Transformer winding deformation on-line broadband monitoring device

Abstract

The utility model discloses a transformer winding deformation on-line broadband monitoring device, in the device, a signal generation module injects excitation signals to a three-phase winding of a transformer to be detected through three Rogowski coils respectively, and a signal acquisition module acquires a mixed response signal through a Rogowski coil; the control module performs analog-to-digital conversion and filtering processing to obtain response data of each phase of winding, and the control module controls the frequency band of the excitation signal injected into the three-phase winding of the tested transformer by the signal generation module to be matched with the filtering processing mode of the signal acquisition module so as to obtain the response data of the three-phase winding of the tested transformer; therefore, the transformer winding deformation monitoring system not only can accurately monitor the deformation condition of the transformer winding on line, but also can wirelessly transmit the monitored data related to the deformation of the transformer winding to a background data analysis system, thereby facilitating timely diagnosis and maintenance of possible faults of the transformer winding.

Description

Technical Field

[0001] The utility model relates to the technical field of transformer fault monitoring, in particular to an online broadband monitoring device for transformer winding deformation. Background Art

[0002] According to statistics from the High Voltage Research Institute of China Electric Power Research Institute: accidents directly related to windings of 110kV and above transformers nationwide account for 55.6% of the total number of transformer accidents, and the damage accident rate is nearly 0.3% per year on average. With the construction of large-scale power grids, equipment has entered the aging and maintenance stage, and the accident rate has further increased.

[0003] At present, there is a lack of sensitive and reliable online monitoring methods for winding deformation, which may affect the maintenance decision of the transformer. The degree of deformation of the transformer winding is related to the energy of the short-circuit impact. If the impact energy reaches one-fourth of the transformer's tolerance, 3-5 times may cause the transformer to be shut down for maintenance or returned to the factory for repair. In order to reduce the degree of damage, avoid unplanned power outages, reduce unexpected power outages, and better arrange maintenance schedules, real-time monitoring of transformer windings is particularly important to ensure that the transformer maintains high reliability and stability during use. Utility Model Content

[0004] The purpose of the utility model is to provide an online broadband monitoring device for transformer winding deformation, which can accurately monitor the transformer winding deformation status online and output the monitored transformer winding deformation-related data, so as to facilitate operation and maintenance personnel or background data analysis systems to diagnose and repair possible transformer winding faults in a timely manner.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0006] An online broadband monitoring device for transformer winding deformation includes: a signal generating module, four Rogowski coils, a signal acquisition module, a control module and a wireless transmission module; wherein:

[0007] The signal generating module is connected to the three Rogowski coils respectively, so as to inject corresponding excitation signals into the three-phase windings of the transformer under test respectively through the three Rogowski coils;

[0008] The signal acquisition module is connected to one of the Rogowski coils to obtain, through the Rogowski coil, a mixed response signal generated by an excitation signal passing through the three-phase winding of the transformer under test; and the signal acquisition module is configured to perform analog-to-digital conversion processing on the mixed response signal to obtain a digital signal corresponding to the mixed response signal; and filter the digital signal corresponding to the mixed response signal to obtain response data corresponding to each phase winding of the transformer under test;

[0009] The control module is connected to the signal generating module, the signal acquisition module and the wireless transmission module respectively, and is configured to control the signal generating module to inject the corresponding frequency bands of the excitation signals into the three-phase windings of the transformer under test respectively, and control the signal acquisition module to perform adaptive filtering on the mixed response signal according to the frequency bands of the excitation signals; and receive the response data corresponding to each phase winding output by the signal acquisition module, and transmit the response data of the three-phase windings of the transformer under test to the background data analysis system through the wireless transmission module.

[0010] According to a specific implementation, in the transformer winding deformation online broadband monitoring device provided by the utility model, the signal generating module includes at least three signal sources; and the control module is configured to control the three signal sources to respectively output excitation signals of different frequency bands.

[0011] According to a specific implementation, in the online broadband monitoring device for transformer winding deformation provided by the utility model, the signal acquisition module includes a high-speed analog-to-digital converter and an FPGA; wherein the high-speed analog-to-digital converter is used to convert the mixed response signal into a digital signal; the FPGA is respectively connected to the high-speed analog-to-digital converter and the control module to perform adaptive filtering processing on the digital signal corresponding to the mixed response signal.

[0012] According to a specific implementation, in the transformer winding deformation online broadband monitoring device provided by the utility model, the FPGA is configured to include: at least three digital filtering links; wherein each of the digital filtering links is configured to include: at least one low-pass filter, at least one high-pass filter and at least one switch unit; and the control module is configured to control the switch unit of the FPGA to switch the adapted digital filtering link to filter the digital signal corresponding to the mixed response signal according to the frequency band of the excitation signal output by each signal source.

[0013] According to a specific implementation, in the transformer winding deformation online broadband monitoring device provided by the utility model, the FPGA is configured to include: a FIFO memory; and the FPGA is configured to cache the digital signal corresponding to the mixed response signal into the FIFO memory.

[0014] According to a specific implementation, in the online broadband monitoring device for transformer winding deformation provided by the utility model, the FPGA is configured to include: an IRIG-B code decoding unit; and the FPGA is configured to obtain timing information through the IRIG-B code decoding unit after obtaining an external input IRIG-B encoded signal through a TTL interface, and generate a timestamp of the digital signal corresponding to the mixed response signal based on the obtained timing information.

[0015] According to a specific implementation, in the transformer winding deformation online broadband monitoring device provided by the utility model, the high-speed analog-to-digital converter is a high-speed analog-to-digital converter with a sampling rate not less than 10Msps; the FPGA adopts a Spartan6 series FPGA chip.

[0016] According to a specific implementation, in the online broadband monitoring device for transformer winding deformation provided by the utility model, the control module includes: a microprocessor and a DRAM memory; wherein the microprocessor is respectively connected to the FPGA and the wireless transmission module to process the response data corresponding to each phase winding output by the FPGA into the transmission data of the wireless transmission module; the microprocessor is configured to store the response data corresponding to each phase winding output by the FPGA into the DRAM memory.

[0017] According to a specific implementation, in the transformer winding deformation online broadband monitoring device provided by the utility model, a signal conditioning module is further arranged between the signal acquisition module and the Rogowski coil; wherein the signal conditioning module comprises: a bandpass filter and a proportional-integral operational amplifier, and the mixed response signal is sequentially filtered by the bandpass filter and integratedly amplified by the proportional-integral operational amplifier and then output to the high-speed analog-to-digital converter.

[0018] According to a specific implementation, the transformer winding deformation online broadband monitoring device provided by the utility model also includes a power supply module for providing direct current to the signal generating module, the signal acquisition module, the control module and the wireless transmission module respectively.

[0019] In summary, due to the adoption of the above technical solution, the beneficial effects of the utility model are:

[0020] The utility model discloses an online broadband monitoring device for transformer winding deformation. The signal generating module injects excitation signals into the three-phase windings of the transformer under test respectively through three Rogowski coils. The signal acquisition module obtains the mixed response signal through one Rogowski coil, and obtains the response data of each phase winding after analog-to-digital conversion and filtering processing. The control module controls the frequency band of the excitation signal injected into the three-phase winding of the transformer under test by the signal generating module to adapt to the filtering processing mode of the signal acquisition module, so as to obtain the response data of the three-phase winding of the transformer under test. Therefore, the utility model can not only accurately monitor the deformation status of the transformer winding online, but also can wirelessly transmit the monitored data related to the deformation of the transformer winding to the background data analysis system, so as to facilitate the timely diagnosis and maintenance of possible faults of the transformer winding. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the utility model;

[0022] Figure 2 It is a structural schematic diagram of the signal acquisition module in the utility model;

[0023] Figure 3 It is a structural schematic diagram of the control module in the utility model;

[0024] Figure 4 It is a structural schematic diagram of an implementation mode of the utility model;

[0025] Figure 5 It is a structural schematic diagram of the signal conditioning module in the utility model. DETAILED DESCRIPTION

[0026] The utility model is described in detail below in conjunction with the accompanying drawings.

[0027] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0028] like Figure 1 As shown, the transformer winding deformation online broadband monitoring device of the utility model comprises: a signal generating module, four Rogowski coils 101-104, a signal acquisition module, a control module and a wireless transmission module; wherein,

[0029] The signal generating modules are connected to the Rogowski coils 101-103 respectively, and the Rogowski coils 101-103 are respectively sleeved on the A-phase bushing, the B-phase bushing and the C-phase bushing of the transformer, so as to respectively inject corresponding excitation signals into the three-phase windings of the transformer under test through the Rogowski coils 101-103;

[0030] The signal acquisition module is connected to the Rogowski coil 104, which is sleeved on the neutral point bushing, so as to obtain the mixed response signal generated by the excitation signal passing through the three-phase winding of the transformer under test through the Rogowski coil 104; and the signal acquisition module is configured to perform analog-to-digital conversion processing on the mixed response signal to obtain a digital signal corresponding to the mixed response signal; and filter the digital signal corresponding to the mixed response signal to obtain response data corresponding to each phase winding of the transformer under test;

[0031] The control module is connected to the signal generating module, the signal acquisition module and the wireless transmission module respectively, and is configured to control the signal generating module to inject the corresponding frequency bands of the excitation signals into the three-phase windings of the transformer under test respectively, and control the signal acquisition module to perform adaptive filtering on the mixed response signal according to the frequency bands of the excitation signals; and receive the response data corresponding to each phase winding output by the signal acquisition module, and transmit the response data of the three-phase windings of the transformer under test to the background data analysis system through the wireless transmission module.

[0032] The transformer winding deformation online broadband monitoring device provided by the utility model is suitable for the application scenario of detecting transformer winding deformation by frequency response analysis method; as is known to all, the specific principle of the frequency response analysis method is: under the action of a higher frequency voltage, each winding of the transformer can be regarded as a passive linear two-port network composed of distributed parameters such as linear resistance, inductance (mutual inductance), and capacitance, and its internal characteristics can be described by a transfer function; if the winding is deformed, the distributed inductance, capacitance and other parameters inside the winding will inevitably change, resulting in changes in the zero and pole of its equivalent network transfer function, and changes in the frequency response characteristics of the network; therefore, by collecting the port characteristic parameters at both ends of the winding, such as the frequency response curves of the input and output impedance and the voltage and current transfer ratio, and further analyzing the frequency spectrum characteristics of the port characteristic parameters, that is, by longitudinal or transverse comparison, according to the difference in the amplitude-frequency response characteristics, the possible winding deformation of the transformer is judged. However, the frequency response analysis method is widely used in offline testing. Due to the limitations of offline detection, it cannot reflect the real state of the transformer during operation; at the same time, since most transformers in the power system are three-phase windings, it is necessary to collect the response data of the three-phase windings of the transformer at the same time.

[0033] Specifically, in the online broadband monitoring device for transformer winding deformation provided by the utility model, the signal generating module includes at least three signal sources; and the control module is configured to control the three signal sources to respectively output excitation signals of different frequency bands; in this way, it can be avoided that the response signals generated between the three-phase windings interact with each other and affect the subsequent winding deformation detection sensitivity. For example, taking the commonly used excitation signal frequency of 1kHz to 1MHz and the resolution of 1kHz as an example, 1kHz to 1000kHz is divided into at least three fixed frequency bands, taking the three fixed frequency bands as an example, a low frequency band of 1 to 333kHz, a medium frequency band of 333 to 666kHz, and a high frequency band of 666 to 1000kHz; considering that the frequency of the excitation signal injected by the signal source through the Rogowski coil gradually increases, in the startup phase, the three signal sources are started in sequence, that is, when the excitation signal injected through the Rogowski coil 101 enters the medium frequency band from the low frequency band after the first signal source is started, the second signal source is started, and when the excitation signal injected through the Rogowski coil 102 enters the medium frequency band from the low frequency band after the second signal source is started, the third signal source is started, and the injection of the excitation signal is repeated in this way. In this way, the control module can control the three different signal sources to output excitation signals of different frequency bands respectively.

[0034] Specifically, Figure 2 and Figure 3 As shown, in the online broadband monitoring device for transformer winding deformation provided by the utility model, the signal acquisition module includes a high-speed analog-to-digital converter and an FPGA; wherein the high-speed analog-to-digital converter is used to convert the mixed response signal into a digital signal; the FPGA is respectively connected to the high-speed analog-to-digital converter and the control module to perform adaptive filtering processing on the digital signal corresponding to the mixed response signal.

[0035] During implementation, in the online broadband monitoring device for transformer winding deformation provided by the utility model, the FPGA is configured to include: at least three digital filtering links; wherein each of the digital filtering links is configured to include: at least one low-pass filter, at least one high-pass filter and at least one switch unit; and the control module is configured to control the switch unit of the FPGA to switch the adapted digital filtering link to filter the digital signal corresponding to the mixed response signal according to the frequency band of the excitation signal output by each signal source.

[0036] In fact, the number of digital filter links configured in the FPGA is adapted to the number of frequency bands into which the excitation signal is divided, that is, the passband function of different frequency bands of the excitation signal is realized through the digital filter link. To realize specific logic functions in the FPGA, it is necessary to implement it through the wiring programming of logic blocks, connection blocks and switch blocks.

[0037] Still taking the example of dividing 1kHz~1000kHz into three fixed frequency bands, three digital filtering links are required. The first digital filtering link extracts the digital signal of the low frequency band 1~333kHz from the digital signal, the second digital filtering link extracts the digital signal of the medium frequency band 333~666kHz from the digital signal, and the third digital filtering link extracts the digital signal of the high frequency band 666~1000kHz from the digital signal; at this time, the control module can directly select the three digital filtering links at the same time by controlling the switch unit of the FPGA, and only needs to determine the corresponding relationship between the response data output by each digital filtering link and the transformer winding according to the frequency band of the excitation signal output by each signal source; if the number of frequency bands divided by the excitation signal is greater than three, the control module needs to select the corresponding three digital filtering links for filtering processing according to the frequency band of the excitation signal output by each signal source. In this way, through the filtering processing of different digital filtering links, the response signal generated by each phase winding of the tested transformer according to its injected excitation signal can be extracted from the mixed response signal; therefore, the utility model can not only realize the online deformation monitoring of the three-phase winding of the transformer at the same time, but also avoid the interaction between the response signals generated between the three-phase windings, which affects the subsequent winding deformation detection sensitivity.

[0038] In order to ensure more accurate analysis of transformer winding deformation, the sampling rate of the mixed response signal can be appropriately increased, that is, the sampling rate of the high-speed analog-to-digital converter can be increased; however, as the sampling rate of the high-speed analog-to-digital converter increases, the digital signals it converts are also more. Therefore, in the transformer winding deformation online broadband monitoring device provided by the utility model, the FPGA is configured to include: a FIFO memory; and the FPGA is configured to cache the digital signal corresponding to the mixed response signal into the FIFO memory; by increasing the FIFO memory, the efficiency of subsequent digital filtering processing can be guaranteed to avoid loss of response data.

[0039] Specifically, in the transformer winding deformation online broadband monitoring device provided by the utility model, the FPGA is configured to include: an IRIG-B code decoding unit; and the FPGA is configured to obtain the external input IRIG-B coded signal through the TTL interface, obtain the timing information through the IRIG-B code decoding unit, and generate the timestamp of the digital signal corresponding to the mixed response signal according to the obtained timing information. In the above manner, it is possible to achieve time synchronization with other devices or systems in the power system, such as the background data analysis system, the power dispatching system, etc.

[0040] During implementation, in the transformer winding deformation online broadband monitoring device provided by the utility model, the high-speed analog-to-digital converter is a high-speed analog-to-digital converter with a sampling rate not less than 10Msps; the FPGA adopts a Spartan6 series FPGA chip.

[0041] like Figure 3 As shown, in the online broadband monitoring device for transformer winding deformation provided by the utility model, the control module includes: a microprocessor and a DRAM memory; wherein the microprocessor is respectively connected to the FPGA and the wireless transmission module to process the response data corresponding to each phase winding output by the FPGA into the transmission data of the wireless transmission module; the microprocessor is configured to store the response data corresponding to each phase winding output by the FPGA into the DRAM memory.

[0042] Specifically, the transformer winding deformation online broadband monitoring device provided by the utility model also includes a power supply module, which is used to provide direct current to the signal generation module, the signal acquisition module, the control module and the wireless transmission module respectively. During implementation, the power supply module can use external alternating current, through a wide voltage input range AC / DC switching power supply, support direct current power supply, and can complete the conversion of high voltage of AC: 85~264V or DC: 88~370V into a direct current voltage output of 5V.

[0043] like Figure 4 and Figure 5 As shown, in the transformer winding deformation online broadband monitoring device provided by the utility model, a signal conditioning module is also provided between the signal acquisition module and the Rogowski coil; wherein, the signal conditioning module comprises: a bandpass filter and a proportional integral operational amplifier, and the mixed response signal is sequentially filtered by the bandpass filter and integrated and amplified by the proportional integral operational amplifier before being output to the high-speed analog-to-digital converter. In this way, the noise outside the frequency range of the excitation signal can be removed by setting the bandpass filter, and the proportional integral operational amplifier is provided because the output voltage of the Rogowski coil is proportional to the differential of the measured current, and as long as the output passes through the integrator, an output voltage proportional to the primary current can be obtained.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An online broadband monitoring device for transformer winding deformation, characterized in that: include: Signal generation module, four Rogowski coils, signal acquisition module, control module and wireless transmission module; among them, The signal generating module is connected to the three Rogowski coils respectively, so as to inject corresponding excitation signals into the three-phase windings of the transformer under test respectively through the three Rogowski coils; The signal acquisition module is connected to one of the Rogowski coils to obtain, through the Rogowski coil, a mixed response signal generated by an excitation signal passing through the three-phase winding of the transformer under test; and the signal acquisition module is configured to perform analog-to-digital conversion processing on the mixed response signal to obtain a digital signal corresponding to the mixed response signal; and filter the digital signal corresponding to the mixed response signal to obtain response data corresponding to each phase winding of the transformer under test; The control module is connected to the signal generating module, the signal acquisition module and the wireless transmission module respectively, and is configured to control the signal generating module to inject the corresponding frequency bands of the excitation signals into the three-phase windings of the transformer under test respectively, and control the signal acquisition module to perform adaptive filtering on the mixed response signal according to the frequency bands of the excitation signals; and receive the response data corresponding to each phase winding output by the signal acquisition module, and transmit the response data of the three-phase windings of the transformer under test to the background data analysis system through the wireless transmission module.

2. The on-line broadband monitoring device for transformer winding deformation according to claim 1, characterized in that: The signal generating module comprises at least three signal sources; and the control module is configured to control the three signal sources to respectively output excitation signals of different frequency bands.

3. The transformer winding deformation online broadband monitoring device according to claim 2, characterized in that: The signal acquisition module includes a high-speed analog-to-digital converter and an FPGA; wherein the high-speed analog-to-digital converter is used to convert the mixed response signal into a digital signal; the FPGA is connected to the high-speed analog-to-digital converter and the control module respectively to perform adaptive filtering processing on the digital signal corresponding to the mixed response signal.

4. The on-line broadband monitoring device for transformer winding deformation according to claim 3, characterized in that: The FPGA is configured to include: at least three digital filtering links; wherein each of the digital filtering links is configured to include: at least one low-pass filter, at least one high-pass filter and at least one switch unit; and the control module is configured to control the switch unit of the FPGA to switch the adapted digital filtering link to filter the digital signal corresponding to the mixed response signal according to the frequency band of the excitation signal output by each signal source.

5. The on-line broadband monitoring device for transformer winding deformation according to claim 4, characterized in that: The FPGA is configured to include: a FIFO memory; and the FPGA is configured to cache the digital signal corresponding to the mixed response signal in the FIFO memory.

6. The on-line broadband monitoring device for transformer winding deformation according to claim 5, characterized in that: The FPGA is configured to include: an IRIG-B code decoding unit; and the FPGA is configured to obtain timing information through the IRIG-B code decoding unit after obtaining an externally input IRIG-B encoded signal through a TTL interface, and generate a timestamp of a digital signal corresponding to the mixed response signal based on the obtained timing information.

7. The on-line broadband monitoring device for transformer winding deformation according to claim 6, characterized in that: The high-speed analog-to-digital converter is a high-speed analog-to-digital converter with a sampling rate of not less than 50Msps; the FPGA adopts a Spartan6 series FPGA chip.

8. The on-line broadband monitoring device for transformer winding deformation according to claim 7, characterized in that: The control module includes: a microprocessor and a DRAM memory; wherein the microprocessor is connected to the FPGA and the wireless transmission module respectively to process the response data corresponding to each phase winding output by the FPGA into the transmission data of the wireless transmission module; the microprocessor is configured to store the response data corresponding to each phase winding output by the FPGA into the DRAM memory.

9. The on-line broadband monitoring device for transformer winding deformation according to claim 8, characterized in that: A signal conditioning module is also provided between the signal acquisition module and the Rogowski coil; wherein the signal conditioning module comprises: a bandpass filter and a proportional-integral operational amplifier, and the mixed response signal is sequentially filtered by the bandpass filter and integratedly amplified by the proportional-integral operational amplifier before being output to the high-speed analog-to-digital converter.

10. The on-line broadband monitoring device for transformer winding deformation according to claim 9, characterized in that: It also includes a power supply module for providing direct current to the signal generating module, the signal collecting module, the control module and the wireless transmission module respectively.

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