KR102548750B1 - Method for Diagnosing Partial Discharge of Transformer and Apparatus therefor - Google Patents

Abstract

Disclosed is a method for diagnosing partial discharge of a transformer and an apparatus therefor.
According to one aspect of the present disclosure, a partial discharge sensor for sensing a partial discharge signal; a voltage waveform measuring unit for indirectly measuring a voltage waveform of a high voltage part of at least one phase of the transformer in a low voltage part of the transformer; a converter for converting the partial discharge signal and the voltage waveform of the high-voltage part for the same time interval into digital signals; A reference voltage waveform of one period and a phase resolved partial discharge (PRPD) distribution for the reference voltage waveform are obtained from the digital signals, and partial discharge of the transformer is generated based on a phase relationship between the reference voltage waveform and the PRPD distribution. Provided is a partial discharge diagnosis device characterized in that it includes a signal processing unit for determining at least one or more of whether or not the partial discharge has occurred.

Description

Method for Diagnosing Partial Discharge of Transformer and Apparatus therefor}

The present disclosure relates to a method for diagnosing partial discharge of a transformer and an apparatus therefor.

The contents described below merely provide background information related to the present embodiment and do not constitute prior art.

Online partial discharge sensors that measure the partial discharge of transformers in operation include electromagnetic wave sensors that measure partial discharge signals propagated from partial discharge sources inside the transformer, such as UHF sensors, or electrical sensors that measure the partial discharge signals of transformers such as frames or enclosures. A high frequency current transformer (HFCT) may be used to measure a partial discharge signal flowing through the ground line connected to the ground line.

However, these partial discharge sensors are not directly connected electrically to the phase that occurs in the partial discharge for the electrical safety of personnel or measuring devices. It is very difficult to determine which phase the measured partial discharge signal is generated with only the discharge sensor. Moreover, even if the partial discharge sensor is electrically connected to each phase separately, the three phases in the transformer are magnetically connected to each other, so that a partial discharge signal generated in one phase can be measured in the other phase. Because of these characteristics, it is very difficult to identify a phase in which partial discharge has occurred in a three-phase transformer only with a partial discharge signal measured through a partial discharge sensor.

In addition, when the noise generated around the transformer shows a pattern similar to the signal pattern of the partial discharge, it is difficult to distinguish whether the measured signal is caused by the partial discharge of the transformer or noise introduced from the outside.

The main object of the present disclosure is to provide a method and apparatus capable of distinguishing a phase in which a partial discharge has occurred in a transformer and/or determining whether or not external noise is introduced.

The problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

According to one aspect of the present disclosure, a partial discharge sensor for sensing a partial discharge signal; a voltage waveform measuring unit for indirectly measuring the voltage of the high voltage part of at least one phase of the transformer in the low voltage part of the transformer; a converter for converting the partial discharge signal and the high-voltage part voltage for the same time interval into digital signals; A reference voltage waveform of one period and a phase resolved partial discharge (PRPD) distribution for the reference voltage waveform are obtained from the digital signals, and partial discharge of the transformer is generated based on a phase relationship between the reference voltage waveform and the PRPD distribution. Provided is a partial discharge diagnosis device characterized in that it includes a signal processing unit for determining at least one or more of whether or not the partial discharge has occurred.

According to another aspect of the present disclosure, a method for diagnosing a partial discharge of a transformer includes sensing a partial discharge signal; indirectly measuring the voltage of the high voltage part of at least one phase of the transformer in the low voltage part of the transformer; converting the partial discharge signal and the high-voltage part voltage for the same time interval into digital signals; obtaining a reference voltage waveform of one cycle and a phase resolved partial discharge (PRPD) distribution for the reference voltage waveform from the digital signals; And based on the phase relationship between the reference voltage waveform and the PRPD distribution, determining at least one or more of whether or not a partial discharge has occurred in the transformer and a partial discharge occurrence phase. do.

According to an embodiment of the present disclosure, it is possible to more economically and efficiently perform partial discharge diagnosis on a transformer, such as recognizing a phase in which a partial discharge has occurred in a transformer or determining whether or not external noise is introduced. Accordingly, by reliably diagnosing the failure of the transformer, it is possible to prevent a power outage due to the failure of the transformer and economic loss to the industry due thereto.

According to an embodiment of the present disclosure, in the case of a three-phase transformer, partial discharge PRPD distribution information for voltage waveforms of all phases can be obtained even when voltage waveforms of one phase are measured. Accordingly, it is possible to diagnose the partial discharge of a three-phase transformer with a device configuration similar to that used in a single-phase transformer, enabling economical manufacturing and use of the device.

According to an embodiment of the present disclosure, since the voltage waveform of the high-voltage part is indirectly measured through the low-voltage part of the transformer, the high withstand voltage required characteristic of the device according to the direct connection of the high-voltage part is unnecessary, and the device can be economically manufactured.

According to an embodiment of the present disclosure, it is possible to expand the scope of the transformer partial discharge diagnosis market by providing an economical and more advanced partial discharge diagnosis technology to the distribution class transformer partial discharge diagnosis market having a large number of units and a low price.

The effects of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

1 is an exemplary diagram schematically illustrating a transformer according to an embodiment of the present disclosure.
2A is a schematic block diagram of a partial discharge diagnosis apparatus according to an embodiment of the present disclosure.
2B is an exemplary diagram illustrating an example in which a partial discharge diagnosis device according to an embodiment of the present disclosure is installed in a three-phase transformer.
3 is an exemplary diagram showing an example of a relationship between a voltage waveform of a partial discharge phase and a partial discharge distribution.
4A is an exemplary view for explaining a voltage phase difference of each phase in a three-phase transformer.
4B is an exemplary diagram showing an example of a relationship between a voltage waveform of each phase of a three-phase transformer and a partial discharge distribution generated in each phase.
5A and 5B are exemplary diagrams showing an example of a relationship between voltage waveforms and partial discharge distributions of phases other than a phase in which partial discharge occurs in a three-phase transformer.
6 is an exemplary view showing a phase relationship between a voltage waveform of a high voltage part and a voltage waveform of a low voltage part of a transformer.
7 is a flowchart illustrating a method for diagnosing partial discharge of a transformer according to an embodiment of the present disclosure.

Hereinafter, some embodiments of the present disclosure are described in detail using exemplary drawings. In adding reference numerals to components of each drawing, it should be noted that the same components have the same numerals as much as possible even if they are displayed on different drawings. In addition, in describing the present disclosure, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present disclosure, the detailed description will be omitted.

In describing the components of the embodiment according to the present disclosure, symbols such as first, second, i), ii), a), and b) may be used. These codes are only for distinguishing the component from other components, and the nature or sequence or order of the corresponding component is not limited by the codes. In the specification, when a part is said to 'include' or 'include' a certain component, it means that it may further include other components, not excluding other components unless explicitly stated otherwise. .

The detailed description set forth below in conjunction with the accompanying drawings is intended to describe exemplary embodiments of the present disclosure, and is not intended to represent the only embodiments in which the present disclosure may be practiced.

1 is an exemplary diagram schematically illustrating a transformer according to an embodiment of the present disclosure.

In general, the winding of the transformer 10 is composed of three phases or single phase, and each phase is composed of a high voltage part and a low voltage part. In order to support and protect the windings, the windings of the transformer are installed in a state clamped to the frame 100 like a molded transformer or installed in an enclosure 120 like an oil-immersed transformer. Here, the frame 100 and the enclosure 120 are made of metal and are electrically connected to the grounding unit 140 through a grounding line.

2A is a schematic block diagram of a partial discharge diagnosis apparatus according to an embodiment of the present disclosure.

2B is an exemplary diagram illustrating an example in which a partial discharge diagnosis device according to an embodiment of the present disclosure is installed in a three-phase transformer.

As shown in FIG. 2A , the partial discharge diagnosis apparatus 20 according to an embodiment of the present disclosure includes a partial discharge sensor 200, a voltage waveform measuring unit 220, a conversion unit 240, a signal processing unit 260, and All or part of the display unit 280 may be included. All blocks shown in FIG. 2A are not essential components, and some blocks included in the partial discharge diagnosis device 20 may be added, changed, or deleted in another embodiment. Meanwhile, the components shown in FIG. 2A represent functionally differentiated functional elements, and at least one component may be implemented in a form integrated with each other in an actual physical environment.

The partial discharge sensor 200 may sense a partial discharge signal generated in the transformer 10 . In one embodiment, the partial discharge sensor 200 may be implemented as a sensor that is not directly electrically connected to the high voltage part and the low voltage part of the transformer 10 . For example, as shown in FIG. 2B , the partial discharge sensor 200 passes through a ground wire electrically connected to the ground portion 140 of the transformer 10 such as the frame 100 or the enclosure 120. It may include a high frequency current transformer 200-1 for measuring a partial discharge signal flowing through the transformer 10 and/or an electromagnetic wave sensor 200-2 for measuring a partial discharge signal propagated from a partial discharge source inside the transformer 10.

The voltage waveform measuring unit 220 may measure the voltage waveform of the high voltage part of the transformer 10 . Measuring the voltage waveform may include acquiring voltage values at a plurality of time points.

As shown in FIG. 2B , the voltage waveform measuring unit 220 according to an embodiment of the present disclosure may be installed in the low voltage part of the transformer 10 and indirectly measure the voltage waveform of the high voltage part. . Meanwhile, FIG. 2B shows an example in which voltage waveform measuring units 220-u, 220-v, and 220-w are installed in the low voltage part of all phases of the three-phase transformer 10, but the present disclosure is limited thereto. It is not. In another embodiment of the present disclosure, the voltage waveform measuring unit 220 may be installed only in a low voltage part of any one of the three phases. At this time, the voltage waveforms for the remaining phases in which the voltage waveform measuring unit 220 is not installed may be obtained through a phase angle shift function to be described later.

Details on how the voltage waveform measurement unit 220 indirectly measures the voltage waveform of the high-voltage unit will be described later with reference to FIG. 6 .

The conversion unit 240 may convert the partial discharge signal and the voltage waveform of the high-voltage unit into digital signals, respectively. The conversion unit 240 may be implemented as a known A/D converter (Analog-to-Digital Converter), but is not limited thereto. The conversion unit 240 may sample and convert the partial discharge signal and voltage waveform input during the same time interval into a digital signal. According to embodiments, the conversion unit 240 may include a storage for storing the converted digital signal.

In some embodiments, the conversion unit 240 may receive only a signal sensed from any one of the high frequency current transformer 200-1 and the electromagnetic wave sensor 200-2 and convert it into a digital signal, but is not limited thereto.

The signal processing unit 260 may process the digital signals transmitted from the conversion unit 240 according to a pre-stored program.

The signal processing unit 260 may obtain a reference voltage waveform of one period and a phase resolved partial discharge (PRPD) distribution for the reference voltage waveform from the digital signals. The signal processing unit 260 may obtain a reference voltage waveform of one period and a PRPD distribution for the reference voltage waveform by using a known PRPD analysis algorithm.

In one embodiment, when the voltage waveform measurement unit 220 is provided separately for each phase, the signal processing unit 260 obtains a reference voltage waveform for each phase by using a digital signal converted from the voltage waveform of each phase Alternatively, the PRPD distribution for the reference voltage waveform of each phase may be obtained.

In another embodiment, when the voltage waveform measuring unit 220 is provided only in one phase, the signal processing unit 260 moves the phase angle of the reference voltage waveform to generate a virtual voltage waveform for another phase and/or Alternatively, the PRPD distribution for a virtual voltage waveform can be obtained. For example, the signal processor 260 may generate a first virtual voltage waveform by shifting the phase angle of the reference voltage waveform by 120 degrees, and generate a second virtual voltage waveform by shifting the phase angle of the reference voltage waveform by 240 degrees. there is.

The signal processor 260 may diagnose the partial discharge of the transformer 10 based on the phase relationship between the reference voltage waveform(s) and/or the virtual voltage waveform(s) and the PRPD distribution. In one embodiment, when the PRPD distribution according to the voltage phase of a predetermined reference voltage waveform has a predefined distribution, the signal processing unit 260 determines a phase corresponding to the reference voltage waveform as a partial discharge generating phase. can do. For example, the signal processing unit 260 determines that the PRPD distribution is a first region within a predefined range from the point where the phase angle of the reference voltage waveform is 0 degrees and a second region within a predefined range from the point where the phase angle of the reference voltage waveform is 180 degrees. When located in area 2, the phase obtained by measuring the voltage waveform of the high-voltage part corresponding to the reference voltage waveform can be determined as the phase in which partial discharge occurs, but it is not limited to this example, and the phase in which partial discharge is distributed based on the voltage phase The range and its specific form of distribution may vary depending on the embodiment. In another embodiment, the signal processor 260 determines which voltage waveform among the reference voltage waveform, the first virtual voltage waveform, and the second virtual voltage waveform has a predefined phase relationship with the PRPD distribution, the transformer 10 ) among the three phases, the phase in which partial discharge occurred can be identified. On the other hand, when there is no voltage waveform having a predefined phase relationship with the PRPD distribution among the reference voltage waveform, the first virtual voltage waveform, and the second virtual voltage waveform, the signal processing unit 260 performs the partial discharge sensor 200 It may be determined that the noise introduced from the outside has been sensed.

A detailed description of a method for diagnosing partial discharge based on the phase relationship between the voltage waveform and the PRPD distribution by the signal processing unit 260 will be described later with reference to FIGS. 3 to 6 .

The display unit 280 may visually provide the result processed by the signal processing unit 260 to the user. For example, the display unit 280 displays a reference voltage waveform, a virtual voltage waveform, a PRPD distribution, a result of determining whether a partial discharge has occurred in the transformer 10, and/or a result of determining a partial discharge phase on a graphic user interface. can be displayed.

Hereinafter, referring to FIGS. 3 to 6, the signal processing unit 260 recognizes a phase in which partial discharge has occurred in the transformer 10 based on the phase relationship between the voltage waveform and the partial discharge PRPD distribution and/or whether or not external noise is introduced. Describe how to determine

3 is an exemplary diagram showing an example of a relationship between a voltage waveform of a partial discharge phase and a partial discharge distribution.

3 shows the distribution of the partial discharge signal 32 with respect to the voltage waveform 30 of one cycle. Assuming that the partial discharge is normally measured, the partial discharge signal 32 is mainly distributed in a portion where the voltage rises from around 0 and a portion where the voltage falls. The pattern of the partial discharge signal 32 distributed according to the voltage waveform 30 is called PRPD (Phase Resolved Partial Discharge).

4A is an exemplary view for explaining a voltage phase difference of each phase in a three-phase transformer.

4B is an exemplary diagram showing an example of a relationship between a voltage waveform of each phase of a three-phase transformer and a partial discharge distribution generated in each phase.

Figure 4a shows the voltage waveform 400 of the U phase, the voltage waveform 420 of the V phase, and the voltage waveform 440 of the W phase, respectively. ), regions 422 and 424 where the signal of the partial discharge generated in the V phase is mainly distributed, and regions 442 and 444 where the signal of the partial discharge generated in the W phase is mainly distributed.

As shown in FIG. 4A, the voltage waveforms 400, 420, and 440 of each phase in the three-phase transformer 10 have a phase difference of 120 degrees, and as shown in FIG. 4B, distribution areas of partial discharge signals generated in each phase It also has a phase difference of 120 degrees.

Therefore, when the voltage waveform of each phase and the partial discharge distribution for one cycle voltage waveform are simultaneously measured and compared, it is possible to identify in which phase the partial discharge has occurred.

In addition, as described above, since the voltage waveforms of each phase have a phase angle difference of 120 degrees, only one phase is measured, and the voltage waveforms for the other two phases are software phase angles of 120 degrees and 240 degrees in the signal processing unit 260. It can be obtained by moving

5A and 5B are exemplary diagrams showing an example of a relationship between voltage waveforms and partial discharge distributions of phases other than a phase in which partial discharge occurs in a three-phase transformer.

In FIG. 5A , it can be confirmed that the partial discharge signal 52 is not distributed from the vicinity of the phase of the voltage 50 to 0, but is distributed near the highest and/or lowest voltage. This is the relationship between the voltage waveform 400 of the U phase shown in FIG. 4B and the distribution areas 442 and 444 of the partial discharge signal generated in the W phase, and the voltage waveform 420 of the V phase and the distribution area of the partial discharge signal generated in the U phase. It can be seen that the relationship between 402 and 404 and/or the relationship between the voltage waveform 440 of the W phase and the distribution area 422 and 424 of the partial discharge signal generated in the V phase is similar.

In FIG. 5B , it can be confirmed that the partial discharge signal 56 appears long before the magnitude of the voltage 54 becomes zero. This is the relationship between the voltage waveform 400 of the U phase shown in FIG. 4B and the distribution areas 422 and 424 of the partial discharge signal generated in the V phase, and the distribution area of the partial discharge signal generated in the W phase and the voltage waveform 420 of the V phase. It can be seen that the relationship between 442 and 444 and/or the relationship between the voltage waveform 440 of the W phase and the distribution area 402 and 404 of the partial discharge signal generated in the U phase is similar.

Based on the phase relationship between the partial discharge distribution and the voltage waveform, the partial discharge diagnosis device 20 simultaneously measures the voltage waveform and partial discharge of at least one phase and compares and analyzes the partial discharge PRPD distribution for the voltage waveform. The phase where partial discharge has occurred can be found. For example, when a voltage waveform of one cycle in any one phase (hereinafter referred to as reference phase) and a PRPD distribution thereof have a shape similar to that of FIG. 3 , it may be determined that partial discharge has occurred on the reference phase. As another example, when the voltage waveform of one period on the reference phase and the PRPD distribution thereof have a form similar to that of FIG. 5A or 5B, it may be determined that partial discharge has occurred on a phase other than the reference phase. In this case, since which of the three phases is the reference phase is known in advance, the phase in which the partial discharge has occurred may be identified according to which form of the voltage waveform of one cycle and the PRPD distribution thereof is similar to that of FIG. 5A or 5B.

Meanwhile, in an actual electric system, external noise similar to the PRPD distribution of the transformer 10 may flow through the electric line of the transformer 10 or may exist spatially around the transformer 10 . Such external noise may be detected by a partial discharge sensor installed in the transformer 10 . Since the external noise at this time is measured regardless of the voltage waveform of the transformer 10, when the voltage waveform and the PRPD distribution are compared, an abnormal shape outside the shape shown in FIG. 4B is shown.

As such, the signal processing unit 260 according to the present disclosure can not only check the phase in which the partial discharge has occurred from the comparison of the voltage waveform and the PRPD distribution, but also determine whether the measured signal is due to the partial discharge generated in the transformer 10 or It is possible to distinguish whether it is caused by external noise.

Next, referring to FIG. 6 , a method of measuring a voltage waveform of a high voltage part of a transformer according to an embodiment of the present disclosure will be described.

6 is an exemplary view showing a phase relationship between a voltage waveform of a high voltage part and a voltage waveform of a low voltage part of a transformer.

Partial discharge in the transformer 10 mainly occurs in a high-voltage section where a relatively high voltage is applied rather than in a low-voltage section. In order to determine a phase in which partial discharge has occurred in the high voltage part of the transformer 10 or a partial discharge phenomenon such as checking external noise, it is most preferable to simultaneously measure the PRPD for the voltage waveform of the high voltage part. However, in order to directly measure the voltage of the high-voltage part, the voltage measuring device must have sufficiently high withstand voltage characteristics to withstand the high voltage, so the price is very high and the size is very large.

In order to solve this problem, the present disclosure proposes a method of using the voltage waveform of the low voltage part of the transformer 10 to replace the voltage waveform of the high voltage part.

6 is a waveform diagram in which a high-voltage part voltage waveform 600 and a low-voltage part voltage waveform 610 of the transformer 10 are superimposed in different voltage units. As shown in FIG. 6 , it can be seen that the phases of the voltage waveform 600 of the high voltage part and the voltage waveform 610 of the low voltage part of the transformer 10 are substantially coincident. That is, in terms of electrical engineering, the voltage waveform 600 of the high voltage part and the voltage waveform 610 of the low voltage part of the transformer 10 coincide.

Due to this, the voltage waveform measurement unit 220 according to an embodiment of the present disclosure may indirectly measure the voltage waveform of the high voltage unit in the voltage unit of the transformer 10, and the signal processing unit 260 may measure the voltage of the high voltage unit. In comparing the waveform and the PRPD distribution, the voltage waveform of the low voltage part can be used instead of the voltage waveform of the high voltage part.

Meanwhile, the conversion unit 240 generally has a lower input voltage range than the low voltage unit of the transformer 10 . If this input voltage range is exceeded, the output of the conversion unit 240 is saturated, making it impossible to accurately measure the voltage waveform, and elements constituting the conversion unit 240 may be destroyed. In order to prevent this problem, the voltage waveform measurement unit 220 may reduce the voltage of the low voltage part of the transformer 10 to a level that can be converted by the conversion unit 240 . To this end, the voltage waveform measurement unit 220 may include a transformer or voltage divider for generating low voltage.

7 is a flowchart illustrating a method for diagnosing partial discharge of a transformer according to an embodiment of the present disclosure.

Since the method shown in FIG. 7 can be performed by at least one of the partial discharge diagnosis apparatus 20 and/or its components, detailed descriptions thereof will be omitted.

The partial discharge diagnosis apparatus 20 may sense the partial discharge signal (S700). For example, the partial discharge diagnosis device 20 includes an electromagnetic wave sensor 200-2 that measures a partial discharge signal propagated from a partial discharge source inside the transformer 10 and/or a grounding unit 140 of the transformer 10. The partial discharge signal may be sensed using the high frequency current transformer 200-1 that measures the partial discharge signal flowing through the ground line by penetrating the ground line electrically connected to the ground line, but is not limited thereto.

The partial discharge diagnosis apparatus 20 may indirectly measure the voltage waveform of the high voltage part of at least one phase of the transformer 10 in the low voltage part of the transformer 10 (S720). For example, the partial discharge diagnosis apparatus 20 may measure the voltage waveform of the low voltage part on one reference selected from the three phases of the transformer 10 as the voltage waveform of the high voltage part. As another example, the partial discharge diagnosis device 20 may measure the voltage waveform of the low voltage part of each phase of the transformer 10 as the voltage waveform of the high voltage part. The partial discharge diagnosis device 20 may convert the voltage of the low voltage part of the transformer 10 into a voltage within a predefined voltage range. Here, the predefined voltage range may be, for example, an input allowable range of an A/D converter included in the partial discharge diagnosis device 20 . To this end, the partial discharge diagnosis device 20 may include a low voltage generating transformer and/or a voltage divider, but is not limited thereto.

The partial discharge diagnosis apparatus 20 may convert the partial discharge signal and the high-voltage part voltage waveform for the same time period into digital signals (S740).

The partial discharge diagnosis apparatus 20 may obtain a reference voltage waveform of one cycle and a PRPD distribution for the reference voltage waveform from the converted digital signals (S760).

Based on the phase relationship between the reference voltage waveform and the PRPD distribution, the partial discharge diagnosis apparatus 20 may determine at least one of whether partial discharge occurs in the transformer 10 and at least one of partial discharge occurrence phases (S780).

The partial discharge diagnosis apparatus 20 may additionally perform a process of providing the determination result to the user. For example, the partial discharge diagnosis apparatus 20 displays the reference voltage waveform, the PRPD distribution, the determination result on whether or not the partial discharge has occurred in the transformer 10, and the determination result on the occurrence phase of the partial discharge on a graphic user interface. can

Meanwhile, in the above, the case where the partial discharge diagnosis device 20 according to an embodiment of the present disclosure is installed in the three-phase transformer 10 has been described as an example, but the technical idea of the present disclosure diagnoses partial discharge in a single-phase transformer. It should be noted that it can be applied without changing the actual technical idea even in the case of For example, the partial discharge diagnosis device 20 senses a partial discharge signal using a partial discharge sensor, indirectly measures a voltage waveform of a high voltage part in a low voltage part of a single-phase transformer, and measures the partial discharge signal and the high voltage part for the same time period. Each voltage waveform is converted into a digital signal, a reference voltage waveform of one cycle and a PRPD distribution for the reference voltage waveform are obtained from the digital signals, and the partial discharge signal is converted to a single-phase transformer based on the phase relationship between the reference voltage waveform and the PRPD distribution. It can be determined whether it is caused by partial discharge or noise introduced from the outside.

Each component of the apparatus or method according to the present invention may be implemented as hardware or software, or a combination of hardware and software. Also, the function of each component may be implemented as software, and the microprocessor may be implemented to execute the software function corresponding to each component.

Various implementations of the systems and techniques described herein may include digital electronic circuits, integrated circuits, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), computer hardware, firmware, software, and/or their can be realized in combination. These various implementations may include being implemented as one or more computer programs executable on a programmable system. A programmable system includes at least one programmable processor (which may be a special purpose processor) coupled to receive data and instructions from and transmit data and instructions to a storage system, at least one input device, and at least one output device. or may be a general-purpose processor). Computer programs (also known as programs, software, software applications or code) contain instructions for a programmable processor and are stored on a "computer readable medium".

A computer-readable recording medium includes all types of recording devices in which data that can be read by a computer system is stored. These computer-readable recording media include non-volatile or non-transitory media such as ROM, CD-ROM, magnetic tape, floppy disk, memory card, hard disk, magneto-optical disk, and storage device. It may be a medium, and may further include a transitory medium such as a data transmission medium. Also, computer-readable recording media may be distributed in computer systems connected through a network, and computer-readable codes may be stored and executed in a distributed manner.

In the flow chart/timing diagram of the present specification, it is described that each process is sequentially executed, but this is merely an example of the technical idea of one embodiment of the present disclosure. In other words, those skilled in the art to which an embodiment of the present disclosure belongs may change and execute the order described in the flowchart/timing diagram within the range that does not deviate from the essential characteristics of the embodiment of the present disclosure, or one of each process Since the above process can be applied by performing various modifications and variations in parallel, the flow chart/timing chart is not limited to a time-series sequence.

The above description is merely an example of the technical idea of the present embodiment, and various modifications and variations can be made to those skilled in the art without departing from the essential characteristics of the present embodiment. Therefore, the present embodiments are not intended to limit the technical idea of the present embodiment, but to explain, and the scope of the technical idea of the present embodiment is not limited by these embodiments. The scope of protection of this embodiment should be construed according to the claims below, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of rights of this embodiment.

10: transformer 100: frame
120: enclosure 140: ground
20: partial discharge diagnosis device

Claims (9)

a partial discharge sensor for sensing a partial discharge signal;
a voltage waveform measuring unit for indirectly measuring a voltage waveform of a high voltage part of at least one phase of the transformer in a low voltage part of the transformer;
a converter for converting the high-voltage part voltage waveform measured at a plurality of points in time into a digital signal and converting the partial discharge signal sensed at the same points in time as the high-voltage part voltage waveform into a digital signal;
A reference voltage waveform of one period and a phase resolved partial discharge (PRPD) distribution for the reference voltage waveform are obtained using the partial discharge signal converted to the digital signal and the high-voltage part voltage waveform converted to the digital signal, and the reference voltage A signal processing unit for determining whether or not partial discharge has occurred in the transformer and at least one of partial discharge occurrence phases based on a phase relationship between a waveform and the PRPD distribution;
The voltage waveform measuring unit is provided in the low voltage part of at least one phase of the transformer, and measures the voltage waveform of the low voltage part of the at least one phase as a voltage waveform of the high voltage part of the corresponding phase,
The signal processing unit obtains a voltage waveform of one cycle for each phase of the transformer, and among the voltage waveforms of one cycle for each phase, a voltage waveform having a predefined phase relationship with the PRPD distribution does not exist. case, it is characterized in that it is determined that the partial discharge sensor has sensed the noise introduced from the outside. According to claim 1,
The signal processing unit, when the PRPD distribution according to the voltage phase of the reference voltage waveform has a distribution of a predefined form, the phase obtained by measuring the voltage waveform of the high-voltage part corresponding to the reference voltage waveform as a partial discharge occurrence phase. Partial discharge diagnostic device, characterized in that for determining. According to claim 1,
The voltage waveform measuring unit,
It is provided only in the low voltage part on one reference selected from among the three phases of the transformer, and measures the voltage waveform of the low voltage part on the reference as the voltage waveform of the high voltage part,
The signal processing unit,
A first virtual voltage waveform obtained by shifting the phase angle of the reference voltage waveform by 120 degrees and a second virtual voltage waveform obtained by shifting the phase angle of the reference voltage waveform by 240 degrees are generated for the remaining phases not provided with the voltage waveform measurement unit. Obtained as a voltage waveform of one cycle,
Based on whether any one of the reference voltage waveform, the first virtual voltage waveform, and the second virtual voltage waveform has a predefined phase relationship with the PRPD distribution, the phase in which partial discharge occurred among the three phases of the transformer Partial discharge diagnostic device, characterized in that for identifying. According to claim 3,
The signal processing unit,
When there is no voltage waveform having a predefined phase relationship with the PRPD distribution among the reference voltage waveform, the first virtual voltage waveform, and the second virtual voltage waveform, the partial discharge sensor has noise introduced from the outside. Partial discharge diagnosis apparatus, characterized in that it is determined by sensing. delete According to claim 1,
The voltage waveform measuring unit,
Including a transformer or voltage divider for generating low voltage,
The partial discharge diagnosis device according to claim 1 , wherein the low voltage generating transformer or the voltage divider reduces the voltage of the low voltage part of the transformer to a voltage within an input allowable range of the conversion part and applies the voltage to the conversion part. According to claim 1,
The conversion unit,
A partial discharge sensor of any one of an electromagnetic wave sensor that measures a partial discharge signal propagated from a partial discharge source inside the transformer and a high-frequency current transformer that measures a partial discharge signal flowing through a ground wire that passes through a ground wire electrically connected to a grounding part of the transformer. Characterized in that only the signal sensed from the received signal is converted into a digital signal, the partial discharge diagnosis device. According to claim 1,
A display unit for displaying the reference voltage waveform, the PRPD distribution, the determination result on whether or not the partial discharge has occurred in the transformer, and the determination result on the occurrence phase of the partial discharge on a graphic user interface.
Characterized in that it further comprises, partial discharge diagnostic device. As a method for diagnosing partial discharge of a transformer,
A process of sensing a partial discharge signal;
indirectly measuring a voltage waveform of a high voltage part of at least one phase of the transformer in a low voltage part of the transformer;
converting the high-voltage part voltage waveform measured at a plurality of points in time into a digital signal, and converting the partial discharge signal sensed at the same points in time as the high-voltage part voltage waveform into a digital signal;
Acquiring a reference voltage waveform of one period and a phase resolved partial discharge (PRPD) distribution for the reference voltage waveform by using the partial discharge signal converted to the digital signal and the high-voltage voltage waveform converted to the digital signal; and
Based on the phase relationship between the reference voltage waveform and the PRPD distribution, determining at least one of whether partial discharge occurs in the transformer and a partial discharge phase,
The measuring process includes measuring the voltage waveform of the low voltage part of the at least one phase as a voltage waveform of the high voltage part of the corresponding phase using a voltage waveform measuring unit provided in the low voltage part of the at least one phase of the transformer,
The obtaining step includes acquiring a voltage waveform of one cycle for each phase of the transformer,
In the determining process, a voltage waveform of one cycle for each phase of the transformer is obtained, and among the voltage waveforms of one cycle for each phase, a voltage waveform having a predefined phase relationship with the PRPD distribution does not exist. If not, determining that noise introduced from the outside has been sensed in the sensing process.

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