A transformer winding deformation online monitoring system and method

Abstract

The present invention discloses an online monitoring system and method for transformer winding deformation, which relates to the technical field of transformers, including a current sensor and a voltage sensor, which are respectively used to sample the three-phase current and voltage waveforms of the transformer, and send the collected data to a data processing device for further processing; the data processing device is used to control the sensor to perform sampling operations, and analyze and process the sampling results, calculate the short-circuit impedance, determine whether the winding is deformed, and give the degree of deformation; the data processing device provides a network interface to the outside, and sends the winding deformation monitoring results to a server; the client is used to connect to the server to display the real-time monitoring results of the winding deformation and the winding deformation alarm information. The present invention can perform long-term online monitoring of transformer winding deformation, discover transformer winding deformation problems early, deal with them as soon as possible, and improve the stability and safety of transformer operation.

Description

Technical Field

[0001] The present invention relates to the technical field of transformers, and in particular to an online monitoring system and method for transformer winding deformation. Background Art

[0002] During the installation and transportation of the transformer, the transformer winding may be deformed due to vibration, collision, etc., and it is inevitable to be subjected to various short-circuit shocks during operation. The electric force generated by the strong short-circuit shock current can cause irreversible deformation of the transformer winding. Transformer winding deformation is manifested as irreversible changes in size and shape, including changes in axial and radial dimensions, body displacement, winding distortion, etc., resulting in winding bulging, winding insulation damage, inter-turn short circuit, and ultimately transformer failure, causing serious harm.

[0003] As the capacity of the power system continues to expand, the harm caused by transformer winding deformation is becoming more and more serious, and the operation and maintenance costs are increasing. Short-circuit impedance measurement is a common method for detecting transformer winding deformation, but traditional short-circuit impedance measurement requires power outage, which is complicated to operate and has large uncertainty in the measurement process. It is difficult to detect small deformations in the early stage. In addition, since power outage is required, regular inspections can only be carried out, and it is difficult to detect winding deformation problems in time. The existing transformer winding deformation online monitoring device still has many line connections, inconvenient installation, and inaccurate monitoring results, and is not very applicable. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an online monitoring system and a corresponding method for transformer winding deformation that are easy to install and accurately monitor, reduce on-site operation and inspection costs, perform long-term online monitoring of transformer winding deformation, discover transformer winding deformation problems early, handle them as early as possible, and improve the stability and safety of transformer operation.

[0005] In order to solve the above technical problems, the present invention provides a technical solution: a transformer winding deformation online monitoring system, comprising:

[0006] Current sensor, used to sample the three-phase current waveform of the high voltage / medium voltage / low voltage side of the transformer, and send the collected data to the data processing device through Lora communication for further processing;

[0007] Voltage sensor, used to sample the three-phase voltage waveforms on the high / medium / low voltage sides of the transformer, and send the collected data to the data processing device through Lora communication for further processing;

[0008] A data processing device is used to control the sensor to perform sampling operations, analyze and process the sampling results, calculate the short-circuit impedance, determine whether the winding is deformed, and give the degree of deformation; the data processing device provides a network interface to the outside to send the winding deformation monitoring results to the server;

[0009] The client is used to connect to the server and display the real-time monitoring results and alarm information of winding deformation.

[0010] Further, the current sensor includes a first power supply unit and a first measuring unit;

[0011] The first power supply unit includes a power taking coil, a first rectifier circuit, a first filter circuit, and a first voltage stabilizing circuit; the power taking coil is used to obtain energy from the measured circuit; the first rectifier circuit performs full-wave rectification on the alternating current from the power taking coil, and outputs pulsating direct current to the first filter circuit; the first filter circuit performs low-pass filtering on the pulsating direct current to filter out high-frequency interference; the first voltage stabilizing circuit adopts a feedback voltage stabilizing circuit to provide a working voltage for the first measuring unit;

[0012] The first measuring unit includes a measuring coil, a first analog signal conditioning circuit, a first AD conversion circuit, a first microprocessor, and a first low-power consumption Lora module;

[0013] The measuring coil is used to sense the current of the line to be measured, and the measuring range is adjusted by adjusting the number of turns to be suitable for different current levels on the high voltage side, the medium voltage side, and the low voltage side;

[0014] The first analog signal conditioning circuit is used to sample the induced current from the measuring coil, convert it into a voltage signal, filter and amplify it, and then output a zero-crossing signal, an analog signal, and an impact signal;

[0015] The first AD conversion circuit is used to sample the analog signal from the first analog signal conditioning circuit and convert it into a digital signal;

[0016] The first microprocessor controls the overall operation of the current sensor;

[0017] The first low-power Lora module is used to send and receive Lora signals, send the first microprocessor processing result data to the data processing device through the Lora signal, receive the sampling trigger instruction and working parameter setting instruction sent by the data processing device, and hand them over to the first microprocessor for further processing.

[0018] Further, the voltage sensor includes a voltage input interface, a second power supply unit, and a second measuring unit;

[0019] The voltage input interface is used to connect the three-phase voltage to be measured;

[0020] The second power supply unit includes a step-down circuit, a second rectifier circuit, a second filter circuit, and a second voltage stabilizing circuit; the step-down circuit takes a single-phase voltage from a voltage input interface and steps it down to a low voltage; the second rectifier circuit performs full-wave rectification on the AC voltage from the step-down circuit, and outputs a pulsating DC voltage to the second filter circuit; the second filter circuit performs low-pass filtering on the pulsating DC voltage to filter out high-frequency interference; the second voltage stabilizing circuit adopts a feedback voltage stabilizing circuit to provide a working voltage for the second measuring unit;

[0021] The second measuring unit includes a voltage transformer, a second analog signal conditioning circuit, a second AD conversion circuit, a second microprocessor, and a second low-power consumption Lora module;

[0022] The voltage transformer is used to sense the voltage of the line to be measured, and the range is adjusted by adjusting the number of turns to be suitable for different voltage levels on the high voltage side, medium voltage side, and low voltage side;

[0023] The second analog signal conditioning circuit samples and filters the induced voltage from the voltage transformer, amplifies the voltage signal and outputs a zero-crossing signal and an analog output signal;

[0024] The second AD conversion circuit is used to sample the analog signal from the analog signal conditioning circuit and convert it into a digital signal;

[0025] The second microprocessor controls the overall operation of the voltage sensor;

[0026] The second low-power Lora module is used to send and receive Lora signals, send the second microprocessor processing result data to the data processing device through the Lora signal, receive the sampling trigger instruction and working parameter setting instruction sent by the data processing device, and hand them over to the second microprocessor for further processing.

[0027] Further, the data processing device includes a high-speed processor, a high-precision clock module, a third low-power Lora module, a network communication module, and a display interaction module;

[0028] The high-speed processor is responsible for controlling the workflow of the data processing device and performing data operations, including: obtaining the received waveform data from the third low-power lora module and performing preliminary processing on the data; performing operations on the voltage and current waveform data to obtain the effective values ​​of the voltage and current; sending a working parameter setting instruction to the voltage sensor and the current sensor through the third low-power lora module to set the sensor delay sending time; sending a sampling trigger instruction to the voltage sensor and the current sensor through the third low-power lora module to start the sensor sampling operation; sending monitoring data and transformer winding deformation judgment result data to the server through the network communication module; reading time from the high-precision clock module for phase information identification, data generation time mark, etc.; comparing the solved short-circuit impedance with the standard short-circuit impedance, and considering the influence of the number of impacts, dividing the transformer deformation degree into multiple levels;

[0029] The high-precision clock module is used to provide high-precision clock information for aligning data acquisition time and improving phase detection accuracy;

[0030] The third low-power Lora module is used to send and receive Lora signals, including sending the sampling trigger instruction and the working parameter setting instruction of the high-speed processor to the voltage sensor and the current sensor, and receiving the sampling waveform data and the impulse signal data of the voltage sensor and the current sensor;

[0031] The network communication module provides R485, Ethernet, and 4G network function interfaces to send data to the server in a variety of ways;

[0032] The display interaction module adopts a capacitive touch screen, which is used to display the working status of the device, detect data in real time, modify working parameters, and configure working modes.

[0033] The present invention also provides a transformer winding deformation online monitoring method, comprising the following steps:

[0034] Synchronous sampling of voltage and current:

[0035] S1, the data processing device sends a sampling trigger instruction by broadcasting;

[0036] S2. Each sensor receives a sampling trigger instruction at the same time, and starts waveform sampling at the first positive zero crossing of voltage or current, continuously collecting waveform data for 5 cycles;

[0037] S3, after each sensor completes sampling, it delays accordingly according to its own delay transmission time, and then sends the data;

[0038] S4, the data processing device successively receives the waveform data of each sensor and marks the receiving time of the waveform data of each sensor;

[0039] S5. After receiving all sensor data, the data processing device performs time alignment on the data according to the marked data receiving time, the delayed sending time of each sensor, and the inherent delay of system data transmission and reception, obtains waveform data containing phase information, and completes a sampling process;

[0040] Transformer winding deformation judgment:

[0041] S1. The high-speed processor calculates the waveform data measured multiple times to obtain multiple sets of voltage and current effective values;

[0042] S2. Calculate the short-circuit impedance based on multiple sets of voltage and current effective values;

[0043] S3. Compare the solved short-circuit impedance with the standard short-circuit impedance, and consider the impact of the number of impacts to divide the transformer deformation degree into multiple levels.

[0044] The advantages of the present invention compared with the prior art are:

[0045] 1. The system of the present invention realizes online monitoring of transformer winding deformation. Users can remotely obtain monitoring results through the client, timely and effectively discover the deformation trend of transformer windings, and perform maintenance in time, thereby reducing the harm and losses caused by transformer winding deformation.

[0046] 2. The voltage sensor and current sensor use wireless data transmission to send waveform data, and according to the synchronous sampling process, the synchronous sampling of each sensor is realized, and no additional power is required, which is very convenient to install, reduces construction costs, avoids excessive secondary line connections, and enhances the adaptability of transformer winding deformation monitoring. The data processing device obtains voltage and current waveform data, which provides support for the use of more complex winding deformation degree judgment methods.

[0047] 3. Multiple sets of measurement data are used to calculate the short-circuit impedance. The short-circuit impedance is obtained by calculation and then compared with the standard impedance. The influence of the number of short-circuit impacts on the deformation of the transformer winding is comprehensively considered to measure the deformation degree of the transformer winding, thereby improving the detection accuracy and sensitivity, improving the accuracy of the transformer winding deformation judgment results, and reducing misjudgment. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is the system block diagram of the transformer winding deformation online monitoring system.

[0049] Figure 2 This is the principle block diagram of the current sensor.

[0050] Figure 3 It is the principle block diagram of the first analog signal conditioning circuit.

[0051] Figure 4 This is the principle block diagram of the voltage sensor.

[0052] Figure 5 It is the principle block diagram of the second analog signal conditioning circuit.

[0053] Figure 6 It is a system block diagram of a data processing device.

[0054] Figure 7 It is a synchronous sampling flow chart of the online monitoring method of transformer winding deformation.

[0055] Figure 8 The invention is a transformer winding deformation judgment flow chart of the transformer winding deformation online monitoring method. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0057] It should be understood that in the description of the present application, unless the context clearly requires otherwise, words such as "include", "comprises" and the like in the entire specification and claims should be interpreted as inclusive rather than exclusive or exhaustive; that is, the meaning of "including but not limited to".

[0058] It should also be understood that the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of this application, unless otherwise specified, "plurality" means two or more.

[0059] It should be noted that the terms "S1", "S2", etc. are only used for the purpose of describing the steps, and do not specifically refer to the order or sequence, nor are they used to limit the present application. They are only for the convenience of describing the method of the present application, and cannot be understood as indicating the order of the steps. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present application.

[0060] The following is a further detailed description of a transformer winding deformation online monitoring system and method according to the present invention in conjunction with the accompanying drawings.

[0061] Combined with Figure 1-8The specific implementation process of the transformer winding deformation online monitoring system and method of the present invention is as follows:

[0062] 1. Overall system:

[0063] As attached Figure 1 As shown, a transformer winding deformation online monitoring system includes a transformer, a current sensor, a voltage sensor, a data processing device, a server, and a client.

[0064] Attached Figure 1 The middle transformer is a three-turn transformer with 3 voltage sensors and 12 current sensors, which measure the three-phase voltage and current on the high-voltage side, medium-voltage side, and low-voltage side of the transformer respectively. This system is also applicable to two-turn transformers.

[0065] The current sensor is used to sample the three-phase current waveform of the high / medium / low voltage side of the transformer, and send the collected data to the data processing device through Lora communication for further processing. The current sensor is powered by CT power supply, no additional power supply is required, and the installation method is snap-on, which is easy to install.

[0066] The voltage sensor is used to sample the three-phase voltage waveforms on the high / medium / low voltage sides of the transformer, and send the collected data to the data processing device through Lora communication for further processing.

[0067] The data processing device is used to control the sensor to perform sampling operations, analyze and process the sampling results, calculate the short-circuit impedance, determine whether the winding is deformed, and give the degree of deformation; the data processing device provides external interfaces such as R485, Ethernet, and 4G network, and can send the winding deformation monitoring results to the server through various networks.

[0068] The client provides services for operation and maintenance personnel. Through the client, operation and maintenance personnel can connect to the server and display real-time monitoring results of winding deformation, winding deformation alarm information, etc.

[0069] The advantages of this system are: the voltage sensor, current sensor and data processing device are separated, Lora communication is used to transmit data, and the voltage sensor and current sensor do not require additional power supply, which reduces the line connection during installation. The data processing device can be installed flexibly without volume restrictions, the construction is simple, and it has good engineering adaptability.

[0070] 2. Current sensor

[0071] As attached Figure 2 As shown, the current sensor includes a first power supply unit and a first measuring unit.

[0072] The first power supply unit includes a power taking coil, a first rectifier circuit, a first filter circuit, and a first voltage stabilizing circuit.

[0073] The power coil is used to obtain energy from the measured line; the first rectifier circuit performs full-wave rectification on the AC power from the power coil and outputs pulsating DC to the first filter circuit; the first filter circuit performs low-pass filtering on the pulsating DC to filter out high-frequency interference; the first voltage regulator circuit adopts a feedback voltage regulator design to provide a DC voltage with high stability and low ripple coefficient, providing working voltage for the first analog signal conditioning circuit, the first AD conversion circuit, the first microprocessor, and the first low-power Lora module. The first voltage regulator circuit is equipped with a large-capacity energy storage capacitor, which can provide a large short-term burst current for the first low-power Lora module to transmit wireless signals.

[0074] The first measuring unit includes a measuring coil, a first analog signal conditioning circuit, a first AD conversion circuit, a first microprocessor, and a first low-power consumption Lora module.

[0075] The measuring coil is used to sense the current of the line to be measured. The measuring range can be adjusted by adjusting the number of turns to adapt to different current levels on the high voltage side, medium voltage side and low voltage side, thereby improving the measurement accuracy.

[0076] The first analog signal conditioning circuit is shown in the attached Figure 3 As shown, it includes a first sampling circuit, a first bandpass filter, a first amplifier, a first output buffer, a first zero-crossing comparator, and an impact detection circuit. The first sampling circuit samples the induced current from the measuring coil and converts it into a voltage signal; the first bandpass filter filters the voltage signal, and its lower limit cutoff frequency is 10Hz and the upper limit cutoff frequency is 1250Hz, and the DC signal and the high-frequency interference signal are filtered out. When implemented, an elliptical filter circuit can be used; the first amplifier is implemented by an integrated operational amplifier, and the signal is low-multiple amplified. The output signal is connected to the first output buffer, the first zero-crossing comparator, and the first impact detection circuit; the first output buffer is used to isolate the front-stage and rear-stage circuits, and its input impedance is large and the output impedance is small. The output signal is an analog signal after filtering and amplification, which is used for the first AD conversion circuit to perform analog-to-digital sampling; the first zero-crossing comparator is used to capture the zero-crossing point of the signal, and output a digital rising edge / falling edge signal at the zero-crossing point of the signal for detection by the first microprocessor, which is used for phase discrimination and triggering AD sampling. The impact detection circuit is used to detect short-circuit impact current. When a short-circuit impact current occurs, the amplifier output exceeds the threshold, and the impact detection circuit will output a high-level digital signal to trigger an external interrupt of the microprocessor. After further processing by the first microprocessor, different short-circuit impact current trigger values ​​can be selected through the dip switch to adapt to transformers of various capacities.

[0077] The first AD conversion circuit is used to sample the analog signal from the first analog signal conditioning circuit and convert it into a digital signal.

[0078] The first microprocessor controls the overall operation of the current sensor, including controlling the first AD conversion circuit to perform AD conversion and read the conversion result, detecting the zero-crossing signal output by the first analog signal conditioning circuit, detecting the impact signal output by the first analog signal conditioning circuit, processing the current sampling result data, controlling the first low-power lora module to send and receive data, etc.

[0079] The first low-power Lora module is used to send and receive Lora signals, and send the processing result data of the first microprocessor to the data processing device through the Lora signal. It can also receive the sampling trigger instruction and working parameter setting instruction sent by the data processing device, and hand them over to the first microprocessor for further processing.

[0080] 3. Voltage sensor

[0081] As attached Figure 4 As shown, the voltage sensor includes a voltage input interface, a second power supply unit, and a second measuring unit.

[0082] The voltage input interface is used to connect the three-phase voltage to be measured;

[0083] The second power supply unit includes a step-down circuit, a second rectifier circuit, a second filter circuit, and a second voltage stabilizing circuit.

[0084] The step-down circuit takes a single-phase voltage from the voltage input interface and steps it down to a low voltage; the second rectifier circuit performs full-wave rectification on the AC voltage from the step-down circuit and outputs a pulsating DC voltage to the second filter circuit; the second filter circuit performs low-pass filtering on the pulsating DC voltage to filter out high-frequency interference; the second voltage regulator circuit adopts a feedback voltage regulator design to provide a DC voltage with high stability and low ripple coefficient, providing the working voltage for the second analog signal conditioning circuit, the second AD conversion circuit, the second microprocessor, and the second low-power Lora module. The second voltage regulator circuit is equipped with a large-capacity energy storage capacitor, which can provide a large short-term burst current for the second low-power Lora module to transmit wireless signals.

[0085] The second measuring unit includes a voltage transformer, a second analog signal conditioning circuit, a second AD conversion circuit, a second microprocessor, and a second low-power consumption Lora module.

[0086] The voltage transformer is used to sense the voltage of the line to be measured. The range can be adjusted by adjusting the number of turns to adapt to different voltage levels on the high voltage side, medium voltage side, and low voltage side, thereby improving the measurement accuracy.

[0087] The second analog signal conditioning circuit needs to process three voltage signals: Figure 5The figure shows one of the voltage signal processing circuits, including a second sampling circuit, a second bandpass filter, a second amplifier, a second output buffer, and a second zero-crossing comparator. The second sampling circuit samples the induced voltage from the voltage transformer; the second bandpass filter filters the voltage signal, and its lower limit cutoff frequency is 10Hz and the upper limit cutoff frequency is 1250Hz, filtering out DC signals and high-frequency interference signals. When implemented, an elliptical filter circuit can be used; the second amplifier is implemented by an integrated operational amplifier, which amplifies the signal at a low magnification, and the output signal is connected to the second output buffer and the second zero-crossing comparator; the second output buffer is used to isolate the front-stage and rear-stage circuits, and its input impedance is large and the output impedance is small. The output signal is an analog signal after filtering and amplification, which is used for analog-to-digital sampling by the second AD conversion circuit; the second zero-crossing comparator is used to capture the signal zero-crossing point, and output a digital rising edge / falling edge signal at the signal zero-crossing point for detection by the second microprocessor, which is used for phase discrimination and triggering AD sampling.

[0088] The second AD conversion circuit is used to sample the analog signal from the second analog signal conditioning circuit and convert it into a digital signal.

[0089] The second microprocessor controls the overall operation of the voltage sensor, including controlling the second AD conversion circuit to perform AD conversion and read the conversion result, detecting the zero-crossing signal output by the second analog signal conditioning circuit, processing the voltage sampling result data, controlling the second low-power lora module to send and receive data, etc.

[0090] The second low-power Lora module is used to send and receive Lora signals, and send the second microprocessor processing result data to the data processing device through the Lora signal. It can also receive sampling trigger instructions and working parameter setting instructions sent by the data processing device, and hand them over to the second microprocessor for further processing.

[0091] 4. Data processing device

[0092] As attached Figure 6 As shown, the data processing device includes a high-speed processor, a high-precision clock module, a third low-power Lora module, a network communication module, and a display interaction module.

[0093] The high-speed processor is responsible for controlling the workflow of the data processing device and performing data operations, including: obtaining the received waveform data from the third low-power lora module and performing preliminary processing on the data; performing operations on the voltage and current waveform data to obtain the effective values ​​of the voltage and current; sending working parameter setting instructions to the voltage sensor and the current sensor through the third low-power lora module to set the sensor delay sending time; sending sampling trigger instructions to the voltage sensor and the current sensor through the third low-power lora module to start the sensor sampling operation; sending monitoring data, transformer winding deformation judgment results and other data to the server through the network communication module; reading time from the high-precision clock module for phase information identification, data generation time marking, etc.; comparing the solved short-circuit impedance with the standard short-circuit impedance, and considering the influence of the number of impacts, dividing the degree of transformer deformation into multiple levels.

[0094] The high-precision clock module is used to provide high-precision clock information to align data acquisition time and improve phase detection accuracy;

[0095] The third low-power Lora module is used to send and receive Lora signals, including sending the sampling trigger instructions and working parameter setting instructions of the high-speed processor to the voltage sensor and the current sensor, and receiving the sampling waveform data and impulse signal data of the voltage sensor and the current sensor.

[0096] The network communication module provides R485, Ethernet, 4G network and other functional interfaces, and can send data to the server in a variety of ways.

[0097] The display interaction module uses a capacitive touch screen to display the working status of the device, detect data in real time, modify working parameters, configure working modes, etc.

[0098] 5. Server

[0099] The server can be a local server or a cloud server, and is mainly used to store data uploaded by the data processing device, including transformer voltage and current data, transformer winding deformation judgment results, short-circuit impact times, etc., and provide client remote access services to facilitate remote viewing of monitoring data anytime and anywhere. The server can also further analyze the stored transformer voltage and current historical data, and combine the analysis with long-term monitoring data to better warn of transformer winding deformation trends.

[0100] 6. Client

[0101] The client has network access function and can run on common devices and operating systems such as PCs, mobile phones, industrial computers, etc. It is mainly used to obtain monitoring data from the server and display it in the form of curves, charts, etc., so that users can obtain transformer winding deformation monitoring results in a timely manner.

[0102] Based on the same concept as the above-mentioned transformer winding deformation online monitoring system, this embodiment also provides a transformer winding deformation online monitoring method, which is a method step for executing the above-mentioned transformer winding deformation online monitoring system.

[0103] The working process of the online monitoring method for transformer winding deformation:

[0104] 1. Voltage and current synchronous sampling process

[0105] Since the voltage sensor and current sensor use the Lora module for wireless communication with the data processing device, the key to the sampling process is how to achieve synchronous sampling of each sensor and how to obtain phase information. Since measuring the deformation of the transformer winding does not require real-time continuous measurement, the system uses a fixed time interval and timed trigger sampling method for sampling. Since the Lora wireless communication method is used to transmit waveform data, the data volume is large, so each sensor needs to send data in a time-sharing manner to avoid channel congestion and correctly obtain phase information.

[0106] Before starting sampling, the data processing device needs to set the delayed sending time for each sensor by sending a working parameter setting instruction. The delayed sending time refers to the time interval from the completion of sampling to the start of data sending. The delayed sending time of each sensor is different, and the minimum interval between them is 20ms to ensure that the data of each sensor is sent.

[0107] The sampling operation is triggered by the data processing device at a fixed time. The following is the basic process of a sampling:

[0108] S1: The data processing device sends a sampling trigger instruction by broadcasting;

[0109] S2: Each sensor receives the sampling trigger instruction at the same time, and starts waveform sampling at the first positive zero crossing of voltage or current, and continuously collects waveform data for 5 cycles;

[0110] S3: After each sensor completes sampling, it delays according to its own delay transmission time and then sends the data;

[0111] S4: The data processing device successively receives the waveform data of each sensor and marks the receiving time of the waveform data of each sensor;

[0112] S5: After receiving all sensor data, the data processing device performs time alignment on the data according to the marked data reception time, the delayed transmission time of each sensor, and the inherent delay of system data transmission and reception to obtain waveform data containing phase information, thus completing a sampling process.

[0113] For the monitoring of short-circuit impact current, each current sensor continuously monitors through interruption mode. Once the short-circuit impact current is detected, the short-circuit impact data will be immediately recorded in the sending buffer queue. When the system is idle, the data will be sent to the data processing device, and the data processing device will accumulate and count the number of impacts.

[0114] 2. Transformer winding deformation judgment process

[0115] The transformer winding condition can be determined by calculating the short-circuit impedance of the transformer winding and comparing it with the standard short-circuit impedance, which can be obtained from the transformer parameters.

[0116] The specific process of transformer winding deformation judgment is as follows:

[0117] S1: The high-speed processor calculates the waveform data measured multiple times to obtain multiple sets of voltage and current effective values;

[0118] S2: Calculate the short-circuit impedance based on multiple sets of voltage and current effective values;

[0119] S3: Compare the solved short-circuit impedance with the standard short-circuit impedance, and consider the impact of the number of impacts to divide the transformer deformation degree into multiple levels.

[0120] The present invention realizes online monitoring of transformer winding deformation. Users can remotely obtain monitoring results through a client, timely and effectively discover transformer winding deformation trends, perform maintenance in a timely manner, and reduce the harm and losses caused by transformer winding deformation.

[0121] The voltage sensor and the current sensor use wireless data transmission to send waveform data, and according to the synchronous sampling process, the synchronous sampling of each sensor is realized, and no additional power is required, which is very convenient to install, reduces construction costs, avoids excessive secondary line connections, and enhances the adaptability of transformer winding deformation monitoring. The data processing device obtains voltage and current waveform data, which provides support for the use of more complex winding deformation degree judgment methods.

[0122] The present invention and its embodiments are described above, and such description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if ordinary technicians in the field are inspired by it, without departing from the purpose of the invention, they can design a structure and embodiment similar to the technical solution without creativity, which should belong to the protection scope of the present invention.

Claims

1. A transformer winding deformation online monitoring system, characterized in that: include Current sensor, used to sample the three-phase current waveform of the high voltage / medium voltage / low voltage side of the transformer, and send the collected data to the data processing device through Lora communication for further processing; The current sensor includes a first measuring unit, which includes a measuring coil, a first analog signal conditioning circuit, a first AD conversion circuit, a first microprocessor, and a first low-power consumption Lora module; The measuring coil is used to sense the current of the line to be measured, and the measuring range is adjusted by adjusting the number of turns to be suitable for different current levels on the high voltage side, the medium voltage side, and the low voltage side; The first analog signal conditioning circuit is used to sample the induced current from the measuring coil, convert it into a voltage signal, filter and amplify it, and then output a zero-crossing signal, an analog signal, and an impact signal; The first AD conversion circuit is used to sample the analog signal from the first analog signal conditioning circuit and convert it into a digital signal; The first microprocessor controls the overall operation of the current sensor; The first low-power Lora module is used to send and receive Lora signals, send the first microprocessor processing result data to the data processing device through the Lora signal, receive the sampling trigger instruction and the working parameter setting instruction sent by the data processing device, and hand them over to the first microprocessor for further processing; Voltage sensor, used to sample the three-phase voltage waveforms on the high / medium / low voltage sides of the transformer, and send the collected data to the data processing device through Lora communication for further processing; A data processing device is used to control the sensor to perform sampling operations, analyze and process the sampling results, calculate the short-circuit impedance, determine whether the winding is deformed, and give the degree of deformation; The data processing device includes a high-speed processor, a high-precision clock module, a third low-power consumption Lora module, and a network communication module; The high-speed processor is responsible for controlling the workflow of the data processing device and performing data operations, including: obtaining the received waveform data from the third low-power lora module and performing preliminary processing on the data; performing operations on the voltage and current waveform data to obtain the effective values ​​of the voltage and current; sending a working parameter setting instruction to the voltage sensor and the current sensor through the third low-power lora module to set the sensor delay sending time; sending a sampling trigger instruction to the voltage sensor and the current sensor through the third low-power lora module to start the sensor sampling operation; sending monitoring data and transformer winding deformation judgment result data to the server through the network communication module; reading time from the high-precision clock module for phase information identification and data generation time marking; comparing the solved short-circuit impedance with the standard short-circuit impedance, and considering the influence of the number of impacts, dividing the transformer deformation degree into multiple levels; The high-precision clock module is used to provide high-precision clock information for aligning data acquisition time and improving phase detection accuracy; The third low-power Lora module is used to send and receive Lora signals, including sending the sampling trigger instruction and the working parameter setting instruction of the high-speed processor to the voltage sensor and the current sensor, and receiving the sampling waveform data and the impulse signal data of the voltage sensor and the current sensor; The network communication module provides R485, Ethernet, and 4G network function interfaces to send the winding deformation monitoring results to the server; The client is used to connect to the server and display the real-time monitoring results and alarm information of winding deformation.

2. The transformer winding deformation online monitoring system according to claim 1 is characterized in that: The current sensor also includes a first power supply unit, which includes a power supply coil, a first rectifier circuit, a first filter circuit, and a first voltage stabilizing circuit; the power supply coil is used to obtain energy from the circuit under test; the first rectifier circuit performs full-wave rectification on the alternating current from the power supply coil, and outputs pulsating direct current to the first filter circuit; the first filter circuit performs low-pass filtering on the pulsating direct current to filter out high-frequency interference; the first voltage stabilizing circuit adopts a feedback voltage stabilizing circuit to provide working voltage for the first measuring unit.

3. The transformer winding deformation online monitoring system according to claim 2 is characterized in that: The first analog signal conditioning circuit includes a first sampling circuit, a first bandpass filter, a first amplifier, a first output buffer, a first zero-crossing comparator, and an impact detection circuit; The first sampling circuit samples the induced current from the measuring coil and converts it into a voltage signal; the first bandpass filter filters the voltage signal to remove the DC signal and the high-frequency interference signal; the first amplifier amplifies the signal at a low magnification, and the output signal is connected to the first output buffer, the first zero-crossing comparator, and the impact detection circuit; the first output buffer is used to isolate the front-stage and the back-stage circuits, and the output signal is an analog signal after filtering and amplification, which is provided for analog-to-digital sampling by the first AD conversion circuit; the first zero-crossing comparator is used to capture the zero-crossing point of the signal, and output a digital rising edge / falling edge signal at the zero-crossing point of the signal for detection by the first microprocessor, which is used for phase discrimination and triggering AD sampling; the impact detection circuit is used to detect short-circuit impact current. When a short-circuit impact current occurs, the amplifier output exceeds the threshold, and the impact detection circuit will output a high-level digital signal to trigger an external interrupt of the first microprocessor for further processing by the first microprocessor.

4. The transformer winding deformation online monitoring system according to claim 3 is characterized in that: The voltage sensor includes a voltage input interface, a second power supply unit, and a second measuring unit; The voltage input interface is used to connect the three-phase voltage to be measured; The second power supply unit includes a step-down circuit, a second rectifier circuit, a second filter circuit, and a second voltage stabilizing circuit; the step-down circuit takes a single-phase voltage from a voltage input interface and steps it down to a low voltage; the second rectifier circuit performs full-wave rectification on the AC voltage from the step-down circuit, and outputs a pulsating DC voltage to the second filter circuit; the second filter circuit performs low-pass filtering on the pulsating DC voltage to filter out high-frequency interference; the second voltage stabilizing circuit adopts a feedback voltage stabilizing circuit to provide a working voltage for the second measuring unit; The second measuring unit includes a voltage transformer, a second analog signal conditioning circuit, a second AD conversion circuit, a second microprocessor, and a second low-power consumption Lora module; The voltage transformer is used to sense the voltage of the line to be measured, and the range is adjusted by adjusting the number of turns to be suitable for different voltage levels on the high voltage side, medium voltage side, and low voltage side; The second analog signal conditioning circuit samples and filters the induced voltage from the voltage transformer, amplifies the voltage signal and outputs a zero-crossing signal and an analog output signal; The second AD conversion circuit is used to sample the analog signal from the analog signal conditioning circuit and convert it into a digital signal; The second microprocessor controls the overall operation of the voltage sensor; The second low-power Lora module is used to send and receive Lora signals, send the second microprocessor processing result data to the data processing device through the Lora signal, receive the sampling trigger instruction and working parameter setting instruction sent by the data processing device, and hand them over to the second microprocessor for further processing.

5. The transformer winding deformation online monitoring system according to claim 4 is characterized in that: The second analog signal conditioning circuit includes a second sampling circuit, a second bandpass filter, a second amplifier, a second output buffer, and a second zero-crossing comparator; The second sampling circuit samples the induced voltage from the voltage transformer; the second bandpass filter filters the voltage signal to remove the DC signal and the high-frequency interference signal; the second amplifier amplifies the signal at a low magnification, and the output signal is connected to the second output buffer and the second zero-crossing comparator; the second output buffer is used to isolate the front-stage and the rear-stage circuits, and the output signal is an analog signal after filtering and amplification, which is provided for analog-to-digital sampling by the second AD conversion circuit; the second zero-crossing comparator is used to capture the zero-crossing point of the signal, and output a digital rising edge / falling edge signal at the zero-crossing point of the signal for detection by the second microprocessor, which is used for phase discrimination and triggering AD sampling.

6. The transformer winding deformation online monitoring system according to claim 5, characterized in that: The data processing device also includes a display interaction module, which uses a capacitive touch screen and is used to display the working status of the device, detect data in real time, modify working parameters, and configure working modes.

7. The transformer winding deformation online monitoring system according to claim 6, characterized in that: The server adopts a local server or a cloud server, which is used to store the data uploaded by the data processing device, including transformer voltage and current data, transformer winding deformation judgment results, short-circuit impact times, and provide client remote access services; The server further analyzes the stored historical data of transformer voltage and current, combines the analysis with long-term monitoring data, and issues early warnings on transformer winding deformation trends.

8. The transformer winding deformation online monitoring system according to claim 7, characterized in that: The client has a network access function and runs on common devices and operating systems such as PCs, mobile phones, and industrial computers. It is used to obtain monitoring data from the server and display it in the form of curves and charts.

9. A method for online monitoring of transformer winding deformation, characterized in that: The method is implemented based on the transformer winding deformation online monitoring system according to any one of claims 1 to 8, and the method comprises the following steps: Synchronous sampling of voltage and current: S1, the data processing device sends a sampling trigger instruction by broadcasting; S2. Each sensor receives a sampling trigger instruction at the same time, and starts waveform sampling at the first positive zero crossing of voltage or current, continuously collecting waveform data for 5 cycles; S3, after each sensor completes sampling, it performs a corresponding delay according to its own delayed sending time, and then sends the data; S4, the data processing device successively receives the waveform data of each sensor and marks the receiving time of the waveform data of each sensor; S5. After receiving all sensor data, the data processing device performs time alignment on the data according to the marked data receiving time, the delayed sending time of each sensor, and the inherent delay of system data transmission and reception, obtains waveform data containing phase information, and completes a sampling process; Transformer winding deformation judgment: S1. The high-speed processor calculates the waveform data measured multiple times to obtain multiple sets of voltage and current effective values; S2. Calculate the short-circuit impedance based on multiple sets of voltage and current effective values; S3. Compare the solved short-circuit impedance with the standard short-circuit impedance, and consider the impact of the number of impacts to divide the transformer deformation degree into multiple levels.

10. The method for online monitoring of transformer winding deformation according to claim 9, characterized in that: Before starting sampling, the data processing device sets a delayed sending time for each sensor by sending a working parameter setting instruction. The delayed sending time refers to the time interval from the completion of sampling to the start of data sending. The delayed sending time of each sensor is different, and the minimum interval between them is 20ms to ensure that the data of each sensor is sent. For the monitoring of short-circuit impact current, each current sensor continuously monitors through interruption mode. Once the short-circuit impact current is detected, the short-circuit impact data will be immediately recorded in the sending buffer queue. When the system is idle, the data will be sent to the data processing device, and the data processing device will accumulate and count the number of impacts.

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