Current signal processing circuit applied to capacitive equipment on-line monitoring

Abstract

The utility model discloses a current signal processing circuit applied to capacitive equipment on-line monitoring, comprising an operational amplifier U25A and an operational amplifier U25B, a pin 3 of the operational amplifier U25A receives a current signal AI1 +, the pin 3 of the operational amplifier U25A is connected with a resistor R77 for converting the current signal AI1 + into a voltage signal AI4, a pin 1 of the operational amplifier U25A is connected with a resistor R82, the resistor R82 is connected with a pin 5 of the operational amplifier U25B, and the pin 5 of the operational amplifier U25B is connected with the resistor R77 for converting the current signal AI1 + into the voltage signal AI4. A pin 6 of the operational amplifier U25B is connected with a resistor R84, a pin 7 of the operational amplifier U25B is connected with a resistor R83, the resistor R83 is connected with the resistor R84, and the pin 7 of the operational amplifier U25B outputs a voltage amplification signal. According to the utility model, a small number of electronic devices are used for independently processing large current in a range of 1A-10A, and as an independent processing channel, the electronic devices do not use one processing channel with 50UA-1A current, so that signals of capacitive equipment are better processed, the precision is high, the effect is good, the linearity is good, and the insulation condition is better monitored and analyzed.

Description

Technical Field

[0001] This utility model relates to online monitoring of capacitive electrical equipment, specifically a current signal processing circuit for online monitoring of capacitive equipment. Background Technology

[0002] Capacitive electrical equipment mainly refers to current transformers, bushings, coupling capacitors, and capacitive voltage transformers. They are widely used in power systems, primarily serving functions such as power compensation, rectification and filtering, and overvoltage protection. The performance of capacitors directly affects the normal operation of the power grid. Since most high-voltage electrical equipment failures are caused by insulation damage, timely and effective detection of insulation defects is crucial for ensuring power grid safety.

[0003] Online monitoring devices for capacitive equipment insulation can monitor the insulation status of high-voltage equipment in real time, making up for the shortcomings of periodic offline testing. Among many electrical devices, for capacitive equipment (voltage transformers, transformer bushings, coupling capacitors, etc.), the main monitoring parameters are dielectric loss, end-screen current, and equivalent capacitance, and the real-time information is uploaded to the terminal display device.

[0004] Online monitoring devices for capacitive equipment insulation need to detect and process the current of the capacitive equipment. Currently, the current processing is suitable for small currents in the range of 50UA-1A. If it processes currents of 1A-10A, it will be inaccurate, the processing effect will be poor, and the linearity will be poor. Utility Model Content

[0005] To address the shortcomings of the existing technology, this invention provides a current signal processing circuit for online monitoring of capacitive equipment. It utilizes a small number of electronic components to process large currents in the range of 1A-10A separately as a dedicated processing channel, instead of sharing a processing channel with currents ranging from 50UA to 1A. This allows for better processing of signals from capacitive equipment, resulting in higher accuracy, better performance, better linearity, and improved monitoring and analysis of insulation conditions.

[0006] To achieve the above technical objectives, this utility model adopts the following technical solution: a current signal processing circuit for online monitoring of capacitive equipment, including operational amplifier U25A and operational amplifier U25B. Pin 3 of operational amplifier U25A receives the current signal AI1+, and simultaneously, pin 3 of operational amplifier U25A is connected to resistor R77 to convert the current signal AI1+ into a voltage signal AI4. Pin 1 of operational amplifier U25A is connected to resistor R82, resistor R82 is connected to pin 5 of operational amplifier U25B, pin 6 of operational amplifier U25B is connected to resistor R84, pin 7 of operational amplifier U25B is connected to resistor R83, resistor R83 is connected to resistor R84, and pin 7 of operational amplifier U25B outputs a voltage amplification signal.

[0007] Pin 3 of the operational amplifier U25A is connected to resistor R80, which is grounded; pin 8 of the operational amplifier U25A is connected to capacitor C55, which is grounded; pin 2 of the operational amplifier U25A is connected to resistor R79, which is connected to pin 1 of the operational amplifier U25A; and pin 4 of the operational amplifier U25A is connected to capacitor C54, which is grounded.

[0008] The 5th pin of the operational amplifier U25B is connected to capacitor C90, which is grounded; the 7th pin of the operational amplifier U25B is connected to capacitor C92, which is grounded.

[0009] Both operational amplifiers U25A and U25B are of the AD822 model.

[0010] In summary, this utility model achieves the following technical effects:

[0011] This invention utilizes a small number of electronic components to process large currents in the range of 1A-10A independently, as a separate processing channel, instead of sharing a processing channel with currents of 50UA-1A. This allows for better processing of signals from capacitive devices, resulting in higher accuracy, better performance, better linearity, and improved monitoring and analysis of insulation conditions. Attached Figure Description

[0012] Figure 1 This utility model provides a current signal processing circuit for online monitoring of capacitive devices. Detailed Implementation

[0013] The present invention will be further described in detail below with reference to the accompanying drawings.

[0014] This specific embodiment is merely an explanation of the present utility model and is not intended to limit the present utility model. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present utility model, they are protected by patent law.

[0015] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0016] 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0017] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," 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 utility model according to the specific circumstances.

[0018] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0019] Example:

[0020] Figure 1 This is a current signal processing circuit used for online monitoring of capacitive devices, including operational amplifier U25A and operational amplifier U25B. Operational amplifier U25A and operational amplifier U25B are the same operational amplifier U25. In the diagram, they are divided into two parts, A and B, according to different pins.

[0021] Pin 3 of operational amplifier U25A receives the current signal AI1+. Simultaneously, pin 3 of operational amplifier U25A is connected to resistor R77 to convert the current signal AI1+ into a voltage signal AI4. Pin 1 of operational amplifier U25A is connected to resistor R82, which is connected to pin 5 of operational amplifier U25B. Pin 6 of operational amplifier U25B is connected to resistor R84. Pin 7 of operational amplifier U25B is connected to resistor R83, which is connected to resistor R84. Pin 7 of operational amplifier U25B outputs a voltage amplification signal.

[0022] This invention utilizes resistor R77 to convert the current signal AI1+ into a voltage signal AI4. The current signal AI1+ is a large current in the range of 1A-10A, and converting it into a voltage signal allows for better processing and amplification.

[0023] Pins 2 and 3 of op-amp U25A isolate the voltage signal to prevent signal interference. Op-amp U25B, together with R83 and R84, amplifies the filtered voltage signal. Pin 7 outputs the amplified voltage signal AI5 to the subsequent processing circuit and MCU for processing.

[0024] Pin 3 of op-amp U25A is connected to resistor R80, which is grounded; pin 8 of op-amp U25A is connected to capacitor C55, which is grounded; pin 2 of op-amp U25A is connected to resistor R79, which is connected to pin 1 of op-amp U25A; pin 4 of op-amp U25A is connected to capacitor C54, which is grounded. Pins 2 and 3 are isolated to prevent interference.

[0025] Pin 5 of op-amp U25B is connected to capacitor C90, which is grounded; pin 7 of op-amp U25B is connected to capacitor C92, which is grounded.

[0026] Capacitors C90 and C92 are filter capacitors. Resistors R83 and R84 are amplification resistors.

[0027] Op-amps U25A and U25B are of the AD822 model.

[0028] The preprocessing circuit (not shown) determines when the current of the capacitive device falls into the range of 1A-10A. When the resistor R77 receives the large current signal, it converts it into a voltage signal. After isolation by the operational amplifier, filtering by the capacitor, and amplification by the operational amplifier, the voltage amplified signal is output and sent to the subsequent circuit and MCU for processing. It can handle large currents well with high accuracy, solving the problem of inaccuracy when handling large currents in the original current channel.

[0029] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model shall fall within the scope of the technical solution of the present utility model.

Claims

1. A current signal processing circuit for online monitoring of capacitive devices, characterized in that: The system includes operational amplifiers U25A and U25B. Pin 3 of operational amplifier U25A receives a current signal AI1+. Simultaneously, pin 3 of operational amplifier U25A is connected to resistor R77 to convert the current signal AI1+ into a voltage signal AI4. Pin 1 of operational amplifier U25A is connected to resistor R82, which is connected to pin 5 of operational amplifier U25B. Pin 6 of operational amplifier U25B is connected to resistor R84. Pin 7 of operational amplifier U25B is connected to resistor R83, which is connected to resistor R84. Pin 7 of operational amplifier U25B outputs a voltage amplification signal.

2. The current signal processing circuit for online monitoring of capacitive equipment according to claim 1, characterized in that: Pin 3 of the operational amplifier U25A is connected to resistor R80, which is grounded; pin 8 of the operational amplifier U25A is connected to capacitor C55, which is grounded; pin 2 of the operational amplifier U25A is connected to resistor R79, which is connected to pin 1 of the operational amplifier U25A; and pin 4 of the operational amplifier U25A is connected to capacitor C54, which is grounded.

3. The current signal processing circuit for online monitoring of capacitive equipment according to claim 1, characterized in that: The 5th pin of the operational amplifier U25B is connected to capacitor C90, which is grounded; the 7th pin of the operational amplifier U25B is connected to capacitor C92, which is grounded.

4. The current signal processing circuit for online monitoring of capacitive equipment according to claim 1, characterized in that: Both operational amplifiers U25A and U25B are of the AD822 model.

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