Lightning arrester resistive current live detection device field calibration method and system

Abstract

The invention discloses a field calibration method and system for a resistive current live detection device of a lightning arrester. The method comprises the following steps: acquiring a power frequency voltage signal from a monitored bus through a voltage phase sampling unit, and performing high-fidelity digitalization on the power frequency voltage signal to generate a continuous sampling digital quantity sequence; continuously sending the sampling digital quantity sequence through a wireless radio frequency unit; receiving the sampling digital quantity sequence through a wireless receiving unit in the resistive / capacitive / harmonic current generator, and reconstructing a reference sine wave signal with the same frequency and phase as the bus voltage by using a digital signal processing algorithm based on the sampling digital quantity sequence; synthesizing a required standard current signal based on the reconstructed reference sine wave signal according to set parameters; the standard current signal is applied to the resistive current live detection device of the calibrated lightning arrester, and the measurement performance of the calibrated lightning arrester is evaluated by comparing the reading increment of the device with the injection increment of the standard current signal.

Description

A method and system for on-site verification of a surge arrester resistive current live detection device. Technical Field

[0001] This invention relates to the field of surge arrester condition detection technology, and more specifically, to a field verification method and system for a surge arrester resistive current live detection device. Background Technology

[0002] Surge arresters are typically installed at the line outlets and on the main transformer side of substations. They are the primary devices in substations for limiting operational and lightning overvoltages, protecting other main power equipment from damage caused by transient overvoltage surges. Over long-term operation, surge arresters may develop defects, which can lead to serious malfunctions. A surge arrester malfunction will cause the line or main transformer to trip, severely impacting safe and stable power supply. Therefore, monitoring the operational status of surge arresters is of paramount importance.

[0003] Leakage current is the most important condition monitoring quantity for surge arresters, among which resistive current is the most sensitive and effective in reflecting the arrester's condition. Surge arrester resistive current live-line testing devices include live-line testers and online monitoring devices. According to industry regulations, surge arresters must undergo resistive current live-line testing annually. Currently, substations at various voltage levels have also installed a large number of surge arrester resistive current online monitoring devices, hoping to achieve accurate monitoring of the arrester's operating status through resistive current detection. Since resistive current is an indirect state quantity calculated based on the phase of the bus voltage and the total current, it may deviate from the actual value obtained by the online monitoring device due to factors such as the accuracy of phase angle measurement and inter-phase coupling interference of three-phase surge arresters. The accuracy of the measurement directly affects the reliability of the surge arrester resistive current detection data. How to quickly and accurately assess the measurement accuracy of surge arrester resistive current live-line testing devices (including live-line testers and online monitoring devices) at the substation site is an urgent problem to be solved. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method and system for on-site verification of a surge arrester resistive current live detection device.

[0005] According to one aspect of the present invention, a method for on-site verification of a surge arrester resistive current live-line detection device is provided, comprising: acquiring a power frequency voltage signal from the monitored bus via a voltage phase sampling unit, and performing high-fidelity digitization on the power frequency voltage signal to generate a continuous sampling digital sequence; continuously transmitting the sampling digital sequence via a wireless radio frequency unit; receiving the sampling digital sequence via a wireless receiving unit in a resistive / capacitive / harmonic current generator, and reconstructing a reference sine wave signal with the same frequency and phase as the bus voltage based on the sampling digital sequence using a digital signal processing algorithm; synthesizing a required standard current signal based on the reconstructed reference sine wave signal according to set parameters; applying the standard current signal to the resistive current live-line detection device of the surge arrester under verification, and evaluating the measurement performance of the surge arrester under verification by comparing the increment of the device reading with the injection increment of the standard current signal.

[0006] Optionally, the power frequency voltage signal is digitized with high fidelity to generate a continuous sequence of sampled digital quantities, including: sampling the conditioned power frequency voltage signal in real time through a high-speed analog-to-digital converter to generate the sampled digital quantity sequence.

[0007] Optionally, based on the sampled digital sequence, a high-precision reference sine wave signal with the same frequency and phase as the bus voltage is reconstructed using a digital signal processing algorithm. This includes: using a digital signal processing algorithm based on a digital phase-locked loop and interpolation filtering technology, the reference signal is reconstructed in real time using the continuously received sampled digital sequence, and software algorithms are used to compensate for data points lost during wireless transmission to obtain the reference sine wave signal.

[0008] Optionally, the standard current signal includes at least one of the following: an equivalent resistive current in phase with the voltage, an equivalent capacitive current leading by 90°, and a harmonic current, and its amplitude can be precisely adjusted in multiple levels.

[0009] Optionally, it also includes: outputting the reconstructed voltage signal waveform and the standard current signal waveform to an oscilloscope through a signal self-verification output interface to calibrate the current amplitude and phase output by the verification device itself.

[0010] According to another aspect of the present invention, a field calibration system for a surge arrester resistive current live detection device is provided. The method for implementing any of the above aspects of the present invention includes: a voltage phase sampling unit for acquiring a voltage signal from a bus and generating a sampled digital sequence; a wireless radio frequency unit connected to the voltage phase sampling unit for transmitting the sampled digital sequence; and a resistive / capacitive / harmonic current generator, including: a wireless receiving unit for receiving the sampled digital sequence; a control unit for reconstructing a reference sine wave signal based on the received sampled digital sequence and controlling the generation of a standard current signal according to set parameters; and a signal synthesis and output unit for synthesizing the standard current signal and outputting it to the device being calibrated.

[0011] Optionally, the voltage phase sampling unit includes a high-precision transformer, a signal conditioning circuit, and a high-speed analog-to-digital converter connected in sequence.

[0012] Optionally, the control unit is configured to execute a digital phase-locked loop and interpolation filtering algorithm to reconstruct a reference signal using a sequence of sampled digital quantities.

[0013] Optionally, the signal synthesis and output unit includes a high-precision digital-to-analog converter and a programmable gain amplifier.

[0014] Optionally, the resistive / capacitive / harmonic current generator also includes a signal self-checking output interface.

[0015] According to another aspect of the present invention, a computer-readable storage medium is provided, the storage medium storing a computer program for performing the methods described in any of the above aspects of the present invention.

[0016] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising: a processor; a memory for storing executable instructions of the processor; the processor being configured to read the executable instructions from the memory and execute the instructions to implement the method described in any of the preceding aspects of the present invention.

[0017] Therefore, by connecting the voltage phase sampling unit of this invention to the secondary circuit of a voltage transformer, the resistive current reference phase is obtained. Connecting the resistive / capacitive / harmonic current generator in parallel with the live-line detection device to be calibrated can generate resistive current signals of different amplitudes, and can also generate resistive-capacitive current signals of different amplitudes as needed. Recording the resistive current reading of the live-line detection device to be calibrated, adjusting and recording the resistive current output amplitude on the resistive / capacitive / harmonic current generator, simultaneously recording the reading of the live-line detection device, calculating the change in the measured value before and after the live-line detection device is activated, and comparing it with the resistive current output amplitude of the resistive / capacitive / harmonic current generator, the measurement error of the online monitoring device can be obtained. Attached Figure Description

[0018] The exemplary embodiments of the present invention can be more fully understood by referring to the following figures: Figure 1 is a schematic flowchart of an on-site verification method for a surge arrester resistive current live detection device provided by an exemplary embodiment of the present invention; Figure 2 is a schematic structural diagram of an on-site verification system for a surge arrester resistive current live detection device provided by an exemplary embodiment of the present invention; Figure 3 is a system block diagram of a voltage phase sampling unit provided by an exemplary embodiment of the present invention; Figure 4 is a system block diagram of a resistive / capacitive / harmonic current generator provided by an exemplary embodiment of the present invention. Detailed Implementation

[0019] Hereinafter, exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments of the present invention. It should be understood that the present invention is not limited to the exemplary embodiments described herein.

[0020] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention.

[0021] Those skilled in the art will understand that the terms "first," "second," etc., in the embodiments of the present invention are only used to distinguish different steps, devices, or modules, and do not represent any specific technical meaning, nor do they indicate a necessary logical order between them.

[0022] It should also be understood that in the embodiments of the present invention, "multiple" can refer to two or more, and "at least one" can refer to one, two or more.

[0023] It should also be understood that any component, data or structure mentioned in the embodiments of the present invention can generally be understood as one or more unless explicitly defined or given contrary instructions in the context.

[0024] Furthermore, the term "and / or" in this invention is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this invention generally indicates that the preceding and following related objects have an "or" relationship.

[0025] It should also be understood that the description of the various embodiments in this invention emphasizes the differences between the various embodiments, and the similarities or similarities can be referred to each other. For the sake of brevity, they will not be described in detail.

[0026] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0027] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0028] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0029] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0030] Figure 1 is a schematic flowchart of an exemplary embodiment of the present invention for the field verification method of a surge arrester resistive current live-line detection device. As shown in Figure 1, the field verification method 100 for a surge arrester resistive current live-line detection device includes the following steps: Step 101, acquiring a power frequency voltage signal from the monitored bus through a voltage phase sampling unit, and performing high-fidelity digitization on the power frequency voltage signal to generate a continuous sampling digital sequence; Step 102, continuously transmitting the sampling digital sequence through a wireless radio frequency unit; Step 103, receiving the sampling digital sequence through a wireless receiving unit in a resistive / capacitive / harmonic current generator, and reconstructing a reference sine wave signal with the same frequency and phase as the bus voltage based on the sampling digital sequence using a digital signal processing algorithm; Step 104, synthesizing the required standard current signal based on the reconstructed reference sine wave signal according to set parameters; Step 105, applying the standard current signal to the resistive current live-line detection device of the surge arrester under verification, and evaluating the measurement performance of the surge arrester under verification by comparing the increment of the device reading with the injection increment of the standard current signal.

[0031] Specifically, in order to achieve rapid verification of the resistive current live detection device for surge arresters at the substation site, two problems need to be solved: first, how to conveniently obtain the resistive current reference value on site; and second, how to inject the resistive current reference value into the live detection device for calibration. CN202010379667.2 discloses a portable online monitoring device for surge arresters and a method for on-site verification. By comparing the measured values ​​of the standard current by a high-precision clamp sensor and an online monitoring device, the measurement error of the online monitoring device is obtained. Due to the performance limitations of the high-precision clamp sensor itself: (1) If an open-type high-precision clamp sensor is used, the range is large, generally at 100mA or above, while the leakage current of the surge arrester is only at mA or below. The range mismatch affects the accuracy of measurement and verification effect; (2) If a closed-type zero-flux coil is used, it needs to be connected in series to the surge arrester lead-down circuit, and there is no wiring condition available on site. Therefore, the applicability on site is limited.

[0032] The purpose of this invention is to achieve rapid calibration of the resistive current live detection device for surge arresters used in substations, and to propose a field verification method for the resistive current live detection device for surge arresters.

[0033] This instrument can generate an equivalent resistive current in phase with the bus voltage or an equivalent capacitive current leading by 90°, as well as 3rd / 5th / 7th harmonic currents. The current amplitude is adjustable in multiple ranges. This current signal is then applied to both ends of the surge arrester resistive current live detection device. By comparing the increment of the resistive current with the increment of the device's test result, the accuracy of the resistive current live detection device can be verified traceably without the need for an additional current measurement unit.

[0034] This invention proposes a field verification method for a surge arrester resistive current live-line detection device to address the problem of insufficient standard resistive current sources in substations, which hinders accurate verification of the device's measurement accuracy. By adding a specific magnitude of resistive, capacitive, and harmonic current to the surge arrester resistive current live-line detection device, the changes in the device's output are observed to evaluate the measurement principle and the repeatability, validity, and accuracy of the data.

[0035] Referring to Figure 2, the present invention is implemented by a voltage phase sampling unit and a resistive-capacitive harmonic current generator. Referring to Figure 3, the core function of the voltage phase sampling unit is to achieve high-fidelity digitization of the bus voltage signal. This device acquires the power frequency voltage signal from the bus through a high-precision transformer and signal conditioning circuit. Subsequently, the internal unit samples this analog voltage signal in real time at a fixed high sampling rate, converting the instantaneous voltage value at each sampling point into a digital quantity, thereby generating a continuous sequence of sampled digital quantities containing complete waveform amplitude and phase information. This digital sequence is continuously transmitted through a wireless radio frequency unit, transmitting precise numerical information rather than analog waveforms or simple zero-crossing pulses, exhibiting strong anti-interference capabilities and providing a high-fidelity data source for backend signal reconstruction.

[0036] Referring to Figure 4, the core task of the resistive / capacitive / harmonic current generator is to receive and analyze these sampled digital quantities to reconstruct a synchronized reference signal. The internal wireless receiving unit continuously receives sampled digital data packets, which the control unit decodes and buffers. Based on the design concept of "full-phase output," the control unit uses the received continuous sampled digital sequence to reconstruct a high-precision reference sine wave signal that is in phase and frequency with the bus voltage in real time using a digital signal processing algorithm (based on a digital phase-locked loop and interpolation filtering). Even if accidental data packet loss occurs during wireless transmission, the algorithm can compensate for and restore the lost data in real time using software algorithms based on the successfully received values ​​of the preceding and following sampling points, thereby ensuring the continuity and phase accuracy of the reconstructed waveform and fundamentally avoiding calibration reference failure caused by brief communication interruptions.

[0037] After obtaining a stable and synchronized reference signal, the resistive / capacitive / harmonic current generator, according to the set parameters, synthesizes the required standard current signal through a high-precision digital-to-analog converter and a programmable gain amplifier. This can be an equivalent resistive current in phase with the voltage, an equivalent capacitive current leading by 90°, or a harmonic current. A resistive / capacitive / harmonic selection switch is used to switch between these modes, and the amplitude can be precisely adjusted in multiple ranges via an output current selection switch. Through the signal self-calibration output interface, the voltage and standard current signal waveforms can be output to an oscilloscope to calibrate the current amplitude and phase of the calibration device itself. This standard current is applied to the resistive current live-line detection device of the surge arrester being calibrated. By comparing the increment of the device reading with the increment of the injected standard current, traceable on-site verification of its measurement accuracy, repeatability, and the validity of its principle can be achieved.

[0038] Therefore, the present invention provides a traceable and high-precision verification method for resistive current detection devices operating in the field, fundamentally solving the problem of low reliability of measurement data caused by the lack of field verification methods (1). In terms of measurement accuracy and reliability, the present invention has achieved a technological breakthrough. The bus voltage signal is digitized with high fidelity through the "voltage phase sampling unit", and the reference signal is reconstructed by an algorithm based on digital phase-locked loop and interpolation filtering, ensuring strict synchronization between resistive, capacitive and harmonic standard current signals and grid voltage. Its phase accuracy is much higher than that of software simulation methods.

[0039] Experimental data show that, under simulated complex electromagnetic interference conditions, the phase jitter of the reference signal generated by this device can be controlled within 0.1 degrees, thus ensuring the accuracy and reliability of the standard current injection increment. By comparing the reading increment of the calibrated device with the standard current injection increment, its measurement accuracy, repeatability, and principle validity can be directly evaluated. The verification uncertainty is better than ±1%, providing a traceable basis for judging the validity of field data.

[0040] (2) This invention greatly improves the convenience and safety of on-site verification. Traditional verification methods often require disassembling the equipment back to the laboratory or relying on complex on-site wiring, which is time-consuming, labor-intensive, and poses safety hazards. The wireless radio frequency transmission technology used in this invention achieves electrical isolation and non-contact signal transmission between the voltage signal sampling unit and the current generation unit. Verification personnel do not need to perform complex wiring work, which significantly reduces workload and the risk of electric shock. At the same time, the device design takes into account portability for on-site use. The whole system has a high degree of integration and simplified operation process. A single person can complete most of the verification work. Compared with traditional methods, it is expected to save more than 70% of on-site operation time and effectively avoid accidents such as short circuits or open circuits on the secondary side of the PT due to incorrect wiring.

[0041] (3) This invention possesses strong anti-interference capabilities and environmental adaptability. The electromagnetic environment at substation sites is complex, and traditional analog signal transmission is susceptible to interference. The voltage phase sampling unit of this invention transmits a digital sequence converted by a high-speed ADC, rather than an analog waveform, fundamentally enhancing anti-interference capabilities. The "full-phase output" design at the current generator end can use software algorithms to compensate for occasional packet loss during wireless transmission, ensuring the continuity and phase accuracy of the reconstructed waveform, avoiding calibration benchmark failure due to brief communication interruptions, and guaranteeing the stability of the verification process in harsh industrial environments.

[0042] Furthermore, embodiments of the present invention also provide A field calibration system for a surge arrester resistive current live-line detection device, implementing the method of any one aspect of the present invention, includes: a voltage phase sampling unit for acquiring a voltage signal from a bus and generating a sampled digital sequence; a wireless radio frequency unit connected to the voltage phase sampling unit for transmitting the sampled digital sequence; and a resistive / capacitive / harmonic current generator, including: a wireless receiving unit for receiving the sampled digital sequence; a control unit for reconstructing a reference sine wave signal based on the received sampled digital sequence and controlling the generation of a standard current signal according to set parameters; and a signal synthesis and output unit for synthesizing the standard current signal and outputting it to the device being calibrated.

[0043] Optionally, the voltage phase sampling unit includes a high-precision transformer, a signal conditioning circuit, and a high-speed analog-to-digital converter connected in sequence.

[0044] Optionally, the control unit is configured to execute a digital phase-locked loop and interpolation filtering algorithm to reconstruct a reference signal using a sequence of sampled digital quantities.

[0045] Optionally, the signal synthesis and output unit includes a high-precision digital-to-analog converter and a programmable gain amplifier.

[0046] Optionally, the resistive / capacitive / harmonic current generator also includes a signal self-checking output interface.

[0047] Therefore, the key point of this invention is: (1) Connect the voltage phase sampling unit of the present invention to the secondary circuit of the voltage transformer to obtain the resistive current reference. Phase.

[0048] (2) Connecting a resistive / capacitive / harmonic current generator in parallel with the live detection device to be calibrated can generate different amplitudes. It can generate resistive current signals of varying values, as well as resistive-capacitive current signals of different amplitudes as needed.

[0049] (3) Record the resistive current reading of the live detection device to be calibrated, and adjust and record the resistive / capacitive / harmonic current. The amplitude of the resistive current output on the generator is recorded synchronously, and the readings of the live detection device are calculated to determine the measured values ​​before and after the live detection device is activated. By comparing the change in magnitude with the resistive current output amplitude of the resistive / capacitive / harmonic current generator, the online monitoring device can obtain the result. Set measurement error.

[0050] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of the invention to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A method for on-site verification of a surge arrester resistive current live-line detection device, characterized in that, include: The power frequency voltage signal is acquired from the monitored bus by the voltage phase sampling unit, and the power frequency voltage signal is digitized with high fidelity to generate a continuous sampling digital sequence; the sampling digital sequence is continuously transmitted through the wireless radio frequency unit. The sampled digital sequence is received by the wireless receiving unit in the resistive / capacitive / harmonic current generator, and a reference sine wave signal with the same frequency and phase as the bus voltage is reconstructed based on the sampled digital sequence using a digital signal processing algorithm. According to the set parameters, the required standard current signal is synthesized based on the reconstructed reference sine wave signal. The standard current signal is applied to the resistive current live detection device of the surge arrester under test, and the measurement performance of the surge arrester under test is evaluated by comparing the increment of the device reading with the injection increment of the standard current signal.

2. The method according to claim 1, characterized in that, The process of performing high-fidelity digitization on the power frequency voltage signal to generate a continuous sequence of sampled digital quantities includes: real-time sampling of the conditioned power frequency voltage signal using a high-speed analog-to-digital converter to generate the sampled digital quantity sequence.

3. The method according to claim 1, characterized in that, Based on the sampled digital sequence, a high-precision reference sine wave signal with the same frequency and phase as the bus voltage is reconstructed using a digital signal processing algorithm. This includes: using the digital signal processing algorithm based on digital phase-locked loop and interpolation filtering technology, the reference signal is reconstructed in real time using the continuously received sampled digital sequence, and software algorithm compensation is performed on data points lost during wireless transmission to obtain the reference sine wave signal.

4. The method according to claim 1, characterized in that, The standard current signal includes at least one of the following: equivalent resistive current in phase with voltage, equivalent capacitive current leading by 90°, and harmonic current, and its amplitude can be precisely adjusted in multiple levels.

5. The method according to claim 1, characterized in that, Also includes: The reconstructed voltage signal waveform and the standard current signal waveform are output to an oscilloscope through the signal self-verification output interface to calibrate the current amplitude and phase output by the verification device itself.

6. A field verification system for a surge arrester resistive current live-line detection device for implementing the method of any one of claims 1-5, characterized in that, include: The voltage phase sampling unit is used to acquire the voltage signal from the bus and generate a sampled digital sequence; A wireless radio frequency unit, connected to the voltage phase sampling unit, is used to transmit the sampled digital sequence; A resistive / capacitive / harmonic current generator, comprising: a wireless receiving unit for receiving the sampled digital sequence; The control unit is used to reconstruct a reference sine wave signal based on the received sampled digital sequence and control the generation of a standard current signal according to set parameters; the signal synthesis and output unit is used to synthesize the standard current signal and output it to the device being verified.

7. The system according to claim 6, characterized in that, The voltage phase sampling unit includes a high-precision transformer, a signal conditioning circuit, and a high-speed analog-to-digital converter connected in sequence.

8. The system according to claim 6, characterized in that, The control unit is configured to execute a digital phase-locked loop and interpolation filtering algorithm to reconstruct a reference signal using the sampled digital sequence.

9. The system according to claim 6, characterized in that, The signal synthesis and output unit includes a high-precision digital-to-analog converter and a programmable gain amplifier.

10. The system according to claim 6, characterized in that, The resistive / capacitive / harmonic current generator also includes a signal self-verification output interface.

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