KR20220011050A - Method for failure detection of OLTC(on load tab changer) and apparatud for performing the same - Google Patents

Abstract

The present invention relates to a method for diagnosing a failure of an on load tab changer (OLTC) and a device for performing the same. The method for diagnosing a state of an OLTC may comprise: a step of receiving, by an OLTC state diagnosis device, a vibration signal of an OLTC; a step of determining, by the OLTC state diagnosis device, a vibration signal (diverter switch) of the vibration signal; and a step of diagnosing, by the OLTC state diagnosis device, a state of the OLTC based on the vibration signal (diverter switch). Therefore, the present invention is capable of providing a stable and reliable power supply.

Description

Method for failure detection of OLTC (on load tab changer) and apparatud for performing the same}

The present invention relates to a method for diagnosing an OLTC fault and an apparatus for performing such method. More particularly, it relates to an OLTC fault diagnosis method for improving the quality of electricity by diagnosing the possibility of a fault of the OLTC based on the operation of a diverter switch of the OLTC, and an apparatus for performing the method.

In addition, in the recent rapid increase in power consumption in Korea and the increase in breaking capacity, the complexity of the system configuration, the occurrence of a line that exceeds the transmission capacity in the event of a transmission line failure, a transformer overload dropout in the event of a complex failure of a substation, overload of the connected substation, adjustment of the transfer load, etc. A system failure is occurring.

Consumers' expectations for the quality of electricity for electricity have also increased, and the number of customer facilities that can be affected by product quality even after a momentary power outage or momentary voltage drop is gradually increasing. Responsibilities are being emphasized.

Failure of a transformer in the power system has a fatal effect on the power supply and causes inconvenience to customers due to the unexpected shutdown of the transformer. When looking at the causes of transformer failure, there are on load tab changer (OLTC) related failures, internal failures, and protective relay failures. Among the causes of transformer failure, OLTC-related failure causes continue to occur. Therefore, in order to meet customer needs and provide more stable and reliable power supply, it is essential to analyze the causes of OLTC-related failures to prevent peripheral voltage stoppage and to provide more accurate OLTC A study on a method for pre-diagnosing failures is necessary.

An object of the present invention is to solve all of the above problems.

In addition, an object of the present invention is to determine the state of the OLTC based on the vibration signal generated in the OLTC to enable a stable and reliable power supply to the transformer.

In addition, an object of the present invention is to prevent problems in the power system due to OLTC in advance by predicting the current and future states of OLTC based on machine learning.

A representative configuration of the present invention for achieving the above object is as follows.

According to an embodiment of the present invention, the method for diagnosing an on load tab changer (OLTC) state includes: receiving, by an OLTC state diagnosis apparatus, a vibration signal of the OLTC; ) and, by the OLTC state diagnosis apparatus, diagnosing the state of the OLTC based on the vibration signal (a diverter switch).

On the other hand, the step of diagnosing the state of the OLTC based on the vibration signal (diverter switch) is the step of determining, by the OLTC state diagnosis apparatus, the excitation of the vibration signal (diverter switch), and the OLTC state diagnosis apparatus The method may include determining excitation information and diagnosing, by the OLTC state diagnosis apparatus, the state of the OLTC based on the excitation information.

In addition, the excitation information may include excitation time difference information and excitation magnitude ratio information.

According to another embodiment of the present invention, an on load tab changer (OLTC) state diagnosis apparatus includes a vibration signal receiver configured to receive a vibration signal of the OLTC, and a processor operatively connected to the vibration signal receiver, The processor may be implemented to determine a vibration signal (a diverter switch) from among the vibration signals and diagnose the state of the OLTC based on the vibration signal (a diverter switch).

Meanwhile, the processor may be implemented to determine the excitation of the vibration signal (diverter switch), determine the excitation information of the excitation, and diagnose the state of the OLTC based on the excitation information.

In addition, the excitation information may include excitation time difference information and excitation magnitude ratio information.

According to the present invention, it is possible to determine the state of the OLTC based on the vibration signal generated in the OLTC so that the transformer can supply stable and reliable power.

In addition, according to the present invention, problems in the power system due to OLTC can be prevented in advance by predicting the current and future OLTC states based on machine learning.

1 is a conceptual diagram illustrating an OLTC structure.
2 is a conceptual diagram illustrating an operation of an OLTC according to an embodiment of the present invention.
3 is a graph illustrating a vibration signal according to a delay operation of a diverter switch according to an embodiment of the present invention.
4 is a conceptual diagram illustrating an OLTC diagnosis method according to an embodiment of the present invention.
5 is a conceptual diagram illustrating an OLTC state diagnosis apparatus according to an embodiment of the present invention.
6 is a conceptual diagram illustrating an OLTC diagnosis method according to an embodiment of the present invention.
7 is a conceptual diagram illustrating a method of determining an excitation of a vibration signal of a diverter switch according to an embodiment of the present invention.
8 is a conceptual diagram illustrating a learning procedure based on information with an embodiment according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0010] Reference is made to the accompanying drawings, which show by way of illustration specific embodiments in which the present invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present invention. It should be understood that the various embodiments of the present invention are different but need not be mutually exclusive. For example, certain shapes, structures, and characteristics described herein may be implemented with changes from one embodiment to another without departing from the spirit and scope of the present invention. In addition, it should be understood that the location or arrangement of individual components within each embodiment may be changed without departing from the spirit and scope of the present invention. Accordingly, the following detailed description is not to be taken in a limiting sense, and the scope of the present invention should be taken as encompassing the scope of the claims and all equivalents thereto. In the drawings, like reference numerals refer to the same or similar elements throughout the various aspects.

Hereinafter, various preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings in order to enable those of ordinary skill in the art to easily practice the present invention.

An on load tab changer (OLTC) may be implemented to change the transmission voltage according to power demand. As the type of OLTC, there may be an oil method and a vacuum method depending on the insulation method, and may be divided into a three-phase batch type and a three-phase separation type according to a phase. In addition, it may be divided into a diverter switch and a selector switch according to a switching method.

1 is a conceptual diagram illustrating an OLTC structure.

1 discloses an OLTC structure.

1, in order to adjust the voltage of the transformer, separating the transformer from the supply line and adjusting the tap is very unreasonable in terms of cumbersome operation and supply of high-quality power. Therefore, it is an on-load tap-changer installed in a transformer with the function of automatically adjusting a specified range of winding voltage to adjust the voltage while supplying a load, and the transformer installed with this on-load tap changer (OLTC) on-load tap-changer transformer)

Transformation ratio adjustment of the transformer can be performed by connecting the tap selector of the OLTC and the tap winding of the transformer.

The diverter switch 100 performs a function of opening the tap being used to switch the tap from the main energization circuit and at the same time connecting the tap selected by the tap selector to the main energization circuit without generating an arc.

A contact point 110 may be a contact between the diverter switch and the tap selector.

The transition resistor 120 may be used to limit a circulating current flowing due to a potential difference between two taps forming a closed circuit during opening and closing of a contact on the OLTC.

The tap selector 130 is connected to the changeover switch by a driving device to select a desired tap before the changeover switch operates and to connect to the changeover switch.

The drive device moves the tap selector 130 to the next desired position and then

The diverter switch 100 may operate to electrically connect to the next tap selected by the tap selector 130 . When the diverter switch 100 operates, a circulating current by the step voltage flows by shorting the tap of one stage in general. A transition resistor 120 may be used to appropriately limit the magnitude of this circulating current.

Hereinafter, in an embodiment of the present invention, a method for diagnosing an OLTC failure based on a vibration signal generated due to the movement of the tap selector 130 and the diverter switch 100 is disclosed.

2 is a conceptual diagram illustrating an operation of an OLTC according to an embodiment of the present invention.

2 discloses an operation method of OLTC. In the present invention, it is possible to diagnose whether the OLTC is malfunctioning based on the vibration signal generated by the movement of the tap selector and the diverter switch. An OLTC operation and an OLTC vibration signal are initiated.

Referring to FIG. 2 , the voltage may be set while the tap selector is moved (steps S210 and S220).

In the case of three phases, three vibration signals (tap selectors) can be generated. According to the operation of the tap selector, three vibration signals (tap selector) may be generated for each of the contacts when the contacts are disconnected and the contacts are connected.

Since the vibration signal (tap selector), which is the vibration signal of the tap selector, is smaller than the vibration signal (diverter switch), which is the vibration signal of the diverter switch, the vibration signal with the largest variance (diverter switch) is used as the standard. Diagnosis of OLTC conditions may be performed.

A circuit connection may be performed with a set voltage while the diverter switch is moved (step S220).

It is three-phase, and in the case of a diverter switch, three vibration signals are generated per phase, so that a total of nine vibration signals (diverter switch) can be generated.

Circuit connections based on diverter switches must occur simultaneously in a short time due to circulating current issues and arcing issues. Therefore, the diverter switch should perform switching in a short moment by storing energy in the spring.

In the present invention, a vibration signal (diverter switch) is extracted from the obtained vibration signal, and the state of the OLTC may be determined based on the vibration signal (diverter switch).

3 is a graph illustrating a vibration signal according to a delay operation of a diverter switch according to an embodiment of the present invention.

The left side of FIG. 3 is a graph when three phases are simultaneously switched by the diverter switch.

The right side of FIG. 3 is a case in which a time difference occurs between three-phase switching by a diverter switch. There is a time difference between the transitions of the three phases, which results in a circulating current.

Therefore, it is possible to determine whether the diverter switch is abnormal based on the vibration signal (the diverter switch) generated when the diverter switch is switched.

4 is a conceptual diagram illustrating an OLTC diagnosis method according to an embodiment of the present invention.

4 discloses a procedure for diagnosing OLTC.

Referring to Fig. 4, a vibration signal (diverter switch) is determined (step S400).

A vibration signal (diverter switch) can be determined from the entire vibration signal. The vibration signal (diverter switch) may be determined in consideration of the magnitude of the vibration signal, the order of the vibration signal, and the like in the entire vibration signal.

In addition, an analysis range of the vibration signal (diverter switch) may be determined through a procedure of extending a moving time range of the vibration signal (diverter switch). The movement time range may be a time range of a vibration signal (diverter switch) generated while the diverter switch moves.

Excitation for the vibration signal (diverter switch) is determined (step S410).

Excitation with respect to the vibration signal (diverter switch) may be determined through signal processing for the extracted vibration signal (diverter switch). The excitation may be a physical force that causes the vibration signal, and a signal processing method for determining the excitation will be described later.

Excitation information for the vibration signal (diverter switch) is determined (step S420).

Time difference information and size ratio information with information can be extracted from the information.

OLTC status diagnosis is performed based on the information with respect to the vibration signal (diverter switch) (step S430).

Based on the excitation time difference information and excitation size ratio information, an OLTC condition diagnosis model that has performed machine learning for OLTC condition diagnosis can be created. Excitation time difference information extracted from the information on the generated OLTC diagnosis model, The size ratio information with which it has may be input. OLTC status diagnosis can be performed based on the input excitation time difference information and excitation magnitude ratio information

5 is a conceptual diagram illustrating an OLTC state diagnosis apparatus according to an embodiment of the present invention.

Referring to FIG. 5 , the OLTC state diagnosis apparatus includes a vibration signal receiver 500 , a vibration signal determiner 510 , an excitation determiner 520 , an excitation information determiner 530 , an OLTC state diagnosis unit 540 and a processor. (550).

The vibration signal receiver 500 may be implemented to receive a vibration signal from the OLTC.

The vibration signal determiner 510 may be implemented to determine a vibration signal (a diverter switch) from the received vibration signal.

The excitation determining unit 520 may be implemented to determine the excitation of the vibration signal (diverter switch). Excitation with respect to the vibration signal (diverter switch) may be determined through signal processing for the extracted vibration signal (diverter switch).

The excitation information determining unit 530 may determine information on a time difference between excitation of a vibration signal (a diverter switch) and information on a magnitude ratio of excitation.

The OLTC state diagnosis unit 540 may be implemented to diagnose the OLTC state through the excitation information determined by the excitation information determiner. The OLTC state diagnosis unit 540 may include an OLTC state diagnosis model in which machine learning for OLTC state diagnosis is performed based on existing excitation time difference information and excitation magnitude ratio information.

The processor 550 may be implemented to control the operation of the vibration signal receiving unit 500 , the vibration signal determining unit 510 , the excitation determining unit 520 , the excitation information determining unit 530 , or the OLTC state diagnosis unit 540 . can

6 is a conceptual diagram illustrating an OLTC diagnosis method according to an embodiment of the present invention.

6 discloses a method of analyzing a vibration signal (a diverter switch) for diagnosing a state of OLTC.

Referring to FIG. 6 , a vibration signal (diverter switch) by the diverter switch is determined from the entire vibration signal (step S600),

The total vibration signal may include a vibration signal (tap selector) and a vibration signal (diverter switch), and a vibration signal (diverter switch) may be extracted from the total vibration signal.

A moving time range of the vibration signal (diverter switch) by the diverter switch is determined (step S610).

The variance of the rolling window is determined using the relatively large variance of the moving time range of the vibration signal (diverter switch), and time points with the top 5% of variance are extracted. . Specifically, a data group consisting of the values may be extracted while extracting the variance of a specific window through rolling window variance and calculating the variance of the next section. If there is a time point in the top 5% within -0.05 second to +0.05 second from the time point with the largest variance, the corresponding time point may be added to the moving time range.

If there is a time point in the top 5% within -0.05 seconds to +0.05 seconds in the movement time range, it may be additionally added to the movement time range.

When extending the movement time range in this way, the movement time range may be extended until the top 5% time point does not exist within -0.05 seconds to +0.05 seconds.

A time range of -0.05 second to +0.05 second that extends the movement time range may be changed to an arbitrary value, and a time point of the top 5% may also be changed to an arbitrary value.

7 is a conceptual diagram illustrating a method for determining an excitation of a vibration signal of a diverter switch according to an embodiment of the present invention.

Referring to FIG. 7 , the excitation of the vibration signal of the diverter switch is a force and cause for generating vibration. Excitation may be determined through analysis of the vibration signal (diverter switch), and information about excitation (excitation generation time, excitation magnitude, etc.) may be determined.

First, noise of the vibration signal (diverter switch) is removed through a noise removal filter (eg, a median (MED) filter) (step S700).

Thereafter, an envelope for the denoised vibration signal (diverter switch) may be extracted through the transform function (step S710).

For example, the transform function may be a Hilbert transform function. Through envelope extraction, judgment is performed on the timing of having a large vibration generated by excitation.

The fluctuation of the denoised vibration signal (diverter switch) signal is removed based on the moving max function (step S720).

Specifically, by smoothing a vibration signal having a high frequency through a moving maximum function, it is easy to find peak points.

A moving maximum function is applied to accurately find the peak point on the denoised vibration signal (diverter switch) signal.

A peak point is determined on the denoised vibration signal (diverter switch) signal (step S730).

Through the procedure of finding the peak point, information on the excitation generation point and excitation magnitude information, which are vibration information, is determined.

8 is a conceptual diagram illustrating a learning procedure based on information with an embodiment according to the present invention.

In FIG. 8 , a method of performing machine learning for OLTC status diagnosis using information with the present invention is disclosed.

Referring to FIG. 8 , time difference information and size ratio information are extracted from the information, machine learning for OLTC status diagnosis is performed based on the time difference information and size ratio information, and based on the learning result An OLTC condition diagnostic model may be generated.

Graph 1 810 is excitation time difference information, and may include information on a difference in time when excitation occurs, and information about the number of excitations - 1 excitation time difference in one excitation pattern may be determined.

The graph 2 820 may include information on the state ratio of the amplitudes as excitation magnitude ratio information, and information about the number of excitations-1 excitation magnitude ratio information in one excitation pattern may be determined.

The excitation time difference information and the excitation magnitude ratio information are input to the machine learning model as each feature, so that a probability value can be determined in the state (abnormal, normal) of the OLTC.

Excitation time difference information, excitation magnitude ratio information, and information on an actual OLTC state may be input, and a weight for the OLTC state diagnosis model may be learned according to these input values.

When excitation time difference information and excitation magnitude ratio information included in the excitation information after learning are input, judgment values for abnormal probability and normal probability for the current OLTC state may be output.

The embodiments according to the present invention described above may be implemented in the form of program instructions that can be executed through various computer components and recorded in a computer-readable recording medium. The computer-readable recording medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the computer-readable recording medium may be specially designed and configured for the present invention, or may be known and available to those skilled in the computer software field. Examples of computer-readable recording media include hard disks, magnetic media such as floppy disks and magnetic tapes, optical recording media such as CD-ROMs and DVDs, and magneto-optical media such as floppy disks. medium), and hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. A hardware device may be converted into one or more software modules to perform processing in accordance with the present invention, and vice versa.

In the above, the present invention has been described with reference to specific matters such as specific components and limited embodiments and drawings, but these are only provided to help a more general understanding of the present invention, and the present invention is not limited to the above embodiments, Those of ordinary skill in the art to which the invention pertains can make various modifications and changes from these descriptions.

Therefore, the spirit of the present invention should not be limited to the above-described embodiments, and the scope of the spirit of the present invention is not limited to the scope of the scope of the present invention. will be said to belong to

Claims (6)

OLTC (on load tab changer) status diagnosis method,
receiving, by the OLTC state diagnosis apparatus, a vibration signal of the OLTC;
determining, by the OLTC state diagnosis apparatus, a vibration signal (a diverter switch) among the vibration signals; and
and diagnosing, by the OLTC state diagnosis apparatus, the state of the OLTC based on the vibration signal (a diverter switch). The method of claim 1, wherein diagnosing the state of the OLTC based on the vibration signal (diverter switch) comprises:
determining, by the OLTC state diagnosis apparatus, an excitation of the vibration signal (a diverter switch);
determining, by the OLTC state diagnosis apparatus, information about the excitation; and
and diagnosing the state of the OLTC based on the information possessed by the OLTC state diagnosis apparatus. 3. The method of claim 2,
The excitation information includes excitation time difference information and excitation magnitude ratio information. OLTC (on load tab changer) status diagnosis device,
a vibration signal receiver implemented to receive a vibration signal of the OLTC;
Including a processor operatively connected to the vibration signal receiver,
The processor determines a vibration signal (a diverter switch) among the vibration signals,
OLTC state diagnosis apparatus, characterized in that it is implemented to diagnose the state of the OLTC based on the vibration signal (diverter switch). 5. The method of claim 4,
The processor determines the excitation of the vibration signal (diverter switch),
Determine the information with the excitation,
OLTC state diagnosis apparatus, characterized in that it is implemented to diagnose the state of the OLTC based on the information with the OLTC. 6. The method of claim 5,
The excitation information includes excitation time difference information and excitation magnitude ratio information.

Images