KR102231150B1 - Bushing diagnostic system - Google Patents

Abstract

The present invention provides a bushing diagnosis system, which comprises: a bushing monitoring signal acquisition block for receiving a monitoring signal from an external bushing monitoring device; a signal processing block for separating a current signal of a power frequency band and a current signal of a high frequency band of a degradation discharge signal from the received monitoring signal; and a diagnostic block for analyzing the current signal of the power frequency band to determine whether a transformer current is leaking, and linking the current signal of the high frequency band with nearby partial discharge diagnostic information to diagnose whether the bushing is defective and the degree of defection.

Description

Bushing diagnostic system {BUSHING DIAGNOSTIC SYSTEM}

The present invention relates to a bushing monitoring device and system capable of diagnosing deterioration or insulation damage of a bushing provided in a transformer, and in particular, to a bushing monitoring system that accurately diagnoses the type of damage by analyzing signals in low and high frequency bands. About.

The importance of electric energy cannot be overemphasized, so today electric energy is widely used in various industrial fields. Such electrical energy is produced and transported through a system called the Electric Power System.

Electric energy produced in various types of power plants is delivered to distribution facilities through high-voltage transmission facilities and substations, and the distribution facilities serve to supply the received electrical energy back to each customer. The customer is supplied from the distribution facility through the distribution line.

Various electric devices are used by using electric energy. A plurality of transformers for transformation/insulation are disposed in the power transmission facility, substation, distribution facility, and distribution line described above.

Transformer fires at power companies have been frequent recently, and one of the causes is poor insulation of the transformer bushing. In general, transformers, circuit breakers, motors, etc. that transmit or generate power using AC power must have the insulation performance determined according to the voltage used, and failures due to short circuits and ground faults occur when the insulation performance is deteriorated.

Insulation deterioration of a transmission and substation device means that the basic properties of an insulating material for electrical isolation between a phase conductor and a ground (or between other conductors) deteriorate due to certain factors. In particular, when various insulating materials inside the power transformer are deteriorated and the deteriorated insulating material is mechanically damaged by shocks such as surge, vibration, and external short circuits, the transformer is burnt by contacting between windings and between windings and cores.

The insulating oil is contaminated by the heat generated inside the transformer, and the strength of the insulating material is deteriorated, resulting in an abnormal voltage such as surge, shock such as earthquake, vibration, or electromagnetic force in the event of an external short circuit. In the end, insulation breakdown occurs inside the transformer due to short-circuit, contact between the winding and the core, and the contact between the winding and the enclosure.

In general, methods for analyzing the insulation state of a transformer bushing include a tan delta analysis method, which measures the total leakage current, measures the size of the resistive current component, and analyzes the measured current and reactive component current, and a partial discharge diagnosis method. .

On the other hand, a switchgear that connects or separates a transmission line and a distribution line in a substation, in particular, a partial discharge occurs when a gas insulated switchgear and a transformer are damaged.

The partial discharge causes a high frequency of a specific frequency.In the transmission/distribution management/monitoring system, partial discharge detection sensors capable of detecting the high frequency are arranged at multiple locations of the system switchgear and transformer, and the sensing signal received from them is analyzed. To monitor the entire system.

However, the prior art partial discharge diagnosis system only detects the occurrence of an abnormality in the vicinity of the detection sensor, and it is not possible to know whether the bushing is deteriorated, and the conventional bushing diagnosis method is a separate equipment and system from the partial discharge diagnosis system of the prior art. It became a factor of wasting cost by configuring it.

Republic of Korea Registered Gazette No. 10-1126291

An object of the present invention is to provide a bushing diagnostic system capable of accurately detecting a deterioration state of a bushing.

An object of the present invention is to provide a bushing diagnosis system that is easy to integrate with a partial discharge monitoring system.

Bushing monitoring apparatus according to an aspect of the present invention, a low-frequency sensing unit for sensing a current signal in a power frequency band while surrounding the power line passing through the bushing; A high-frequency sensing unit that surrounds the power line passing through the bushing and detects a current signal in a high-frequency band of the deterioration discharge signal; A collection unit for collecting signals sensed by the low-frequency sensing unit and the high-frequency sensing unit and transmitting them to an external server; And a power line communication unit for forming a data communication channel using the external server and the power line.

A bushing diagnostic system according to another aspect of the present invention includes: a bushing monitoring signal acquisition block for receiving a monitoring signal from an external bushing monitoring device; A signal processing block for separating a current signal in a power frequency band and a current signal in a high frequency band of the deterioration discharge signal from the received monitoring signal; And a diagnostic block that analyzes the current signal in the power frequency band to determine whether a transformer current leaks, and diagnoses whether or not a bushing is defective by linking the current signal in the high frequency band with nearby partial discharge diagnostic information. have.

Here, the bushing monitoring signal acquisition block includes: a signal separation unit for separating a current signal in the power frequency band and a current signal in the high frequency band; A signal acquisition unit for receiving the separated current signal in the power frequency band and the current signal in the high frequency band; And a digital signal conversion unit that samples the current signal in the power frequency band and the current signal in the high frequency band and converts it into a digital signal.

Here, the signal processing block includes: a sampling signal receiving unit for receiving signals received from the bushing monitoring signal acquisition block for each type; A phase difference calculator that calculates a phase difference of leakage power from the received signal; And a PRPD/PRPS analyzer for generating and analyzing a PRPD/PRPS signal from the high-frequency current signal.

Here, the sampling signal receiving unit includes: an RF spectrum output unit for receiving a sampling signal for the current signal in the high frequency band and outputting an RF spectrum signal; And a band selector for filtering a frequency band to generate a PRPD/PRPS signal by selecting a measurement frequency band from the RF spectrum signal.

Here, the diagnostic block includes: a diagnostic data linking unit that acquires partial discharge information from an external comprehensive diagnostic system; A defect determination unit determining a defect of a bushing from the PRPD/PRPS signal and the partial discharge information; A power factor calculator that calculates a transformer-related capacitance and a power factor from the calculated phase difference; A leakage size analyzer for analyzing a voltage/current degree of a leakage current from the current signal; And a comparison unit comparing the transformer-related capacitance, power factor, and leakage current magnitude with a reference value.

Here, the diagnostic block includes: analyzing the bushing partial discharge signal spectrum and selecting a measurement frequency band; Acquiring PRPD/PRPS data, discharge signal magnitude and frequency of occurrence data for the selected frequency band; Comparing the obtained PRPD/PRPS data pattern with a pattern for bushing defects and partial discharges recorded in a standard library; If it is determined as noise as a result of the two pattern comparison, notifying that it is noise; Checking whether it is similar to a defect pattern that is uniquely generated only in the transformer except for the bushing if it is not noise; Comparing the size and frequency of occurrence of the signal pattern from the bushing with the size and frequency of occurrence of the signal pattern from the transformer if it is not similar to the transformer-specific defect pattern; Alarming a bushing defect if the size and frequency of occurrence are larger on the bushing side; If the size and frequency of occurrence are larger on the transformer side or similar to the transformer-specific defect pattern, transmitting the corresponding defect information to an external transformer diagnosis system; And when the response to the transmission is received, reflecting the contents of the received response to the standard library.

According to another aspect of the present invention, a method for diagnosing a bushing includes: collecting a sensing signal from an electromagnetic wave detection sensor installed in the bushing: separating a power frequency band signal from the collected electromagnetic wave sensing signal; Extracting frequency and phase information from the collected electromagnetic wave sensing signal; Comparing the frequency phase information with pre-stored frequency phase information in case of an accident or frequency phase information provided from the outside; Determining whether or not a transformer is coupled based on a degree of similarity between the two frequency phase information to be compared; And determining a current leakage failure of the bushing when the magnitude of the separated power frequency band signal exceeds a predetermined reference value.

If the bushing diagnosis system and the bushing diagnosis method of the present invention having the above-described configuration are implemented, there is an advantage of accurately detecting the deterioration state of the bushing.

The bushing diagnosis system of the present invention has an advantage in that it is easy to link a service with a partial discharge monitoring system or a substation comprehensive preventive diagnosis system when the bushing diagnosis method is performed.

1 is a block diagram showing a bushing diagnostic apparatus of a simple structure that is inserted into a bushing tab and detects an electrical signal.
2 is a perspective view showing a bushing monitoring device capable of simultaneously sensing a low frequency band signal and a high frequency band signal according to the idea of the present invention.
Figure 3 is a block diagram showing an embodiment of a transformer bushing diagnostic system using the bushing monitoring device of Figure 2;
4 is an example of a change in a PRPD pattern according to a defect deterioration, and patterns showing a creepage discharge defect.
FIG. 5 is a flowchart illustrating a bushing precision diagnosis method using RF signal information that may be performed in the diagnosis block of FIG. 3.
6 is a flowchart illustrating a bushing diagnosis method using a signal detected by a bushing monitoring device capable of simultaneously detecting a low-frequency band signal and a high-frequency band signal according to the spirit of the present invention.
7 is a screen block diagram showing an embodiment of an HMI screen capable of notifying a user (administrator) of a state of a bushing.
Figure 8 is a block diagram showing another embodiment of a transformer bushing diagnostic system using the bushing monitoring device of Figure 2;
9 is a screen block diagram showing an embodiment of an HMI screen when a wideband measurement method is used in the transformer bushing diagnosis system of FIG. 8.

In describing the present invention, terms such as first and second may be used to describe various elements, but the elements may not be limited by terms. The terms are only for the purpose of distinguishing one component from another component. For example, without departing from the scope of the present invention, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

When a component is connected to or is referred to as being connected to another component, it can be understood that it is directly connected to or may be connected to the other component, but other components may exist in the middle. .

The terms used in the present specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions may include plural expressions unless the context clearly indicates otherwise.

In the present specification, terms such as include or include are intended to designate the presence of features, numbers, steps, actions, components, parts, or a combination thereof described in the specification, and one or more other features or numbers, It may be understood that the possibility of the presence or addition of steps, actions, components, parts, or combinations thereof, is not preliminarily excluded.

In addition, shapes and sizes of elements in the drawings may be exaggerated for clearer explanation.

The bushing diagnosis apparatus of a simple structure that is inserted into the bushing tab and detects an electrical signal is constructed as shown in FIG. 1. The illustrated bushing diagnosis apparatus is largely divided into a diagnosis unit 910 and an HMI support unit 920, and the diagnosis unit 910 includes a signal acquisition unit, a signal analysis unit, and a diagnosis unit.

In the bushing diagnosis method using the illustrated bushing diagnosis device, it is possible to diagnose the general condition of the bushing, but precise diagnosis such as the degree of insulation deterioration and the occurrence of defects inside the bushing is impossible. Surveillance is impossible. Particularly, since there is a risk that a bushing accident due to insulation breakdown may spread to a serious accident accompanied by a fire, failure prevention through real-time precise diagnosis is essential, and the difficulty in monitoring for this deteriorates practicality.

In addition, the illustrated bushing partial discharge diagnosis is a method of storing discharge energy in a capacitor and measuring the energy level, and the measurement frequency band is about several kHz. This is a band that shares a frequency domain with external noise such as general radio signals, mobile phones, and radios. There are many problems when acquiring actual signals. Without noise reduction measures, it is impossible to measure partial discharges due to normal deterioration, thereby reducing durability and practicality.

In addition, the discharge signal measurement of the illustrated method is extremely vulnerable to noise.

For measuring the discharge signal, instead of the conventional bushing tap adapter, which is extremely vulnerable to noise, the present invention proposes a high frequency band measurement method using a high frequency current transformer (HFCT) sensor.

Then, the influence of external noise can be reduced, and the effect of noise can be minimized by adding a narrow-band measurement function capable of measuring a very small internal deterioration discharge through frequency spectrum analysis and selection of a specific frequency band.

However, since a typical CT sensor for measuring leakage current is specialized in obtaining a leakage current of 60 Hz, it is impossible to obtain a current signal in the HF (1 MHz) band. Therefore, since it is impossible to measure the deterioration discharge signal, a CT sensor having a different turn ratio than the conventional one is preferable.

2 shows a bushing monitoring device capable of simultaneously sensing a low-frequency band signal and a high-frequency band signal according to the inventive concept.

The illustrated bushing monitoring device may be installed in a continuous form on the transformer bushing tab in a form in which the power line 10 of the transformer is mounted therein.

The illustrated bushing monitoring device includes: a low frequency sensing unit 120 surrounding the power line 10 passing through the bushing and sensing a current signal in a power frequency band; A high frequency sensing unit 110 surrounding the power line 10 passing through the bushing and sensing a current signal in a high frequency band of the deterioration discharge signal; A collection unit 160 for collecting signals sensed by the low-frequency sensing unit 120 and the high-frequency sensing unit 110 and transmitting them to an external server; And a power line communication unit 190 for forming a data communication channel using the external server and the power line 10.

The signal acquisition method of the bushing monitoring device shown is a method of simultaneously acquiring a leakage current signal of 60 Hz component and a deterioration discharge signal detectable in HF (High Frequency) component of 1 MHz or higher from the leakage current generated inside the bushing. We present a kind of multi-stage sensor capable of acquiring and measuring discharge signals.

Bushing diagnosis is divided into insulation error check and internal precision diagnosis step, and insulation error is checked through calculation values (leakage current, capacitance, power factor) using the voltage and current of the existing fundamental wave (60Hz) component. Diagnosis is a diagnosis of the degree of deterioration through analysis of the magnitude of the deterioration discharge signal, determination of the type of defect through the Phase Resolved PD Analysis at aging signal, and the location of the fault in conjunction with the transformer partial discharge diagnosis function of the substation comprehensive prevention diagnosis system. It is done through estimation.

The illustrated bushing monitoring device includes a low-frequency sensing unit 120 and a high-frequency sensing unit 110 to simultaneously detect a fundamental wave component signal and the deterioration discharge signal.

For example, the illustrated bushing monitoring device has a dual structure of cores having different turns ratios inside a single CT sensor, so that signals in the 60Hz band and 1MHz band can be acquired only with the leakage current signal generated from the bushing. Core type CT sensor can be applied. The sensor can be installed in a form surrounding the transformer lead power line 10 in a way that is built into the bushing tap adapter or built into the bushing precision diagnosis device.

The low-frequency sensing unit 120 and the high-frequency sensing unit 110 may be connected to the collection unit 160 through different lines, respectively, or may be connected to the collection unit 160 through a single line in a state in which they are connected in series or in parallel with each other. have. In the latter case, although the structure is simpler, the difference between the frequency bands of the signals sensed by the low-frequency sensing unit 120 and the high-frequency sensing unit 110 is clear, so it is easy to separate the two signals.

The power line communication unit 190 is in various ways using a power line, such as a type of loading a high-frequency communication signal on the power line itself, a type of loading a communication signal on an electromagnetic wave shielding layer of a power line, a type of loading a communication signal on a ground line of a power line, etc. Can be implemented.

3 is a block diagram illustrating an embodiment of a transformer bushing diagnosis system using the bushing monitoring device of FIG. 2.

The illustrated transformer bushing diagnostic system includes: a bushing monitoring signal acquisition block 100 for receiving a monitoring signal from an external bushing monitoring device; A signal processing block 200 for separating a current signal in a power frequency band and a current signal in a high frequency band of the deterioration discharge signal from the received monitoring signal; And a diagnostic block 300 that analyzes the current signal in the power frequency band to determine whether a transformer current leaks, and diagnoses whether the bushing is defective and the degree by linking the current signal in the high frequency band with nearby partial discharge diagnostic information. Can include.

The bushing monitoring signal acquisition block 100 transfers current and voltage data transmitted from the dual-core CT sensors 110 and 120 of the bushing to the A/D converter 164 to perform a sampling process. After acquiring a 60Hz leakage current component and a partial discharge signal of 1MHz or more through the dual-core CT sensors 110 and 120 and separating them by using a signal separation unit 140 such as a filter, the signal acquisition unit 162 is A/ In addition to transmitting the measured value to the D converter 164, the voltage measured at the PT: Power Transformer terminal is acquired, and the measured value is also transmitted to the A/D converter 164. The A/D converter 164 samples and digitizes an input physical signal and transmits a value to the signal processing block 200.

Specifically, the bushing monitoring signal acquisition block 100 includes: a signal separation unit 140 for separating a high-frequency signal and a low-frequency signal by means of an analog band-pass filter or the like; A signal acquisition unit (162) for receiving the high-frequency signal and the low-frequency signal; A digital signal conversion unit (A/D converter) 164 for converting the high-frequency signal and the low-frequency signal into a digital signal may be provided.

Depending on the implementation, the bushing monitoring signal acquisition block 100 may further include a voltage signal receiving unit 180 for acquiring a voltage measured at a power transformer (PT) terminal. The voltage measured at the terminal of the instrument transformer (PT: Power Transformer) is generally similar to the three-phase system voltage.

The signal separation unit 140 may be further divided into a low pass filter 144 for acquiring the low frequency analog signal and an RF band (1 MHz to 500 MHz) pass filter 142 for acquiring the high frequency analog signal.

The signal processing block 200 serves to process the received data into diagnostic data, and may be largely divided into a leakage current signal processing part and a partial discharge signal processing part.

The leakage current signal processing part calculates a phase difference by using the received data, and transmits the leakage current and voltage magnitude and phase information to the diagnosis block 300.

The partial discharge signal processing part is a spectrum analysis module for measuring the spectrum of the deteriorated discharge signal, and the RF spectrum output unit 212 and frequency tuning (tuning) that can measure the partial discharge signal in a narrow band by selecting a specific frequency band. A band selector 213 may be provided as a module.

Specifically, the signal processing block 200 includes: a sampling signal receiving unit (not shown) for receiving signals received from the bushing monitoring signal acquisition block for each type; A phase difference calculation unit 220 for calculating a phase difference between the system power (ie, leakage power) from the voltage signal and the current signal; A noise removing unit 230 providing a reference signal for removing noise; A PRPD/PRPS analysis unit 240 for generating and analyzing a PRPD/PRPS signal from the RF signal may be provided.

Here, the sampling signal receiver includes: an RF signal receiver for receiving an RF signal detected by the bushing; A voltage signal receiver for receiving a voltage signal of grid power; And a current signal receiving unit that receives a leakage current signal. In the case of an implementation in which the time zones (timeslots) in which the three signals are transmitted are allocated, the three signal receivers receive the signals sampled in the corresponding time zones. Alternatively, in the case of an implementation in which communication channels (eg, communication lines, wireless channels) through which the three signals are transmitted are separately assigned, the three signal receivers may simply be separate communication modules connected to each communication channel.

The RF signal receiver may include an RF spectrum output unit 212 for receiving a sampling signal for an RF signal and outputting an RF spectrum signal; And a band selector 213 for filtering a frequency band to generate a PRPD/PRPS signal by selecting a measurement frequency band from the RF spectrum signal.

Depending on the implementation, the user (administrator) may select a frequency band with less noise by using the band selector 213 as a frequency tuning module from the spectrum analysis result of the RF spectrum output unit 212. When the measurement frequency band is selected, after measuring only the discharge signal in the corresponding frequency band and storing the maximum value in the memory, the PRPD/PRPS analyzer 240 is a PRPD having the x-axis as a phase of 360 degrees and the y-axis as the signal size. It can be converted to /PRPS information and transmitted to the diagnosis unit.

Depending on the implementation, a noise sensor and/or a noise removal (filtering or gating) module may be installed for the noise removal unit 230 in the signal processing block 200 to remove additional noise in the measurement frequency band.

The diagnostic block 300 calculates a diagnosis result for the leakage current, capacitance, power factor, and partial discharge characteristics of the bushing by using the data received from the signal processing block 200 to determine the current state of the bushing in real time. ).

The diagnosis block 300 may be largely divided into a partial discharge diagnosis part and a bushing leakage current diagnosis part. In the bushing leakage current diagnosis part, the magnitude of the voltage/current may be analyzed using the terminal voltage, the magnitude of the leakage current, and the phase difference, and a comparison with a finally built-in reference value may be performed by calculating a capacitance and a power factor.

At this time, when the leakage current magnitude, capacitance, and power factor values exceed the error range specified by the user compared to the reference value, an alarm is generated through the built-in algorithm, so that the user can recognize that precise diagnosis through partial discharge diagnosis is necessary. .

The partial discharge diagnosis part acquires the partial discharge signal generated from the bushing defect and always acquires data on the signal size, frequency of occurrence, and PRPD pattern, and then performs precise diagnosis on the defect, and generates an alarm when the bushing defect is definite. I can. In addition, it is possible to perform the algorithm of the flowchart of FIG. 5 below.

Specifically, the diagnostic block 300 includes a diagnostic data linking unit 322 for acquiring partial discharge information from the comprehensive diagnostic system 1000; A defect determination unit (324, 326, 327) determining a defect of a bushing from the PRPD/PRPS signal and the partial discharge information; A frequency band analysis unit 350 for analyzing a frequency band of occurrence of a combination from the RF signal; A power factor calculator 344 that calculates a transformer-related capacitance and a power factor from the calculated phase difference; A leakage size analysis unit 342 for analyzing a voltage/current degree of a leakage current from the current signal; A comparison unit 346 for comparing the transformer-related capacitance, power factor, and leakage current magnitude with a reference value may be provided.

Here, the defect determination unit 324, 326, 327 may include a defect determination unit 324 that determines whether the bushing is defective; A type analysis unit 326 that analyzes the type of the defect if there is a defect; And a deterioration analysis unit 327 that analyzes a degree of deterioration of the defect when there is a defect.

A result of comparing the defect type, the degree of deterioration, and the magnitude of the leakage current with a reference value may be output by a human machine interface (HMI) 800.

4 illustrates a method of determining a defect by the defect determination units 324, 326, and 327 based on an RF signal pattern. 4 is an example of a change in a PRPD pattern according to a defect deterioration, and shows a creepage discharge defect.

The degree of deterioration of the defect can be analyzed by utilizing the change in the PRPD pattern according to the deterioration of the defect. In general, as the deterioration of the defect progresses, the voltage per unit area applied to the defect increases, and the PRPD pattern accordingly shows a trend in which the phase width at which discharge occurs is wide and the signal size increases, as can be seen in FIG. Is shown.

The deterioration analysis unit 327 uses the result to compare the current data with the data at the time of partial discharge stored in the diagnostic system when there is a bushing in which the deterioration of the defect has progressed for a certain amount or more, and the phase width change rate and signal of the PRPD data. By calculating the rate of change of the size, the degree of deterioration of the defect can be recognized by the user.

5 is a flowchart illustrating a bushing precision diagnosis method using RF signal information (PRPD data) that can be performed in the diagnosis block 300.

The illustrated bushing precision diagnosis method includes the steps of analyzing a bushing partial discharge signal spectrum and selecting a measurement frequency band (S110); Acquiring PRPD/PRPS data, discharge signal magnitude and frequency of occurrence data for the selected frequency band (S115); Comparing the obtained PRPD/PRPS data pattern with a pattern for bushing defects and partial discharges recorded in a standard library (S120); If it is determined as noise as a result of comparing the two patterns (S130), notifying that it is noise (S135); If it is not noise, checking whether it is similar to a defect pattern that is uniquely generated only in the transformer except for the bushing (S140); Comparing the magnitude and frequency of occurrence of the signal pattern from the bushing (ie, measured by the bushing monitoring device) with the magnitude and frequency of occurrence of the signal pattern from the transformer if it is not similar to the transformer-specific defect pattern (S150); (In this case, information on the size and frequency of occurrence of the signal pattern from the transformer may be recorded in the standard library in advance.) If the size and frequency of occurrence are larger on the bushing side, the step of alarming the bushing defect (S180, S185, S188) ); If the size and frequency of occurrence are greater on the transformer side or similar to the transformer-specific defect pattern in the step S140, transmitting (querying) the corresponding defect information to an external transformer diagnosis system (S145); And when receiving the answer to the transmission (query), reflecting the content of the received answer to the standard library (S148).

Here, the steps of alarming the bushing defect (S180, S185, S188) may include warning that a defect occurs inside the bushing (S188); Warning of the type of bushing defect (S185); And warning of the degree of deterioration of the bushing defect (S180).

6 is a diagram illustrating a bushing diagnosis method using a signal detected by a bushing monitoring device capable of simultaneously detecting a low-frequency band signal and a high-frequency band signal according to the idea of the present invention.

The illustrated bushing diagnosis method includes the steps of collecting a sensing signal from an electromagnetic wave detection sensor installed in the bushing (S10): separating a power frequency band signal from the collected electromagnetic wave sensing signal (S20); Extracting frequency phase information (PRPD) from the collected electromagnetic wave sensing signal (S40); Comparing the frequency phase information with pre-stored frequency phase information at the time of an accident or frequency phase information provided from an external power management system (S60); Determining whether or not a transformer is coupled based on a degree of similarity between the two frequency phase information to be compared (S100); And determining that a current leakage failure of the bushing is caused when the magnitude of the separated power frequency band signal exceeds a predetermined reference value (S200).

The step S10 may be performed as described above in the signal acquisition block 100 of FIG. 3.

The step S20 may be performed as described above in the signal processing block 200 of FIG. 3.

The steps S60, S100, and S200 may be performed as described above in the diagnostic block 300 of FIG. 3, and in particular, step S100 may be subdivided and performed as shown in the flowchart of FIG. 5.

7 shows an embodiment of an HMI screen capable of notifying a user (administrator) of a state of a bushing. The illustrated HMI outputs the frequency spectrum analysis result and frequency selection, the PRPD/PRPS data of the bushing, and the transformer PRPD data transmitted from the transformer preventive diagnosis system, the bushing leakage current, power factor, capacitance value, the degree of deterioration, and the diagnosis result including the type of fault. The diagnosis results are synthesized and the user can continuously check the current status of the bushing through the monitoring steps such as caution, caution, and danger from the point of initial defect detection according to a certain standard. The cumulative change of the PRPD pattern shown in FIG. 4 may be shown on the screen. This reflects that the degree of deterioration of the bushing due to the cumulative change in the PRPD pattern can be inferred by an experienced manager by looking at the cumulative change in the PRPD pattern.

8 is a block diagram showing another embodiment of a transformer bushing diagnosis system using the bushing monitoring device of FIG. 2.

The transformer bushing diagnostic system of the illustrated embodiment removes the spectrum analysis part and the frequency tuning part of the signal processing block of FIG. 3, and performs only the maximum value measurement on the partial discharge RF signal acquired from the signal acquisition block 100 to obtain a broadband. This is a method of acquiring the PRPD signal. Since the spectrum measurement and frequency tuning functions are excluded, the configuration 1230 for the noise removal function is almost essential because it may be vulnerable to noise compared to the narrowband system according to the embodiment of FIG. 3. On the other hand, although the structure is simple, there is an advantage that it is possible to provide a linked service with the external comprehensive preventive diagnosis system 1001 in various ways using a broadband PRPD signal pattern.

9 is another embodiment of an HMI screen capable of notifying a user (administrator) of the state of a bushing, and shows an HMI screen that can be output from the wideband measuring method transformer bushing diagnosis system of FIG. 8. It can be seen that the broadband PRPD signal pattern is output on the screen in more detail so that the user (administrator) can sufficiently examine it.

Those skilled in the art to which the present invention pertains, since the present invention may be implemented in other specific forms without changing the technical spirit or essential features thereof, the embodiments described above are illustrative in all respects and should be understood as non-limiting. Only do it. The scope of the present invention is indicated by the claims to be described later rather than the detailed description, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention. .

For example, in another embodiment, there is a method of utilizing the system as a portable device rather than a method of installing it in a substation. By using a portable computer with sensors, a small diagnostic unit, and an HMI environment, the configuration can be changed somewhat by performing direct facility diagnosis in the field. In addition, in this case, it is difficult to interlock with the substation comprehensive preventive diagnosis system, and the bushing defect location estimation function may be excluded, but changes can be easily inferred by omitting some components of the above-described embodiments. Of course, it belongs to the scope of the rights.

100: bushing monitoring signal acquisition block
110: high frequency sensing unit
120: low frequency sensing unit
160: collection unit
190: power line communication unit
200: signal processing block
300: diagnostic block

Claims (8)

delete A bushing monitoring signal acquisition block for receiving a monitoring signal from an external bushing monitoring device;
A signal processing block for separating a current signal in a power frequency band and a current signal in a high frequency band of the deterioration discharge signal from the received monitoring signal; And
A diagnostic block that analyzes the current signal in the power frequency band to determine whether a transformer current leaks, and diagnoses whether a bushing is defective or not by linking the current signal in the high frequency band with nearby partial discharge diagnostic information,
The diagnostic block,
Analyzing the bushing partial discharge signal spectrum and selecting a measurement frequency band;
Acquiring PRPD/PRPS data, discharge signal magnitude and frequency of occurrence data for the selected frequency band;
Comparing the obtained PRPD/PRPS data pattern with a pattern for bushing defects and partial discharges recorded in a standard library;
If it is determined as noise as a result of the two pattern comparison, notifying that it is noise;
Checking whether it is similar to a defect pattern that is uniquely generated only in the transformer except for the bushing if it is not noise;
Comparing the size and frequency of occurrence of the signal pattern from the bushing with the size and frequency of occurrence of the signal pattern from the transformer if it is not similar to the transformer-specific defect pattern;
Alarming a bushing defect if the size and frequency of occurrence are larger on the bushing side;
If the size and frequency of occurrence are larger on the transformer side or similar to the transformer-specific defect pattern, transmitting the corresponding defect information to an external transformer diagnosis system; And
Upon receiving the response to the transmission, reflecting the contents of the received response to the standard library
Bushing diagnostic system for performing a bushing precision diagnostic method comprising a.
The method of claim 2,
The bushing monitoring signal acquisition block,
A signal separation unit for separating the current signal in the power frequency band and the current signal in the high frequency band;
A signal acquisition unit for receiving the separated current signal in the power frequency band and the current signal in the high frequency band; And
Digital signal conversion unit for converting a digital signal by sampling the current signal in the power frequency band and the current signal in the high frequency band
Bushing diagnostic system comprising a.
The method of claim 2,
The signal processing block,
A sampling signal receiver for receiving signals received from the bushing monitoring signal acquisition block for each type;
A phase difference calculator that calculates a phase difference of leakage power from the received signal; And
PRPD/PRPS analysis unit that generates and analyzes PRPD/PRPS signals from the high-frequency current signals
Bushing diagnostic system comprising a.
The method of claim 4,
The sampling signal receiving unit,
An RF spectrum output unit for receiving a sampling signal for the high frequency band current signal and outputting an RF spectrum signal; And
A band selector for filtering a frequency band to generate a PRPD/PRPS signal by selecting a measurement frequency band from the RF spectrum signal
Bushing diagnostic system comprising a.
The method of claim 4,
The diagnostic block,
A diagnostic data linking unit that acquires partial discharge information from an external comprehensive diagnostic system;
A defect determination unit determining a defect of a bushing from the PRPD/PRPS signal and the partial discharge information;
A power factor calculator that calculates a transformer-related capacitance and a power factor from the calculated phase difference;
A leakage size analyzer for analyzing a voltage/current degree of a leakage current from the current signal; And
A comparison unit that compares the transformer-related capacitance, power factor, and leakage current magnitude with a reference value
Bushing diagnostic system comprising a.
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