CN117590312A - Separated double-compensation broadband current comparator - Google Patents
Separated double-compensation broadband current comparator Download PDFInfo
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- CN117590312A CN117590312A CN202311504845.XA CN202311504845A CN117590312A CN 117590312 A CN117590312 A CN 117590312A CN 202311504845 A CN202311504845 A CN 202311504845A CN 117590312 A CN117590312 A CN 117590312A
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- 238000004804 winding Methods 0.000 claims abstract description 216
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 83
- 238000001514 detection method Methods 0.000 claims abstract description 20
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910052802 copper Inorganic materials 0.000 claims abstract description 8
- 239000010949 copper Substances 0.000 claims abstract description 8
- 230000006698 induction Effects 0.000 claims description 14
- 239000003990 capacitor Substances 0.000 claims description 9
- 230000001939 inductive effect Effects 0.000 claims description 6
- 230000035699 permeability Effects 0.000 claims description 6
- 239000004519 grease Substances 0.000 claims description 5
- 229920001296 polysiloxane Polymers 0.000 claims description 5
- 239000000463 material Substances 0.000 claims description 3
- 229910000889 permalloy Inorganic materials 0.000 claims description 3
- 230000004907 flux Effects 0.000 description 9
- 238000010586 diagram Methods 0.000 description 5
- 239000013080 microcrystalline material Substances 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 230000035945 sensitivity Effects 0.000 description 3
- 230000005684 electric field Effects 0.000 description 2
- 230000005672 electromagnetic field Effects 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 229910000976 Electrical steel Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R35/00—Testing or calibrating of apparatus covered by the other groups of this subclass
- G01R35/02—Testing or calibrating of apparatus covered by the other groups of this subclass of auxiliary devices, e.g. of instrument transformers according to prescribed transformation ratio, phase angle, or wattage rating
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R35/00—Testing or calibrating of apparatus covered by the other groups of this subclass
- G01R35/005—Calibrating; Standards or reference devices, e.g. voltage or resistance standards, "golden" references
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Abstract
The invention relates to a split type double-compensation broadband current comparator which comprises a main iron core, a detection winding, a primary winding, a secondary winding, an externally-attached auxiliary transformer, a copper shield, a first-layer magnetic shielding iron core, a second-layer magnetic shielding iron core and a small current transformer, wherein the primary winding and the secondary winding are respectively provided with a compensation winding, and the primary winding, the second-layer magnetic shielding iron core and the secondary winding form an internally-attached auxiliary transformer; the external auxiliary transformer is connected with the internal auxiliary transformer in series, an external secondary compensation winding of the external auxiliary transformer is connected with a secondary compensation winding corresponding to the secondary winding through a virtual load, and the virtual load is connected with the secondary compensation winding in series. The invention reduces the magnetic error and the capacitive error of the comparator, improves the accuracy of the current comparator, and reaches 5 multiplied by 10 at the frequency of 1kHz ‑7 。
Description
Technical Field
The invention relates to the technical field of current comparators, in particular to a split type double-compensation broadband current comparator.
Background
The current proportion standard is a current transformer which is specially used for detecting that the magnetic flux of the current transformer is extremely small and even reaches zero magnetic flux. Currently, there are mainly two-stage current transformers, compensation type current transformers, zero-flux current transformers, induction shunts, current comparators and the like. The current comparator has the highest accuracy, and the difference between the current comparator and a common current transformer is that the main iron core of the current comparator is in a zero-flux or near-zero-flux working state. The iron core does not need exciting current, has no or little error of a current transformer, and has magnetic error and capacitive error, so the accuracy is very high. The current comparator consists of an iron core and a coil except for a proportion primary coil N 1 And a second order N 2 In addition, there is a nulling coil N D And (5) connecting a zero indicator. When the zero indicator D indicates zero, the iron core of the comparator is in zero magnetic flux state, soThe ampere-turns are balanced, so the comparator is also called an ampere-turn balance indicator for calibrating the current transformer.
Early current comparators were passive comparators with the principle lines shown in fig. 2 below.
The passive comparator has compensating coil N besides the iron core proportion coil and the zero-pointing coil B The error current of the current transformer to be detected is input. Calibrating current to each other using passive comparatorWhen the sensor is used, the internal resistance of the secondary coil of the current comparator is an additional secondary load of the current transformer, and the error of the current transformer is affected. Therefore, currently, compensation type current comparators are mostly adopted in the verification of current transformers, and principle circuits of the compensation type current comparators are shown in fig. 3.
The shielding iron core of the comparator is used as an auxiliary transformer iron core; the secondary load is carried by the auxiliary transformer, including the internal impedance load of the secondary coil of the comparator. The compensation type comparator has the advantages that although the auxiliary transformer is used for bearing most secondary load, the impedance of a compensation winding loop, including the internal resistance of the secondary compensation winding, cannot be overcome or compensated, so that the proportional winding of the current comparator has induced potential, and therefore capacitive errors are generated, particularly, the current of the proportional winding is small, the number of winding turns is large, the frequency is high (1 kHz), and the capacitive errors can be large; in addition, the compensation type current comparator generally compensates only the secondary load of the comparator, and does not compensate the primary winding of the comparator, and in particular, when the number of turns of the primary winding is relatively large, capacitive errors are similarly generated when the frequency is relatively high. The compensation type current comparator only uses an auxiliary transformer iron core as a magnetic shielding iron core, has poor shielding effect, is easily influenced by electromagnetic interference signals inside and outside the current comparator, has poor adjustment sensitivity and poor stability for adjusting zero magnetic flux of the current comparator, and has the current proportion standard that the common working frequency is 50Hz and the highest accuracy is 10 at present -6 The magnitude of the voltage is large, and the induced potential is large, so that the zeroing range of the comparator is large, and the zeroing stability and sensitivity are affected. In order to develop the wideband (1 kHz) current proportion standard and self-calibration system, the accuracy of the development is 10 -7 The magnitude broadband current proportion standard must be improved on the basis of the traditional compensation type, measures are taken to improve the working frequency of the current comparator on one hand and the accuracy level of the current comparator on the other hand, and therefore, the compensation separated broadband current comparator with multiple shielding and multiple compensation is provided.
Disclosure of Invention
In order to solve the technical problems in the prior art, the invention aims to provide a split type double-compensation broadband current comparator which solves the problem that the broadband high-accuracy current proportion cannot be met in the prior art.
In order to achieve the above purpose, the invention provides a split type double-compensation broadband current comparator, which comprises a main iron core, a detection winding, a primary winding, a secondary winding, an externally-attached auxiliary transformer, a copper shield, a first layer of magnetic shielding iron core, a second layer of shielding iron core and a small current transformer, wherein the primary winding and the secondary winding are respectively provided with a compensation winding, and the primary winding, the second layer of shielding iron core and the secondary winding form an internally-attached auxiliary transformer;
the external auxiliary transformer is connected with the internal auxiliary transformer in series, an external secondary compensation winding of the external auxiliary transformer is connected with a secondary compensation winding corresponding to the secondary winding through a virtual load, and the virtual load is connected with the secondary compensation winding in series.
According to one aspect of the present invention, the first layer magnetic shielding iron core surrounds the main iron core and the detection winding, and the first layer magnetic shielding iron core is a high-permeability iron core;
the second layer of shielding is an iron core with high saturation induction intensity.
According to one aspect of the invention, the detection winding is uniformly wound on the main iron core by adopting a non-directional structure, and two ends of the detection winding are led out by shielding wires.
According to one aspect of the invention, the small current transformer comprises a first small current transformer for compensating angular difference and a second small current transformer for directly compensating ratio difference;
the first small current transformer is provided with a resistance-capacitance shunt compensation circuit.
According to one aspect of the invention, the secondary load of the split double-compensation broadband current comparator is borne by the internal auxiliary current transformer, and the total secondary load impedance Z of the split double-compensation broadband current comparator 02 Compensating for by compensation windings
According to one aspect of the invention, the first layer of magnetic shielding iron core is composed of 4 magnetic cores, and the overlapping parts of the magnetic cores are arranged in an insulating mode.
According to one aspect of the invention, the iron core of the externally-attached auxiliary transformer is a microcrystalline material iron core, a protection box is wrapped outside the iron core, and silicone grease paper is wound outside the protection box.
According to one aspect of the invention, the dummy load at least comprises a resistor, a capacitor, a current transformer, a voltage transformer and a multi-disc induction voltage divider, wherein the input current of the dummy load is provided by the external auxiliary transformer, the input current passes through the current transformer, the voltage with quadrature phase and in-phase is generated at the induction end of the current transformer through the resistor and the capacitor, the phase and amplitude adjustable phasor voltage is generated through the voltage division of the induction voltage divider, and the phasor voltage is output after passing through the voltage transformerThe impedance of the dummy load is +.>
According to one aspect of the invention, the primary winding and the secondary winding are of a split winding structure.
According to one aspect of the invention, the main iron core is a permalloy iron core with high initial magnetic permeability.
According to the conception of the invention, the split type double-compensation broadband current comparator adopts a layer of copper shielding and a layer of magnetic shielding of two layers of electromagnetic shielding, and the detection coil adopts a non-directional structure, so that the magnetic error and the capacitive error of the comparator are reduced, and the accuracy of the current comparator is improved.
The separated double-compensation broadband current comparator provided by the invention has the advantages that the primary winding and the secondary winding are both compensation windings, so that the double-compensation current comparator is formed, the induced potential of the primary winding and the secondary winding is compensated, the capacitive error of the comparator is reduced, meanwhile, the primary compensation winding can be indirectly grounded, and the problem that a primary loop can be grounded without adopting a Van branch when a transformer is detected is solved.
According to the split type double-compensation broadband current comparator, the primary winding and the secondary winding are of the split winding structure, the number of turns of an empty winding is effectively reduced, the induced potential of the winding is reduced, and therefore capacitive errors are reduced, and the accuracy of the current comparator is improved.
The split type double-compensation broadband current comparator adopts the external auxiliary current transformer, the error of the external auxiliary current transformer bears the total impedance of most or all secondary loops originally borne by the internal auxiliary current transformer, on one hand, the magnetic induction intensity of an iron core of the internal current transformer is greatly reduced, the induced potential of a proportional winding of the comparator is reduced, and on the other hand, the ampere-turns number of the proportional winding can be reduced, so that the capacitance error of the current comparator is further reduced by 1-2 orders of magnitude. Meanwhile, the error of the externally attached auxiliary transformer is small, and the stability of the current comparator can be improved.
The invention relates to a separated double-compensation broadband current comparator, wherein the potential of a secondary compensation loop adopts negative impedance compensation, and an adjustable simulation current load Z is connected in series F The total impedance of the secondary compensation loop is ensured to be zero, and the induced electromotive force is ensured to be zero, so that the current comparator is ensured to reach a zero magnetic flux state, and the highest accuracy level is achieved. After the potential compensation of the secondary compensation winding, the adjustment range of the negative impedance and the impedance angle are very convenient, and dead angles can not occur.
The split type double-compensation broadband current comparator adopts a small current transformer and resistance-capacitance shunt local error compensation, and ensures that all transformation ratios of current proportion standards are adjusted to the highest accuracy level.
In summary, the accuracy of the split double-compensation broadband current comparator reaches 5 multiplied by 10 under the frequency of 1kHz -7 。
Drawings
FIG. 1 schematically shows a schematic diagram of a split dual-compensation broadband current comparator according to an embodiment of the present invention;
FIG. 2 schematically shows a schematic diagram of a passive current comparator of the prior art;
FIG. 3 is a schematic diagram of a prior art compensated current comparator;
FIG. 4 is a schematic diagram showing the principle of a 5A/5A-50A/5A broadband current comparator according to one embodiment of the present invention;
FIG. 5 schematically illustrates a main body of a broadband current comparator according to an embodiment of the present invention;
fig. 6 schematically shows a schematic view of a coil wound structure section (single loop) of a compensation current comparator according to an embodiment of the invention.
Detailed Description
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments will be briefly described below. It is apparent that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained from these drawings without inventive effort for a person of ordinary skill in the art.
In describing embodiments of the present invention, the terms "longitudinal," "transverse," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in terms of orientation or positional relationship shown in the drawings for convenience of description and simplicity of description only, and do not denote or imply that the devices or elements in question must have a particular orientation, be constructed and operated in a particular orientation, so that the above terms are not to be construed as limiting the invention.
The present invention will be described in detail below with reference to the drawings and the specific embodiments, which are not described in detail herein, but the embodiments of the present invention are not limited to the following embodiments.
Referring to FIG. 1, the split dual-compensation broadband current comparator of the invention comprises a main iron core T 1 Detection winding N D Primary winding N L Secondary winding N K External auxiliary transformer and copper shield T C First layer magnetic shielding iron core T 2 Second layer shielding iron core T 3 The primary winding and the secondary winding are respectively provided with a compensation winding, and the primary winding, the second layer of shielding iron core and the secondary winding form an internal auxiliary transformer;
the external auxiliary transformer is connected with the internal auxiliary transformer in series, and an external secondary compensation winding of the external auxiliary transformer is connected with a secondary compensation winding corresponding to the secondary winding through a virtual load Z, wherein the virtual load Z is connected with the secondary compensation winding in series.
In this embodiment, the primary winding and the secondary winding of the current comparator are both provided with compensation windings, and copper shield T is used C First layer magnetic shielding iron core T 2 Second layer shielding iron core T 3 Triple electromagnetic shielding improves shielding effect, reduces magnetic error, and increases an externally-attached auxiliary transformer, wherein the error of the externally-attached auxiliary transformer is far smaller than that of an internally-attached transformer, the externally-attached auxiliary transformer is used for bearing most or all total secondary loop impedance originally borne by the internally-attached auxiliary transformer, on one hand, the magnetic induction intensity of an iron core of the internally-attached current transformer is greatly reduced, the induction potential of a proportional winding of a comparator is reduced, and on the other hand, the ampere turn number of the proportional winding can be reduced, so that the capacitive error of the current comparator is further reduced, the externally-attached auxiliary transformer is small in error, and the stability of the current comparator can be improved.
Further, the externally-attached auxiliary transformer is connected into the secondary compensation winding N through the virtual load Z k Virtual load is connected in series with the secondary compensation winding N k And therefore, the current comparator is ensured to reach a zero magnetic flux state and reach the highest accuracy level. Through the secondary compensation winding N k After the potential compensation of the capacitor is carried out, the adjusting range of the negative impedance is obviously reduced, the impedance angle is very convenient to adjust, and dead angles can not occur.
Specifically, the secondary load of the compensation type current comparator is supported by an auxiliary transformer, the magnetic induction intensity of the auxiliary iron core is higher, the number of turns of a secondary proportional winding (secondary winding) is more, the distributed capacitance is large, the induced electromotive force is high along with the improvement of the working frequency, the capacitive error is large, in order to reduce the capacitive error caused by the induced potential of the proportional winding of the current comparator, a separated structure is adopted, a current transformer with the same current ratio is added as an externally-attached current transformer, the current transformer is connected in series with the original compensation type current comparator, and the current transformer and the original compensation type current comparator form the separation compensation type current comparator.
In one embodiment of the present invention, preferably, the first layer magnetic shield iron core T 2 Surrounding the main iron core T 1 And detecting winding N D First layer magnetic shielding iron core T 2 Is a high permeability iron core;
the second layer of shielding is an iron core with high saturation induction intensity.
In this embodiment, a layer of copper shield T is used C Two layers of magnetic shielding, wherein, the first layer of magnetic shielding iron core T 2 The main iron core T is made of high-permeability iron core 1 And detecting winding N D The magnetic flux leakage generated by the internal magnetic field and the external magnetic field is effectively prevented from entering the detection winding N after being surrounded D To reduce magnetic errors; the second layer of shielding adopts an iron core with higher saturation induction intensity, so that local internal and external magnetic fields can be effectively prevented from entering the compensation winding and the detection winding N D The shielding effect is further improved, and the magnetic error is reduced; besides magnetic shielding, copper shielding T is also adopted C The influence of an external electric field can be effectively reduced, and the capacitive error introduced by the space electromagnetic field of the current comparator is reduced. The magnetic core with high magnetic permeability is adopted, and before zero magnetic flux is reached in the zeroing process of the main magnetic core, the error of the current comparator is determined by the magnetic core formed by combining the shielding magnetic core and the main magnetic core.
In one embodiment of the invention, the winding N is preferably detected D Uniformly winding and main iron core T by adopting unoriented structure 1 On the detection winding N D The two ends of the coil are led out by the shielding wires, so that leakage current generated by a space electric field is effectively reduced and enters the detection winding N D The capacitive error caused by the electromagnetic field in the external space is reduced, so that the main iron core T is improved 1 The stability and sensitivity of the zero magnetic flux are adjusted.
In practice, each winding adopts a uniform winding, particularly the primary winding and the secondary winding are required to be wound uniformly, and the two windings are required to be close to each other as much as possible, so that the magnetic coupling is improved, the internal magnetic leakage is reduced, and the magnetic error is reduced. And the primary winding and the secondary winding are of a breaking winding structure, so that the number of turns of an empty winding is effectively reduced, the induced potential of the winding is reduced, and the capacitive error is reduced.
In one embodiment of the present invention, preferably, the small current transformer includes a first small current transformer for compensating for an angular difference and a second small current transformer for directly compensating for a ratio difference;
the first small current transformer is provided with a resistance-capacitance shunt compensation circuit.
In this embodiment, to fine tune the accuracy of the individual ratios, a small current transformer shunt local ratio difference and angle compensation are employed, and the compensated loop current is input into the compensation winding N through the small current transformer shunt P The small magnetic potential of the fractional turn is obtained to compensate the ratio difference of the comparator, and the small current transformer is shunted and then shunted through the resistance-capacitance, and is input into the compensation winding N P The fractional turn minute magnetic potential obtained compensates the angular difference of the comparator.
In one embodiment of the present invention, preferably, the secondary load of the split-type dual-compensation broadband current comparator is borne by the internal auxiliary current transformer, and the total secondary load impedance Z of the split-type dual-compensation broadband current comparator 02 Compensating for by compensation windings
In this embodiment of the present invention, in one embodiment,is a first layer magnetic shielding iron core T 2 The exciting current of the auxiliary transformer is more than two orders of magnitude smaller than the secondary current of the proportional winding of the current comparator, so that the total secondary load of the current comparator is achievedImpedance Z 02 The voltage drop can be reduced by about two orders of magnitude, thereby reducing the induced potential of the proportional winding of the current comparator and thus reducing the capacitive error of the current comparator. Meanwhile, when the mutual inductor is detected, the primary compensation winding N of the comparator b The circuit can be used for indirect grounding of a primary loop, so that the grounding problem of adopting a Van der Waals branch circuit to adjust is avoided, and convenience is improved.
In one embodiment of the present invention, preferably, the first layer magnetic shield iron core T 2 The magnetic core is composed of 4 magnetic cores, and the overlapped parts of the magnetic cores are arranged in an insulating way.
In this embodiment, the first layer magnetic shield core T composed of 4 magnetic cores 2 Is greater than the total section of the main iron core T 1 The magnetic core is made of a material with high magnetic conductivity, so that the error of the comparator is reduced, and the stability of the current comparator is improved.
In one embodiment of the present invention, it is preferable that the core T of the auxiliary transformer is externally attached 4 A microcrystalline iron core is adopted, a protection box is wrapped outside the microcrystalline iron core, and silicone grease paper is wound on the outer side of the protection box.
In one embodiment of the present invention, preferably, the dummy load Z at least includes a resistor, a capacitor, a current transformer, a voltage transformer and a multi-disc inductive voltage divider, the input current of the dummy load is provided by the external auxiliary transformer, the input current passes through the current transformer, the voltages of quadrature and in-phase are generated at the inductive end of the current transformer through the resistor and the capacitor load, the voltage divided by the inductive voltage divider generates phasor voltages with adjustable phase and amplitude, and the phasor voltages are output after passing through the voltage transformerThe impedance of the dummy load is +.>
In one embodiment of the present invention, preferably, the main iron core T 1 Is a permalloy material iron core with higher initial permeability.
The invention is illustrated in more detail by the following examples.
The general structure of the broadband current comparator is shown in FIG. 4, and consists of a main iron core T 1 Detection winding N D Copper shield T C First layer magnetic shielding iron core T 2 Secondary compensation winding N B Primary compensation winding N b Second layer shielding iron core T 3 (also with auxiliary transformer core), secondary winding N K Primary winding N L Iron core T of externally-attached auxiliary transformer 4 Secondary winding N of externally-attached auxiliary transformer k Primary compensation winding N of externally-attached auxiliary transformer l And an adjustable virtual load Z, a small current transformer resistance-capacitance shunt compensation circuit and the like. The internal structure of the main body of the broadband current comparator is shown in fig. 5, and the schematic diagram of the structural section (single ring) of the coil winding of the main body (including the main iron core) is shown in fig. 6.
Case 1
In the figure, L1L2, L3L4, L5L6 and L7L8 are 4 groups of independent primary windings, respectively N L12 、N L34 、N L56 、N L78 The corresponding turns are respectively 15 turns, 30 turns, 60 turns and 120 turns, K1-K8 are respectively 4 independent groups of secondary windings of the comparator, and are respectively N k12 、N k34 、N k56 、N k78 Corresponding turns are 120 turns, 60 turns, 30 turns and 15 turns respectively, corresponding B1-B8 and B1-B8 are respectively 4 groups of independent primary compensation windings and secondary compensation windings, the turns are the same as the corresponding primary and secondary windings, and the primary compensation windings are respectively N b12 、N b34 、N b56 、N b78 . Corresponding l 1-l 8 and k 1-k 8 are respectively independent primary windings and secondary windings of the auxiliary current transformer 4 groups, wherein the primary windings of the auxiliary current transformer are respectively N l12 、N l34 、N l56 、N l78 The corresponding turns are respectively 15 turns, 30 turns, 60 turns and 120 turns; the secondary windings are respectively N k12 、N k34 、N k56 、N k78 The corresponding turns are 120 turns, 60 turns, 30 turns and 15 turns respectively. J is a shielding socket of a detection winding of the comparator, and the outer shielding and ground terminal button of the shielding socketIs connected with each other.
In the figure, the marks L1L2, L3L4, L5L6 and L7L8 are 4 groups of independent primary windings, and are respectively N L12 、N L34 、N L56 、N L78 The corresponding turns are respectively 15 turns, 30 turns, 60 turns and 120 turns, are not connected in series and are used independently. The marks K1-K8 are respectively independent 4 groups of secondary windings of the comparator, and are connected in series and respectively N k12 、N k34 、N k56 、N k78 The corresponding turns are 120 turns, 60 turns, 30 turns and 15 turns respectively, and are not connected in parallel, and four secondary windings of 135 turns, 150 turns, 180 turns and 210 turns can be formed by adopting positive series connection, so that five secondary winding turns of 120 turns, 135 turns, 150 turns, 180 turns and 210 turns can be obtained, and 600 ampere turns, 675 ampere turns, 750 ampere turns, 900 ampere turns and 1050 ampere turns can be obtained, and accordingly, 10 current ratios of 5A/5A, 10A/5A, 15A/5A, 20A/5A, 25A/5A, 30A/5A, 35A/5A, 40A/5A, 45A/5A, 50A/5A and the like can be formed. The corresponding B1-B8 and B1-B8 are respectively 4 groups of independent primary compensation windings and secondary compensation windings, the number of turns of the primary compensation windings is the same as that of the corresponding primary and secondary windings, and the primary compensation windings are respectively N b12 、N b34 、N b56 、N b78 . Corresponding l 1-l 8 and k 1-k 8 are respectively independent primary windings and secondary windings of the auxiliary current transformer 4 groups, wherein the primary windings of the auxiliary current transformer are respectively N l12 、N l34 、N l56 、N l78 The corresponding turns are respectively 15 turns, 30 turns, 60 turns and 120 turns; the secondary windings are respectively N k12 、N k34 、N k56 、N k78 The corresponding turns are 120 turns, 30 turns, 15 turns and 15 turns respectively. J is a shielding socket of a detection winding of the comparator, and the outer shielding and ground terminal button of the shielding socketIs connected with each other.
The current comparators 5A/5A-50A/5A have 10 rated current ratios, and the wiring of each winding is shown in Table 1 under different ratios.
TABLE 1
In each winding table 1 of the broadband current comparator of 5A/5A-50A/5A, L1L2L 2 represents that L1L2 is connected with two windings of L1L2 in series, K1K2, K3K4, K5K6, K1K2, K3K4 and K5K6 represent that 6 windings K1K2, K3K4 and K5K6 are connected with K1K2, K3K4 and K5K6 in series. The corresponding compensation winding connections are also identical.
Case 2
In the figure, the marks L1L2, L3L4, L5L6 and L7L8 are 4 groups of independent primary windings, and are respectively N L12 、N L34 、N L56 、N L78 The corresponding turns are respectively 15 turns, 30 turns, 60 turns and 120 turns, are not connected in series and are used independently. The sign is K1-K8, the secondary windings of 4 groups of comparators are independent, and are connected in series (positive or negative strings) respectively as Nk 12 、Nk 34 、Nk 56 、Nk 78 The corresponding turns are 120 turns, 30 turns, 15 turns and 15 turns respectively, three secondary windings which can form 135 turns, 150 turns and 180 turns in positive series connection are not adopted, one secondary winding which can form 105 turns in reverse series connection is adopted, thus five secondary winding turns of 105 turns, 120 turns, 135 turns, 150 turns and 180 turns can be obtained, and 525 ampere turns, 600 ampere turns, 675 ampere turns and 750 ampere turns can be obtained, and accordingly, 10 current ratios of 5A/5A, 10A/5A, 15A/5A, 20A/5A, 25A/5A, 30A/5A, 35A/5A, 40A/5A, 45A/5A, 50A/5A and the like can be formed. The corresponding B1-B8 and B1-B8 are respectively 4 groups of independent primary compensation windings and secondary compensation windings, the number of turns of the primary compensation windings is the same as that of the corresponding primary and secondary windings, and the primary compensation windings are respectively N b12 、N b34 、N b56 、N b78 . Corresponding l 1-l 8 and k 1-k 8 are respectively independent primary windings and secondary windings of the auxiliary current transformer 4 groups, wherein the primary windings of the auxiliary current transformer are respectively N l12 、N l34 、N l56 、N l78 The corresponding turns are respectively 15 turns, 30 turns, 60 turns and 120 turns; the secondary windings are respectively N k12 、N k34 、N k56 、N k78 The corresponding turns are 120 turns, 30 turns, 15 turns and 15 turns respectively. J is a comparisonShielding socket of instrument detection winding, its outer shielding and ground terminal buttonIs connected with each other.
The current comparators 5A/5A-50A/5A have 10 rated current ratios, and the wiring of each winding is shown in Table 2 under different ratios.
TABLE 2
In table 2, L1L2 represents that L1L2 and L1L2 are connected in series in a positive series of two windings, K1K2, K3K4, K5K6, K7K8 represent that 8 windings K1K2, K3K4, K5K6 and K1K2, K3K4, K5K6, K7K8 are connected in series in a negative series of K1K2 and K5K 6. The corresponding compensation winding connections are also identical.
The invention relates to a separated double-compensation broadband current comparator, which comprises the following components in detail:
main iron core T 1 The method comprises the steps of adopting a Bomo alloy material iron core with higher initial magnetic conductivity, firstly, arranging a main magnetic core T 1 Winding a thin layer of silicone grease paper, and then uniformly winding a detection winding N in a non-directional manner d The winding is wound around the iron core in opposite mode with wire, and the two ends of the winding are led out with the shielding wire. Then at the detection winding N d After a layer of insulating paper is wound around the periphery of the transformer, a first layer of magnetic shielding iron core T is arranged 2 First layer magnetic shielding iron core T 2 Consists of 4 magnetic cores, namely an inner screen, an outer screen and two side screens, wherein N is as follows d The windings are wrapped around but when the 4 cores are stacked together, insulation should be applied to the overlap to prevent the 4 cores from forming a turn short circuit.
At the magnetic shielding core T 2 Firstly, winding a layer of insulating paper, then uniformly winding a secondary compensation winding, and winding a layer of insulating paper outside the secondary compensation winding to wind a primary compensation winding. Wherein the number of turns of the primary and secondary compensation windings is the same as the number of turns of the primary and secondary windings of the comparator. The primary and secondary compensation windings consist of four separate independent coils of 120 turns, 60 turns, 30 turns and 15 turns, respectively. After primary insulating paper is wound outside the primary compensation winding, 10 single-turn compensation windings are wound for fractional turn error compensation, and a second layer of magnetic shielding T is arranged around the compensation windings 3 The two layers of magnetic shielding structures are identical, but the latter is formed by a cold-rolled silicon steel sheet magnetic core. The magnetic shielding layer is used as the magnetic core of the auxiliary current transformer of the comparator, and the exciting current of the magnetic shielding layer causes errors of the auxiliary current transformer. And then shielding the magnetic core T at the second layer 3 And firstly, winding a layer of insulating paper, then uniformly winding a secondary proportional winding, and winding a layer of insulating paper outside the secondary proportional winding and then winding a primary proportional winding. Finally, an insulating protection layer is wound outside the primary proportional winding.
The outer auxiliary transformer iron core adopts a microcrystalline material iron core, the microcrystalline material is protected by a protection box, a thin layer of silicone grease paper is wound outside the protection box of the microcrystalline iron core, then a secondary winding is uniformly wound, and a layer of insulating paper is wound outside the secondary winding to wind a primary winding. The primary and secondary windings consist of four separate independent coils of 120 turns, 60 turns, 30 turns and 15 turns, respectively.
Non-polar end l of primary winding of externally-attached auxiliary transformer 2 And a non-polar end k of the secondary winding 2 Respectively with the non-polar end L of the primary winding of the comparator 2 And a non-polar end K of the secondary winding 2 Are connected in series.
Adjustable virtual load Z F The device consists of a resistor, a capacitor, a current transformer, a voltage transformer, a multi-disc induction voltage divider and the like. The input current is supplied by the secondary of the auxiliary transformer, after the input current passes through the current transformer, the secondary of the current transformer generates quadrature and in-phase voltages through a resistor and a capacitor load, the voltage is divided by an induction voltage divider to generate phasor voltages with adjustable phase and amplitude, and finally the phasor voltages are output after passing through the voltage transformerThereby simulating the impedance of the analog output asThe load regulation range (±0.02mΩ±0.02mΩ) to (±22.2mΩ±22.2mΩ) was simulated.
The small current transformer adopts a through current transformer, the iron core adopts a microcrystalline material iron core, the primary winding is 1 turn, the secondary winding consists of 1000 turns, 10 turns and 10 turns, the winding method is same as that of an externally attached auxiliary transformer, the three windings can be connected in a positive string and a negative string, and a maximum of 10020 turns and a minimum of 9980 turns can be formed for fine adjustment of fractional turns. The transformation ratio of the auxiliary transformer is K t The comparator is secondarily N 2 Shunt input compensation winding N p Obtaining fractional turn ratio difference compensationFractional turn angular difference compensation ++>
Through the improvement measures, the current proportion standard is at the frequency of 1kHz, and the level of the current comparator reaches the level of 0.00005.
The above description is only one embodiment of the present invention and is not intended to limit the present invention, and various modifications and variations of the present invention will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A split type double-compensation broadband current comparator is characterized by comprising a main iron core (T 1 ) Detection winding (T) D ) Primary winding (N) L ) Secondary winding (N) K ) An externally attached auxiliary transformer, a copper shield (T) C ) First layer magnetic shielding iron core (T) 2 ) Second layer shielding iron core (T) 3 ) And a small current transformer, the primary winding (N L ) Is provided with a primary compensationWinding (N) b ) And the secondary winding (N K ) Is provided with a secondary compensation winding (N B ) The primary winding (N L ) Second layer shielding iron core (T) 3 ) And secondary winding (N) K ) Forming an internal auxiliary transformer;
the external auxiliary transformer is connected in series with the internal auxiliary transformer, and an external secondary compensation winding (N k ) Is connected to the secondary winding (N) by a virtual load (Z) K ) Corresponding secondary compensation winding (N B ) The dummy load is connected in series with the secondary compensation winding (N B ) And (3) upper part.
2. The split dual-compensation broadband current comparator according to claim 1, wherein the first layer magnetic shielding core (T 2 ) Surrounding the main core (T) 1 ) And the detection winding (T D ) The first layer magnetic shielding iron core (T) 2 ) Is a high permeability iron core;
the second layer of shielding is an iron core with high saturation induction intensity.
3. The split dual-compensation broadband current comparator according to claim 2, wherein the sense winding (T D ) Uniformly wound on the main iron core (T) by adopting a non-directional structure 1 ) And the two ends of the detection winding are led out by shielding wires.
4. A split dual-compensation broadband current comparator according to claim 3, characterized in that the small current transformer comprises a first small current transformer (T A1 ) And a second small current transformer (T A2 )；
The first small current transformer is provided with a resistance-capacitance shunt compensation circuit.
5. The split dual-compensation broadband current comparator according to claim 4, wherein the secondary load of the split dual-compensation broadband current comparator is represented byThe internal auxiliary current transformer bears the total impedance Z of the secondary load of the separated double-compensation broadband current comparator 02 Compensating for by compensation windings
6. The split dual-compensation broadband current comparator according to claim 5, wherein said first layer magnetic shielding core (T 2 ) The magnetic core is composed of 4 magnetic cores, and the overlapped parts of the magnetic cores are arranged in an insulating way.
7. The split dual-compensation broadband current comparator according to claim 6, wherein the core (T 4 ) A microcrystalline iron core is adopted, a protection box is wrapped outside the microcrystalline iron core, and silicone grease paper is wound on the outer side of the protection box.
8. The split dual-compensation broadband current comparator according to claim 7, wherein said dummy load (Z) comprises at least a resistor, a capacitor, a current transformer, a voltage transformer and a multi-disc inductive voltage divider, wherein the input current of said dummy load is provided by said external auxiliary transformer, the input current passes through said current transformer, the voltages of quadrature and in-phase are generated at the inductive end of said current transformer through the resistor and the capacitor load, the phasor voltage with adjustable phase and amplitude is generated by the voltage division of the inductive voltage divider, and is output after passing through said voltage transformerThe impedance of the dummy load is +.>
9. The split dual-compensation broadband current comparator according to claim 8, wherein the primary winding (N L ) And the secondary winding (N K ) Adopts a breaking winding structure.
10. The split dual-compensation broadband current comparator according to claim 9, wherein the main core (T 1 ) Is a permalloy material iron core with higher initial permeability.
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