Transformer iron core grounding multi-dimensional current signal fusion sensing system and method

Abstract

In the system, a broadband current sensor is connected with a transformer iron core grounding wire to measure a multi-dimensional current signal flowing through the transformer iron core grounding wire so as to obtain an output voltage signal; and the upper computer carries out calculation based on the output voltage signal to obtain a time domain waveform and amplitude-frequency characteristics of the multi-dimensional current signal so as to carry out fault detection. According to the system, comprehensive fault detection is carried out on the transformer by measuring the grounding current of the iron core of the transformer and utilizing multi-scale frequency spectrum and amplitude information.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer detection, and in particular to a transformer core grounding multi-dimensional current signal fusion sensing system and method. Background Art

[0002] There are stray capacitors between the transformer windings and the core. Most of the AC signals on the windings can be coupled to the core through these capacitors to form multi-dimensional current signals, and finally flow into the earth through the core grounding wire. The multi-dimensional current signal not only includes the power frequency (and its harmonic current) on the core grounding wire, but also includes a variety of other high-frequency pulse signals, such as partial discharge pulses coupled on the grounding wire by internal partial discharge, impulse pulses coupled by external operation, lightning impulse pulses, etc. By extracting broadband signals at the core, the transformer core grounding multi-dimensional current signal fusion perception can be performed to achieve transformer fault monitoring.

[0003] At present, low-frequency current sensors are mainly used to monitor the core grounding current of the transformer during steady-state operation to determine whether there is a multi-point grounding fault in the transformer core. However, since the frequency band of the current sensor is too low, it cannot present the full picture of the multi-dimensional current signal on the transformer core grounding wire, and therefore cannot realize fault monitoring of the transformer under operation / lightning impulse voltage and high-frequency partial discharge.

[0004] The information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0005] In view of the shortcomings or defects of the above-mentioned prior art, a transformer core grounding multi-dimensional current signal fusion sensing system and method are provided, which measures the transformer core grounding current and uses multi-scale spectrum and amplitude information to perform comprehensive fault detection on the transformer.

[0006] The purpose of the present invention is achieved through the following technical solutions.

[0007] A transformer core grounding multi-dimensional current signal fusion sensing system includes:

[0008] The broadband current sensor is connected to the transformer core ground wire to measure the multi-dimensional current signal flowing through it to obtain the output voltage signal.

[0009] The host computer calculates the time domain waveform and amplitude-frequency characteristics of the multi-dimensional current signal based on the output voltage signal to perform fault detection.

[0010] The transformer core grounding multi-dimensional current signal fusion sensing system also includes a back-end data processing module, which is connected to the broadband current sensor and the host computer to upload the output voltage signal to the host computer.

[0011] In the transformer core grounding multi-dimensional current signal fusion perception system, the back-end data processing module includes a filter.

[0012] In the transformer core grounding multi-dimensional current signal fusion sensing system, the output voltage signal includes an output voltage waveform U(t).

[0013] In the transformer core grounding multi-dimensional current signal fusion sensing system, the host computer obtains the current waveform I(t) of the multi-dimensional current signal based on the output voltage waveform U(t).

[0014] In the transformer core grounding multi-dimensional current signal fusion sensing system, the host computer obtains the amplitude-frequency characteristic I(w) based on the current waveform I(t).

[0015] In the transformer core grounding multi-dimensional current signal fusion sensing system, the host computer includes a central processing unit.

[0016] The processing method of the transformer core grounding multi-dimensional current signal fusion sensing system includes the following steps:

[0017] Step 1, placing a broadband current sensor on the transformer core grounding wire;

[0018] Step 2, measuring and obtaining the output voltage waveform U(t) of the broadband current sensor;

[0019] Step 3, the voltage waveform U(t) is uploaded to the host computer via the back-end data processing module;

[0020] Step 4, the host computer calculates the current waveform I (t) of the multi-dimensional current signal passing through the transformer core grounding wire;

[0021] Step 5, calculating the amplitude-frequency characteristic I(w) of the current waveform I(t);

[0022] Step 6: Obtain transformer fault information based on the current waveform I(t) and the amplitude-frequency characteristic I(w).

[0023] In the processing method, the back-end data processing module uploads the voltage waveform U(t) for filtering.

[0024] In the processing method, based on the current waveform I(t) and the amplitude-frequency characteristic I(w), the leakage current under the steady-state operating voltage, the impulse current under the operation / lightning impulse, and the high-frequency partial discharge current signal are distinguished to determine the transformer fault.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention collects the multi-dimensional current signal of the transformer core grounding, and uploads it to the host computer after being processed by the back-end data processing module. There are stray capacitors between the transformer winding and the core. Most of the AC signals on the winding can be coupled to the core through these capacitors to form a multi-dimensional current signal, and finally flow into the earth through the core grounding wire. The system uses a broadband current sensor to collect the multi-dimensional current signal on the transformer core grounding wire, uploads the output signal of the broadband current sensor to the host computer software, extracts signals of different frequency bands and different amplitudes, distinguishes the leakage current under the steady-state operating voltage, the impact current under the operation / lightning impact, and the high-frequency partial discharge current signal, and uses the time domain and spectrum information of the multi-dimensional current signal to perform comprehensive fault detection on the transformer.

[0027] The above description is only an overview of the technical solution of the present invention. In order to make the technical means of the present invention clearer and to achieve the extent that those skilled in the art can implement it according to the contents of the specification, and in order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are exemplified below. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] By reading the detailed description of the preferred specific embodiments below, various other advantages and benefits of the present invention will become clear to those of ordinary skill in the art. The drawings in the specification are only for the purpose of illustrating the preferred embodiments and are not considered to be limitations of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative work. Moreover, the same reference numerals are used to represent the same components throughout the drawings.

[0029] In the attached picture:

[0030] Figure 1 This is the system structure diagram of this application;

[0031] Figure 2 This is a schematic diagram of the application system usage process;

[0032] Figure 3 A schematic diagram of a broadband current sensor in the system structure of the present application;

[0033] Figure 4 A schematic diagram of a back-end data processing module in the system structure of this application;

[0034] Figure 5This is a schematic diagram of the upper computer processing data in the system structure of this application.

[0035] The present invention is further explained below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0036] The specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the specific embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0037] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present invention, but the description is based on the general principles of the specification and is not intended to limit the scope of the present invention. The scope of protection of the present invention shall be determined by the attached claims.

[0038] To facilitate understanding of the embodiments of the present invention, several specific embodiments will be further explained below with reference to the accompanying drawings, and each of the accompanying drawings does not constitute a limitation on the embodiments of the present invention.

[0039] For a better understanding, Figures 1 to 5 As shown, a transformer core grounding multi-dimensional current signal fusion sensing system includes:

[0040] The broadband current sensor is connected to the transformer core ground wire to measure the multi-dimensional current signal flowing through it to obtain the output voltage signal.

[0041] The host computer calculates the time domain waveform and amplitude-frequency characteristics of the multi-dimensional current signal based on the output voltage signal to perform fault detection.

[0042] In a preferred embodiment of the transformer core grounding multi-dimensional current signal fusion sensing system, it also includes a back-end data processing module, which is connected to the broadband current sensor and the host computer to upload the output voltage signal to the host computer.

[0043] In a preferred embodiment of the transformer core grounding multi-dimensional current signal fusion sensing system, the back-end data processing module includes a filter.

[0044] In a preferred embodiment of the transformer core grounding multi-dimensional current signal fusion sensing system, the output voltage signal includes an output voltage waveform U(t).

[0045] In a preferred embodiment of the transformer core grounding multi-dimensional current signal fusion sensing system, the host computer obtains the current waveform I(t) of the multi-dimensional current signal based on the output voltage waveform U(t).

[0046] In a preferred embodiment of the transformer core grounding multi-dimensional current signal fusion sensing system, the host computer obtains the amplitude-frequency characteristic I(w) based on the current waveform I(t).

[0047] In a preferred embodiment of the transformer core grounding multi-dimensional current signal fusion sensing system, the host computer includes a central processing unit.

[0048] The processing method of the transformer core grounding multi-dimensional current signal fusion sensing system includes the following steps:

[0049] Step 1, placing a broadband current sensor on the transformer core grounding wire;

[0050] Step 2, measuring and obtaining the output voltage waveform U(t) of the broadband current sensor;

[0051] Step 3, the voltage waveform U(t) is uploaded to the host computer via the back-end data processing module;

[0052] Step 4, the host computer calculates the current waveform I (t) of the multi-dimensional current signal passing through the transformer core grounding wire;

[0053] Step 5, calculating the amplitude-frequency characteristic I(w) of the current waveform I(t);

[0054] Step 6: Obtain transformer fault information based on the current waveform I(t) and the amplitude-frequency characteristic I(w).

[0055] In a preferred implementation of the processing method, the back-end data processing module uploads the voltage waveform U(t) for filtering.

[0056] In a preferred embodiment of the processing method, the leakage current under the steady-state operating voltage, the impulse current under the operation / lightning impulse, and the high-frequency partial discharge current signal are distinguished based on the current waveform I(t) and the amplitude-frequency characteristic I(w) to determine the transformer fault.

[0057] In one embodiment, see Figure 1 A transformer core grounding multi-dimensional current signal fusion sensing system is provided, the system comprising a broadband current sensor, a back-end data processing module and a host computer.

[0058] See also Figure 2 A use process of a transformer core grounding multi-dimensional current signal fusion sensing system,

[0059] First, place a broadband current sensor on the transformer core ground wire;

[0060] Furthermore, the output voltage waveform U(t) of the broadband current sensor is measured;

[0061] Furthermore, the voltage waveform U(t) is uploaded to the host computer software by the back-end data processing module;

[0062] Further, the multi-dimensional current signal waveform I(t) passing through the transformer core grounding wire is calculated;

[0063] Further, the amplitude-frequency characteristic I(w) of the current waveform I(t) is calculated;

[0064] Furthermore, the fault information of the transformer is calculated by combining the I(t) and I(w) data of the current waveform.

[0065] like Figures 3 to 5 As shown, a broadband current sensor is used to measure the multi-dimensional current signal flowing through the transformer core grounding wire. The output voltage signal of the broadband current sensor is uploaded to the host computer through the back-end data processing module. The time domain waveform and amplitude-frequency characteristics of the multi-dimensional current signal are calculated, and the time domain and frequency spectrum information of the multi-dimensional current signal are used to perform comprehensive fault detection on the transformer.

[0066] The amplitude ranges and spectrum distribution characteristics of the three types of currents are different. The current waveform I(t) and amplitude-frequency characteristics I(w) can be used to determine whether the transformer has core multi-point grounding, lightning / operation overvoltage, and partial discharge faults, thereby achieving the purpose of fault detection. Multi-scale means that the amplitude ranges and spectrum distribution characteristics of the three types of current signals are different. The system realizes multi-scale fusion perception in amplitude range and multi-scale spectrum distribution. The amplitude ranges and spectrum distribution characteristics of the three types of currents are different. For example, taking a certain transformer as an example, the leakage current amplitude range under the steady-state operating voltage is 1mA~10A, and the spectrum distribution range is 50Hz~2.5kHz; the impulse current amplitude range under the operation / lightning impulse is 1A~2kA, and the spectrum distribution range is 10kHz~400kHz; the high-frequency partial discharge current amplitude range is 1mA~1A, and the spectrum distribution range is 1MHz~30MHz.

[0067] Therefore, when the amplitude and / or spectral distribution of the transformer's multi-dimensional current signal exceeds: 1) the leakage current amplitude range and / or its spectral distribution range under the steady-state operating voltage; 2) the impulse current amplitude range and / or its spectral distribution range under operation / lightning impulse; 3) the high-frequency partial discharge current amplitude range and / or its spectral distribution range; it is judged that the corresponding fault has occurred.

[0068] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0069] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A transformer core grounding multi-dimensional current signal fusion sensing system, characterized in that: These include, The broadband current sensor is connected to the transformer core ground wire to measure the multi-dimensional current signal flowing through it to obtain the output voltage signal. The host computer calculates the time domain waveform and amplitude-frequency characteristics of the multi-dimensional current signal based on the output voltage signal to perform fault detection.

2. The transformer core grounding multi-dimensional current signal fusion sensing system according to claim 1, characterized in that: Preferably, it also includes a back-end data processing module, which is connected to the broadband current sensor and a host computer to upload the output voltage signal to the host computer.

3. The transformer core grounding multi-dimensional current signal fusion sensing system according to claim 2, characterized in that: The back-end data processing module includes a filter.

4. The transformer core grounding multi-dimensional current signal fusion sensing system according to claim 1, characterized in that: The output voltage signal includes an output voltage waveform U(t).

5. The transformer core grounding multi-dimensional current signal fusion sensing system according to claim 4, characterized in that: The host computer obtains the current waveform I(t) of the multi-dimensional current signal based on the output voltage waveform U(t).

6. The transformer core grounding multi-dimensional current signal fusion sensing system according to claim 5, characterized in that: The host computer obtains the amplitude-frequency characteristic I(w) based on the current waveform I(t).

7. The transformer core grounding multi-dimensional current signal fusion sensing system according to claim 1, characterized in that: The host computer includes a central processing unit.

8. A processing method for a transformer core grounding multi-dimensional current signal fusion sensing system according to any one of claims 1 to 7.

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