of this utility model, the output module does not need to perform signal conditioning function, but only outputs the output signal adjusted by the signal conditioning module. Therefore, in order to minimize the circuit structure, the output module and the power module are organically integrated. The output module can be a socket with an output interface, a power interface and a ground interface.

[0042] Reference Figure 2 By utilizing the electric field sensor circuit of this invention to achieve a small-scale modular design of the electric field sensor, the electric field sensor 1 is placed on the overhead line online integrated monitoring device. Since the electric field sensor of this invention requires only 11 passive components, the overall size of the overhead line online integrated monitoring device is greatly reduced, facilitating its portability. The electric field sensor and the high-voltage input signal are in a non-contact relationship, avoiding the risk of voltage divider capacitor breakdown. The high-voltage input signal is sensed using the principle of charge induction to obtain a weak induced signal. A π-type RC low-pass filter network in the high-impedance input module is connected to the induced signal to suppress high-frequency noise and power supply ripple, improving DC stability. The induced signal is converted by an operational amplifier in the high-impedance input module to obtain an output voltage signal. A signal conditioning module performs high-frequency phase shift correction and output impedance matching on the voltage output module, avoiding self-excited oscillation and signal clipping, ultimately achieving the monitoring of the high-voltage input signal. The electric field sensor 1 transmits the monitored data to the data processing module of the overhead line online integrated monitoring device. After analyzing and processing the detection data, it is then sent to the staff via the communication module.

[0043] The above is a detailed description of the preferred embodiments of the present utility model. However, the present utility model is not limited to the described embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present utility model. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. An electric field sensor circuit for an overhead line integrated detection device, characterized in that, It includes a high-impedance input module, a signal conditioning module, an output module, a data acquisition and processing unit, a power supply module, and a communication module, wherein: The high-impedance input module is used to convert the induced signal into a voltage signal, and its input terminal is connected to the induced signal port. The output terminal of the high-impedance input module is connected to the input terminal of the signal conditioning module. The output terminal of the signal conditioning module is connected to the input terminal of the output module. The output terminal of the output module is connected to the input terminal of the data acquisition and processing unit, which is used to acquire analog voltage signals and perform analysis and processing. The output terminal of the data acquisition and processing unit is connected to the input terminal of the communication module. The high-impedance input module includes a sixth resistor, a fifteenth capacitor, a sixteenth capacitor, an eighteenth capacitor, a fourth resistor, a fourteenth capacitor, a seventeenth capacitor, a seventh resistor, a fifth resistor, and an operational amplifier. The first terminal of the sixth resistor is connected to the sensing signal port; the second terminal of the sixth resistor is connected to the first terminals of the fifteenth and sixteenth capacitors and the input terminal of the operational amplifier module; the second terminals of the fifteenth and sixteenth capacitors are grounded; the negative input gain adjustment pin of the operational amplifier is connected to the first terminal of the fourth resistor; the positive input gain adjustment pin of the operational amplifier is connected to the second terminal of the fourth resistor; and the differential input negative pin of the operational amplifier is connected to the fifth resistor. The second terminal of the resistor is connected; the first terminal of the fifth resistor is grounded; the differential input positive pin of the operational amplifier is connected to the second terminal of the sixth resistor; the negative power supply pin of the operational amplifier is connected to the second terminal of the eighteenth capacitor and the negative terminal of the power supply module; the first terminal of the eighteenth capacitor is grounded; the positive power supply pin of the operational amplifier is connected to the first terminal of the fourteenth capacitor and the positive terminal of the power supply module; the second terminal of the fourteenth capacitor is grounded; the reference voltage input pin of the operational amplifier is connected to the first terminal of the seventeenth capacitor and the first terminal of the seventh resistor; the second terminals of the seventeenth capacitor and the second terminal of the seventh resistor are grounded; the output pin of the operational amplifier is connected to the first terminal of the eighth resistor. The signal conditioning module includes an eighth resistor, a ninth resistor, and a nineteenth capacitor. The first end of the eighth resistor is connected to the output terminal of the operational amplifier. The second end of the eighth resistor is connected to the first end of the ninth resistor, the first end of the nineteenth capacitor, and the signal output interface of the output module. The second end of the ninth resistor and the second end of the nineteenth capacitor are grounded.

2. The electric field sensor circuit of the overhead line integrated detection device according to claim 1, characterized in that, The sixth resistor, the fifteenth capacitor, and the sixteenth capacitor constitute a π-type RC low-pass filter network, which is used to suppress high-frequency noise and power supply ripple in the induced signal.

3. The electric field sensor circuit of the overhead line integrated detection device according to claim 1, characterized in that, The fourth resistor and the fifth resistor constitute the feedback resistor network of the inverting input of the operational amplifier, which is used to set the closed-loop gain of the operational amplifier.

4. The electric field sensor circuit of the overhead line integrated detection device according to claim 1, characterized in that, The seventh resistor and the seventeenth capacitor form a static bias resistor network, which is used to provide a midpoint voltage for the differential input stage.

5. The electric field sensor circuit of the overhead line integrated detection device according to claim 1, characterized in that, The ninth resistor and the nineteenth capacitor constitute the output stage RC compensation network, which is used to match the output impedance and correct high-frequency phase shift.

6. The electric field sensor circuit of the overhead line integrated detection device according to claim 1, characterized in that, The eighth resistor and the ninth resistor constitute an output stage voltage divider feedback network, which is used to adjust the output voltage swing.

7. The electric field sensor circuit of the overhead line integrated detection device according to claim 1, characterized in that, The fourteenth capacitor is a positive power rail decoupling capacitor, used to suppress voltage fluctuations caused by transient currents.

8. The electric field sensor circuit of the overhead line integrated detection device according to claim 1, characterized in that, The eighteenth capacitor is a negative power rail decoupling capacitor, used to filter out low-frequency power frequency interference and high-frequency switching noise.

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