CN114496551A - Direct current heating system and method for air-core coil heating - Google Patents

Direct current heating system and method for air-core coil heating Download PDF

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Publication number
CN114496551A
CN114496551A CN202210013998.3A CN202210013998A CN114496551A CN 114496551 A CN114496551 A CN 114496551A CN 202210013998 A CN202210013998 A CN 202210013998A CN 114496551 A CN114496551 A CN 114496551A
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heated
coil
heating
direct current
air
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Inventor
童彬
俞振兴
董巍
蒋胜琦
陆炜俊
周青青
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Suzhou Huadian Electric Co Ltd
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Suzhou Huadian Electric Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/04—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing coils
    • H01F41/06—Coil winding
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/04—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing coils
    • H01F41/12—Insulating of windings
    • H01F41/127—Encapsulating or impregnating
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B1/00—Details of electric heating devices
    • H05B1/02—Automatic switching arrangements specially adapted to apparatus ; Control of heating devices
    • H05B1/0202—Switches
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B1/00—Details of electric heating devices
    • H05B1/02—Automatic switching arrangements specially adapted to apparatus ; Control of heating devices
    • H05B1/0227—Applications
    • H05B1/023—Industrial applications

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  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • General Induction Heating (AREA)

Abstract

The invention discloses a direct current heating system for heating an air core coil, which is used for heating the air core coil to be heated in a dry-type transformer to a target temperature, wherein the control system comprises: the direct current power supply comprises a direct current power supply, a first direct current contactor, a second direct current contactor and a control circuit, wherein the positive electrode and the negative electrode of the direct current power supply are respectively connected with a DC + terminal and a DC-terminal; the two ends of the freewheeling diode are connected with the two ends of the hollow coil to be heated and are connected with the DC + terminal and the DC-terminal in an anti-parallel mode; the measurement system includes: the voltage acquisition card and the current acquisition card are respectively used for acquiring voltage and current data of the hollow coil to be heated in real time. The invention can electrically heat the hollow coil by the direct current power supply, can calculate the real-time temperature of the coil to be heated, can realize the rapid heating of the hollow coil to be heated in the dry-type transformer to the target temperature, and has the advantages of high heating efficiency and uniform heating.

Description

Direct current heating system and method for air-core coil heating
Technical Field
The invention relates to the technical field of dry-type transformer production, in particular to a direct current heating system and a direct current heating method for heating a hollow coil in a dry-type transformer.
Background
Transformers are one of the important devices of power systems, and play a particularly important role in power systems. The dry type transformer has the characteristics of flame retardancy, safety, convenience in maintenance, small size and the like. In recent years, dry transformers, which simply mean transformers in which the core and the winding are not immersed in insulating oil, are widely used in places such as local lighting, high-rise buildings, airports, and docks for CNC machines.
In the production of the dry-type transformer, the wound hollow coil needs epoxy pouring and curing and then can be installed on the iron core. The hollow coil needs to be heated to 80 degrees before casting, and the inside and the outside of the coil need to be heated uniformly, otherwise, bubbles are generated during casting of the coil or casting is not uniform, which can seriously affect the insulation level of the transformer.
The hollow coil is formed by copper product or aluminum product coiling to mould is pour to outside suit, and the heating of current hollow coil is all accomplished by large-scale oven heating, generally need heat about 12 hours, leads to low in production efficiency, extravagant energy, and can't guarantee completely that the coil is heated evenly, and the heating effect is relatively poor, can not satisfy the reality demand, and the urgent need is a new heating method to solve above-mentioned problem.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a direct current heating system for heating an air core coil, which can realize rapid heating, high heating efficiency and uniform heating of the air core coil in a dry type transformer.
In order to solve the above problems, the present invention provides a direct current heating system for air coil heating, for heating an air coil to be heated in a dry-type transformer to a target temperature, the direct current heating system for air coil heating comprising a control center, a control system and a measurement system, both of which are electrically connected to the control center;
the control system includes:
the direct current power supply comprises a direct current power supply, a first direct current contactor and a second direct current contactor, wherein the positive electrode and the negative electrode of the direct current power supply are respectively connected with a DC + terminal and a DC-terminal;
the two ends of the freewheeling diode are connected with the two ends of the hollow coil to be heated and are connected with the DC + terminal and the DC-terminal in an anti-parallel mode;
the measurement system includes:
the device comprises a voltage acquisition card and a current acquisition card, wherein the voltage acquisition card and the current acquisition card are respectively used for acquiring voltage and current data of the hollow coil to be heated in real time;
and the control center is used for calculating the real-time temperature of the hollow coil to be heated by combining the cold resistance and the cold temperature of the hollow coil to be heated according to the voltage and current data of the hollow coil to be heated.
As a further improvement of the invention, the real-time temperature calculation formula of the hollow coil to be heated is as follows:
Figure BDA0003459088600000021
wherein, txFor the real-time temperature of the air core coil to be heated, U is the voltage of the air core coil to be heated, I is the current of the air core coil to be heated, R0Is the cold resistance of the air core coil to be heated, t0The temperature is the cold state temperature of the hollow coil to be heated, and K is the material temperature coefficient of the hollow coil to be heated.
As a further improvement of the present invention, the control center is configured to calculate an instantaneous resistance of the to-be-heated coil according to instantaneous voltage and current data of the to-be-heated hollow coil acquired by the voltage acquisition card and the current acquisition card when the to-be-heated hollow coil is preheated, and calculate an error between the instantaneous resistance and a cold resistance of the to-be-heated hollow coil, and if the error is within a threshold range, continue to perform electric heating, otherwise, stop heating and find a cause of a large error.
As a further development of the invention, a second direct current contactor is connected between the DC + terminal connection and the DC-terminal for short-circuiting the DC + terminal and the DC-terminal in the non-heated state.
As a further improvement of the invention, the direct current power supplies are multiple and different in type, and the positive pole of each direct current power supply is connected with the DC + terminal through a first direct current contactor.
As a further improvement of the present invention, the control center is configured to determine a corresponding dc power supply according to a target temperature and a cold resistance of the air-core coil to be heated, and close the first dc contactor corresponding to the corresponding dc power supply when heating is required.
As a further improvement of the invention, the direct current power supply comprises a 100A/20KW constant current source, a 300A/20KW constant current source and a 600A/20KW constant current source.
In order to solve the above problems, the present invention further provides a direct current heating method for air coil heating, which is applied to the direct current heating system for air coil heating, and comprises the following steps:
A. connecting an air core coil to be heated to a preset position in the direct current heating system for heating the air core coil;
B. electrically heating the hollow coil to be heated, and respectively collecting voltage and current data of the hollow coil to be heated in real time through the voltage collection card and the current collection card;
C. the control center calculates the real-time temperature of the hollow coil to be heated according to the voltage and current data of the hollow coil to be heated and by combining the cold resistance and the cold temperature of the hollow coil to be heated;
D. and stopping electric heating until the real-time temperature of the hollow coil to be heated reaches the target temperature.
As a further improvement of the invention, between the steps A and B, the method also comprises the following steps:
s1, preheating the hollow coil to be heated, and acquiring instantaneous voltage and current data of the hollow coil to be heated through the voltage acquisition card and the current acquisition card;
and S2, calculating the instantaneous resistance of the coil to be heated by the control center according to the instantaneous voltage and current data of the hollow coil to be heated acquired by the voltage acquisition card and the current acquisition card, calculating the error between the instantaneous resistance and the cold resistance of the hollow coil to be heated, continuing to perform electric heating if the error is within a threshold range, and otherwise, stopping heating and finding out the reason of larger error.
As a further improvement of the invention, in step B, voltage and current data of the air core coil to be heated are acquired every 1 second.
The invention has the beneficial effects that:
the direct current heating system for heating the air core coil of the invention electrically heats the air core coil by the direct current power supply, can calculate the real-time temperature of the coil to be heated, can realize the rapid heating of the air core coil to be heated in the dry type transformer to the target temperature, has the advantages of high heating efficiency and uniform heating compared with the heating mode of the existing oven, and can shorten the heating time of the air core coil from the original 12-hour oven to about 1.5 hours.
The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented in accordance with the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more clearly understood, the following preferred embodiments are described in detail with reference to the accompanying drawings.
Drawings
FIG. 1 is a schematic diagram of a DC electric heating system for air coil heating according to one embodiment of the present invention;
FIG. 2 is a schematic diagram of a DC electric heating system for air coil heating according to a second embodiment of the present invention;
fig. 3 is a schematic diagram of a dc electric heating system for air-core coil heating according to a third embodiment of the present invention.
Detailed Description
The present invention is further described below in conjunction with the following figures and specific examples so that those skilled in the art may better understand the present invention and practice it, but the examples are not intended to limit the present invention.
Example one
As shown in fig. 1, the direct current heating system for air coil heating in the present embodiment is used for heating an air coil to be heated in a dry-type transformer to a target temperature, and includes a control center, a control system, and a measurement system, and the control system and the measurement system are both electrically connected to the control center.
The control system includes:
the positive electrode and the negative electrode of the direct current power supply are respectively connected with the DC + terminal and the DC-terminal, and a first direct current contactor KM1 is connected between the positive electrode and the DC + terminal of the direct current power supply;
the two ends of the freewheeling diode D are connected with the two ends of the hollow coil to be heated and are connected with the DC + terminal and the DC-terminal in an anti-parallel mode; the circuit breaker can prevent the break fault of the burst line in the direct current heating process, provide a counterattack electromotive force follow current path generated by the hollow coil and prevent the damage of the direct current power supply.
The measurement system includes:
the device comprises a voltage acquisition card and a current acquisition card, wherein the voltage acquisition card and the current acquisition card are respectively used for acquiring voltage and current data of the hollow coil to be heated in real time;
and the control center is used for calculating the real-time temperature of the hollow coil to be heated by combining the cold resistance and the cold temperature of the hollow coil to be heated according to the voltage and current data of the hollow coil to be heated.
In the present embodiment, the number of the direct-current power sources is one. Optionally, the direct current power supply is a 100A/20KW constant current source, a 300A/20KW constant current source, a 600A/20KW constant current source or the like.
Preferably, a second direct current contactor KM4 is connected between the DC + terminal connection and the DC-terminal, and the second direct current contactor KM4 is used for short-circuiting the DC + terminal and the DC-terminal in a non-heating state so as to prevent a direct current power supply from failing to output high voltage.
And the control center is also used for calculating the instantaneous resistance of the to-be-heated coil according to the instantaneous voltage and current data of the to-be-heated hollow coil acquired by the voltage acquisition card and the current acquisition card when the to-be-heated hollow coil is preheated, calculating the error between the instantaneous resistance and the cold resistance of the to-be-heated hollow coil, continuing to perform electric heating if the error is within a threshold range, and otherwise, stopping heating and finding out the reason of larger error.
Preferably, the voltage acquisition card is arranged at the position, closest to the hollow coil, of the tail end of the line, so that the influence of line impedance on measurement is reduced, and the current acquisition card is connected to the negative electrode of the direct-current power supply in series, so that the synchronous measurement of voltage and current is ensured.
The hollow coil is made of copper or aluminum, the resistance of the hollow coil also increases along with the rise of the temperature, and the calculation formula of the resistance along with the rise of the temperature is as follows:
Figure BDA0003459088600000051
wherein K is the temperature coefficient of the hollow coil material, copper is 235 and aluminum is 225; r0Is the cold resistance of the air core coil; t is t0Is the cold temperature of the air-core coil; rxReal-time resistance of air-core coil, txReal time temperature of the air core coil.
Wherein, the real-time resistance R of the air-core coilxCalculated by the following formula:
Figure BDA0003459088600000052
the real-time temperature calculation formula of the air core coil can be derived from the formula as follows:
Figure BDA0003459088600000053
wherein, txFor hollow wire to be heatedReal-time temperature of the coil, U being the voltage of the air core coil to be heated, I being the real-time current of the air core coil to be heated, R0Is the cold resistance of the air core coil to be heated, t0Is the cold temperature of the hollow coil to be heated, and K is the material temperature coefficient of the hollow coil to be heated.
Example two
As shown in fig. 2, the direct current heating system for air coil heating in the present embodiment is used for heating an air coil to be heated in a dry-type transformer to a target temperature, and includes a control center, a control system, and a measurement system, and the control system and the measurement system are both electrically connected to the control center.
The control system includes:
the positive electrode and the negative electrode of the direct current power supply are respectively connected with the DC + terminal and the DC-terminal, and a first direct current contactor KM1 is connected between the positive electrode and the DC + terminal of the direct current power supply;
the two ends of the freewheeling diode D are connected with the two ends of the hollow coil to be heated and are connected with the DC + terminal and the DC-terminal in an anti-parallel mode; the circuit breaker can prevent the break fault of the burst line in the direct current heating process, provide a counterattack electromotive force follow current path generated by the hollow coil and prevent the damage of the direct current power supply.
The measurement system includes:
the device comprises a voltage acquisition card and a current acquisition card, wherein the voltage acquisition card and the current acquisition card are respectively used for acquiring voltage and current data of the hollow coil to be heated in real time;
and the control center is used for calculating the real-time temperature of the hollow coil to be heated by combining the cold resistance and the cold temperature of the hollow coil to be heated according to the voltage and current data of the hollow coil to be heated.
In the present embodiment, the number of the direct-current power sources is two. The positive pole of each DC power source is connected to the DC + terminal through a first DC contactor. Optionally, the two DC power supplies are a 100A/20KW constant current source and a 300A/20KW constant current source, respectively, and the 100A/20KW constant current source and the 300A/20KW constant current source are connected through first DC contactors KM1 and KM2 and a DC + terminal, respectively. In other embodiments of the present invention, the two dc power supplies may be combined in other models according to needs, and are not limited specifically. And the control center is used for determining a corresponding direct current power supply according to the target temperature and the cold resistance of the hollow coil to be heated, and closing a first direct current contactor corresponding to the corresponding direct current power supply when heating is needed.
Preferably, a second direct current contactor KM4 is connected between the DC + terminal connection and the DC-terminal, and the second direct current contactor KM4 is used for short-circuiting the DC + terminal and the DC-terminal in a non-heating state so as to prevent a direct current power supply from failing to output high voltage.
And the control center is also used for calculating the instantaneous resistance of the to-be-heated coil according to the instantaneous voltage and current data of the to-be-heated hollow coil acquired by the voltage acquisition card and the current acquisition card when the to-be-heated hollow coil is preheated, calculating the error between the instantaneous resistance and the cold resistance of the to-be-heated hollow coil, continuing to perform electric heating if the error is within a threshold range, and otherwise, stopping heating and finding out the reason of larger error.
Preferably, the voltage acquisition card is arranged at the position, closest to the hollow coil, of the tail end of the line, so that the influence of line impedance on measurement is reduced, and the current acquisition card is connected to the negative electrode of the direct-current power supply in series, so that the synchronous measurement of voltage and current is ensured.
The formula and the origin of the real-time temperature calculation of the air-core coil are as described in the first embodiment, and are not described herein again.
EXAMPLE III
As shown in fig. 3, the direct current heating system for air coil heating in the present embodiment is used for heating an air coil to be heated in a dry-type transformer to a target temperature, and includes a control center, a control system, and a measurement system, and the control system and the measurement system are both electrically connected to the control center.
The control system includes:
the positive electrode and the negative electrode of the direct current power supply are respectively connected with the DC + terminal and the DC-terminal, and a first direct current contactor KM1 is connected between the positive electrode and the DC + terminal of the direct current power supply;
the two ends of the freewheeling diode D are connected with the two ends of the hollow coil to be heated and are connected with the DC + terminal and the DC-terminal in an anti-parallel mode; the circuit breaker can prevent the break fault of the burst line in the direct current heating process, provide a counterattack electromotive force follow current path generated by the hollow coil and prevent the damage of the direct current power supply.
The measurement system includes:
the device comprises a voltage acquisition card and a current acquisition card, wherein the voltage acquisition card and the current acquisition card are respectively used for acquiring voltage and current data of the hollow coil to be heated in real time;
and the control center is used for calculating the real-time temperature of the hollow coil to be heated by combining the cold resistance and the cold temperature of the hollow coil to be heated according to the voltage and current data of the hollow coil to be heated.
In the present embodiment, the number of the direct-current power sources is three. The positive pole of each DC power source is connected to the DC + terminal through a first DC contactor. Optionally, the three DC power sources are a 100A/20KW constant current source, a 300A/20KW constant current source, and a 600A/20KW constant current source, respectively, and the 100A/20KW constant current source, the 300A/20KW constant current source, and the 600A/20KW constant current source are connected through the first DC contactors KM1, KM2, KM3, and the DC + terminal, respectively. In other embodiments of the present invention, the three dc power supplies may be combined in other models according to requirements, and are not limited in particular. And the control center is used for determining a corresponding direct current power supply according to the target temperature and the cold resistance of the hollow coil to be heated, and closing a first direct current contactor corresponding to the corresponding direct current power supply when heating is needed.
Preferably, a second direct current contactor KM4 is connected between the DC + terminal connection and the DC-terminal, and the second direct current contactor KM4 is used for short-circuiting the DC + terminal and the DC-terminal in a non-heating state so as to prevent a direct current power supply from failing to output high voltage.
And the control center is also used for calculating the instantaneous resistance of the to-be-heated coil according to the instantaneous voltage and current data of the to-be-heated hollow coil acquired by the voltage acquisition card and the current acquisition card when the to-be-heated hollow coil is preheated, calculating the error between the instantaneous resistance and the cold resistance of the to-be-heated hollow coil, continuing to perform electric heating if the error is within a threshold range, and otherwise, stopping heating and finding out the reason of larger error.
Preferably, the voltage acquisition card is arranged at the position, closest to the hollow coil, of the tail end of the line, so that the influence of line impedance on measurement is reduced, and the current acquisition card is connected to the negative electrode of the direct-current power supply in series, so that the synchronous measurement of voltage and current is ensured.
The formula and the origin of the real-time temperature calculation of the air-core coil are as described in the first embodiment, and are not described herein again.
Example four
The embodiment discloses a direct current heating method for air coil heating, which is applied to the direct current heating system for air coil heating in the first embodiment, and the direct current heating method for air coil heating comprises the following steps:
A. connecting an air core coil to be heated to a preset position in the direct current heating system for heating the air core coil;
B. electrically heating the hollow coil to be heated, and respectively collecting voltage and current data of the hollow coil to be heated in real time through the voltage collection card and the current collection card;
C. the control center calculates the real-time temperature of the hollow coil to be heated according to the voltage and current data of the hollow coil to be heated and by combining the cold resistance and the cold temperature of the hollow coil to be heated;
D. and stopping electric heating until the real-time temperature of the hollow coil to be heated reaches the target temperature.
Preferably, between the steps A and B, the following steps are further included:
s1, preheating the hollow coil to be heated, and acquiring instantaneous voltage and current data of the hollow coil to be heated through the voltage acquisition card and the current acquisition card;
and S2, calculating the instantaneous resistance of the coil to be heated by the control center according to the instantaneous voltage and current data of the hollow coil to be heated acquired by the voltage acquisition card and the current acquisition card, calculating the error between the instantaneous resistance and the cold resistance of the hollow coil to be heated, continuing to perform electric heating if the error is within a threshold range, and otherwise, stopping heating and finding out the reason of larger error.
Optionally, in step B, voltage and current data of the air core coil to be heated are acquired every 1 second. Further, in other embodiments, the time interval of acquisition may be adjusted, such as 0.5 seconds, etc.
EXAMPLE five
The embodiment discloses a direct current heating method for air coil heating, which is applied to the direct current heating system for air coil heating in the second or third embodiment, and the direct current heating method for air coil heating comprises the following steps:
A. connecting an air core coil to be heated to a preset position in the direct current heating system for heating the air core coil;
B. the control center determines a corresponding direct current power supply according to the target temperature and the cold resistance of the hollow coil to be heated, closes a first direct current contactor corresponding to the corresponding direct current power supply, and disconnects other first direct current contactors;
C. electrically heating the hollow coil to be heated, and respectively acquiring voltage and current data of the hollow coil to be heated in real time through the voltage acquisition card and the current acquisition card;
D. the control center calculates the real-time temperature of the hollow coil to be heated according to the voltage and current data of the hollow coil to be heated and by combining the cold resistance and the cold temperature of the hollow coil to be heated;
E. and stopping electric heating until the real-time temperature of the hollow coil to be heated reaches the target temperature.
Preferably, between the steps B and C, the following steps are further included:
s1, preheating the hollow coil to be heated, and collecting instantaneous voltage and current data of the hollow coil to be heated through the voltage acquisition card and the current acquisition card;
and S2, calculating the instantaneous resistance of the coil to be heated by the control center according to the instantaneous voltage and current data of the hollow coil to be heated acquired by the voltage acquisition card and the current acquisition card, calculating the error between the instantaneous resistance and the cold resistance of the hollow coil to be heated, continuing to perform electric heating if the error is within a threshold range, and otherwise, stopping heating and finding out the reason of larger error.
Optionally, in step C, voltage and current data of the air core coil to be heated is acquired every 1 second. Further, in other embodiments, the time interval of acquisition may be adjusted, such as 0.5 seconds, etc.
The direct current heating system for heating the air core coil of the invention electrically heats the air core coil by the direct current power supply, can calculate the real-time temperature of the coil to be heated, can realize the rapid heating of the air core coil to be heated in the dry type transformer to the target temperature, has the advantages of high heating efficiency and uniform heating compared with the heating mode of the existing oven, and can shorten the heating time of the air core coil from the original 12-hour oven to about 1.5 hours.
The above embodiments are merely preferred embodiments for fully illustrating the present invention, and the scope of the present invention is not limited thereto. The equivalent substitution or change made by the technical personnel in the technical field on the basis of the invention is all within the protection scope of the invention. The protection scope of the invention is subject to the claims.

Claims (10)

1. The direct current heating system is used for heating the air core coil to be heated in the dry type transformer to a target temperature, and is characterized by comprising a control center, a control system and a measuring system, wherein the control system and the measuring system are electrically connected with the control center;
the control system includes:
the direct current power supply comprises a direct current power supply, a first direct current contactor and a second direct current contactor, wherein the positive electrode and the negative electrode of the direct current power supply are respectively connected with a DC + terminal and a DC-terminal;
the two ends of the freewheeling diode are connected with the two ends of the hollow coil to be heated and are connected with the DC + terminal and the DC-terminal in an anti-parallel mode;
the measurement system includes:
the device comprises a voltage acquisition card and a current acquisition card, wherein the voltage acquisition card and the current acquisition card are respectively used for acquiring voltage and current data of the hollow coil to be heated in real time;
and the control center is used for calculating the real-time temperature of the hollow coil to be heated by combining the cold resistance and the cold temperature of the hollow coil to be heated according to the voltage and current data of the hollow coil to be heated.
2. Direct current electric heating system for air coil heating according to claim 1, characterized in that the real-time temperature calculation formula of the air coil to be heated is as follows:
Figure FDA0003459088590000011
wherein, txFor the real-time temperature of the air core coil to be heated, U is the voltage of the air core coil to be heated, I is the current of the air core coil to be heated, R0Is the cold resistance of the air core coil to be heated, t0Is the cold temperature of the hollow coil to be heated, and K is the material temperature coefficient of the hollow coil to be heated.
3. The direct current heating system for air coil heating according to claim 1, wherein the control center is configured to calculate an instantaneous resistance of the air coil to be heated according to instantaneous voltage and current data of the air coil to be heated acquired by the voltage acquisition card and the current acquisition card when the air coil to be heated is preheated, calculate an error between the instantaneous resistance and a cold resistance of the air coil to be heated, continue the electric heating if the error is within a threshold range, and otherwise, stop the heating and find out a cause of a large error.
4. Direct current heating system for air coil heating according to claim 1, characterized in that a second direct current contactor is connected between the DC + terminal connection and the DC-terminal for short-circuiting the DC + terminal and the DC-terminal in a non-heating state.
5. The direct current heating system for air coil heating of claim 1 wherein said direct current power source is a plurality of different types, each having a positive terminal connected to said DC + terminal by a first direct current contactor.
6. The direct current heating system for air coil heating according to claim 5, wherein the control center is configured to determine a corresponding direct current power supply according to the target temperature and the cold resistance of the air coil to be heated, and to close the first direct current contactor corresponding to the corresponding direct current power supply when heating is required.
7. A DC heating system for air coil heating as claimed in claim 5 wherein said DC power source comprises a 100A/20KW constant current source, a 300A/20KW constant current source, a 600A/20KW constant current source.
8. Direct current electric heating method for air coil heating, applied to a direct current electric heating system for air coil heating according to any one of claims 1 to 7, characterized by comprising the steps of:
A. connecting an air core coil to be heated to a preset position in the direct current heating system for heating the air core coil;
B. electrically heating the hollow coil to be heated, and respectively collecting voltage and current data of the hollow coil to be heated in real time through the voltage collection card and the current collection card;
C. the control center calculates the real-time temperature of the hollow coil to be heated according to the voltage and current data of the hollow coil to be heated and by combining the cold resistance and the cold temperature of the hollow coil to be heated;
D. and stopping electric heating until the real-time temperature of the hollow coil to be heated reaches the target temperature.
9. The direct current heating method for air coil heating according to claim 8, further comprising, between steps a and B, the steps of:
s1, preheating the hollow coil to be heated, and acquiring instantaneous voltage and current data of the hollow coil to be heated through the voltage acquisition card and the current acquisition card;
and S2, calculating the instantaneous resistance of the coil to be heated by the control center according to the instantaneous voltage and current data of the hollow coil to be heated, which are acquired by the voltage acquisition card and the current acquisition card, calculating the error between the instantaneous resistance and the cold resistance of the hollow coil to be heated, continuing to perform electric heating if the error is within a threshold range, and otherwise, stopping heating and finding out the reason of larger error.
10. The direct current heating method for air coil heating according to claim 8, wherein in step B, voltage and current data of the air coil to be heated are collected every 1 second.
CN202210013998.3A 2022-01-06 2022-01-06 Direct current heating system and method for air-core coil heating Pending CN114496551A (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1656578A (en) * 2001-09-21 2005-08-17 Abb技术公开股份有限公司 DC voltage/current heating/gelling/curing of resin encapsulated distribution transformer coils
CN104801812A (en) * 2015-05-04 2015-07-29 辽宁工程技术大学 Arc striking device and arc striking method for vacuum brazing
CN105115620A (en) * 2015-07-15 2015-12-02 广州日滨科技发展有限公司 Winding temperature detection method and system and overheating protection method and system of three-phase synchronous door motor
CN109217591A (en) * 2018-07-20 2019-01-15 福建浦汇科技发展有限公司 A kind of casting aluminum rotor heating system and heating means

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1656578A (en) * 2001-09-21 2005-08-17 Abb技术公开股份有限公司 DC voltage/current heating/gelling/curing of resin encapsulated distribution transformer coils
CN104801812A (en) * 2015-05-04 2015-07-29 辽宁工程技术大学 Arc striking device and arc striking method for vacuum brazing
CN105115620A (en) * 2015-07-15 2015-12-02 广州日滨科技发展有限公司 Winding temperature detection method and system and overheating protection method and system of three-phase synchronous door motor
CN109217591A (en) * 2018-07-20 2019-01-15 福建浦汇科技发展有限公司 A kind of casting aluminum rotor heating system and heating means

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