A high-voltage live measurement circuit for GIS

Abstract

The utility model relates to the technical field of electrified display measurement, concretely is a kind of high voltage electrified measurement circuit for GIS, including the sensor input module, signal clamping protection module, signal filter module, signal amplification module and zero-crossing comparison module connected in turn;The utility model constructs the complete measurement process of " signal input - step-by-step processing - result output " by setting the sensor input module, signal clamping protection module, signal filter module, signal amplification module and zero-crossing comparison module connected in turn, each module is clear in division of labour, collaborative work, can gradually eliminate electromagnetic interference, optimize signal quality, finally output the zero-crossing waveform signal that can accurately judge the electrified state of GIS equipment, improve the anti-interference ability and detection accuracy of measurement loop from overall architecture, and circuit structure logic is clear, easy to assemble and maintain.

Description

Technical Field

[0001] This utility model relates to the field of live-line display measurement technology, specifically a high-voltage live-line measurement circuit for GIS. Background Technology

[0002] Gas-insulated switchgear (GIS) is a complete set of power equipment that integrates various high-voltage electrical devices into a closed metal enclosure and uses gases such as SF6 (sulfur hexafluoride) as insulation and arc-extinguishing media. It is widely used in high-voltage power systems of 110KV and above and is one of the key equipment in the power transmission and distribution process.

[0003] As an important supporting component of GIS equipment, the high-voltage live display device has the core function of detecting whether the GIS equipment is energized in real time and outputting corresponding interlocking signals. This prevents maintenance personnel from making erroneous operations due to misjudging the energized state of the equipment, thus ensuring personnel safety and the stable operation of the power system.

[0004] However, because GIS equipment is used in high-voltage scenarios, it suffers from significant electromagnetic interference, primarily including rapid transient overvoltage interference caused by operational overvoltages, partial discharge interference, and magnetic field interference generated by bus currents. These interferences exist in both conducted and radiated forms and can easily intrude into the measurement circuits of high-voltage live indicator devices, causing "energized / de-energized" errors. This not only affects the normal function of the device but may also pose safety hazards for power system operation and maintenance.

[0005] In view of the shortcomings of the prior art, this application aims to provide a high-voltage live measurement circuit for GIS, which improves the electromagnetic interference resistance of the measurement circuit by optimizing the signal processing flow and circuit structure, and ensures accurate detection of the live state of GIS equipment. Utility Model Content

[0006] The purpose of this invention is to provide a high-voltage live measurement circuit for GIS, which improves the electromagnetic interference resistance of the measurement circuit by optimizing the signal processing flow and circuit structure, thereby ensuring accurate detection of the live state of GIS equipment.

[0007] To achieve the above objectives, the technical solution provided by this utility model is as follows: A high-voltage live measurement circuit for GIS includes a sensor input module, a signal clamping protection module, a signal filtering module, a signal amplification module, and a zero-crossing comparison module connected in sequence. The sensor input module is used to receive the signal output by the high-voltage live sensor, and transmit the received signal to the signal clamping protection module, the signal filtering module, the signal amplification module, and the zero-crossing comparison module for sequential processing, and outputs a zero-crossing waveform signal for judging the live state of the GIS equipment.

[0008] Preferably, the sensor input module includes a discharge tube FLG1 and a magnetic bead ACZ1; One end of the discharge tube FLG1 is connected to the signal output terminal of the external high-voltage live sensor and one end of the magnetic bead ACZ1, respectively. The other end of the discharge tube FLG1 is grounded, and the other end of the magnetic bead ACZ1 is connected to the signal clamping protection module and the signal filtering module, respectively. The discharge tube FLG1 is used to achieve lightning protection, and the magnetic bead ACZ1 is used to filter out high-frequency noise interference.

[0009] Preferably, the signal clamping protection module includes diode AD1 and diode AD2; The anode of diode AD1 is connected to the cathode of diode AD2 and the signal filtering module, respectively. The cathode of diode AD1 is grounded, and the anode of diode AD2 is connected to the signal filtering module.

[0010] Preferably, the signal filtering module includes resistor AR1, capacitor AC1, resistor AR2, and capacitor AC2; One end of resistor AR1 is connected to the sensor input module. The other end of resistor AR1 is electrically connected to the signal clamping protection module, one end of resistor AR2, and one end of capacitor AC1. The other end of resistor AR2 is connected to the signal amplification module and one end of capacitor AC2. The other end of capacitor AC2 is grounded to both the other end of capacitor AC1 and the other end of capacitor AC1.

[0011] Preferably, the signal amplification module includes amplifier AU1A and amplifier AU1B; The non-inverting input terminal of the amplifier AU1A is connected to a 3.3V power supply, and the inverting input terminal of the amplifier AU1A is connected to the output terminal of the amplifier AU1A and the zero-crossing comparator module, respectively. The non-inverting input terminal of the amplifier AU1B is connected to the signal filtering module, and the inverting input terminal of the amplifier AU1B is connected to the output terminal of the amplifier AU1B and the zero-crossing comparator module, respectively.

[0012] Preferably, the signal amplification module further includes resistors PR1 and PR2 and capacitor PC1; One end of resistor PR1 is connected to a 3.3V power supply. The other end of resistor PR1 is connected to one end of resistor PR2, one end of capacitor PC1, and the non-inverting input terminal of amplifier AU1A. The other end of resistor PR2 is connected to the other end of capacitor PC1, and both the other ends of resistor PR2 and capacitor PC1 are grounded.

[0013] Preferably, the signal amplification module further includes resistor AR3 and resistor AR6; One end of resistor AR3 is connected to the output terminal of amplifier AU1A, the other end of resistor AR3 is connected to the signal clamping protection module and one end of resistor AR6, and the other end of resistor AR6 is connected to the non-inverting input terminal of amplifier AU1B.

[0014] Preferably, the signal amplification module further includes resistor AR5, resistor AR4, resistor AR7, and capacitor AC3; One end of resistor AR5 is connected to the inverting input terminal of amplifier AU1B and one end of resistor AR4, respectively. The other end of resistor AR5 is grounded. The other end of resistor AR4 is connected to one end of resistor AR7 and the output terminal of amplifier AU1B, respectively. The other end of resistor AR7 is connected to one end of capacitor AC3 and the zero-crossing comparator module, respectively. The other end of capacitor AC3 is grounded.

[0015] Preferably, the zero-crossing comparison module includes a comparator AU2A, the non-inverting input terminal of the comparator AU2A is connected to the reference signal output terminal of the signal amplification module, and the inverting input terminal of the comparator AU2A is connected to the sampling signal output terminal of the signal amplification module. The comparator AU2A compares the sampled signal output by the signal amplification module with a reference signal to achieve zero-crossing comparison and generate a zero-crossing waveform representing the input signal.

[0016] Preferably, the zero-crossing comparison module further includes capacitor AC13, resistor AR11, diode AD6, and diode AD7; One end of capacitor AC13 is connected to the signal amplification module, the anode of diode AD6, the cathode of diode AD7, and the non-inverting input of comparator AU2A, respectively. The other end of capacitor AC13 is connected to one end of resistor AR11, the cathode of diode AD6, the anode of diode AD7, and the inverting input of comparator AU2A, respectively. The other end of resistor AR11 is connected to the signal amplification module.

[0017] Compared with the prior art, the beneficial effects of this utility model are as follows: This invention constructs a complete measurement process of "signal input - step-by-step processing - result output" by setting up a sensor input module, a signal clamping protection module, a signal filtering module, a signal amplification module and a zero-crossing comparison module connected in sequence. Each module has a clear division of labor and works in concert, which can gradually eliminate electromagnetic interference, optimize signal quality, and finally output a zero-crossing waveform signal that can accurately determine the energized state of GIS equipment. From the overall architecture, it improves the anti-interference capability and detection accuracy of the measurement loop. At the same time, the circuit structure logic is clear and easy to assemble and maintain. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a block diagram showing the module connection of the measurement circuit of this utility model; Figure 2 This is a circuit diagram of the sensor input module, signal clamping protection module, signal filtering module, and signal amplification module in the measurement circuit of this utility model; Figure 3 This is a circuit diagram of the signal amplification module in the measurement circuit of this utility model; Figure 4 This is a circuit diagram of the zero-crossing comparison module in the measurement circuit of this utility model.

[0020] The attached diagram lists the components represented by each number as follows: 1. Sensor input module; 2. Signal clamping protection module; 3. Signal filtering module; 4. Signal amplification module; 5. Zero-crossing comparison module. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0022] like Figure 1-4 As shown: Embodiment 1 of this utility model is as follows: A high-voltage live measurement circuit for GIS includes a sensor input module 1, a signal clamping protection module 2, a signal filtering module 3, a signal amplification module 4, and a zero-crossing comparison module 5 connected in sequence. The sensor input module 1 is used to receive the signal output by the high-voltage live sensor, and transmit the received signal to the signal clamping protection module 2, the signal filtering module 3, the signal amplification module 4, and the zero-crossing comparison module 5 for sequential processing, and outputs a zero-crossing waveform signal for judging the live state of the GIS equipment.

[0023] As can be seen from the above description, this utility model constructs a complete measurement process of "signal input - step-by-step processing - result output" by setting up a sensor input module, a signal clamping protection module, a signal filtering module, a signal amplification module and a zero-crossing comparison module connected in sequence. Each module has a clear division of labor and works in concert, which can gradually eliminate electromagnetic interference, optimize signal quality, and finally output a zero-crossing waveform signal that can accurately determine the energized state of GIS equipment. From the overall architecture, it improves the anti-interference capability and detection accuracy of the measurement circuit. At the same time, the circuit structure logic is clear and easy to assemble and maintain.

[0024] Specifically, the sensor input module 1 includes a discharge tube FLG1 and a magnetic bead ACZ1; One end of the discharge tube FLG1 is connected to the signal output terminal of the external high-voltage live sensor and one end of the magnetic bead ACZ1, respectively. The other end of the discharge tube FLG1 is grounded, and the other end of the magnetic bead ACZ1 is connected to the signal clamping protection module 2 and the signal filtering module 3, respectively. The discharge tube FLG1 is used to achieve lightning protection, and the magnetic bead ACZ1 is used to filter out high-frequency noise interference.

[0025] As described above, in the sensor input module, the discharge tube FLG1 is grounded at one end and connected to the high-voltage live sensor signal output terminal at the other end. It can quickly discharge in the event of lightning strikes or transient overvoltages, thus providing lightning protection for the entire measurement circuit and preventing damage to subsequent circuit components from extreme voltages. The ferrite bead ACZ1 can specifically filter out high-frequency noise interference in the signal, reducing interference components at the signal source and providing a cleaner initial signal for subsequent module signal processing, effectively reducing the impact of high-frequency interference on the accuracy of subsequent measurements. Specifically, the signal clamping protection module 2 includes diode AD1 and diode AD2; The anode of diode AD1 is connected to the cathode of diode AD2 and the signal filtering module 3, respectively. The cathode of diode AD1 is grounded, and the anode of diode AD2 is connected to the signal filtering module 3.

[0026] As described above, the signal clamping protection module, through the cooperation of diode AD1 (cathode grounded) and diode AD2, utilizes the unidirectional conductivity of diodes to forcibly limit the signal voltage input to subsequent modules within the 0-3.3V range. This effectively intercepts abnormal signals that are too high or too low, preventing abnormal voltage breakdown or damage to precision circuits such as downstream signal filtering modules and signal amplification modules, extending circuit lifespan, and ensuring the stability of the measurement process.

[0027] Specifically, the signal filtering module 3 includes resistor AR1, capacitor AC1, resistor AR2, and capacitor AC2; One end of resistor AR1 is connected to sensor input module 1. The other end of resistor AR1 is electrically connected to signal clamping protection module 2, one end of resistor AR2, and one end of capacitor AC1. The other end of resistor AR2 is connected to signal amplification module 4 and one end of capacitor AC2. The other end of capacitor AC2 is grounded to both the other end of capacitor AC1 and the other end of resistor AR1.

[0028] As can be seen from the above description, the signal filtering module adopts a second-order RC filter circuit composed of resistor AR1, capacitor AC1, resistor AR2, and capacitor AC2. Compared with the first-order filter circuit, it has a stronger ability to suppress high-frequency interference and a more stable filtering effect. It can further filter out the high-frequency interference signals that remain after being processed by the sensor input module and the signal clamping protection module, making the signal waveform more stable and providing a high-quality signal with low noise and low fluctuation for the subsequent signal amplification stage, thereby improving the accuracy of the amplified signal.

[0029] Specifically, the signal amplification module 4 includes amplifier AU1A and amplifier AU1B; The non-inverting input terminal of the amplifier AU1A is connected to a 3.3V power supply, and the inverting input terminal of the amplifier AU1A is connected to the output terminal of the amplifier AU1A and the zero-crossing comparator module 5, respectively. The non-inverting input terminal of the amplifier AU1B is connected to the signal filtering module 3, and the inverting input terminal of the amplifier AU1B is connected to the output terminal of the amplifier AU1B and the zero-crossing comparator module 5, respectively.

[0030] As described above, the signal amplification module, through the coordinated operation of amplifiers AU1A and AU1B, respectively achieves the functions of generating a reference signal and amplifying a sampled signal: amplifier AU1A can output a stable reference signal, providing a reliable reference for subsequent zero-crossing comparison; amplifier AU1B can amplify the filtered weak signal, solving the problem of excessively low induced voltage (mV level) caused by electromagnetic induction and capacitive voltage division of high-voltage live sensors, ensuring that the signal strength meets the requirements of subsequent zero-crossing comparison, and improving the detection sensitivity of the live state of GIS equipment.

[0031] Specifically, the signal amplification module 4 also includes resistors PR1 and PR2 and capacitor PC1; One end of resistor PR1 is connected to a 3.3V power supply. The other end of resistor PR1 is connected to one end of resistor PR2, one end of capacitor PC1, and the non-inverting input terminal of amplifier AU1A. The other end of resistor PR2 is connected to the other end of capacitor PC1, and both the other ends of resistor PR2 and capacitor PC1 are grounded.

[0032] As described above, the addition of resistors PR1 and PR2, along with capacitor PC1, constitutes a voltage divider and filter circuit for the 3.3V power supply. Resistors PR1 and PR2 adjust the reference signal voltage through voltage division, ensuring the accuracy of the reference signal VREF. Capacitor PC1 filters out power supply noise introduced during the voltage division process, making the reference signal output by amplifier AU1A more stable. This design further improves the reliability of the reference signal, laying the foundation for the accuracy of subsequent zero-crossing comparisons.

[0033] Specifically, the signal amplification module 4 also includes resistor AR3 and resistor AR6; One end of resistor AR3 is connected to the output terminal of amplifier AU1A, the other end of resistor AR3 is connected to signal clamping protection module 2 and one end of resistor AR6 respectively, and the other end of resistor AR6 is connected to the non-inverting input terminal of amplifier AU1B.

[0034] As described above, resistors AR3 and AR6 provide a stable path for signal transmission within the signal amplification module: AR3 connects the output of amplifier AU1A to resistor AR6, ensuring that the reference signal is accurately transmitted to the non-inverting input of amplifier AU1B; resistor AR6 further optimizes signal transmission efficiency, preventing signal attenuation or interference during transmission. Together, they ensure accurate superposition of the reference signal and the sampled signal at amplifier AU1B, guaranteeing the accuracy of signal amplification and achieving stable zero-point raising of the sampled signal.

[0035] Specifically, the signal amplification module 4 also includes resistors AR5, AR4, and AR7, and capacitor AC3; One end of resistor AR5 is connected to the inverting input terminal of amplifier AU1B and one end of resistor AR4, respectively. The other end of resistor AR5 is grounded. The other end of resistor AR4 is connected to one end of resistor AR7 and the output terminal of amplifier AU1B, respectively. The other end of resistor AR7 is connected to one end of capacitor AC3 and zero-crossing comparator module 5, respectively. The other end of capacitor AC3 is grounded.

[0036] As described above, resistors AR5 and AR4 form the feedback loop of amplifier AU1B. By adjusting the resistance value of the feedback resistors, the amplification factor of amplifier AU1B can be flexibly controlled to meet the signal amplification requirements of GIS equipment at different voltage levels, thereby improving the versatility of the circuit. Resistor AR7 and capacitor AC3 can further optimize the amplified signal output by amplifier AU1B, filter out residual noise introduced during the amplification process, make the sampling signal output to the zero-crossing comparator module purer, and reduce the impact of interference on the zero-crossing comparison results.

[0037] Specifically, the zero-crossing comparison module 5 includes a comparator AU2A, the non-inverting input terminal of the comparator AU2A is connected to the reference signal output terminal of the signal amplification module 4, and the inverting input terminal of the comparator AU2A is connected to the sampling signal output terminal of the signal amplification module 4. The comparator AU2A compares the sampled signal output by the signal amplification module 4 with the reference signal to achieve zero-crossing comparison and generate a zero-crossing waveform representing the input signal.

[0038] As described above, the zero-crossing comparison module uses a comparator AU2A. By directly comparing the sampled signal output from the signal amplification module with the reference signal, it can quickly determine the "zero-crossing" moment of the sampled signal relative to the reference signal, thereby generating a zero-crossing waveform representing the input signal. This design principle is simple and reliable, converting analog signals into easily interpretable waveform signals. This allows subsequent circuits to accurately determine whether the GIS equipment is energized based on the zero-crossing waveform, improving the intuitiveness and accuracy of the detection results.

[0039] Specifically, the zero-crossing comparison module 5 also includes a capacitor AC13, a resistor AR11, a diode AD6, and a diode AD7; One end of capacitor AC13 is connected to signal amplification module 4, the anode of diode AD6, the cathode of diode AD7, and the non-inverting input of comparator AU2A. The other end of capacitor AC13 is connected to one end of resistor AR11, the cathode of diode AD6, the anode of diode AD7, and the inverting input of comparator AU2A. The other end of resistor AR11 is connected to signal amplification module 4.

[0040] As described above, the addition of capacitor AC13, resistor AR11, and diodes AD6 and AD7 further optimizes the zero-crossing comparison process. Capacitor AC13 and resistor AR11 filter out high-frequency noise in the comparator input signal, preventing noise-induced false triggering of the comparator. Diodes AD6 and AD7 limit the voltage range of the comparator input signal, preventing abnormal signals from damaging the comparator. These components work together to improve the anti-interference capability and stability of the zero-crossing comparison module, ensuring that the generated zero-crossing waveform accurately reflects the energized state of the GIS equipment.

[0041] The specific working process of the above embodiments is as follows: This GIS high-voltage live measurement circuit uses "sensor signal input → multi-stage signal processing → zero-crossing waveform output" as its core process. The specific principle is as follows: 1. Sensor Input Module: Initial Signal Acquisition and Preprocessing The high-voltage live sensor first collects the live status signal of the GIS equipment (mV level, generated based on the principle of electromagnetic induction and capacitive voltage division). This "sensor signal input" is first connected to the core components of the sensor input module - the discharge tube FLG1 and the magnetic bead ACZ1.

[0042] Discharge tube FLG1 (model 2R090L): One end is directly connected to the "sensor signal input" terminal, and the other end is connected to the ground terminal KGND. When a lightning strike occurs or a transient overvoltage occurs inside the GIS equipment, the discharge tube FLG1 quickly conducts and conducts the abnormal high voltage to the ground through KGND, preventing the overvoltage from breaking down subsequent circuit components and achieving lightning protection.

[0043] The ACZ1 ferrite bead (model BLM18PG102SN1) is connected at one end to the "sensor signal input" side of the discharge tube FLG1, and at the other end to both the signal clamping protection module and the signal filtering module. The ACZ1 ferrite bead utilizes its high impedance characteristics to high-frequency signals to specifically filter out high-frequency noise interference (such as partial discharge interference and bus current magnetic field radiation interference) mixed in the "sensor signal input", outputting a pre-purified initial signal to provide a low-interference signal source for subsequent modules.

[0044] 2. Signal clamping protection module: Voltage range limitation The initial signal, purified by the ferrite bead ACZ1, is synchronously fed into the signal clamping protection module by diodes AD1 (model 1N4148) and AD2 (model 1N4148). The core function of this module is to forcibly limit the signal voltage to a safe range of 0-3.3V (to meet the 3.3V power supply requirements of subsequent circuits).

[0045] Diode AD1: The anode is connected to the cathode of diode AD2 and one end of resistor AR1 in the signal filtering module, and the cathode is directly connected to KGND. When the signal voltage is lower than 0V, diode AD1 conducts in the forward direction, clamping the signal voltage at 0V to prevent negative overvoltage from damaging downstream components.

[0046] Diode AD2: The cathode is connected to the anode of diode AD1 and one end of resistor AR1, and the anode is connected to one end of resistor AR2 of the signal filtering module; when the signal voltage is higher than 3.3V, diode AD2 breaks down in reverse and conducts, clamping the signal voltage at 3.3V, preventing forward overvoltage from breaking down the RC circuit of the signal filtering module or the amplifier of the signal amplification module.

[0047] By utilizing the unidirectional conductivity of diodes AD1 and AD2, the signal voltage entering subsequent modules is kept stable at 0-3.3V, ensuring the overall safety of the circuit.

[0048] 3. Signal filtering module: High-frequency interference deep suppression After being clamped and protected, the signal enters the signal filtering module. This module consists of resistors AR1 and AR2 (both are 0805 packaged metal film resistors with a resistance of 10kΩ) and capacitors AC1 and AC2 (both are 0805 packaged multilayer ceramic capacitors (MLCC)). Together, they form a second-order RC filter circuit to further eliminate residual high-frequency interference.

[0049] Resistor AR1: One end is connected to the connection point of ferrite bead ACZ1 and diode AD1 / diode AD2, and the other end is split into two paths: one path is connected to capacitor AC1, and the other path is connected to resistor AR2; resistor AR1 acts as a current limiting resistor to control the amount of signal flowing to capacitor AC1 and resistor AR2, so as to prevent the capacitor from burning out due to excessive current.

[0050] Capacitor AC1: One end is connected to the "shunt terminal" of resistor AR1, and the other end is connected to KGND; Capacitor AC1 presents low impedance to high-frequency signals, and filters out the high-frequency interference signals transmitted by resistor AR1 through KGND, thus achieving the first stage of filtering.

[0051] Resistor AR2: One end is connected to the "splitter" of resistor AR1, and the other end is split into two paths: one path is connected to capacitor AC2, and the other path is connected to the non-inverting input of amplifier AU1B of the signal amplification module; resistor AR2 continues the current limiting function, and at the same time, it transmits the signal that has been initially filtered by AC1 to capacitor AC2, completing the signal transition before the second stage of filtering.

[0052] Capacitor AC2: One end is connected to the "shunt terminal" of resistor AR2, and the other end is connected to KGND; Capacitor AC2 further filters out the high-frequency interference (such as fast transient overvoltage interference caused by operating overvoltage) remaining in the signal transmitted by resistor AR2, and finally outputs a stable "filtered signal" to the non-inverting input terminal of amplifier AU1B, providing a low-noise signal basis for signal amplification.

[0053] 4. Signal Amplification Module: Weak Signal Enhancement and Reference Adjustment Since the "filtered signal" is still in the mV range, it cannot meet the accuracy requirements of subsequent zero-crossing comparison. Therefore, a signal amplification module is needed to achieve "signal amplification" and "reference rise". The core components include dual amplifiers AU1A / AU1B, resistors PR1 / PR2, capacitor PC1, resistors AR3 / AR6 / AR4 / AR5 / AR7, and capacitor AC3.

[0054] (1) Reference signal generation: VREF rise and stabilization To align the zero point of the sinusoidal sampling signal with the circuit reference (to avoid the inaccurate identification of negative signals), a stable reference signal VREF needs to be generated through resistors PR1, PR2, and capacitor PC1, and then output by amplifier AU1A.

[0055] Resistor PR1 (all models are 0805 packaged precision metal film resistors with a resistance of 20kΩ): one end is connected to a 3.3V power supply, and the other end is split into three paths: one path is connected to resistor PR2, one path is connected to capacitor PC1, and one path is connected to the non-inverting input of amplifier AU1A; resistor PR1 and resistor PR2 form a voltage divider circuit to divide the 3.3V power supply to the required reference voltage VREF (such as 1.65V, which is suitable for the midpoint of the 0-3.3V signal range).

[0056] Resistor PR2 (all models are 0805 packaged precision metal film resistors with a resistance of 20kΩ): one end is connected to the "shunt terminal" of resistor PR1, and the other end is connected to KGND; by adjusting the resistance value, resistor PR2 can precisely control the value of VREF after voltage division, ensuring the stability of the reference voltage.

[0057] Capacitor PC1 (model 0805 package MLCC, capacitance 1μF): One end is connected to the "shunt terminal" of resistor PR1, and the other end is connected to KGND; Capacitor PC1 filters out power supply noise introduced from the 3.3V power supply during the voltage division process, so as to avoid noise affecting the stability of VREF.

[0058] Amplifier AU1A (using dual operational amplifier LMV358): The non-inverting input is connected to the common branch terminal of resistor PR1 / resistor PR2 / capacitor PC1 (to obtain a stable VREF), and the inverting input is directly connected to its own output (forming a voltage follower circuit); the voltage follower is characterized by high input impedance and low output impedance, which can output VREF to resistor AR3 without attenuation and with low interference, ensuring that the reference signal is not distorted during transmission.

[0059] (2) Sampling signal amplification: mV level signal enhancement The filtered sampled signal and the VREF output of amplifier AU1A are superimposed at amplifier AU1B, and signal enhancement is achieved through proportional amplification in the same direction.

[0060] Resistor AR3 (using a 0805 packaged metal film resistor, 1kΩ): One end is connected to the output of amplifier AU1A, and the other end is split into two paths: one path is connected to the connection point of diode AD1 / diode AD2 of the signal clamping protection module, and the other path is connected to resistor AR6; AR3 serves as the reference signal transmission resistor, stably transmitting the VREF output of amplifier AU1A to resistor AR6, while avoiding mutual interference between the reference signal and the sampling signal.

[0061] Resistor AR6 (using a 0805 packaged metal film resistor with a resistance of 1kΩ): One end is connected to AR3, and the other end is connected to the non-inverting input of amplifier AU1B; Resistor AR6 introduces VREF into the non-inverting input of amplifier AU1B, which is superimposed on the "filtered sampled signal" (input from resistor AR2) to raise the zero point of the sampled signal (so that the zero point of the sine wave is aligned with VREF).

[0062] Amplifier AU1B (model LMV358 dual operational amplifier): The non-inverting input is connected to the VREF signal transmitted by resistor AR6 and the sampling signal transmitted by resistor AR2 (the superimposed signal). The inverting input is split into two paths: one is connected to resistor AR5 and the other is connected to resistor AR4. Amplifier AU1B operates in non-inverting proportional amplification mode. The amplification factor is determined by the ratio of feedback resistor AR4 to ground resistor AR5 (amplification factor A = 1 + resistor AR4 / resistor AR5). It can amplify the mV-level sampling signal to the 1-3V range to meet the accuracy requirements of subsequent zero-crossing comparison.

[0063] Resistor AR5 (model 0805 packaged metal film resistor, resistance value 1kΩ): One end is connected to the inverting input terminal of amplifier AU1B, and the other end is connected to KGND; Resistor AR5 serves as a grounding resistor, working in conjunction with resistor AR4 to set the amplification factor of amplifier AU1B, while stabilizing the potential of the inverting input terminal of amplifier AU1B.

[0064] Resistor AR4 (model 0805 package metal film resistor, resistance value 49kΩ): One end is connected to the inverting input terminal of amplifier AU1B, and the other end is connected to the output terminal of amplifier AU1B; Resistor AR4 acts as a feedback resistor, feeding back part of the output signal of amplifier AU1B to the inverting terminal, forming negative feedback, ensuring stable amplification process without self-oscillation, and avoiding distortion of amplified signal.

[0065] Resistor AR7 (model 0805 packaged metal film resistor, resistance value 2kΩ): One end is connected to the output terminal of amplifier AU1B, and the other end is split into two paths: one path is connected to capacitor AC3, and the other path is connected to the inverting input terminal of comparator AU2A of the zero-crossing comparator module; Resistor AR7 acts as a current limiting resistor to control the output current of the amplified signal and prevent excessive current from damaging comparator AU2A.

[0066] Capacitor AC3 (model 0805 package MLCC, capacitance 1nF): One end is connected to resistor AR7, and the other end is connected to KGND; capacitor AC3 filters out residual noise introduced during the amplification process of amplifier AU1B (such as the amplifier's own thermal noise), and outputs a clean "amplified sampled signal" to the inverting input of comparator AU2A.

[0067] 5. Zero-crossing comparison module: Zero-crossing waveform generation The core of the zero-crossing comparison module is the comparator AU2A, which generates a zero-crossing waveform (such as square wave signal UaFPLS) that represents the energized state of the GIS equipment by comparing the "amplified sampled signal" with the "reference signal VREF". The core components include comparator AU2A, capacitor AC13 / resistor AR11, diode AD6 / diode AD7.

[0068] Capacitor AC13 (model 0805 package MLCC, capacitance 100pF): One end is connected to the connection point of AR3 / resistor AR6 of the signal amplification module (to obtain VREF), the anode of diode AD6, the cathode of diode AD7, and the non-inverting input terminal of comparator AU2A; the other end is connected to one end of resistor AR11, the cathode of diode AD6, the anode of diode AD7, and the inverting input terminal of comparator AU2A. Capacitor AC13 performs a final high-frequency filter on the VREF input to comparator AU2A and the sampled signal to avoid residual noise causing the comparator to trigger falsely.

[0069] Resistor AR11 (model 0805 package metal film resistor, resistance value 10kΩ): One end is connected to capacitor AC13, and the other end is connected to resistor AR7 of the signal amplification module (to obtain the "amplified sampled signal"); Resistor AR11 serves as the sampling signal transmission resistor, stably guiding the "amplified sampled signal" to the inverting input of comparator AU2A, and at the same time, it works with capacitor AC13 to optimize the signal filtering effect.

[0070] Diode AD6 (model 1N4148): The anode is connected to capacitor AC13 and the non-inverting input terminal of comparator AU2A, and the cathode is connected to the other end of capacitor AC13 and the inverting input terminal of comparator AU2A; Diode AD6 limits the voltage difference between the non-inverting and inverting input terminals of comparator AU2A to prevent excessive voltage difference from damaging the comparator.

[0071] Diode AD7 (all models are 1N4148): The cathode is connected to the capacitor AC13 and the non-inverting input of comparator AU2A, and the anode is connected to the other end of capacitor AC13 and the inverting input of comparator AU2A; Diode AD7 is connected in reverse parallel with diode AD6 to further limit the input voltage range of comparator AU2A and enhance the comparator's anti-interference capability.

[0072] Comparator AU2A (high-speed comparator LMV7219): The non-inverting input is connected to VREF (filtered by capacitor AC13), and the inverting input is connected to the "amplified sampled signal" (filtered by resistor AR11 and capacitor AC13). When the sampled signal voltage is higher than VREF, comparator AU2A outputs a high level (e.g., 3.3V); when the sampled signal voltage is lower than VREF, comparator AU2A outputs a low level (e.g., 0V), ultimately generating a periodically switching "zero-crossing waveform signal" (e.g., UaFPLS).

[0073] This "zero-crossing waveform signal" can be directly used to determine the power status of GIS equipment: if the waveform shows a stable high / low level periodic switching, it indicates that the GIS equipment is powered; if the waveform always maintains a single level (high or low), it indicates that the GIS equipment is not powered, thus achieving accurate detection of the power status of GIS equipment.

[0074] In this utility model, unless otherwise explicitly specified and limited, the terms "installation", "setting", "connection", "fixing", "screw connection", 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 connection of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0075] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that modifications may be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-voltage live-line measurement circuit for GIS, characterized in that: It includes a sensor input module (1), a signal clamping protection module (2), a signal filtering module (3), a signal amplification module (4), and a zero-crossing comparison module (5) connected in sequence. The sensor input module (1) is used to receive the signal output by the high voltage live sensor and transmit the received signal to the signal clamping protection module (2), the signal filtering module (3), the signal amplification module (4), and the zero-crossing comparison module (5) for sequential processing, and output the zero-crossing waveform signal used to determine the live state of the GIS equipment.

2. The high-voltage live-line measurement circuit for GIS according to claim 1, characterized in that: The sensor input module (1) includes a discharge tube FLG1 and a magnetic bead ACZ1; One end of the discharge tube FLG1 is connected to the signal output terminal of the external high-voltage live sensor and one end of the magnetic bead ACZ1, respectively. The other end of the discharge tube FLG1 is grounded, and the other end of the magnetic bead ACZ1 is connected to the signal clamping protection module (2) and the signal filtering module (3), respectively. The discharge tube FLG1 is used to achieve lightning protection, and the magnetic bead ACZ1 is used to filter out high-frequency noise interference.

3. The high-voltage live-line measurement circuit for GIS according to claim 1, characterized in that: The signal clamping protection module (2) includes diode AD1 and diode AD2; The anode of diode AD1 is connected to the cathode of diode AD2 and the signal filtering module (3) respectively. The cathode of diode AD1 is grounded, and the anode of diode AD2 is connected to the signal filtering module (3).

4. The high-voltage live-line measurement circuit for GIS according to claim 1, characterized in that: The signal filtering module (3) includes resistor AR1, capacitor AC1, resistor AR2 and capacitor AC2; One end of resistor AR1 is connected to sensor input module (1), and the other end of resistor AR1 is electrically connected to signal clamping protection module (2), one end of resistor AR2 and one end of capacitor AC1 respectively. The other end of resistor AR2 is connected to signal amplification module (4) and one end of capacitor AC2 respectively. The other end of capacitor AC2 is grounded to both the other end of capacitor AC1 and the other end of capacitor AC1 respectively.

5. A high-voltage live-line measurement circuit for GIS according to claim 1, characterized in that: The signal amplification module (4) includes amplifier AU1A and amplifier AU1B; The non-inverting input terminal of the amplifier AU1A is connected to a 3.3V power supply, and the inverting input terminal of the amplifier AU1A is connected to the output terminal of the amplifier AU1A and the zero-crossing comparator module (5) respectively. The non-inverting input terminal of the amplifier AU1B is connected to the signal filtering module (3), and the inverting input terminal of the amplifier AU1B is connected to the output terminal of the amplifier AU1B and the zero-crossing comparison module (5), respectively.

6. A high-voltage live-line measurement circuit for GIS according to claim 5, characterized in that: The signal amplification module (4) also includes resistors PR1 and PR2 and capacitor PC1; One end of resistor PR1 is connected to a 3.3V power supply. The other end of resistor PR1 is connected to one end of resistor PR2, one end of capacitor PC1, and the non-inverting input terminal of amplifier AU1A. The other end of resistor PR2 is connected to the other end of capacitor PC1, and both the other ends of resistor PR2 and capacitor PC1 are grounded.

7. A high-voltage live-line measurement circuit for GIS according to claim 5, characterized in that: The signal amplification module (4) also includes resistors AR3 and AR6; One end of resistor AR3 is connected to the output terminal of amplifier AU1A, the other end of resistor AR3 is connected to the signal clamping protection module (2) and one end of resistor AR6 respectively, and the other end of resistor AR6 is connected to the non-inverting input terminal of amplifier AU1B.

8. A high-voltage live-line measurement circuit for GIS according to claim 5, characterized in that: The signal amplification module (4) also includes resistors AR5, AR4, AR7 and capacitor AC3; One end of resistor AR5 is connected to the inverting input terminal of amplifier AU1B and one end of resistor AR4 respectively. The other end of resistor AR5 is grounded. The other end of resistor AR4 is connected to one end of resistor AR7 and the output terminal of amplifier AU1B respectively. The other end of resistor AR7 is connected to one end of capacitor AC3 and the zero-crossing comparator module (5) respectively. The other end of capacitor AC3 is grounded.

9. A high-voltage live-line measurement circuit for GIS according to claim 1, characterized in that: The zero-crossing comparison module (5) includes a comparator AU2A. The non-inverting input terminal of the comparator AU2A is connected to the reference signal output terminal of the signal amplification module (4), and the inverting input terminal of the comparator AU2A is connected to the sampling signal output terminal of the signal amplification module (4). The comparator AU2A compares the sampled signal output by the signal amplification module (4) with the reference signal to achieve zero-crossing comparison and generate a zero-crossing waveform that represents the input signal.

10. A high-voltage live-line measurement circuit for GIS according to claim 9, characterized in that: The zero-crossing comparison module (5) also includes capacitor AC13, resistor AR11, diode AD6 and diode AD7; One end of the capacitor AC13 is connected to the signal amplification module (4), the anode of diode AD6, the cathode of diode AD7 and the non-inverting input of comparator AU2A respectively. The other end of the capacitor AC13 is connected to one end of resistor AR11, the cathode of diode AD6, the anode of diode AD7 and the inverting input of comparator AU2A respectively. The other end of resistor AR11 is connected to the signal amplification module (4).

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