CN113933593A - Large-section cable conductor alternating current equivalent resistance test system and method based on current comparator - Google Patents
Large-section cable conductor alternating current equivalent resistance test system and method based on current comparator Download PDFInfo
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Abstract
A large-section cable conductor alternating-current equivalent resistance testing system and method based on a current comparator belong to the technical field of electrical testing and are provided for solving the problems that a testing circuit of an existing large-section cable conductor testing method is complex, weak resistive voltage components are difficult to effectively extract and the like. The device comprises an alternating current source, a large-section cable conductor, a current transformer, an adjustable inductor, an adjustable resistor, an amplifier A, an amplifier B, a current comparator, a primary side first winding of the current comparator, a primary side second winding of the current comparator, a null indicator, a resistor A, a resistor B, a resistor C, a resistor D, a load resistor E and a load resistor F. The method is convenient to operate, the alternating current equivalent resistance of the large-section cable conductor can be measured only by adjusting the adjustable inductor and the adjustable resistor, the sensitivity of the nulling instrument of the current comparator is higher, the ampere-turn balance of the primary winding of the current comparator is realized by increasing the sensitivity of the nulling instrument, and the test precision and the anti-interference capability can be improved.
Description
Technical Field
The invention belongs to the technical field of electrical testing, and particularly relates to a large-section cable conductor alternating current equivalent resistance testing system and method based on a current comparator.
Background
The AC power cable plays an important role in the power supply and distribution aspect of an urban power grid, and the current-carrying capacity of the AC power cable is inseparable from the equivalent AC resistance. Under the action of alternating current excitation, the cable conductor is influenced by the skin effect, the current density on the surface of the cable conductor is higher, the current in the center of the cable conductor is lower, and the equivalent alternating current resistance of the alternating current cable conductor is higher than the direct current resistance of the cable conductor. If the error of the calculation of the current-carrying capacity of the alternating current cable is directly carried out by adopting the direct current resistance of the cable conductor is large. In particular, when the cable conductor cross-sectional area exceeds 1600mm2The ac equivalent resistance is much higher than the conductor dc resistance. Therefore, accurately measuring the AC equivalent resistance of the large-section cable conductor is an important basis for checking the current-carrying capacity of the AC power cable.
At present, the measurement of the alternating current equivalent resistance of a large-section cable conductor can be realized by a compensation voltage signal method, a cable sheath return line method, a digital measurement method and the like. The compensation voltage signal method is to use the inductive voltage component formed by the variable inductor to compensate the inductive voltage component in the large-section conductor loop to be tested, but the test circuit is relatively complex. The cable sheath return line method is a return line using a metal sheath of a cable as a cable conductor, and the test line has a simple structure and high test accuracy, but is only applicable to a power cable with a metal sheath. The digital measurement method comprises converting the obtained voltage and current data at two ends of the cable conductor from time domain to frequency domain by fast Fourier transform, and eliminating the effect of equivalent inductance voltage component of the cable conductor in the frequency domainObtaining the equivalent AC resistance of the cable conductor is suitable for the situation that the resistive voltage component and the inductive voltage component of the cable conductor are similar, but the method is not suitable for the large-section cable conductor: (>1600mm2) Since its resistive voltage component is about one-forty or less of the inductive voltage component.
The prior art also has the problems of inconvenient operation, limited test precision and limited anti-interference capability.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention provides a large-section cable conductor alternating-current equivalent resistance testing system and method based on a current comparator, which can solve the problems that the existing large-section cable conductor testing method is complex in testing circuit, limited in application range, difficult to effectively extract weak resistive voltage components and the like.
The technical scheme adopted by the invention is as follows:
a large-section cable conductor alternating-current equivalent resistance test system based on a current comparator comprises an alternating-current source, a large-section cable conductor, a current transformer, an adjustable inductor, an adjustable resistor, an amplifier A, an amplifier B, a current comparator, a primary side first winding of the current comparator, a primary side second winding of the current comparator, a null indicator, a resistor A, a resistor B, a resistor C, a resistor D, a load resistor E and a load resistor F;
one end of an alternating current source is connected with the head end of a large-section cable conductor, the tail end of the large-section cable conductor is connected with one end of the primary side of a current transformer, the other end of the primary side of the current transformer is connected with the other end of an alternating current source and is grounded, an adjustable inductor is connected with an adjustable resistor in series, two ends of the adjustable inductor and the adjustable resistor are respectively connected with two ends of the secondary side of the current transformer, the other end of the end connected with the adjustable inductor is connected with the ground, the negative polarity input end of an amplifier A is connected with the head end of the large-section cable conductor through a resistor A, the positive polarity input end of the amplifier A is connected with the tail end of the large-section cable conductor, the positive polarity input end of the amplifier A is connected with the resistor B, the other end of the resistor B is connected with the ground, the output end of the amplifier A is sequentially connected with the negative polarity input end of the amplifier A through a primary side first winding and a load resistor E of a current comparator, the negative polarity input end of the amplifier B is connected with the adjustable inductor and the high voltage end of the adjustable resistor through a resistor C, the positive polarity input end of the amplifier B is connected with the ground through a resistor D, the output end of the amplifier B is connected with the negative polarity input end of the amplifier B through a primary side second winding of the current comparator and a load resistor F in sequence, and the nulling instrument is connected with a secondary side winding of the current comparator;
the alternating current source is used for generating an alternating current source;
the large-section cable conductor is used as a measured conductor;
the current transformer is used for current conversion;
the adjustable inductor is used for adjusting the size of the inductance;
the adjustable resistor is used for adjusting the resistance;
the amplifier A is used for passing through the resistor R of the resistor A1Converting the voltage at two ends of the large-section cable conductor into current flowing through a load resistor E and a primary side first winding series branch of a current comparator;
the amplifier B is used for passing through the resistor R of the resistor C2Converting the voltage at two ends of the inductance of the adjustable inductor and the resistance of the adjustable resistor into current flowing through a load resistor F and a primary side second winding series branch circuit of the current comparator;
the current comparator, the primary side first winding of the current comparator and the primary side second winding of the current comparator are used for balancing the ampere turns of the primary side winding of the current comparator and calculating the equivalent alternating current resistance value of the large-section cable conductor from the adjustable inductor and the adjustable resistor;
and the zero indicator is used for representing the ampere-turn balance of the primary winding of the current comparator when the pointer of the zero indicator indicates zero.
A large-section cable conductor alternating current equivalent resistance testing method based on a current comparator comprises the following steps:
step S1, obtaining the equivalent alternating current resistance R of the large-section cable conductorxVoltage of (L), equivalent inductance LxVoltage of (d);
step S2, obtaining the voltage at two ends of the inductance of the adjustable inductor and the voltage at two ends of the resistance of the adjustable resistor;
step S3, solving the current of the primary side first winding branch of the current comparator;
step S4, solving the current of the primary side second winding branch of the current comparator;
in step S5, the equivalent ac resistance value of the large-section cable conductor is obtained.
Further, in step S1, the implementation manner is as follows:
the AC current source generating a sinusoidal excitation current of frequency f
Equivalent alternating current resistance R of large-section cable conductorxThe voltage is generated according to the formula:
in the formula (1), the reaction mixture is,
is equivalent alternating current resistance RxThe voltage of (a) is set to be,
is a current, RxIs equivalent alternating current resistance;
l on the equivalent inductancexGenerating a voltage, the voltage formula being:
in the formula (2), the reaction mixture is,
is an equivalent inductance LxF is the frequency, LxIn order to be an equivalent inductance,
is the current.
Further, in step S2, the implementation manner is as follows:
the proportionality coefficient K of the current transformer is used for converting the current of the main loop
Conversion to a current flowing through a series branch of an adjustable inductor and an adjustable resistor
This current produces a voltage across the inductance of the adjustable inductor, the voltage formula:
in the formula (3), the reaction mixture is,
is the voltage across the inductor, f is the frequency, L is the inductance value of the adjustable inductor,
a current for the series branch of the adjustable resistor;
a voltage is generated across the resistance of the adjustable resistor, the voltage formula:
in the formula (4), the reaction mixture is,
is the voltage across the adjustable resistor, R is the resistance of the adjustable resistor,
the current of the branch is connected in series with the adjustable resistor.
Further, in step S3, the implementation manner is as follows:
the amplifier A passes through the resistance R of the resistor A1Converting the voltage at two ends of the large-section cable conductor into current flowing through a load resistor E and a primary side first winding series branch of a current comparator;
voltage across the large cross-section cable conductor:
in the formula (5), the reaction mixture is,
is the voltage across the large cross-section cable conductor,
in order to adjust the voltage across the resistor,
is an equivalent inductance LxVoltage of (d);
current of the series branch:
in the formula (6), the reaction mixture is,
to the current flowing through the primary side first winding of the current comparator,
in order to adjust the voltage across the resistor,
is an equivalent inductance LxVoltage of R1Is the resistance of the resistor a.
Further, in step S4, the implementation manner is as follows:
the amplifier B passing through a resistor CResistance R2Converting the voltage at two ends of the inductance of the adjustable inductor and the resistance of the adjustable resistor into current flowing through a load resistor F and a primary side second winding series branch circuit of the current comparator;
voltage across the adjustable inductor and the adjustable resistor:
in the formula (7), the reaction mixture is,
for the voltage across the adjustable inductor and the adjustable resistor,
in order to be able to adjust the voltage of the resistor,
is the voltage of the adjustable inductor;
current flowing through the secondary winding on the primary side of the current comparator:
in the formula (8), the reaction mixture is,
to the current flowing through the secondary winding on the primary side of the current comparator,
in order to be able to adjust the voltage of the resistor,
is the voltage of the adjustable inductor, R2Is the resistance of the resistor C.
Further, in step S5, the implementation manner is as follows:
adjusting the number of turns of the primary side first winding of the current comparatorN1Primary secondary winding turn number N of sum current comparator2And observing the change of a pointer of the null indicator, when the pointer of the null indicator points to zero, the ampere-turn of the primary winding of the current comparator is balanced, and the equivalent alternating current resistance value of the large-section cable conductor can be calculated from the adjustable inductor and the adjustable resistor:
Rx＝N2KRR1/N1R2 (9)
in the formula (9), RxIs an equivalent alternating current resistance, N2The number of turns of a primary side second winding of the current comparator, K is the proportionality coefficient of the current transformer, R is the resistance of the adjustable resistor, R is the number of turns of the primary side second winding of the current comparator1A resistance of the resistor A, N1Is the number of turns of the primary side first winding of the current comparator, R2Is the resistance of the resistor C.
The invention has the beneficial effects that:
1. the principle is simple, the operation is convenient, and the measurement of the alternating current equivalent resistance of the large-section cable conductor can be realized only by adjusting the adjustable inductor and the adjustable resistor.
2. The sensitivity of the nulling instrument of the current comparator is higher, the ampere-turn balance of the primary winding of the current comparator is realized by increasing the sensitivity of the nulling instrument, and the test precision and the anti-interference capability can be improved.
3. The equivalent inductance of the large-section cable conductor can be obtained while the alternating current equivalent resistance of the large-section cable conductor is obtained, and experimental basis is provided for analyzing the alternating current characteristic of the large-section conductor.
Drawings
FIG. 1 is a schematic diagram of a large cross-section cable conductor AC equivalent resistance test system and method based on a current comparator;
in the figure: 1. an alternating current source; 2. a large cross-section cable conductor; 3. a current transformer; 4. an adjustable inductor; 5. an adjustable resistor; 6. an amplifier A; 7. an amplifier B; 8. a current comparator; 81. a primary side first winding of the current comparator; 82. a primary side second winding of the current comparator; 9. a null indicator; 10. a resistance A; 11. a resistance B; 12. a resistance C; 13. a resistance D; 14. a load resistance E; 15. a load resistance F.
Detailed Description
As shown in fig. 1, the present embodiment includes: the device comprises an alternating current source 1, a large-section cable conductor 2, a current transformer 3, an adjustable inductor 4, an adjustable resistor 5, an amplifier A6, an amplifier B7, a current comparator 8, a primary side first winding 81 of the current comparator, a primary side second winding 82 of the current comparator, a null indicator 9, a resistor A10, a resistor B11, a resistor C12, a resistor D13, a load resistor E14 and a load resistor F15.
One end of an alternating current source 1 is connected with the head end of a large-section cable conductor 2, the tail end of the large-section cable conductor 2 is connected with one end of the primary side of a current transformer 3, the other end of the primary side of the current transformer 3 is connected with the other end of the alternating current source 1 and is grounded, an adjustable inductor 4 is connected with an adjustable resistor 5 in series, two ends of the adjustable inductor 4 and the adjustable resistor 5 are respectively connected with two ends of the secondary side of the current transformer 3, the other end of the adjustable resistor 5, which is connected with the adjustable inductor 4, is connected with the ground, the negative polarity input end of an amplifier A6 is connected with the head end of the large-section cable conductor 2 through a resistor A10, the positive polarity input end of an amplifier A6 is connected with the tail end of the large-section cable conductor 2, the positive polarity input end of the amplifier A6 is connected with a resistor B11, the other end of a resistor B11 is connected with the ground, the output end of an amplifier A6 is sequentially connected with the negative polarity input end of the amplifier A6 through a primary side first winding 81 and a load resistor E14, the negative polarity input end of the amplifier B7 is connected with the high voltage end of the adjustable inductor 4 and the adjustable resistor 5 through a resistor C12, the positive polarity input end of the amplifier B7 is connected with the ground through a resistor D13, the output end of the amplifier B7 is connected with the negative polarity input end of the amplifier B7 through a current comparator primary side secondary winding 82 and a load resistor F15 in sequence, and the nulling instrument 9 is connected with a current comparator 8 secondary side winding.
The alternating current source 1 is used for generating an alternating current source;
the large-section cable conductor 2 is used as a conductor to be tested;
the current transformer 3 is used for current conversion;
the adjustable inductor 4 is used for adjusting the size of the inductance;
the adjustable resistor 5 is used for adjusting the resistance;
the amplifier A6 is used for passing through the resistor R of the resistor A101Converting the voltage at two ends of the large-section cable conductor 2 into current flowing through a serial branch circuit of a load resistor E14 and a primary side first winding 81 of a current comparator;
the amplifier B7 is used for passing through the resistor R of the resistor C122Converting the voltage across the inductance of the adjustable inductor 4 and the resistance of the adjustable resistor 5 into a current flowing through a series branch of the load resistor F15 and the primary secondary winding 82 of the current comparator;
the current comparator 8, the primary side first winding 81 of the current comparator and the primary side second winding 82 of the current comparator are used for balancing the ampere-turns of the primary side winding of the current comparator, and the equivalent alternating current resistance value of the large-section cable conductor 2 is calculated from the adjustable inductor 4 and the adjustable resistor 5
And the zero indicator 9 is used for representing the ampere-turn balance of the primary winding of the current comparator when the pointer of the zero indicator is zero.
The embodiment of the present invention is as follows:
as shown in fig. 1, the device mainly comprises an alternating current source 1, a large-section cable conductor 2, a current transformer 3, an adjustable reactor 4, an adjustable resistor 5, an amplifier a6, an amplifier B7, a current comparator 8, a null indicator 9 and the like.
The ac current source 1 generates a sinusoidal excitation current with a frequency f
Equivalent alternating current resistance R of the large-section cable conductor 2xThe voltage is generated according to the formula:
in the formula (1), the reaction mixture is,
is equivalent alternating current resistance RxThe voltage of (a) is set to be,
is a current, RxIs equivalent alternating current resistance.
L on the equivalent inductancexGenerating a voltage, the voltage formula being:
in the formula (2), the reaction mixture is,
is an equivalent inductance LxF is the frequency, LxIn order to be an equivalent inductance,
is the current.
The proportionality coefficient K of the current transformer 3 is used for converting the current of the main loop
Into a current flowing through a series branch of an adjustable inductor 4 and an adjustable resistor 5
. This current generates a voltage across the inductance of the adjustable inductor 4, the voltage formula:
in the formula (3), the reaction mixture is,
is the voltage across the inductor, f is the frequency, L is the inductance value of the adjustable inductor 4,
the current of the series branch is the adjustable resistor 5.
A voltage is generated across the resistance of the adjustable resistor 5, the voltage formula:
in the formula (4), the reaction mixture is,
is the voltage across the adjustable resistor 5, R is the resistance of the adjustable resistor 5,
the current of the series branch is the adjustable resistor 5.
The negative polarity input end of the amplifier A6 is connected with the head end of the large-section cable conductor 2 through a resistor A10, the positive polarity input end of the amplifier A6 is connected with the tail end of the large-section cable conductor 2, and the output end of the amplifier A6 is fed back to the negative polarity input end of the amplifier A6 through the primary side first winding 81 of the current comparator and the load resistor E14.
The amplifier a6 passes through the resistor R of the resistor 101The voltage across the large-section cable conductor 2 is converted into a current flowing through the series branch of the load resistor E14 and the primary first winding 81 of the current comparator,
voltage across the large-section cable conductor 2:
in the formula (5), the reaction mixture is,
the voltage across the large cross-section cable conductor 2,
in order to adjust the voltage across the resistor 5,
is an equivalent inductance LxThe voltage of (c).
Current of the series branch:
in the formula (6), the reaction mixture is,
to compare the current flowing through the primary first winding 81 of the current comparator,
in order to adjust the voltage across the resistor 5,
is an equivalent inductance LxVoltage of R1Is the resistance of resistor 10.
The negative polarity input terminal of the amplifier B7 is connected to the high voltage terminal of the adjustable inductor 4 and the adjustable resistor 5 through the resistor C12, the positive polarity input terminal of the amplifier B7 is connected to ground through the resistor D13, and the output terminal of the amplifier B7 is fed back to the negative polarity input terminal of the amplifier B7 through the current comparator primary secondary winding 82 and the load resistor F15.
The amplifier B7 passes through the resistor R of the resistor C122The voltage across the inductance of the adjustable inductor 4 and the resistance of the adjustable resistor 5 is converted into a current flowing through the series branch of the load resistance F15 and the primary secondary winding 82 of the current comparator.
Voltage across the adjustable inductor 4 and the adjustable resistor 5:
in the formula (7), the reaction mixture is,
for the voltage across the adjustable inductor 4 and the adjustable resistor 5,
in order to adjust the voltage of the resistor 5,
is the voltage of the adjustable inductor 4.
Current flowing through the current comparator primary secondary winding 82:
in the formula (8), the reaction mixture is,
to compare the current flowing through the primary secondary winding 82 of the current comparator,
in order to adjust the voltage of the resistor 5,
for regulating the voltage of the inductor 4, R2Is the resistance of the resistor C12.
81 turns N of primary side first winding of regulating current comparator 182 turns N of primary secondary winding of sum current comparator2Observing the pointer change of the null indicator 9, when the pointer of the null indicator 9 points to zero, the ampere-turn of the primary winding of the current comparator is balanced, and at the moment, the equivalent alternating current resistance value of the large-section cable conductor 2 can be calculated from the adjustable inductor 4 and the adjustable resistor 5 as follows:
Rx＝N2KRR1/N1R2 (9)
in the formula (9), RxIs an equivalent alternating current resistance, N 282 turns of a secondary winding on the primary side of the current comparator, K is the proportionality coefficient of the current transformer 3, R is the resistance of the adjustable resistor 5, R1Is the resistance of the resistor 10, N1Is a primary side first winding of a current comparator with 81 turns, R2Is the resistance of the resistor C12.
The equivalent inductance of the large-section cable conductor 2 is
Lx＝N2KLR1/N1R2 (10)
In the formula (10), LxEquivalent inductance of the large-section cable conductor 2, N 282 turns of a secondary winding on the primary side of the current comparator, K is the proportionality coefficient of the current transformer 3, L is the inductance value of the adjustable inductor 4, R1Is the resistance of the resistor 10, N1Is a primary side first winding of a current comparator with 81 turns, R2Is the resistance of the resistor C12.
In the embodiment, the possible alternating current source model is NHAC10V-100A of Jinnannenghua electromechanical device Limited, the differential amplifier model is Nanjing Hongbin Weak Signal detection Limited 815A, the current transformer model is CTA200 of Shenzhen known electronic Limited, and the digital acquisition card model is NI USB 6009.
Claims (7)
1. A large-section cable conductor alternating current equivalent resistance test system based on a current comparator is characterized by comprising an alternating current source (1), a large-section cable conductor (2), a current transformer (3), an adjustable inductor (4), an adjustable resistor (5), an amplifier A (6), an amplifier B (7), a current comparator (8), a current comparator primary side first winding (81), a current comparator primary side second winding (82), a zero indicator (9), a resistor A (10), a resistor B (11), a resistor C (12), a resistor D (13), a load resistor E (14) and a load resistor F (15);
one end of an alternating current source (1) is connected with the head end of a large-section cable conductor (2), the tail end of the large-section cable conductor (2) is connected with one end of the primary side of a current transformer (3), the other end of the primary side of the current transformer (3) is connected with the other end of the alternating current source (1) and is grounded, an adjustable inductor (4) is connected with an adjustable resistor (5) in series, two ends of the adjustable inductor (4) and the adjustable resistor (5) are respectively connected with two ends of the secondary side of the current transformer (3), the other end of the adjustable resistor (5) connected with the adjustable inductor (4) is connected with the ground, the negative polarity input end of an amplifier A (6) is connected with the head end of the large-section cable conductor (2) through a resistor A (10), the positive polarity input end of the amplifier A (6) is connected with the tail end of the large-section cable conductor (2), the positive polarity input end of the amplifier A (6) is connected with a resistor B (11), the other end of the resistor B (11) is connected with the ground, the output end of the amplifier A (6) is connected with the negative polarity input end of the amplifier A (6) through a primary side first winding (81) of a current comparator and a load resistor E (14) in sequence, the negative polarity input end of the amplifier B (7) is connected with the adjustable inductor (4) and the high voltage end of the adjustable resistor (5) through a resistor C (12), the positive polarity input end of the amplifier B (7) is connected with the ground through a resistor D (13), the output end of the amplifier B (7) is connected with the negative polarity input end of the amplifier B (7) through a primary side second winding (82) of the current comparator and a load resistor F (15) in sequence, and the nulling instrument (9) is connected with a secondary side winding of the current comparator (8);
the alternating current source (1) is used for generating an alternating current source;
the large-section cable conductor (2) is used as a conductor to be tested;
the current transformer (3) is used for current conversion;
the adjustable inductor (4) is used for adjusting the size of the inductance;
the adjustable resistor (5) is used for adjusting the resistance;
the amplifier A (6) is used for passing through the resistor R of the resistor A (10)1Converting the voltage at two ends of a large-section cable conductor (2) into current flowing through a series branch of a load resistor E (14) and a primary side first winding (81) of a current comparator;
the amplifier B (7) is used for passing through the resistor R of the resistor C (12)2Converting the voltage at two ends of the inductance of the adjustable inductor (4) and the resistance of the adjustable resistor (5) into current flowing through a serial branch circuit of a load resistor F (15) and a primary secondary winding (82) of a current comparator;
the current comparator (8), the primary side first winding (81) of the current comparator and the primary side second winding (82) of the current comparator are used for balancing ampere turns of the primary side winding of the current comparator, and the equivalent alternating current resistance value of the large-section cable conductor (2) is calculated from the adjustable inductor (4) and the adjustable resistor (5);
and the zero indicator (9) is used for representing ampere-turn balance of the primary winding of the current comparator when the pointer of the zero indicator indicates zero.
2. A large-section cable conductor alternating current equivalent resistance test method based on a current comparator is characterized by comprising the following steps:
step S1, obtaining the equivalent alternating current resistance R of the large-section cable conductor (2)xVoltage of (L), equivalent inductance LxVoltage of (d);
step S2, solving the voltage at two ends of the inductance of the adjustable inductor (4) and the voltage at two ends of the resistance of the adjustable resistor (5);
step S3, solving the current of the branch of the primary side first winding (81) of the current comparator;
step S4, solving the current of the branch circuit of the primary secondary winding (82) of the current comparator;
in step S5, the equivalent AC resistance value of the large-section cable conductor (2) is obtained.
3. The method for testing the alternating current equivalent resistance of the large-section cable conductor based on the current comparator as claimed in claim 2, wherein the step S1 is implemented as follows:
an alternating current source (1) generates a sinusoidal excitation current with a frequency f
The equivalent alternating current resistance R of the large-section cable conductor (2)xThe voltage is generated according to the formula:
in the formula (1), the reaction mixture is,
is equivalent alternating current resistance RxThe voltage of (a) is set to be,
is a current, RxIs equivalent alternating current resistance;
l on the equivalent inductancexGenerating a voltage, the voltage formula being:
in the formula (2), the reaction mixture is,
is an equivalent inductance LxF is the frequency, LxIn order to be an equivalent inductance,
is the current.
4. The method for testing the alternating current equivalent resistance of the large-section cable conductor based on the current comparator as claimed in claim 2, wherein the step S2 is implemented as follows:
the proportionality coefficient K of the current transformer (3) is used for converting the current of the main loop
Is converted into a current flowing through a series branch of an adjustable inductor (4) and an adjustable resistor (5)
The current generates a voltage across the inductance of the adjustable inductor (4), the voltage formula:
in the formula (3), the reaction mixture is,
is the voltage across the inductor, f is the frequency, L is the inductance value of the adjustable inductor (4),
the current of the series branch circuit of the adjustable resistor (5);
-generating a voltage across the resistance of the adjustable resistor (5), the voltage formula:
in the formula (4), the reaction mixture is,
is the voltage at two ends of the adjustable resistor (5), R is the resistance of the adjustable resistor (5),
the current of the series branch of the adjustable resistor (5).
5. The method for testing the alternating current equivalent resistance of the large-section cable conductor based on the current comparator as claimed in claim 2, wherein the step S3 is implemented as follows:
the amplifier A (6) passes through the resistor R of the resistor A (10)1Converting the voltage at two ends of a large-section cable conductor (2) into current flowing through a series branch of a load resistor E (14) and a primary side first winding (81) of a current comparator;
voltage across the large cross-section cable conductor (2):
in the formula (5), the reaction mixture is,
is the voltage at the two ends of the large-section cable conductor (2),
is the voltage at the two ends of the adjustable resistor (5),
is an equivalent inductance LxVoltage of (d);
current of the series branch:
in the formula (6), the reaction mixture is,
for the current flowing through the primary first winding (81) of the current comparator,
is the voltage at the two ends of the adjustable resistor (5),
is an equivalent inductance LxVoltage of R1Is the resistance of the resistor A (10).
6. The method for testing the alternating current equivalent resistance of the large-section cable conductor based on the current comparator as claimed in claim 2, wherein the step S4 is implemented as follows:
the amplifier B (7) passes through the resistor R of the resistor C (12)2Converting the voltage at two ends of the inductance of the adjustable inductor (4) and the resistance of the adjustable resistor (5) into current flowing through a serial branch circuit of a load resistor F (15) and a primary secondary winding (82) of a current comparator;
voltage across the adjustable inductor (4) and the adjustable resistor (5):
in the formula (7), the reaction mixture is,
is the voltage across the adjustable inductor (4) and the adjustable resistor (5),
is the voltage of the adjustable resistor (5),
is the voltage of the adjustable inductor (4);
current flowing through the secondary winding (82) on the primary side of the current comparator:
in the formula (8), the reaction mixture is,
for the current flowing through the secondary winding (82) on the primary side of the current comparator,
is the voltage of the adjustable resistor (5),
is the voltage of the adjustable inductor (4), R2Is the resistance of the resistor C (12).
7. The method for testing the alternating current equivalent resistance of the large-section cable conductor based on the current comparator as claimed in claim 2, wherein the step S5 is implemented as follows:
adjusting the number of turns N of a primary side first winding (81) of a current comparator1And the number N of turns of a primary secondary winding (82) of the current comparator2And observing the change of a pointer of the null indicator (9), when the pointer of the null indicator (9) points to zero, the ampere-turn of the primary winding of the current comparator is balanced, and the equivalent alternating current resistance value of the large-section cable conductor (2) can be calculated from the adjustable inductor (4) and the adjustable resistor (5) as follows:
Rx＝N2KRR1/N1R2 (9)
in the formula (9)，RxIs an equivalent alternating current resistance, N2The number of turns of a primary secondary winding (82) of the current comparator, K is the proportionality coefficient of the current transformer (3), R is the resistance of the adjustable resistor (5), and R is the number of turns of a primary secondary winding of the current comparator1Is the resistance of the resistor A (10), N1The number of turns of a primary side first winding (81), R, of the current comparator2Is the resistance of the resistor C (12).
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115980451A (en) * | 2022-12-05 | 2023-04-18 | 哈尔滨理工大学 | Method for extracting alternating current equivalent resistance of large-section cable conductor |
| CN116381347A (en) * | 2022-12-05 | 2023-07-04 | 哈尔滨理工大学 | Method for acquiring alternating-current equivalent resistance of large-section cable conductor based on peak characteristic |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2376732A1 (en) * | 2002-03-13 | 2003-09-13 | National Research Council Of Canada | A current-comparator-based four-terminal resistance bridge for power frequencies |
| US7106078B1 (en) * | 2005-08-03 | 2006-09-12 | James G. Biddle Company | Method and apparatus for measuring transformer winding resistance |
| CN111505357A (en) * | 2020-04-02 | 2020-08-07 | 江苏省送变电有限公司 | Power supply for testing electrical characteristic parameters of large-section conductor |
| CN111650415A (en) * | 2020-06-09 | 2020-09-11 | 南京师范大学 | Self-powered current detection system and detection method for wide-current-band power transmission line |
| CN212111618U (en) * | 2019-12-31 | 2020-12-08 | 西门子电气传动有限公司 | Capacitance polarity reverse connection detection device and system |
-
2021
- 2021-10-27 CN CN202111254349.4A patent/CN113933593B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2376732A1 (en) * | 2002-03-13 | 2003-09-13 | National Research Council Of Canada | A current-comparator-based four-terminal resistance bridge for power frequencies |
| US7106078B1 (en) * | 2005-08-03 | 2006-09-12 | James G. Biddle Company | Method and apparatus for measuring transformer winding resistance |
| CN212111618U (en) * | 2019-12-31 | 2020-12-08 | 西门子电气传动有限公司 | Capacitance polarity reverse connection detection device and system |
| CN111505357A (en) * | 2020-04-02 | 2020-08-07 | 江苏省送变电有限公司 | Power supply for testing electrical characteristic parameters of large-section conductor |
| CN111650415A (en) * | 2020-06-09 | 2020-09-11 | 南京师范大学 | Self-powered current detection system and detection method for wide-current-band power transmission line |
Non-Patent Citations (1)
| Title |
|---|
| 丛祥旭: "基于全自动流比器电桥的导体交流电阻测试技术研究", 中国优秀硕士学位论文全文数据库 工程科技辑 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115980451A (en) * | 2022-12-05 | 2023-04-18 | 哈尔滨理工大学 | Method for extracting alternating current equivalent resistance of large-section cable conductor |
| CN115980451B (en) * | 2022-12-05 | 2023-06-23 | 哈尔滨理工大学 | Extraction method of alternating-current equivalent resistance of large-section cable conductor |
| CN116381347A (en) * | 2022-12-05 | 2023-07-04 | 哈尔滨理工大学 | Method for acquiring alternating-current equivalent resistance of large-section cable conductor based on peak characteristic |
| CN116381347B (en) * | 2022-12-05 | 2023-10-24 | 哈尔滨理工大学 | Method for acquiring alternating-current equivalent resistance of large-section cable conductor based on peak characteristic |
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