KR101777695B1 - Method for preventing the over-heating of Transformer - Google Patents

Method for preventing the over-heating of Transformer Download PDF

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KR101777695B1
KR101777695B1 KR1020150189861A KR20150189861A KR101777695B1 KR 101777695 B1 KR101777695 B1 KR 101777695B1 KR 1020150189861 A KR1020150189861 A KR 1020150189861A KR 20150189861 A KR20150189861 A KR 20150189861A KR 101777695 B1 KR101777695 B1 KR 101777695B1
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transformer
current
temperature
control mode
harmonic
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KR1020150189861A
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Korean (ko)
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KR20170080802A (en
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권우현
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경북대학교 산학협력단
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/08—Cooling; Ventilating
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R21/00—Arrangements for measuring electric power or power factor
    • G01R21/06—Arrangements for measuring electric power or power factor by measuring current and voltage
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R23/00—Arrangements for measuring frequencies; Arrangements for analysing frequency spectra
    • G01R23/16—Spectrum analysis; Fourier analysis
    • G01R31/027—
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/08—Cooling; Ventilating
    • H01F27/085—Cooling by ambient air

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  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Mathematical Physics (AREA)
  • Protection Of Transformers (AREA)

Abstract

A method for controlling overheating of a transformer performed by a control system for preventing overheating of a transformer including a temperature controller for a transformer, the method comprising: measuring a current temperature of the transformer and an outside air temperature; A measuring step of measuring voltage and current applied to the transformer; Analyzing a magnitude and a waveform of the measured voltage and current to extract a fundamental wave component and a harmonic component; Calculating a total harmonic distortion (THD) by analyzing the extracted harmonic components up to a predetermined order, calculating a driving power amount of the transformer using the measured voltage and current, Executing at least one of a k-factor, a transformer loss, and a harmonic loss using a component to calculate a predicted calorific value of the transformer; A first control mode for outputting a fan relay control signal for driving a cooling fan based on a predicted calorific value of the transformer, and a second control mode for outputting a fan relay control signal for driving the cooling fan based on the temperature rise characteristic according to the amount of thermal flow using the difference between the present temperature and the outside air temperature And a second control mode for outputting the fan relay control signal. Therefore, according to the present invention, a temperature controller for a transformer implements a calorimetric prediction algorithm capable of measuring, analyzing, and displaying the magnitude of voltage, current, and harmonic components as well as a temperature measurement function, thereby estimating a calorific value generated in the transformer, The cooling fan can be driven before the superheated state, thereby preventing a breakdown of the transformer in advance, thereby prolonging the life of the transformer, preventing a long-time interruption or the like caused by an accident of the transformer, By improving the quality of electricity, it is possible to provide more stable electricity to the user, and the manager can directly grasp the fundamental cause of the heat generation of the transformer, and also can use the regular data calculated by the calorific value prediction algorithm to optimize the transformer . ≪ / RTI >

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformer,

The present invention relates to a method for controlling overheating of a transformer, and more particularly, to a method for controlling overheating of a transformer by checking the temperature of the transformer, The present invention relates to a method for controlling overheating of a transformer, which can prevent a temperature rise of a transformer by predicting a calorific value of a transformer.

In a power system, a transformer is a major factor in determining power quality. In the process of converting the magnitude of a voltage, heat is generated by the loss of the transformer. When the heat is continuously generated and accumulated, a very serious electric accident occurs. These transformers are very difficult to check for failures and must be checked for failures using expensive equipment.

If the transformer is burned out, it is very important to prevent the transformer from being burned out due to overload or malfunction due to long-term failure rather than short-term failure in the power system.

In order to prevent the transformer from being burned out, there is a method of using a protection relay which monitors the voltage / current size and temperature. However, since the method using the protection relay can not perform the management of the transformer itself, I am adding a controller.

Transformer protection technology using temperature controller for transformer is equipped with a cooling device that constantly measures the temperature of the transformer in the switchboard, generates a warning sound when it exceeds the set value, or drives the cooling fan to lower the temperature by forced airflow.

However, since the transformer protection technology using the temperature controller for the transformer displays only the temperature of the transformer at present, there is a problem that the cause of the temperature rise can not be grasped because only the temperature rise state is detected from the manager's viewpoint. At present, transformer protection technology can not determine the direct cause of temperature overheating of the transformer because it can not know the magnitude of voltage, the size of current, the amount of harmonics included in voltage / current, which is the main cause of heat generation of transformer, It is difficult to proactively cope with the cause of the heat generation. As time elapses, there is a problem that the transformer malfunctions or burns out.

As a prior art document, a temperature measurement system for a transformer having a harmonic analysis function of a registered patent No. 10-1521979 drives a fan according to a transformer temperature in a temperature measuring apparatus, calculates the energy consumed by the transformer from voltage and current, Predicts the calorific value, detects each harmonic from the voltage and current, and divides the harmonic components according to the order.

Since the above temperature measuring system for a transformer does not show an algorithm for estimating a calorific value of a transformer after detecting a harmonic component from a voltage and a current, it is not possible to calculate formal data, and a manager can not calculate the calorific value of the transformer Therefore, there is a problem in that it is impossible to accurately calculate the values as the control conditions for driving the fan.

Registered Patent No. 10-1521979 entitled "Temperature Measurement System for Transformer with Harmonic Analysis Function" No. 10-1096147 entitled " Temperature Prediction Cooling Control Apparatus Using Load Ratio of Power Transformer and Its Control Method "

The present invention can confirm whether or not the transformer is exothermic through the temperature measurement of the transformer, predict the calorific value of the transformer by using harmonic components included in the magnitude, voltage and current of the voltage and current applied to the transformer, The present invention provides a method of controlling overheating of a transformer that can maintain and manage the performance of a transformer optimally by driving a cooling fan to prevent the transformer from being overheated.

In one embodiment of the present invention, there is provided a method of controlling overheating of a transformer, the method comprising: measuring a current temperature and an outside air temperature of a transformer, A measuring step of measuring voltage and current applied to the transformer; Analyzing a magnitude and a waveform of the measured voltage and current to extract a fundamental wave component and a harmonic component; Calculating a total harmonic distortion (THD) by analyzing the extracted harmonic components up to a predetermined order, calculating a driving power amount of the transformer using the measured voltage and current, Executing at least one of a k-factor, a transformer loss, and a harmonic loss using a component to calculate a predicted calorific value of the transformer; A first control mode for outputting a fan relay control signal for driving a cooling fan based on a predicted calorific value of the transformer, and a second control mode for outputting a fan relay control signal for driving the cooling fan based on the temperature rise characteristic according to the amount of thermal flow using the difference between the present temperature and the outside air temperature And a second control mode for outputting the fan relay control signal.

(P) of the transformer is obtained by multiplying the measured voltage (V) and the current (I), and the transformer loss amount (P loss ) is calculated by multiplying the driving power amount (P) of the transformer Wherein the harmonic loss amount (P thd ) is obtained by multiplying the measured voltage (V) or current (I) by the total harmonic distortion (THD), and the proportional coefficient (P total ) of the transformer is obtained by summing the transformer loss amount (P loss ) and the harmonic loss amount (P thd ).

The execution of the calorific value predicting algorithm may be performed by displaying the extracted harmonic components up to the 25th order and displaying the k-factor, and then displaying the k-factor in the current load state after calculating the k-factor.

The execution of the calorific value prediction algorithm may include calculating a transformable harmonic derating factor (THDF) of a usable transformer using the k-factor of the transformer, and calculating a load capacity according to the measured voltage and current The method of claim 1, further comprising:

The control mode execution step may further include a third control mode for outputting the fan relay control signal when the actual capacity coefficient is less than the load capacity.

The control mode execution step may include a step of processing the first control mode, the second control mode, and the third control mode in an integrated manner, and performing a control operation for any one of the first control mode, the second control mode, Generates the fan relay control signal when the execution condition is satisfied, and displays values corresponding to the execution condition.

And the control mode execution step outputs an alarm relay signal when the total harmonic distortion rate is equal to or greater than a predetermined set value.

The overheat prevention control method of a transformer according to the present invention is characterized in that a temperature controller for a transformer implements a calorimetric prediction algorithm capable of measuring, analyzing, and displaying the magnitude of voltage and current, It is possible to drive the cooling fan before the transformer is overheated by predicting the amount of heat generated thereby to prevent the breakdown of the transformer in advance and to prolong the life of the transformer, And it is possible to provide more stable electric power to the user by improving electric quality.

Further, since the present invention can perform predictive control by adding a voltage / current / harmonic analysis function in addition to a simple wiring in a temperature controller for a transformer, the manager can directly grasp the fundamental cause of the heat generation of the transformer, It is possible to maintain and maintain the transformer with optimum performance by using the formulated data calculated through the algorithm.

1 is a view for explaining a configuration of a control system for overheating prevention of a transformer according to an embodiment of the present invention.
2 is a flowchart illustrating a method of controlling overheat prevention of a transformer according to the first embodiment of the present invention.
3 is a flowchart illustrating a method of controlling overheat prevention of a transformer according to a second embodiment of the present invention.
4 is a flowchart illustrating a method of controlling overheat prevention of a transformer according to a third embodiment of the present invention.

The description of the present invention is merely an example for structural or functional explanation, and the scope of the present invention should not be construed as being limited by the embodiments described in the text. That is, the embodiments are to be construed as being variously embodied and having various forms, so that the scope of the present invention should be understood to include equivalents capable of realizing technical ideas. Also, the purpose or effect of the present invention should not be construed as limiting the scope of the present invention, since it does not mean that a specific embodiment should include all or only such effect.

Meanwhile, the meaning of the terms described in the present invention should be understood as follows.

The terms "first "," second ", and the like are intended to distinguish one element from another, and the scope of the right should not be limited by these terms. For example, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

It is to be understood that when an element is referred to as being "connected" to another element, it may be directly connected to the other element, but there may be other elements in between. On the other hand, when an element is referred to as being "directly connected" to another element, it should be understood that there are no other elements in between. On the other hand, other expressions that describe the relationship between components, such as "between" and "between" or "neighboring to" and "directly adjacent to" should be interpreted as well.

It should be understood that the singular " include "or" have "are to be construed as including a stated feature, number, step, operation, component, It is to be understood that the combination is intended to specify that it does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

In each step, the identification code (e.g., a, b, c, etc.) is used for convenience of explanation, the identification code does not describe the order of each step, Unless otherwise stated, it may occur differently from the stated order. That is, each step may occur in the same order as described, may be performed substantially concurrently, or may be performed in reverse order.

All terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Commonly used predefined terms should be interpreted to be consistent with the meanings in the context of the related art and can not be interpreted as having ideal or overly formal meaning unless explicitly defined in the present invention.

1 is a view for explaining a configuration of a control system for overheating prevention of a transformer according to an embodiment of the present invention.

1, the transformer overheat prevention control system includes a transformer 10, a temperature sensor 11, current transformers CT1 and CT2, transformers PT1 and PT2, digital power meters 31 and 32, A temperature controller 20, a fan relay driver 40, and a cooling fan 41. [

The temperature sensor 11 measures the temperature T t of the current transformer 10 and the outside air temperature T e of the transformer 10 and transmits the measured temperature values to the temperature controller 20.

The transformer (PT1) for the first meter and the transformer (CT1) for the first meter are installed on the primary power supply side from the KEPCO network and measure voltage and current. The first digital power meter 31 analyzes the magnitude and waveform of the voltage and current measured by the first and second meter transformers PT1 and CT1 and calculates the harmonic components included in the voltage and the current .

The transformer PT2 for the second meter and the transformer CT2 for the second meter are installed in the secondary power source on the load side and measure the voltage and current consumed in the load. The second digital power meter 32 analyzes the magnitude and the waveform of the voltage and current measured at the second meter transformer PT2 and the second meter current transformer CT2 and calculates the harmonic components included in the voltage and the current .

These instrumental transformers (PT1, PT2) and instrumental current transformers (CT1, CT2) can be used by connecting existing transformer and current transformer in series / parallel connection. Is possible.

The temperature controller 20 executes a calorific value predicting algorithm for predicting the calorific value of the transformer 10 by using the voltage and current measured at the transformers PT1 and PT2 and the converters CT1 and CT2, And executes the control mode for driving the cooling fan 41 according to the control signal.

The fan relay driving unit 40 drives / stops a plurality of cooling fans 41 for controlling the temperature of the transformer 10 according to a fan relay control signal output from the temperature controller 20. [

The loss of the transformer 10 can be divided into no-load loss and load loss. No-load loss corresponds to iron loss, and load loss corresponds to copper loss. In the case of an ideal sinusoidal wave, copper loss proportional to the magnitude of the current is the biggest cause of loss. Therefore, knowing the present current magnitude, the current loss of the transformer 10 can be easily known, and the calorific value can also be obtained.

In addition, the harmonic component included in the voltage or the current acts as a loss in an L equivalent device such as a motor or a transformer, and the magnitude of the harmonic component is directly calculated by the loss of the transformer 10.

Specifically, the losses consumed by the corrugated magnetic field in the iron core are called no-load losses, and the no-load losses are typically eddy current losses and hysteresis losses. No-load losses increase rapidly as the frequency of the interstitial flux increases, so the harmonic components included in the voltage or current are directly connected to the loss of the transformer. When a current flows through the secondary winding (load side), a copper loss proportional to the square of the current occurs in the transformer. At this time, not only the copper loss occurs on the load side but also losses (stray load loss) occur in the iron core or the enclosure due to the leakage magnetic flux. These losses occur differently depending on the type of transformer, the material of the iron core, and the manufacturer. Typically, about 50% of the no-load loss is a hysteresis loss, and about 20-40% of the load loss is the stray load loss.

Therefore, the harmonic component is one of the large loss components in the transformer. Therefore, if the magnitude of the harmonic component as well as the voltage and current magnitudes can be grasped, the transformer can be prevented from being burned out due to the temperature overheating.

Thus, the harmonic component affects both no-load loss and load loss. When the harmonic current is introduced, the copper loss increases first, that is, when the harmonic current is included in the fundamental wave current, the copper effect of the transformer coil is increased due to the skin effect of the conductor. Also, the eddy current loss in the core due to the harmonic flux increases and the overall loss increases rapidly. Also, iron loss, which is a no-load loss, increases simultaneously due to hysteresis loss and eddy current loss.

As described above, in the transformer at the time of harmonic input,

Figure 112015128886777-pat00001
) ≪ / RTI >

Figure 112015128886777-pat00002

In Equation (1)

Figure 112015128886777-pat00003
Is the loss in the fundamental wave, R is the resistance of the coil,
Figure 112015128886777-pat00004
Including the harmonic current rms current,
Figure 112015128886777-pat00005
Is the nth order high frequency content (
Figure 112015128886777-pat00006
/
Figure 112015128886777-pat00007
), n is the harmonic order, β is the drift loss coefficient (0.1 ~ 0.2) by the fundamental wave, and m is the coefficient (1.6 ~ 2.0).

If Equation 1 includes a 5th harmonic current of magnitude 22.6%, then in extreme conditions, the loss of the transformer increases by 30.6% over the fundamental. That is, there is a greater loss increase than the harmonic content. This increase in losses leads to a vicious cycle in which the winding temperature of the transformer is increased and, as a result, the winding resistance is increased again.

The temperature rise due to the loss is proportional to the loss power, and the rise of the transformer winding temperature due to the harmonic current is as shown in Equation (2) below, which indicates that the temperature of the transformer rises above the increase of the current.

Figure 112015128886777-pat00008

In Equation (2)

Figure 112015128886777-pat00009
Is the temperature rise of the transformer, I 1 is the fundamental wave current, I 0 is the equivalent current including the harmonic current,
Figure 112015128886777-pat00010
Represents the winding temperature rise due to the fundamental wave current, respectively.

For example, if the fundamental wave current is 650 A and the effective current including harmonic current is 800 A, then the transformer temperature rise increases to 39.4%, which is greater than the 23.1% rise in current magnitude. This sudden rise in temperature causes thermal stress on the transformer, which causes transformer burnout.

In addition, harmonics increase the magnitude of the peak current flowing in the transformer, which also reduces the size of the fundamental wave, which causes the output of the transformer to drop.

As a result, the harmonic components included in the voltage or current flowing through the transformer cause heat generation and wasted electrical energy, which is a key management object that has the greatest influence on the capacity, performance, and safety of the transformer.

2 is a flowchart illustrating a method of controlling overheat prevention of a transformer according to the first embodiment of the present invention.

2, the method for controlling overheat prevention of a transformer according to the present invention is characterized in that the transformers PT1 and PT2 for meters and the CT converters CT1 and CT2 are connected to the transformer 10 at a primary power source or a secondary power source side, The current is measured (S11)

The digital power meters 31 and 32 perform fast Fourier transform on the measured voltage and current to analyze the magnitude and the waveform of the voltage and the current and extract the fundamental wave component and the harmonic wave component (S12, S13). At this time, The power meters 31 and 32 display the magnitude of the voltage and the current, and can analyze and display harmonic components up to the 25th order (S14)

The temperature controller 20 calculates a total harmonic distortion THD using a harmonic component by executing a calorific value prediction algorithm and calculates a total harmonic distortion THD by using a voltage V and a current I measured in accordance with Equation 3, (P loss ), which is the amount of power consumed in the transformer 10 according to the driving power amount P used in the transformer 10, by using Equations (4) and (5) And the harmonic loss amount P thd , which is the amount of power consumed in the transformer 10, according to the harmonic components in the voltage and the current. (S15, S16)

Figure 112015128886777-pat00011

Figure 112015128886777-pat00012

Figure 112015128886777-pat00013

Figure 112015128886777-pat00014

In Equation (4), K1 is a loss coefficient of the transformer that can be set according to the characteristics of the transformer, and K2 is a proportional coefficient that can be set according to the use environment of the manager.

The calorific value prediction algorithm calculates the predicted calorific value P total of the transformer by summing the transformer loss amount and the harmonic loss amount as shown in Equation (6) (S17)

Figure 112015128886777-pat00015

 The temperature controller 20 determines that the execution condition of the first control mode is satisfied and outputs a fan relay control signal for driving the cooling fan 41 when the predicted calorific value of the transformer becomes equal to or higher than a predetermined critical calorific value. The fan relay driving unit 40 drives the cooling fan 41 in accordance with the fan relay control signal to prevent the temperature of the transformer 10 from rising.

3 is a flowchart illustrating a method of controlling overheat prevention of a transformer according to a second embodiment of the present invention.

3, the transformer overheat prevention control method includes the steps of measuring the temperature T t of the transformer and the ambient temperature T e of the transformer 10 using the temperature sensor 11, (S21).

The temperature controller 20 calculates a thermal flow rate using the temperature difference (T t -T e ) between the temperature of the transformer and the ambient temperature. (S22) Then, the temperature controller 20 determines whether the temperature of the transformer A temperature rise characteristic value obtained by multiplying the user set value (x)

Figure 112015128886777-pat00016
, It is determined that the execution condition of the second control mode is satisfied and the fan relay control signal for driving the cooling fan 41 is outputted. The fan relay driving unit 40 drives the cooling fan 41 in accordance with the fan relay control signal to prevent the overheat state of the transformer 10. (S23, S24)

4 is a flowchart illustrating a method of controlling overheat prevention of a transformer according to a third embodiment of the present invention.

4, the method for controlling overheat prevention of a transformer according to the present invention is characterized in that the transformers PT1 and PT2 and the CT converters CT1 and CT2 are connected in series between a voltage input to the transformer 10 from the primary power supply or the secondary power supply side, Current is measured (S31)

The digital power meters 31 and 32 perform fast Fourier transform on the measured voltage and current to analyze the magnitude and waveform of the voltage and current and extract the fundamental wave component and the harmonic wave component (S32, S33). At this time, The power meters 31 and 32 display the magnitude of the voltage and the current, and can analyze and display harmonic components up to the 25th order (S34)

The temperature controller 20 executes a calorimetric prediction algorithm and calculates a k-factor as shown in Equation (7) using the harmonic components of voltage and current (S35)

Figure 112015128886777-pat00017

In Equation (7)

Figure 112015128886777-pat00018
to be.

The k-factor is determined by determining the harmonic characteristics in the use environment when determining the capacity or specification of the transformer 10, so as not to cause a thermal problem, and standardizing it as a per-unit. That is, when the k-factor is 1, there is no harmonic, and when the harmonic is included, the k value becomes larger.

If the fifth-order harmonic current of 22.6% is included, the k-factor becomes 2.19 and the loss power becomes 1 + β × k-factor for the normalized magnitude, 2.10 = 1.29 to 1.44. This increase in the loss power acts to reduce the output of the transformer 10, which is referred to as the permissible capacity factor of the transformer.

The calorific value prediction algorithm calculates the actual permissible capacity factor THDF of the usable transformer by using the k-factor using Equation 8 and calculates the load capacity P curr according to the magnitude of the voltage and the current using Equation (9) (S36, S37)

Figure 112015128886777-pat00019

In Equation (8),? Is an eddy current loss rate, which is approximately 0.2.

For a single harmonic, THDF is 91.3 when the k-factor is 2.19, which means that only 91.3% of the transformer's corresponding KVA capacity is available. Since the k-factor is typically 8 in the case of a rectifier load and 13 in a case of a communication device, the THDF is 57.7%, and only about half of the corresponding KVA capacity of the transformer 10 can be normally operated.

Figure 112015128886777-pat00020

In Equation (9), E is the E phase voltage,

Figure 112015128886777-pat00021
And V is the line voltage.

Calculating the total capacity as a single phase

Figure 112015128886777-pat00022
, And the total capacity is calculated as three phases
Figure 112015128886777-pat00023
, But the total capacity is the same as the single-phase value or the three-phase value.

The temperature controller 20 determines that the execution condition of the third control mode is satisfied when the actual allowable capacity coefficient is smaller than the load capacity and outputs a fan relay control signal for driving the cooling fan 41. [ The fan relay driving unit 40 drives the cooling fan 41 in accordance with the fan relay control signal to prevent the transformer 10 from being overheated.

As described in the first to third embodiments, the temperature controller 20 calculates the predicted heat generation amount of the transformer based on the magnitude of voltage and current, the loss due to the harmonics of the voltage and the current, 41), a second control mode for controlling the driving of the cooling fan (41) in consideration of the difference between the temperature of the transformer and the outside air temperature, and the second control mode for calculating the driving power amount And executes the third control mode for controlling the driving of the cooling fan 41 based on the predicted calorific value of the transformer.

At this time, the temperature controller 20 integrally executes the first control mode, the second control mode, and the third control mode, and drives the cooling fan 41 when the execution condition of each control mode is satisfied, Can be prevented from being overheated in advance.

In addition, the temperature controller 20 calculates a value corresponding to the execution condition of each control mode, the magnitude of the voltage and current input to and output from the transformer 10, the k-factor in the current load state, the predicted calorific value, And the like can be displayed.

On the other hand, the temperature controller 20 outputs an alarm relay signal when the total harmonic distortion is equal to or greater than a predetermined set value. At this time, the temperature controller 20 sets the range so that the set value is increased step by step, and the alarm for each step is also adjusted upward, so that the alarm can be generated according to the set range of the total harmonic distortion.

As described above, in the embodiment of the present invention, the temperature controller 20 measures the current temperature of the transformer 10, generates an alarm when the temperature is higher than the set value, drives the cooling fan 41 to cool the transformer 10 . In addition, since the temperature controller 20 includes a harmonic measurement and analysis function, it is possible to generate an alarm according to the magnitude of the harmonic component and drive the cooling fan 41. Therefore, before the temperature of the transformer 10 is raised, Can be operated and managed.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims It can be understood that

10: transformer 20: temperature controller
31, 32: Digital power meter 40: Fan relay driver
11: Temperature sensor 41: Cooling fan

Claims (9)

A method for controlling overheating of a transformer performed by an overheat preventing control system of a transformer including a temperature controller for a transformer,
Measuring a current temperature of the transformer and an outside air temperature;
Calculating a temperature difference between the measured current temperature of the transformer and the outside air temperature;
Calculating a thermal flow rate according to the calculated temperature difference; And
And executing a control mode for outputting a fan relay control signal for driving a cooling fan for cooling the transformer by comparing a current temperature of the transformer with a temperature rising characteristic value according to the calculated thermal expansion amount, The overheat prevention control method of the transformer.
A method for controlling overheating of a transformer performed by an overheat preventing control system of a transformer including a temperature controller for a transformer,
A measuring step of measuring voltage and current applied to the transformer;
Analyzing a magnitude and a waveform of the measured voltage and current to extract a fundamental wave component and a harmonic component;
Calculating a total harmonic distortion (THD) by analyzing the extracted harmonic components up to a predetermined order, calculating a driving power amount of the transformer using the measured voltage and current, Executing at least one of a k-factor, a transformer loss, and a harmonic loss using a component to calculate a predicted calorific value of the transformer; And
And a control mode execution step of executing a first control mode for outputting a fan relay control signal for driving the cooling fan based on the predicted calorific value of the transformer,
The execution of the calorific value prediction algorithm may include:
The driving power amount P of the transformer is obtained by multiplying the measured voltage V and the current I,
The transformer loss amount (P loss ) is obtained by multiplying a driving power amount (P) of the transformer by a loss coefficient (K1) of a transformer set according to the characteristics of the transformer,
The harmonic loss amount P thd is obtained by multiplying the measured voltage V or current I by the total harmonic distortion THD and multiplying it by the proportional coefficient K2,
Wherein the predicted calorific value (P total ) of the transformer is obtained by summing the transformer loss (P loss ) and the harmonic loss amount (P thd ).
A method for controlling overheating of a transformer performed by an overheat preventing control system of a transformer including a temperature controller for a transformer,
A measuring step of measuring voltage and current applied to the transformer;
Analyzing a magnitude and a waveform of the measured voltage and current to extract a fundamental wave component and a harmonic component;
Executing a calorific value prediction algorithm to calculate a predicted calorific value of the transformer by calculating a k-factor using the measured harmonic components of the voltage and the current; And
And a control mode execution step of executing a first control mode for outputting a fan relay control signal for driving the cooling fan based on the predicted calorific value of the transformer,
The execution of the calorific value prediction algorithm may include:
The k-factor is calculated by using Equation (1), then the k-factor in the current load state is displayed,
[Equation 1]
Figure 112017045743915-pat00024

In Equation (1)
Figure 112017045743915-pat00025
Wherein the overheat prevention control method comprises:
A method for controlling overheating of a transformer performed by an overheat preventing control system of a transformer including a temperature controller for a transformer,
A measuring step of measuring voltage and current applied to the transformer;
Analyzing a magnitude and a waveform of the measured voltage and current to extract a fundamental wave component and a harmonic component;
Executing a calorific value prediction algorithm to calculate a predicted calorific value of the transformer by calculating a k-factor using the measured harmonic components of the voltage and the current; And
And a control mode execution step of executing a first control mode for outputting a fan relay control signal for driving the cooling fan based on the predicted calorific value of the transformer,
The execution of the calorific value prediction algorithm may include:
Calculating a transformable harmonic derating factor (THDF) of a usable transformer using the k-factor of the transformer, and calculating a load capacity according to the measured voltage and current magnitude Wherein the transformer is a transformer.
5. The method of claim 4,
Further comprising the step of measuring a current temperature of the transformer and an outside air temperature,
The control mode execution step includes:
A second control mode for outputting the fan relay control signal based on a temperature rise characteristic according to a thermal flow rate using a difference between a current temperature of the transformer and an outside air temperature, And a third control mode for outputting a fan relay control signal to the transformer.
5. The method of claim 4,
The actual allowable capacity coefficient THDF is calculated using Equation (2)
&Quot; (2) "
Figure 112015128886777-pat00026

Wherein, in Equation (2),? Is an eddy current loss rate.
5. The method of claim 4,
The load capacity P curr is calculated using Equation (3)
&Quot; (3) "
Figure 112017045743915-pat00027

In Equation (3)
Figure 112017045743915-pat00028
V is the measured voltage, and I is the measured current.
6. The method of claim 5,
The control mode execution step includes:
The first control mode, the second control mode, and the third control mode, and when the execution condition for any one of the first control mode, the second control mode, and the third control mode is satisfied Generating the fan relay control signal, and displaying values corresponding to the execution condition.
3. The method of claim 2,
The control mode execution step includes:
And outputting an alarm relay signal when the total harmonic distortion is equal to or greater than a predetermined set value.
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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102015466B1 (en) 2019-07-22 2019-08-28 (주)알파앤오메가 Transformer for electric power that prevents deterioration of insulation oil performance by improving heat dissipation performance
KR102030336B1 (en) 2019-08-19 2019-10-10 (주)태화기전 Improved safety power transformer with insulating oil checking and replacement
KR102030334B1 (en) 2019-07-22 2019-10-10 (주)두산전력 Power transformer with enhanced oil filtering function
KR102015453B1 (en) 2019-07-22 2019-10-23 (주)동조전력 Power transformer with enhanced conservator function
KR102015457B1 (en) 2019-07-22 2019-10-23 한국초고압 주식회사 Power transformer simplifies respiratory structure

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KR101521979B1 (en) * 2014-05-08 2015-05-21 주식회사 디케이 (Apparatus for measuring temperature of transformer having functions of harmonic analysis

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KR101521979B1 (en) * 2014-05-08 2015-05-21 주식회사 디케이 (Apparatus for measuring temperature of transformer having functions of harmonic analysis

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102015466B1 (en) 2019-07-22 2019-08-28 (주)알파앤오메가 Transformer for electric power that prevents deterioration of insulation oil performance by improving heat dissipation performance
KR102030334B1 (en) 2019-07-22 2019-10-10 (주)두산전력 Power transformer with enhanced oil filtering function
KR102015453B1 (en) 2019-07-22 2019-10-23 (주)동조전력 Power transformer with enhanced conservator function
KR102015457B1 (en) 2019-07-22 2019-10-23 한국초고압 주식회사 Power transformer simplifies respiratory structure
KR102030336B1 (en) 2019-08-19 2019-10-10 (주)태화기전 Improved safety power transformer with insulating oil checking and replacement

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