A voltage transformer online monitoring device and use method

Abstract

The present invention discloses an online monitoring device for a voltage transformer and a method for using the device. The present invention includes a sensing unit including a voltage sensing unit and a current sensing unit; the voltage sensing unit includes a voltage measurement module, a voltage isolation change module, and an impedance matching output module connected in sequence; the current sensing unit includes a current sampling module, a compensation module, and a magnetic flux detection module connected in sequence. The present invention can directly and accurately obtain the capacitive current and secondary voltage signals of the voltage transformer to be tested in real time, by comparing and analyzing the real-time collected capacitive current and secondary voltage signals of the voltage transformer of the entire station with the real-time operating voltage and capacitive current of the same phase statistically collected in the historical operating big data, and at the same time comparing and analyzing the phase-to-phase operating voltage and capacitive current, thereby achieving online monitoring of the metering performance of the voltage transformer to be tested. This solves the technical problem that the accuracy and sensitivity of the existing capacitive voltage transformer monitoring cannot be effectively guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer status monitoring, and in particular to an online monitoring device for a voltage transformer and a use method thereof. Background Art

[0002] Power transformers are important electrical measurement and protection devices. Their main function is to convert the high current or high voltage on the primary side of the power system into a small current or low voltage on the secondary side according to the rated current or voltage ratio for metering, measurement, protection, and control instruments, meters, relay protection devices, etc. When combined with metering devices and measuring instruments, transformers can obtain information such as the system's voltage, current, and electrical energy. When combined with automatic devices and relay protection, they can automatically control various faults in the power grid and protect power equipment. Ensuring that gateway transformers remain in high-quality operating condition is a key factor in ensuring accurate metering and measurement in the power system. Gateway voltage transformers typically include capacitive voltage transformers and electromagnetic voltage transformers, and it is essential to monitor their condition to ensure their safe operation.

[0003] To ensure the accuracy of voltage transformer energy metering, JJG 1189.4-2022, "Measuring Transformers - Part 4: Verification Procedure for Power Voltage Transformers," stipulates a 10-year verification cycle for electromagnetic voltage transformers and a 4-year verification cycle for capacitive voltage transformers, requiring power outage verification upon expiration. However, due to limitations in power outages and human and material resources, this lack of weekly verification of voltage transformers makes it difficult to ensure full coverage. This poses a risk of inaccurate measurement for voltage transformers currently in operation on the power grid.

[0004] Therefore, existing power systems generally use online monitoring methods for capacitor voltage transformers. This method is based on monitoring the transformer's operating status and is designed to protect the power system. It measures the current flowing through the insulating medium under phase voltage. It mainly monitors the capacitance and dielectric loss values of the capacitor voltage transformer and combines them with relevant algorithms for calculation, such as imbalance compensation, bridge method, zero-crossing comparison method, or digital waveform method, to obtain monitoring results through signal detection and calculation. However, because this method relies on the capacitance and dielectric loss values of the capacitor voltage transformer, which are difficult to accurately measure, the accuracy and sensitivity of the capacitor voltage transformer monitoring cannot be effectively guaranteed, and it is impossible to evaluate the voltage transformer error performance. Summary of the Invention

[0005] The present invention provides an online monitoring device for a voltage transformer and a method for using the device, which solves the technical problem that the accuracy and sensitivity of existing capacitive voltage transformer monitoring cannot be effectively guaranteed and the error performance of the voltage transformer cannot be evaluated.

[0006] A first aspect of the present invention provides an online monitoring device for a voltage transformer, the device comprising a sensing unit, an edge computing module, and a comparison module;

[0007] The sensing unit is connected to the voltage transformer to be tested and the signal processing module respectively;

[0008] The signal processing module, the edge computing module and the comparison module are connected in sequence;

[0009] The sensing unit includes a voltage sensing unit and a current sensing unit;

[0010] The voltage sensing unit includes a voltage measurement module, a voltage isolation change module and an impedance matching output module connected in sequence;

[0011] The current sensing unit includes a current sampling module, a compensation module and a magnetic flux detection module which are connected in sequence.

[0012] Optionally, the voltage measurement module includes a bipolar winding, an iron core and a measurement winding;

[0013] The voltage isolation and variation module includes the bipolar winding, the core and the isolation winding;

[0014] The bipolar winding, the measuring winding and the isolation winding are all wound around the core.

[0015] Optionally, the impedance matching output module includes a constant load, a first semiconductor diode, a second semiconductor diode, a capacitor, a first resistor, a second resistor, a third resistor and an operational amplifier;

[0016] The constant load is connected in parallel with the isolation winding, the first semiconductor diode, the second semiconductor diode and the operational amplifier respectively;

[0017] The first semiconductor diode is connected in series with the first resistor and the capacitor respectively;

[0018] The first resistor and the third resistor are connected in series;

[0019] The capacitor and the second resistor are connected in series;

[0020] The third resistor and the second resistor are both connected in series with the operational amplifier.

[0021] Optionally, the current sampling module includes a one-turn winding, a main iron core, a compensation iron core and a sampling winding;

[0022] The one-turn winding is passed through the main iron core and the compensating iron core arranged coaxially;

[0023] The sampling winding is wound around the main iron core;

[0024] The compensation module includes the compensation core and the compensation winding;

[0025] The compensation winding is wound around the compensation core;

[0026] The magnetic flux detection module includes the main iron core and a detection winding;

[0027] The detection winding is wound around the main iron core.

[0028] Optionally, the current sampling module further includes a current measuring meter;

[0029] The current measuring meter is connected to the detection winding and the edge computing module respectively.

[0030] Optionally, it also includes a signal conversion module, a data exchange module and a data storage module;

[0031] The signal conversion module is connected to the signal processing module and the data exchange module respectively;

[0032] The data exchange module is respectively connected to the signal conversion module, the edge computing module and the data storage module.

[0033] Optionally, a clock module and a display are also included;

[0034] The clock module is connected to the data exchange module;

[0035] The display is connected to the edge computing module.

[0036] Optionally, it also includes an analog circuit power supply, a digital circuit power supply and a communication module;

[0037] The analog circuit power supply is connected to the voltage sensing unit, the signal processing module and the signal conversion module respectively;

[0038] The digital circuit power supply is respectively connected to the data exchange module, the edge computing module and the communication module;

[0039] The communication module is connected to the digital circuit power supply and the edge computing module respectively.

[0040] Optionally, further comprising an insulating tape shielding housing;

[0041] The insulating tape shielding shell is coated with a shielding coating;

[0042] The insulating tape shielding shell is connected to the shell grounding mounting nut;

[0043] The current sensing unit is installed in the insulating tape shielding shell.

[0044] A second aspect of the present invention provides a method for using the voltage transformer online monitoring device described in any one of the above items, comprising:

[0045] Collecting current signals and voltage signals of the voltage transformer to be tested;

[0046] performing signal processing on the current signal and the voltage signal to generate current data and voltage data;

[0047] Based on the current data and the voltage data, the fundamental ratio error, fundamental phase error, capacitive current fundamental amplitude and capacitive current fundamental phase of the voltage transformer to be tested are calculated, and the current operating state of the voltage transformer to be tested is determined according to the calculation results.

[0048] It can be seen from the above technical solutions that the present invention has the following advantages:

[0049] 1) By providing a voltage sensing unit, a current sensing unit, a signal processing module, an edge computing module, and a comparison module, the present invention can directly and accurately obtain the capacitive current and secondary voltage signals of the voltage transformer to be tested in real time. By comparing and analyzing the real-time collected capacitive current and secondary voltage signals of the voltage transformers of the entire station with the real-time operating voltage and capacitive current of the same phase statistically collected from historical operating big data, and at the same time comparing and analyzing the phase-to-phase operating voltage and capacitive current, the online monitoring of the metering performance of the voltage transformer to be tested is achieved.

[0050] 2) The sampling accuracy of voltage and current signals is the basis for ensuring the accuracy of the error performance analysis results of the voltage transformer online error performance monitoring device. The present invention has made innovative designs for the voltage sensing unit and the current sensing unit from the circuit to the structure, so that the sampling accuracy of the voltage signal and the current signal reaches 0.005 level, which is at least 2 levels higher than the existing technology, greatly improving the monitoring accuracy of the voltage transformer online error performance monitoring device.

[0051] 3) The present invention prevents the secondary short circuit of the voltage transformer from threatening the operational safety of the CVT and the power grid / power plant by providing a voltage isolation change module and an impedance matching output module protection device in the voltage sensing unit. When the secondary short circuit of the voltage transformer occurs, the action time is less than 1nS, and the switch is immediately disconnected, thereby protecting the tested voltage transformer.

[0052] 4) By setting up a compensation module and a magnetic flux detection module protection device in the current sensing unit, the secondary open circuit of the current transformer is prevented from threatening the operational safety of the CVT and the power grid / power plant. When the secondary open circuit of the sampling current transformer occurs, the 2.4V nanosecond-level bidirectional TVS tube quickly turns on to protect the tested voltage transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0054] Figure 1 This is a structural block diagram of a voltage transformer online monitoring device provided in the first embodiment of the present invention;

[0055] Figure 2 This is a module block diagram of a voltage transformer online monitoring device provided in the second embodiment of the present invention;

[0056] Figure 3 This is a module block diagram of a voltage sensing unit provided in the first embodiment of the present invention;

[0057] Figure 4 This is a module block diagram of a current sensing unit provided in the first embodiment of the present invention;

[0058] Figure 5 A block diagram showing the modules of a voltage sensing unit provided in the first embodiment of the present invention;

[0059] Figure 6 This is a flowchart of the steps of a method for using a voltage transformer online monitoring device provided in Example 5 of the present invention. DETAILED DESCRIPTION

[0060] The embodiments of the present invention provide a voltage transformer online monitoring device and a method for use, which are used to solve the technical problem that the accuracy and sensitivity of existing capacitive voltage transformer monitoring cannot be effectively guaranteed and the error performance of the voltage transformer cannot be evaluated.

[0061] In order to make the purpose, features, and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0062] Example 1

[0063] See also Figures 1 to 4 , Figure 1 This is a structural block diagram of a voltage transformer online monitoring device provided in Example 1 of the present invention.

[0064] The present invention provides an online monitoring device for a voltage transformer, which includes a sensing unit, an edge computing module and a comparison module; the sensing unit is respectively connected to the voltage transformer to be tested and the signal processing module; the signal processing module, the edge computing module and the comparison module are connected in sequence; the sensing unit includes a voltage sensing unit and a current sensing unit; the voltage sensing unit includes a voltage measurement module, a voltage isolation change module and an impedance matching output module connected in sequence; the current sensing unit includes a current sampling module, a compensation module and a flux detection module connected in sequence.

[0065] It should be noted that the voltage transformer to be tested refers to a capacitive voltage transformer that requires online monitoring.

[0066] In the embodiment of the present invention, Figure 2 As shown, the voltage transformer online monitoring device includes a voltage sensing unit, a current sensing unit, a signal processing module, an edge computing module and a comparison module arranged in the display.

[0067] like Figure 3 As shown, the voltage sensing unit is used to sense the primary voltage signal of the voltage transformer to be tested. The voltage sensing unit includes a voltage measurement module, a voltage isolation change module and an impedance matching output module connected in sequence; the voltage measurement module includes a voltage sampling module; the voltage sampling module is connected to the circuit of the voltage transformer to be tested to monitor the voltage and collect the voltage signal.

[0068] The voltage measurement module measures and records the voltage value of the output signal, providing reliable data support for device monitoring, analysis, and optimization.

[0069] The voltage isolation and variation module is connected after the voltage sampling module to isolate the voltage signal of the subsequent processing circuit, which can ensure the electrical isolation between the input voltage signal of the measured object and the subsequent processor or system, thereby improving the safety and stability of the measured object (measured voltage transformer).

[0070] The impedance matching output module matches the impedance of the output signal to ensure that the signal can be effectively transmitted to the subsequent processing device or system. It can ensure that the impedance of the output signal matches the input requirements of the subsequent processing device or system, thereby maximizing signal transmission and reducing signal loss, achieving signal anti-interference effect.

[0071] The voltage sensing unit obtained by combining the voltage measurement module, the voltage isolation change module and the impedance matching output module can further ensure the accuracy of signal acquisition, impedance matching and isolation protection, so as to ensure the normal operation of the system and accurate acquisition of signal data.

[0072] like Figure 4As shown, the current sensing unit is used to sense the capacitive current of the voltage transformer to be tested. The current sensing unit includes a current sampling module, a compensation module and a magnetic flux detection module connected in sequence.

[0073] The current sampling module can accurately collect the capacitive current signal in the circuit, and an air switch with ns-level fast action is also provided at the connection between the voltage sampling module and the voltage transformer to be tested.

[0074] The compensation module can correct errors caused by factors such as sensor nonlinearity and temperature changes.

[0075] The magnetic flux detection module can assist in monitoring current changes.

[0076] The combination of a current sampling module and a compensation module enables precise control of capacitive current in the circuit. Real-time error correction ensures stable and accurate current control, improving device performance and reliability. The magnetic flux detection module monitors magnetic flux changes in the circuit in real time, reflecting current fluctuations. Together, they provide more comprehensive current monitoring data, enabling the device to adjust its operating state in real time to accommodate varying operating conditions and loads. Real-time monitoring of current and magnetic flux changes allows for better management of energy flow within the device, optimizing energy efficiency, reducing energy consumption, and improving energy efficiency. The combined use of the current sampling module, compensation module, and magnetic flux detection module enhances the device's ability to detect abnormal conditions, enabling timely detection and response to safety issues such as current overloads and short circuits, protecting both equipment and users. Overall, the combined use of the current sampling module, compensation module, and magnetic flux detection module achieves technical benefits such as accurate current measurement, stable control, real-time monitoring, and device safety protection.

[0077] The signal processing module receives the output signals of the voltage sensing unit and the current sensing unit, and performs signal processing, including filtering, amplification, sampling and other operations, to ensure the accuracy and reliability of the input signals.

[0078] The edge computing module is an edge computing CPU. The edge computing CPU is used to process and calculate the input signal. It can execute various algorithms and models to evaluate the error performance of the voltage transformer to be tested and generate corresponding monitoring reports. The edge computing CPU can perform Fourier transform and other calculations on the input signal to realize the calculation of the fundamental ratio error of the voltage transformer to be tested, the fundamental phase error of the voltage transformer to be tested, the fundamental amplitude of the capacitive current, and the fundamental phase of the capacitive current. , It is the primary side voltage signal measured by the voltage sensing unit. It is the secondary side voltage signal measured by the voltage sensing unit; , is the phase angle of the primary side voltage signal measured by the voltage sensing unit, The fundamental amplitude of the capacitive current is calculated using the following steps: A discrete Fourier transform (DFT) is performed on the capacitive current time-domain waveform data to convert it into a frequency-domain representation. In the frequency domain, the fundamental frequency component of the capacitive current signal (typically 50 Hz or 60 Hz) is found, and its corresponding amplitude spectrum is obtained. The fundamental amplitude is the amplitude spectrum value of the fundamental frequency component. The fundamental phase of the capacitive current is calculated using the following steps: The signal processing module obtains the capacitive current time-domain waveform data and performs a discrete Fourier transform (DFT) to obtain a frequency-domain representation. In the frequency domain, the fundamental frequency component of the capacitive current signal is found, and its corresponding phase spectrum is obtained. The fundamental phase is the phase spectrum value of the fundamental frequency component. The edge computing CPU can process and analyze data locally, enabling real-time intelligent control and decision-making, reducing reliance on central servers or the cloud, and lowering latency.

[0079] The comparison module is located in the remote server. The remote server compares and analyzes the fundamental ratio error of the voltage transformer to be tested, the fundamental phase error of the voltage transformer to be tested, the capacitive current fundamental amplitude, and the capacitive current fundamental phase with the relevant data statistically collected in the historical operating data, and also compares and analyzes the phase-to-phase operating voltage and capacitive capacitance, thereby realizing online monitoring of the metering performance of the voltage transformer to be tested.

[0080] Specifically, the comparison analysis algorithm of the comparison module has the following steps:

[0081] 1) Data preprocessing: First, the real-time collected capacitive current and secondary voltage signals of the voltage transformer to be tested, as well as the same-phase real-time operating voltage and capacitive current statistically collected from historical operating big data, are preprocessed, including cleaning and missing value processing, to ensure data quality and consistency.

[0082] 2) Feature Extraction: Extract features related to the voltage transformer's performance from this data. These features can include statistical characteristics such as mean, standard deviation, maximum, and minimum values. Feature extraction can be performed using statistical methods, frequency domain features, and time domain features.

[0083] 3) Establish a time series model: Build a time series model for each data set (capacitive current of all voltage transformers, secondary voltage signals, real-time operating voltage and capacitive current of the same phase, and interphase operating voltage and capacitive current). Suitable models can include ARIMA (Autoregressive Integrated Moving Average), LSTM (Long Short-Term Memory), and Prophet. Choosing an appropriate model requires considering the characteristics of the data and the prediction objectives.

[0084] 4.) Model training: Use historical running big data to train time series models and adjust model parameters to improve prediction accuracy.

[0085] 5) Model evaluation: Use a portion of historical data to evaluate the model's prediction accuracy and performance.

[0086] 6) Comparative Analysis: Comparative analysis is performed using trained time series models. This allows for comparisons between real-time data and historical data, as well as the relationship between capacitive current and secondary voltage signals across all voltage transformers, and the relationship between the real-time operating voltage and capacitive current of the same phase and the operating voltage and capacitive current between phases. This allows for continuous monitoring of voltage transformer performance changes, and adjustments and optimizations based on the results of these comparative analyses.

[0087] The sampling accuracy of voltage and current signals is the basis for ensuring the accuracy of the error performance analysis results of the voltage transformer online error performance monitoring device. The present invention has made innovative designs for the voltage sensing unit and the current sensing unit from the circuit to the structure, so that the sampling accuracy of the voltage signal and the current signal reaches 0.005 level, which is at least 2 levels higher than the existing technology, greatly improving the monitoring accuracy of the voltage transformer online error performance monitoring device.

[0088] Example 2

[0089] See also Figure 3 and Figure 5 , Figure 3 This is a module block diagram of a voltage sensing unit provided in the second embodiment of the present invention.

[0090] The present invention provides an online monitoring device for a voltage transformer, wherein the voltage measurement module includes a two-pole winding, an iron core, and a measurement winding; the voltage isolation and variation module includes a two-pole winding, an iron core, and an isolation winding; the two-pole winding, the measurement winding, and the isolation winding are all wound around the iron core. The impedance matching output module includes a constant load, a first semiconductor diode, a second semiconductor diode, a capacitor, a first resistor, a second resistor, a third resistor, and an operational amplifier; the constant load is connected in parallel with the isolation winding, the first semiconductor diode, the second semiconductor diode, and the operational amplifier; the first semiconductor diode is connected in series with the first resistor and the capacitor; the first resistor is connected in series with the third resistor; the capacitor is connected in series with the second resistor; and the third resistor and the second resistor are both connected in series with the operational amplifier.

[0091] It should be noted that if Figure 3As shown, the two-pole winding is a two-pole winding A-A0-X-X0 with a rated voltage of 57.7V; the isolated winding is an isolated winding a0x0; the constant load is a constant load R0, the resistance of the constant load R0 is constant, and the resistance value is not less than 1 megohm; the first semiconductor diode and the second semiconductor diode are respectively a unidirectional semiconductor diode V1 and a unidirectional semiconductor diode V2, the first resistor, the first resistor and the third resistor are respectively a resistor R1, a resistor R2 and a variable resistor R3, the capacitor is a capacitor C1, and the operational amplifier is a precision operational amplifier.

[0092] In the embodiment of the present invention, Figure 5 As shown, the voltage sampling module is circled in red, the voltage isolation and conversion module is circled in green, the impedance matching output module is circled in blue, and the voltage measurement module is circled in purple. The voltage sampling module, voltage isolation and conversion module, and voltage measurement module share the same two-stage winding A-A0-X-X0. Furthermore, the voltage measurement module and voltage isolation and conversion module share the same core.

[0093] The voltage measurement module consists of a two-stage winding A-A0-X-X0, an iron core, and a measuring winding a1x1. The voltage measurement module includes a voltage sampling module, which consists of a two-stage winding A-A0-X-X0 and has a rated voltage of 57.7V. The voltage isolation change module consists of a two-stage winding A-A0-X-X0, an iron core, and a secondary isolation winding a0x0, forming a voltage transformation ratio of 57.7V / 5V. The impedance matching output module consists of a constant load R0, a unidirectional semiconductor diode V1 and a unidirectional semiconductor diode V2, a capacitor C1, resistors R1 and R2, a variable resistor R3, and a precision operational amplifier. The constant load R0 is connected in parallel to the isolation winding a0x0. The constant load R0 is connected in parallel with the unidirectional semiconductor diodes V1 and V2, and the precision operational amplifier to achieve impedance matching and high-precision output.

[0094] Shielding copper foil is set between the two-stage winding A-A0-X-X0, and the entire winding is wrapped with shielding copper foil after the winding is completed; shielding copper foil is set between the isolation winding a0x0 and the two-stage winding A-A0-X-X0.

[0095] The present invention provides a protection device in the voltage sensing unit to prevent the secondary short circuit of the voltage transformer under test from threatening the operation safety of the CVT and the power grid / power plant. When the secondary short circuit of the voltage transformer under test occurs, the action time is less than 1nS, and the switch is immediately disconnected to protect the voltage transformer under test.

[0096] Example 3

[0097] See also Figure 4 , Figure 4 This is a module block diagram of a current transformer provided in Example 3 of the present invention.

[0098] The present invention provides an online monitoring device for a voltage transformer. The current sampling module includes a single-turn winding, a main core, a compensation core, and a sampling winding. The single-turn winding passes through the coaxial main core and compensation core. The sampling winding wraps around the main core. The compensation module includes a compensation core and a compensation winding. The compensation winding wraps around the compensation core. The magnetic flux detection module includes a main core and a detection winding. The detection winding wraps around the main core. The current sampling module also includes a current measuring meter. The current measuring meter is connected to the detection winding and the edge computing module, respectively.

[0099] It should be noted that the one-turn winding is the through-core one-turn winding N0; the sampling winding is the sampling winding S0-S1; the compensation winding is the compensation winding S2-S3; and the detection winding is the detection winding N3.

[0100] In a specific implementation, the current sampling module and the compensation module share the same compensation core; the current sampling module and the magnetic flux detection module share the same main core.

[0101] See Figure 4 As shown in the figure, from left to right are the magnetic flux detection module T3, the current sampling module T1 and the compensation module T2. The current sampling module T1 includes a through-core one-turn winding N0, a main iron core, a compensation iron core and sampling windings S0-S1. The main iron core and the compensation iron core are stacked concentrically; the through-core one-turn winding N0 passes through the main iron core and the compensation iron core, and the sampling winding is wound on the main iron core. The sampling windings S0-S1 of the current sampling module are connected in parallel with a nanosecond bidirectional TVS tube. The compensation module T2 includes a compensation core and a compensation winding S2-S3. The compensation winding is wound on the compensation core. An appropriate load Z4 is set on the compensation winding S2-S3, and the load is adjustable. The magnetic flux detection module T3 includes a main iron core and a detection winding N3. The detection winding N3 is wound on the main iron core. The detection winding is also connected to a current measuring meter. The monitoring data of the current measuring meter is connected to the edge computing CPU. The load Z4 is adjusted according to the monitoring data so that the main iron core is in a zero magnetic flux state.

[0102] The current acquisition module has an open-close structure and also includes an insulating tape shielded shell, a 2.4V nanosecond bidirectional TVS tube and an armored cable.

[0103] The present invention provides a protection device on the current sensing unit to prevent the primary open circuit of the current transformer from threatening the operational safety of the CVT and the power grid / power plant. When the secondary open circuit of the sampling current transformer occurs, the 2.4V nanosecond-level bidirectional TVS tube quickly turns on to protect the voltage transformer under test.

[0104] Example 4

[0105] See also Figure 2 , Figure 2This is a module block diagram of a voltage transformer online monitoring device provided in Example 4 of the present invention.

[0106] The present invention provides an online monitoring device for a voltage transformer, which also includes a signal conversion module, a data exchange module and a data storage module; the signal conversion module is connected to the signal processing module and the data exchange module respectively; the data exchange module is connected to the signal conversion module, the edge computing module and the data storage module respectively. It also includes a clock module and a display; the clock module is connected to the data exchange module; the display is connected to the edge computing module. It also includes an analog circuit power supply, a digital circuit power supply and a communication module; the analog circuit power supply is connected to the voltage sensing unit, the signal processing module and the signal conversion module respectively; the digital circuit power supply is connected to the data exchange module, the edge computing module and the communication module respectively; the communication module is connected to the digital circuit power supply and the edge computing module respectively. It also includes an insulating tape shielded shell; the insulating tape shielded shell is coated with a shielding coating; the insulating tape shielded shell is connected to the shell grounding mounting nut; and the current sensing unit is installed in the insulating tape shielded shell.

[0107] It should be noted that, see Figure 2 As shown, the signal conversion module converts the voltage and current signals that have undergone signal processing into digital signals to facilitate subsequent data processing and calculation.

[0108] The data exchange module is used to exchange data with other external devices, such as computers or monitoring systems. Specifically, the data exchange module can transmit processed data to other systems or devices, enabling data sharing and integration, thereby improving the overall efficiency and performance of the system.

[0109] The data storage module is used to store the data obtained by the monitoring device, including original signals, processed data, calculation results, etc., which can be used for subsequent analysis, trend analysis and fault diagnosis.

[0110] The clock module is electrically connected to the data exchange module; the display is electrically connected to the edge computing CPU.

[0111] The analog circuit power supply is electrically connected to the voltage sensing unit, the signal processing module and the signal conversion module; the digital circuit power supply is electrically connected to the data exchange module, the edge computing CPU and the GPRS communication module.

[0112] The GPRS communication module transmits monitoring data to a remote server or cloud platform via a wireless communication network. This allows users to remotely monitor and manage the voltage transformer's error performance. The monitoring device directly and accurately obtains the voltage transformer's capacitive current and secondary voltage signals in real time.

[0113] The current sensing unit is installed in an insulating tape shielded shell. The shell is made of insulating material. The inner wall of the insulating tape shielded shell is coated with a shielding coating and is connected to the shell grounding mounting nut. After the through-core one-turn winding N0 is connected to the primary high-voltage tail of the voltage transformer to be tested, the sampling winding S0-S1 is connected to the signal processing module through an armored cable.

[0114] The purpose of the present invention to set up a shielding layer is to reduce the interference of the environmental electromagnetic field on the device. By setting up a shielding layer around the device, the influence of external electromagnetic interference signals can be effectively blocked, ensuring the stability and accuracy of the device.

[0115] The present invention reduces the influence of environmental electromagnetic field, voltage fluctuation and loop impedance transformation on voltage and current sampling accuracy by setting impedance matching output module, setting shielding layer, setting compensation module T2 and magnetic flux detection module T3, and further reduces the equivalent rated load of voltage transformer online monitoring device to less than 10 - 6 VA, so that the impact on the voltage transformer to be measured can be ignored.

[0116] Example 5

[0117] See also Figure 6 , Figure 6 This is a flowchart of the steps of a method for using a voltage transformer online monitoring device provided in Example 5 of the present invention.

[0118] The present invention provides a method for using an online monitoring device for a voltage transformer, comprising the following steps:

[0119] Step 601: collecting current signals and voltage signals of a voltage transformer to be tested;

[0120] Step 601: Process the current signal and the voltage signal to generate current data and voltage data;

[0121] Step 603: Calculate the fundamental ratio error, fundamental phase error, capacitive current fundamental amplitude, and capacitive current fundamental phase of the voltage transformer under test based on the current data and voltage data, and determine the current operating state of the voltage transformer under test according to the calculation results.

[0122] It should be noted that a voltage sensing unit is used to collect the primary voltage signal of the voltage transformer to be tested, and a current sensing unit is used to collect the capacitive current signal of the voltage transformer to be tested. The primary voltage signal and the capacitive current signal are processed by the signal processing module, and the signal conversion module converts the signal-processed voltage and current signals into digital signals to generate current data and voltage data. The fundamental ratio error of the voltage transformer to be tested, the fundamental phase error of the voltage transformer to be tested, the capacitive current fundamental amplitude and the capacitive current fundamental phase of the voltage transformer to be tested are calculated by the edge computing CPU. The calculation results of the fundamental ratio error of the voltage transformer to be tested, the fundamental phase error of the voltage transformer to be tested, the capacitive current fundamental amplitude and the capacitive current fundamental phase are compared with the historical operation data, and the current operating status of the voltage transformer to be tested is determined according to the comparison results.

[0123] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0124] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0125] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0126] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0127] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program code, such as a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0128] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features thereof can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A voltage transformer online monitoring device, characterized in that: The device includes a perception unit, an edge computing module and a comparison module; The sensing unit is connected to the voltage transformer to be tested and the signal processing module respectively; The signal processing module, the edge computing module and the comparison module are connected in sequence; The sensing unit includes a voltage sensing unit and a current sensing unit; The voltage sensing unit includes a voltage measurement module, a voltage isolation change module and an impedance matching output module connected in sequence; The current sensing unit includes a current sampling module, a compensation module and a magnetic flux detection module connected in sequence; The voltage measurement module includes a bipolar winding, an iron core and a measurement winding; The voltage isolation and variation module includes the bipolar winding, the core and the isolation winding; The bipolar winding, the measuring winding and the isolation winding are all wound around the core; The comparison module is specifically used to preprocess the real-time collected capacitive current and secondary voltage signal of the voltage transformer to be tested and the same-phase real-time operating voltage and capacitive current counted in the historical operation big data, and extract statistical features related to the performance of the voltage transformer to be tested from the preprocessed data, construct a time series model based on the statistical features, and use the historical operation big data to train and evaluate the time series model to obtain a trained time series model, use the trained time series model to analyze the capacitive current and secondary voltage signal of the voltage transformer to be tested, the same-phase real-time operating voltage and capacitive current, and output the relationship between the capacitive current and the secondary voltage signal of the voltage transformer to be tested, as well as the relationship between the same-phase real-time operating voltage and capacitive current and the phase-to-phase operating voltage and capacitive current; wherein the statistical features include average value, standard deviation, maximum value, and minimum value; The current sampling module includes a turn winding, a main iron core, a compensation iron core and a sampling winding; The one-turn winding is passed through the main iron core and the compensating iron core arranged coaxially; The sampling winding is wound around the main iron core; The compensation module includes the compensation core and the compensation winding; The compensation winding is wound around the compensation core; The magnetic flux detection module includes the main iron core and a detection winding; The detection winding is wound around the main iron core; The impedance matching output module includes a constant load, a first semiconductor diode, a second semiconductor diode, a capacitor, a first resistor, a second resistor, a third resistor and an operational amplifier; The constant load is connected in parallel with the isolation winding, the first semiconductor diode, the second semiconductor diode and the operational amplifier respectively; The first semiconductor diode is connected in series with the first resistor and the capacitor respectively; The first resistor and the third resistor are connected in series; The capacitor and the second resistor are connected in series; The third resistor and the second resistor are both connected in series with the operational amplifier.

2. The voltage transformer online monitoring device according to claim 1, characterized in that: The current sampling module also includes a current measuring meter; The current measuring meter is connected to the detection winding and the edge computing module respectively.

3. The voltage transformer online monitoring device according to claim 1, characterized in that: It also includes a signal conversion module, a data exchange module and a data storage module; The signal conversion module is connected to the signal processing module and the data exchange module respectively; The data exchange module is respectively connected to the signal conversion module, the edge computing module and the data storage module.

4. The voltage transformer online monitoring device according to claim 3, characterized in that: Also includes a clock module and display; The clock module is connected to the data exchange module; The display is connected to the edge computing module.

5. The voltage transformer online monitoring device according to claim 3, characterized in that: It also includes an analog circuit power supply, a digital circuit power supply and a communication module; The analog circuit power supply is connected to the voltage sensing unit, the signal processing module and the signal conversion module respectively; The digital circuit power supply is respectively connected to the data exchange module, the edge computing module and the communication module; The communication module is connected to the digital circuit power supply and the edge computing module respectively.

6. The voltage transformer online monitoring device according to claim 1, characterized in that: Also included is an insulating tape shielded housing; The insulating tape shielding shell is coated with a shielding coating; The insulating tape shielding shell is connected to the shell grounding mounting nut; The current sensing unit is installed in the insulating tape shielding shell.

7. A method for using the voltage transformer online monitoring device according to any one of claims 1 to 6, characterized in that: include: Collect current and voltage signals of the voltage transformer to be tested; performing signal processing on the current signal and the voltage signal to generate current data and voltage data; Based on the current data and the voltage data, the fundamental ratio error, fundamental phase error, capacitive current fundamental amplitude and capacitive current fundamental phase of the voltage transformer to be tested are calculated, and the current operating state of the voltage transformer to be tested is determined according to the calculation results.

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