CN116106614A - Transformer overvoltage sensor based on double magnetic core complementation principle - Google Patents

Transformer overvoltage sensor based on double magnetic core complementation principle Download PDF

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Publication number
CN116106614A
CN116106614A CN202211373694.4A CN202211373694A CN116106614A CN 116106614 A CN116106614 A CN 116106614A CN 202211373694 A CN202211373694 A CN 202211373694A CN 116106614 A CN116106614 A CN 116106614A
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frequency
magnetic core
winding
low
frequency magnetic
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黄昕
王广真
蔡睿
董建威
付德慧
袁帅
赵建勇
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Beijing Sifang Automation Co Ltd
China Electric Power Research Institute Co Ltd CEPRI
State Grid Beijing Electric Power Co Ltd
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Beijing Sifang Automation Co Ltd
China Electric Power Research Institute Co Ltd CEPRI
State Grid Beijing Electric Power Co Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
    • G01R19/16566—Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533
    • G01R19/16576—Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533 comparing DC or AC voltage with one threshold
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
    • G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
    • G01R15/18—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using inductive devices, e.g. transformers
    • G01R15/183—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using inductive devices, e.g. transformers using transformers with a magnetic core
    • G01R15/185—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using inductive devices, e.g. transformers using transformers with a magnetic core with compensation or feedback windings or interacting coils, e.g. 0-flux sensors
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
    • G01R19/16533—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the application
    • G01R19/16538—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the application in AC or DC supplies
    • 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
    • H01F27/24—Magnetic cores
    • 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
    • H01F27/28—Coils; Windings; Conductive connections
    • 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
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/30—Fastening or clamping coils, windings, or parts thereof together; Fastening or mounting coils or windings on core, casing, or other support
    • H01F27/306—Fastening or mounting coils or windings on core, casing or other support
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F30/00—Fixed transformers not covered by group H01F19/00
    • H01F30/06—Fixed transformers not covered by group H01F19/00 characterised by the structure
    • H01F30/16—Toroidal transformers

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
  • Measuring Magnetic Variables (AREA)
  • Transformers For Measuring Instruments (AREA)

Abstract

A transformer overvoltage sensor based on a double magnetic core complementation principle, wherein a primary side comprises a primary winding, and a secondary side comprises: a high frequency magnetic core, a low frequency magnetic core, a secondary winding, a compensation winding; the secondary winding comprises a high-frequency side second winding and a high-frequency low-frequency coupling winding; the high-frequency magnetic core is a magnetic ring prepared from a high-frequency material, and the low-frequency magnetic core is a magnetic ring prepared from a low-frequency material; and winding a compensation winding on the low-frequency magnetic core, winding a high-frequency side second winding on the high-frequency magnetic core, arranging the high-frequency magnetic core and the low-frequency magnetic core in parallel in the same axial direction, and then jointly winding a high-frequency low-frequency coupling winding on the high-frequency magnetic core and the low-frequency magnetic core to form a secondary winding through the high-frequency side second winding and the high-frequency low-frequency coupling winding. The invention maintains the through-core structure of the transformer, expands the equivalent frequency band of the through-core sensor in a passive complementary mode of the magnetic core, not only considers the reliability and accuracy of the overvoltage monitoring of the bushing end screen, but also solves the accurate transmission and transformation of different frequency signals.

Description

Transformer overvoltage sensor based on double magnetic core complementation principle
Technical Field
The invention relates to the technical field of on-line monitoring of electrical equipment, in particular to a transformer overvoltage sensor based on a double-magnetic-core complementary principle.
Background
The power transformer is one of the main devices in the power grid, and the safe operation of the transformer is a foundation of the reliability of the power grid. After the high-gradient overvoltage is attenuated by a bus or a line, the high-gradient overvoltage is injected into a transformer in different frequency bands, and winding insulation damage caused by high-voltage amplitude is generally not reversible, so that the overvoltage needs to be monitored to early warn of malignant accidents such as winding insulation faults. The main parameter of the overvoltage monitoring is voltage amplitude, the coverage area of the frequency of the overvoltage signal comprises all frequency points between the upper limit and the lower limit of the frequency, and the overvoltage sensor needs to realize stable transmission of the electric signal in the frequency band so as to monitor overvoltage of various incoming wave steepness.
Because the use of independent equipment to obtain overvoltage signals from the high-voltage end increases the occupied area and the maintenance amount of the equipment, the overvoltage monitoring of the transformer in the prior art generally obtains signals from the end screen of the capacitive sleeve, and the amplitude of the overvoltage is calculated through the end screen signals. The end screen of the capacitive sleeve needs to be reliably grounded, the acquisition components are generally not allowed to be connected in series, and the end screen grounding structure has certain requirements on the flux. The through type sensor can ensure that the grounding characteristic of the sleeve is not changed, and the safety of primary equipment is ensured to the greatest extent. Therefore, a through-type broadband sensor is needed for monitoring the overvoltage of the transformer, and the safe operation of the capacitive bushing can be ensured while accurately monitoring the voltage signal.
Conventional capacitive sensors require that the outgoing conductors not be grounded and can only be adapted to bushings that are both outgoing from the end screen and the secondary screen. Although the measuring mode of the series impedance of the transformer end screen has the advantages of good frequency characteristic and easiness in acquisition and measurement, the safety of the mode is generally questioned, the through-flow capacity of the grounding of the transformer sleeve end screen is destroyed, and the safe operation of main equipment is affected. The conventional through type transformer cannot cover the whole monitoring frequency band no matter adopting silicon steel, manganese zinc or nickel zinc materials, so that overvoltage at partial frequency division points cannot be transmitted correctly, and damage to the transformer caused by partial overvoltage cannot be identified. The working frequency band of the Rogowski coil is wider, the frequency band of the overvoltage of the transformer can be covered, but the air is used as a magnetic conduction material, the electromagnetic conversion efficiency is low, the induction potential of the Rogowski coil and the measured current have a differential relation, the measured current signal is required to be restored through an integration link of the broadband, the upper limit and the lower limit of the overvoltage frequency band of the transformer differ by 10 ten thousand times, the fluctuation range of the current change rate is overlarge, the implementation difficulty of an integration circuit of the Rogowski coil is very high, the manufacturing cost is high, and the requirements on components are also high.
Disclosure of Invention
In order to solve the defects in the prior art, the invention provides the transformer overvoltage sensor based on the double-magnetic-core complementation principle, which maintains the through-core structure of the transformer, expands the equivalent frequency band of the through-core sensor in a magnetic-core passive complementation mode, and realizes stable transmission of overvoltage amplitudes with different frequencies; the reliability and the accuracy of the overvoltage monitoring of the bushing end screen are considered, and the accurate transmission of signals with different frequencies is fundamentally solved.
The invention adopts the following technical scheme.
The invention provides a transformer overvoltage sensor based on a double-magnetic core complementation principle, which comprises a primary side and a secondary side, wherein the primary side comprises a winding number N 1 Is characterized in that:
the secondary side includes: a high frequency magnetic core, a low frequency magnetic core, a secondary winding, a compensation winding; the secondary winding comprises a high-frequency side second winding and a high-frequency low-frequency coupling winding;
the high-frequency magnetic core is a magnetic ring prepared from a high-frequency material, and the low-frequency magnetic core is a magnetic ring prepared from a low-frequency material;
winding a compensation winding on the low-frequency magnetic core, wherein the compensation winding is hinged with the low-frequency magnetic core only; winding a high-frequency side second winding on the high-frequency magnetic core, wherein the high-frequency side second winding is hinged with the high-frequency magnetic core only; after the high-frequency magnetic core and the low-frequency magnetic core are coaxially arranged in parallel, a high-frequency low-frequency coupling winding is wound on the high-frequency magnetic core and the low-frequency magnetic core together, and the high-frequency low-frequency coupling winding is hinged with the high-frequency magnetic core and the low-frequency magnetic core;
the secondary winding is formed by a high-frequency side second winding and a high-frequency low-frequency coupling winding.
The primary windings of the high-frequency magnetic core and the low-frequency magnetic core are of a common one-turn through structure.
The inner diameter and the outer diameter of the magnetic ring used by the high-frequency magnetic core and the low-frequency magnetic core are the same, but the heights of the magnetic rings used by the high-frequency magnetic core and the low-frequency magnetic core are different, and the proportional relation between the cross section area of the high-frequency magnetic core and the cross section area of the low-frequency magnetic core is adjusted through the height difference of the two magnetic rings.
The number of turns of the compensation winding is N b2 Turns, the number of turns of the second winding on the high frequency side is N b Turns, the turns of the high-frequency low-frequency coupling winding is N 2 -N b Turns, the number of turns of the secondary winding is N 2 Turns.
The winding direction of each winding is the same, and the winding direction includes: clockwise, anticlockwise.
One end of the compensation winding is connected with one end of the compensation impedance, and the other end of the compensation winding is connected with the other end of the compensation impedance; one end of the secondary winding is connected with one end of the secondary impedance, and the other end of the secondary winding is connected with the other end of the secondary impedance.
The compensating impedance is composed of RLC passive devices and has frequency selection characteristic.
The high-frequency magnetic core induced current satisfies the following relation:
Figure BDA0003925370770000031
the low frequency core induced current satisfies the following relationship:
Figure BDA0003925370770000032
in the middle of
I 1 For the primary current to be a primary current,
Figure BDA0003925370770000033
for the induction of a current to the high-frequency core,
Figure BDA0003925370770000034
a current is induced for the low frequency magnetic core,
N 1 for the number of turns of the primary winding,
N 2 for the number of secondary winding turns,
N b turns of the second winding at the high frequency side;
high frequency magnetic core induced current
Figure BDA0003925370770000035
And low frequency core induced current->
Figure BDA0003925370770000036
The excitation impedance of the high-frequency magnetic core and the low-frequency magnetic core are shunted in series relation and are not equal in size.
In the case of low frequency, the exciting impedance of the high frequency magnetic core is smaller than that of the low frequency magnetic core, the current is shunted from the exciting impedance of the high frequency magnetic core, and the current flowing through the secondary impedance is determined by the transformation ratio of the low frequency magnetic core;
in the case of high frequency, the exciting impedance of the high frequency magnetic core is larger than that of the low frequency magnetic core, the current is shunted from the exciting impedance of the low frequency magnetic core, and the current flowing through the secondary impedance is determined by the transformation ratio of the high frequency magnetic core;
in the case of the intermediate frequency, the equivalent value of the compensation impedance converted to the secondary side has a frequency selection characteristic, and the current on the excitation impedance of the high-frequency core and the excitation impedance of the low-frequency core is split.
Compared with the prior art, the transformer overvoltage sensor has the advantages that the performance is greatly improved, and the through type reliable grounding of the bushing end screen of the transformer is ensured.
The invention is based on the permeability characteristic of the magnetic material, has the characteristic of high signal transmission efficiency, balances the characteristics of different magnetic conductive characteristic materials in a coil turn number and secondary load mode, obtains higher transmission efficiency, can realize flatter transmission characteristics, is convenient for a subsequent circuit to restore an overvoltage signal in a digital acquisition mode, has low difficulty in system realization, and can greatly improve the overvoltage monitoring performance.
The invention uses magnetic medium as the transmission material, and the signal transmission efficiency is greatly improved relative to the Rogowski coil.
According to the invention, different secondary output windings are serially connected and output through the balance magnetic permeability difference of the winding circuit design, and the complementation of signal energy is realized in different frequency bands, so that the relatively flat transmission characteristic is realized in a wider frequency band, and the high-efficiency signal conversion efficiency is maintained.
Drawings
FIG. 1 is a schematic diagram of an overvoltage sensor of a transformer based on the principle of dual magnetic core complementation;
FIG. 2 is a schematic diagram of a transformer overvoltage sensor based on the dual core complementary principle according to the present invention;
FIG. 3 is an equivalent circuit diagram of a transformer overvoltage sensor based on the double magnetic core complementation principle;
the reference numerals in fig. 1 to 3 are explained as follows:
T 1 -high frequency core, T 2 -a low frequency core, a 1-secondary winding, a 2-compensation winding, a 3-high frequency side second winding, a 4-high frequency low frequency coupling winding;
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. The embodiments described herein are merely some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art without inventive faculty, are within the scope of the invention, based on the spirit of the invention.
The invention provides a transformer overvoltage sensor based on a double-magnetic core complementation principle, which comprises a primary side and a secondary side, wherein the primary side comprises a winding number N 1 Primary windings of (a); as shown in fig. 1, the secondary side includes: high-frequency magnetic core T 1 Low frequency core T 2 A secondary winding 1, a compensation winding 2; wherein the secondary winding 1 comprises a high frequency side second winding 3, a high frequency low frequency coupling winding 4.
The high-frequency magnetic core is a magnetic ring prepared by using a high-frequency material, and the low-frequency magnetic core is a magnetic ring prepared by using a low-frequency material. The high-frequency magnetic core and the low-frequency magnetic core are coaxially arranged in parallel. The transformer overvoltage sensor provided by the invention adopts a through-core structure, the current characteristics of the end screen ground are not changed, and the reliability of bushing insulation is ensured while overvoltage is collected.
The magnetic core used in the transformer overvoltage sensor is generally in a magnetic ring structure, and magnetic rings with different characteristics can be used according to different working frequencies of magnetic materials, including but not limited to: silicon steel belt magnetic ring, manganese zinc ferrite magnetic ring and nickel zinc ferrite magnetic ring. The invention selects one magnetic ring of low-frequency material and one magnetic ring of high-frequency material, and forms a broadband through sensor crossing the frequency characteristic of the materials in a compensation mode. Although materials such as silicon steel, manganese zinc, nickel zinc and the like cannot cover an overvoltage working frequency band, the overvoltage sensor provided by the invention adopts a double-magnetic core complementary mode, realizes stable transmission of the amplitude of an electric signal in a wide frequency band, and provides conditions for monitoring overvoltage signals in different frequency bands.
The inner diameter and the outer diameter of the magnetic ring used for the high-frequency magnetic core and the low-frequency magnetic core are the same, but the heights of the magnetic rings are different, and the proportional relation between the cross section area of the high-frequency magnetic core and the cross section area of the low-frequency magnetic core is adjusted through the height difference of the two magnetic rings.
Wherein, at the low-frequency magnetic core T 2 Upper winding N b2 A turn compensation winding 2, the compensation winding 2 being connected to the low-frequency core T only 2 A hinge; at the high-frequency core T 1 Upper winding N b A second winding 3 on the high frequency side, the second winding 3 on the high frequency side being connected to the high frequency core T only 1 A hinge; a high-frequency magnetic core T 1 And a low-frequency magnetic core T 2 After being coaxially arranged in parallel, the high-frequency magnetic core T 1 And a low-frequency magnetic core T 2 Upper common winding N 2 -N b A turn high-frequency low-frequency coupling winding 4, the high-frequency low-frequency coupling winding 4 and a high-frequency magnetic core T 1 And a low-frequency magnetic core T 2 Are hinged. The total number of turns is N through the high-frequency side second winding 3 and the high-frequency low-frequency coupling winding 4 2 Is provided for the secondary winding 1.
The winding direction of each winding is the same. The winding direction comprises: clockwise, anticlockwise.
As shown in fig. 2, one end of the compensation winding 2 is connected to a compensation impedance Z b The other end of the compensation winding 2 is connected with the compensation impedance Z b Is arranged at the other end of the tube; one end of the secondary winding 1 is connected with the secondary impedance Z 2 The other end of the secondary winding 1 is connected with the secondary impedance Z 2 And the other end of (2).
The general rule of magnetic materials is that the permeability of low frequency cores is high and the permeability of high frequency cores is low. High heightThe primary windings of the frequency magnetic core and the low-frequency magnetic core are of a common one-turn through structure, and the number of turns of the secondary windings coupled on the low-frequency magnetic core is N 2 -N b Turns, N, greater than the number of turns coupled to the high frequency core 2 Is small. By adopting the unequal turn mode, the gain of the low-frequency signal is compressed in equal proportion, so that the magnetic permeability of the low-frequency material is reduced equivalently, and the frequency band of the through type sensor is effectively expanded.
The frequency characteristic curve of the magnetic material is not an ideal linear type, the curve of the magnetic permeability changing along with the frequency is often in an arc-shaped attenuation characteristic, the magnetic permeability characteristics of two different materials cannot obtain an ideal transfer characteristic in a proportional superposition mode, a bulge can appear in a frequency band where high frequency and low frequency are connected, namely, the characteristics of the two magnetic materials can play a certain role in a medium frequency range, and the gain characteristic of the sensor is increased after superposition. Thus, the compensation winding and the compensation impedance Z are used b The sensor gain is subtracted.
Compensating impedance Z b The compensation impedance is not a single passive device, is composed of RLC passive devices, and can realize specific intermediate frequency impedance characteristics through proper RLC combination, and has frequency selection characteristics. The compensation impedance is larger in high-frequency band and low-frequency band, and the transmission characteristics of the sensor are not affected; the compensation impedance is smaller in the medium frequency band, so that the medium frequency magnetic flux of the low frequency magnetic core can pass through the second compensation winding degaussing loop, the gain of the low frequency magnetic core in the medium frequency band is reduced, the attenuation effect is achieved on the transmission characteristics of the sensor, and the gain of the sensor is flatter in the full frequency band, namely the transmission characteristics in the full frequency band are flatter. Therefore, the compensation impedance and the compensation winding are used for compensating the curves of different magnetic materials in a targeted manner, so that the overall transmission characteristic of the sensor is corrected.
The transformer overvoltage sensor provided by the invention can balance the magnetic core characteristics of two different working frequencies and different magnetic permeability by adjusting the compensation impedance and the secondary winding, realize linear transformation in a wide frequency band range, isolate overvoltage and relatively accurately transform the waveform of the overvoltage, and realize accurate monitoring of overvoltage with different incoming wave steepness.
An equivalent circuit diagram of the transformer overvoltage sensor with complementary double magnetic cores is shown in fig. 3.
The double-magnetic core sensor with one turn penetrating through the core can be equivalently connected with two transformers with different transformation ratios in series, and the high-frequency magnetic core T 1 The corresponding transformation ratio is large, and the low-frequency magnetic core T 2 The corresponding transformation ratio is small. Because the primary winding is of a through structure, the impedance of the primary part of the transformer is small, the primary current is not influenced, and the primary current can be regarded as a current source. The two mutual inductors induce current in the secondary coil according to respective turn ratios, wherein the high-frequency magnetic core induced current satisfies the following relation:
Figure BDA0003925370770000061
/>
the low frequency core induced current satisfies the following relationship:
Figure BDA0003925370770000062
in the middle of
I 1 For the primary current to be a primary current,
Figure BDA0003925370770000063
for the induction of a current to the high-frequency core,
Figure BDA0003925370770000064
a current is induced for the low frequency magnetic core,
N 1 for the number of turns of the primary winding,
N 2 for the number of secondary winding turns,
N b is the number of turns of the second winding on the high frequency side.
Induced current due to high frequency core
Figure BDA0003925370770000071
And low frequency core induced current->
Figure BDA0003925370770000072
In a series relationship and unequal magnitudes, the current in the equivalent circuit must be shunted through the excitation impedance.
At low frequencies, the excitation impedance Z of the high-frequency core m1 Smaller, the shunt current is mainly from Z m1 Through, due to the excitation impedance Z of the low-frequency core m2 Larger flow through the secondary impedance Z 2 Is basically determined by the transformation ratio of the low-frequency core.
At high frequencies, Z m2 Smaller and Z m1 Larger flow through the secondary impedance Z 2 Is basically determined by the transformation ratio of the high-frequency core.
The frequency characteristics of the core thus determine the main source of signal energy for each frequency band in the case of series. In the intermediate frequency band, due to the fact that the magnetic permeability of the two magnetic cores is not negligible, part of induced current must flow through Z with larger impedance m1 And Z m2 Thereby at the secondary impedance Z 2 The higher voltage is generated, and the gain of the intermediate frequency band signal is increased. The equivalent value of the compensation impedance converted to the secondary side is Z b ’，Z b ' have the characteristic of frequency selection, have lower impedance in the middle frequency band, can shunt Z m1 And Z m2 The intermediate frequency current ensures the stability of the gain in the intermediate frequency band. Z is Z b ' the impedance is large in the low frequency band and the high frequency band, and the transmission characteristics of the two parts are not affected.
The secondary impedance is connected to the secondary winding, is the load impedance of the back-end acquisition system, and can select resistive load and capacitive load according to an overvoltage calculation principle.
The overvoltage sensor provided by the invention uses two magnetic conductive materials with frequency characteristics as the magnetic cores of the through type transformer, balances the magnetic conductivity difference of different magnetic materials through the adjustment actions of turns and secondary load, obtains the proportional output signal of primary current, and realizes the relatively flat transmission characteristic, thereby creating favorable conditions for digital acquisition and digital integration of the rear end and realizing the acquisition of broadband overvoltage signals under the condition of ensuring the safe operation of the transformer sleeve.
Finally, it should be noted that the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that: modifications and equivalents may be made to the specific embodiments of the invention without departing from the spirit and scope of the invention, which is intended to be covered by the claims.

Claims (10)

1. A transformer overvoltage sensor based on a double magnetic core complementation principle comprises a primary side and a secondary side, wherein the primary side comprises a turn number N 1 Is characterized in that:
the secondary side includes: a high frequency magnetic core, a low frequency magnetic core, a secondary winding, a compensation winding; the secondary winding comprises a high-frequency side second winding and a high-frequency low-frequency coupling winding;
the high-frequency magnetic core is a magnetic ring prepared from a high-frequency material, and the low-frequency magnetic core is a magnetic ring prepared from a low-frequency material;
winding a compensation winding on the low-frequency magnetic core, wherein the compensation winding is hinged with the low-frequency magnetic core only; winding a high-frequency side second winding on the high-frequency magnetic core, wherein the high-frequency side second winding is hinged with the high-frequency magnetic core only; after the high-frequency magnetic core and the low-frequency magnetic core are coaxially arranged in parallel, a high-frequency low-frequency coupling winding is wound on the high-frequency magnetic core and the low-frequency magnetic core together, and the high-frequency low-frequency coupling winding is hinged with the high-frequency magnetic core and the low-frequency magnetic core;
the secondary winding is formed by a high-frequency side second winding and a high-frequency low-frequency coupling winding.
2. The transformer overvoltage sensor based on the dual core complementary principle of claim 1, wherein:
the primary windings of the high-frequency magnetic core and the low-frequency magnetic core are of a common one-turn through structure.
3. The transformer overvoltage sensor based on the dual core complementary principle of claim 1, wherein:
the inner diameter and the outer diameter of the magnetic ring used by the high-frequency magnetic core and the low-frequency magnetic core are the same, but the heights of the magnetic rings used by the high-frequency magnetic core and the low-frequency magnetic core are different, and the proportional relation between the cross section area of the high-frequency magnetic core and the cross section area of the low-frequency magnetic core is adjusted through the height difference of the two magnetic rings.
4. The transformer overvoltage sensor based on the dual core complementary principle of claim 1, wherein:
the number of turns of the compensation winding is N b2 Turns, the number of turns of the second winding on the high frequency side is N b Turns, the turns of the high-frequency low-frequency coupling winding is N 2 -N b Turns, the number of turns of the secondary winding is N 2 Turns.
5. The transformer overvoltage sensor based on the dual core complementary principle of claim 1, wherein:
the winding direction of each winding is the same, and the winding direction includes: clockwise, anticlockwise.
6. The transformer overvoltage sensor based on the dual core complementary principle of claim 1, wherein:
one end of the secondary winding is connected with one end of the secondary impedance, and the other end of the secondary winding is connected with the other end of the secondary impedance.
7. The transformer overvoltage sensor based on the dual core complementary principle of claim 1, wherein:
one end of the compensation winding is connected with one end of the compensation impedance, and the other end of the compensation winding is connected with the other end of the compensation impedance; one end of the secondary winding is connected with one end of the secondary impedance, and the other end of the secondary winding is connected with the other end of the secondary impedance.
8. The transformer overvoltage sensor based on the dual core complementary principle of claim 7, wherein:
the compensating impedance is composed of RLC passive devices and has frequency selection characteristic.
9. The transformer overvoltage sensor based on the dual core complementary principle of claim 8, wherein:
the high-frequency magnetic core induced current satisfies the following relation:
Figure QLYQS_1
the low frequency core induced current satisfies the following relationship:
Figure QLYQS_2
in the middle of
I 1 For the primary current to be a primary current,
Figure QLYQS_3
induce current for high frequency core, ">
Figure QLYQS_4
A current is induced for the low frequency magnetic core,
N 1 for the number of turns of the primary winding,
N 2 for the number of secondary winding turns,
N b turns of the second winding at the high frequency side;
high frequency magnetic core induced current
Figure QLYQS_5
And low frequency core induced current->
Figure QLYQS_6
The excitation impedance of the high-frequency magnetic core and the low-frequency magnetic core are shunted in series relation and are not equal in size.
10. The transformer overvoltage sensor based on the dual core complementary principle according to claim 9, wherein:
in the case of low frequency, the exciting impedance of the high frequency magnetic core is smaller than that of the low frequency magnetic core, the current is shunted from the exciting impedance of the high frequency magnetic core, and the current flowing through the secondary impedance is determined by the transformation ratio of the low frequency magnetic core;
in the case of high frequency, the exciting impedance of the high frequency magnetic core is larger than that of the low frequency magnetic core, the current is shunted from the exciting impedance of the low frequency magnetic core, and the current flowing through the secondary impedance is determined by the transformation ratio of the high frequency magnetic core;
in the case of the intermediate frequency, the equivalent value of the compensation impedance converted to the secondary side has a frequency selection characteristic, and the current on the excitation impedance of the high-frequency core and the excitation impedance of the low-frequency core is split.
CN202211373694.4A 2022-11-03 2022-11-03 Transformer overvoltage sensor based on double magnetic core complementation principle Pending CN116106614A (en)

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