A method for measuring parameters of a string line in a strong electromagnetic induction environment

Abstract

The application relates to a method for measuring parameters of a hanging line under a strong electromagnetic induction environment, and belongs to the technical field of testing electrical performance in measuring electrical variables. The method comprises the following steps: firstly, hanging a to-be-measured line, and simultaneously measuring to obtain first measurement parameters; then, electrifying the to-be-measured line, and simultaneously measuring to obtain second measurement parameters; then, calculating voltage correction coefficients and current correction coefficients according to the first measurement parameters and the second measurement parameters; finally, calculating real values of various electrical parameters of the to-be-measured line according to the voltage correction coefficients and the current correction coefficients. The application can simultaneously correct amplitude errors and phase errors under the condition of strong electromagnetic induction, improve the measurement accuracy and stability of the hanging line under the condition that adjacent lines do not stop working, and realize accurate measurement of electrical parameters of the hanging line.

Description

Technical Field

[0001] This invention relates to a method for measuring the parameters of a suspended line under strong electromagnetic induction conditions, belonging to the technical field of electrical performance testing (G01R31 / 00) in measuring electrical variables. Background Technology

[0002] The measurement of electrical parameters of existing lines is easily affected by the coupling effect of voltage and load current of adjacent operating lines when operating without interruption of power to adjacent lines. Electrostatic induction will generate induced voltage on the offline line or test cable under test, and electromagnetic induction will introduce induced voltage and induced current in the test circuit. The superposition of the two will cause the voltage and current amplitude and phase collected by the measuring end to deviate from the true test signal.

[0003] To reduce the impact of induced voltage and current on measurement data, traditional methods include incremental measurement, phase reversal measurement, different frequency measurement, digital filtering, or empirical correction to mitigate interference. These methods are effective when interference is relatively stable or the measurement environment is simple. However, during UAV-based parameter measurement, the load on adjacent lines may change over time, and the amplitude and phase of the induced signal are not constant. Simple amplitude filtering or manual empirical correction is insufficient to simultaneously correct amplitude and phase errors. Summary of the Invention

[0004] The technical problem to be solved by this invention is: how to accurately measure the electrical parameters of the wiring circuit.

[0005] The technical solution proposed by this invention to solve the above-mentioned technical problems is: a method for measuring the parameters of a suspended line under strong electromagnetic induction environment, comprising the following steps:

[0006] Step 1: Connect the wire to be tested and measure it to obtain the first measurement parameter;

[0007] Step 2: Power on the circuit under test and simultaneously measure to obtain the second measurement parameter;

[0008] Step 3: Calculate the voltage correction factor and the current correction factor based on the first measurement parameter and the second measurement parameter;

[0009] Step 4: Calculate the true values ​​of each electrical parameter of the circuit under test based on the voltage correction factor and the current correction factor.

[0010] 2. Further, the first measurement parameters in step 1 include the first induced voltage phasor u1 and the first induced current phasor i1 of the line under test, the first operating voltage amplitude U1, the first operating voltage phase θU1, the first operating current amplitude I1, the first operating current phase θI1, the first active power P1, the first reactive power Q1, the apparent power S, and the first power frequency F1 of the adjacent lines of the line under test.

[0011] 3. Further, the second measurement parameters in step 2 include the second induced voltage phasor u2 and the second induced current phasor i2 of the line under test, the second operating voltage amplitude U2, the second operating voltage phase θU2, the second operating current amplitude I2, the second operating current phase θI2, the second active power P2, the second reactive power Q2, and the second power frequency F2 of the adjacent lines of the line under test.

[0012] 4. Further, the voltage correction coefficient and current correction coefficient in step 3 are calculated through the following steps:

[0013] Step 3.1: Construct the difference vector M according to the following formula (1)

[0014] (1);

[0015] In equation (1), K U It is the voltage amplitude difference; K θU Voltage phase difference; K I Current amplitude difference, K θI It is the current phase difference; K P It is the difference in active power; K Q It is the reactive power difference; K F It is the power frequency difference; K L It is a normalized change in spatial structure and environment, consisting of the parallel length of the measured line and adjacent lines, line spacing, conductor height, soil resistivity, grounding resistance, and phase sequence difference before and after power-on; T is transpose; ε is a positive number to prevent the denominator from being zero; wrap(•) indicates that the phase difference is converted to [-π,π].

[0016] Step 3.2: Calculate the voltage correction factor K according to the following formula (2). u and current correction factor K i

[0017] (2);

[0018] In equation (2), It is the voltage sensing amplitude sensitivity vector; It is the voltage-induced phase amplitude sensitivity vector; is the current-induced amplitude sensitivity vector; is the current-induced phase sensitivity vector; j is the imaginary unit, j²=-1.

[0019] 5. Further, in step 4, the true values ​​of each electrical parameter of the circuit under test are calculated according to the following formula (3).

[0020] (3);

[0021] In equation (3), U is the voltage phasor, I is the current phasor, φ is the true value of phase difference, Z is the true value of impedance, R is the true value of resistance, X is the true value of reactance, Y is the true value of admittance, G is the true value of conductance, B is the true value of susceptance, and C is the true value of capacitance. (•) is the real part function of the complex number; Im (•) is the imaginary part function of the complex number; ω is the power frequency angular frequency.

[0022] 6. Further, after step 4, step 5 is executed: setting the error threshold q and the reference values ​​for each electrical parameter, and normalizing the difference between the actual values ​​of each electrical parameter obtained in step 4 and the corresponding reference values ​​to obtain the impedance error eZ, resistance error eR, reactance error eX, capacitance error eC, and phase difference error eφ.

[0023] Step 5.1: Calculate the total error E using the following formula (4).

[0024] (4);

[0025] In equation (4), γ1~γ5 are all error weights, and the sum of all error weights is 1;

[0026] If E≤q, the true values ​​of each electrical parameter obtained in step 4 are determined to meet the accuracy requirements.

[0027] If E > q, determine that the true values ​​of each electrical parameter obtained in step 4 do not meet the accuracy requirements, and proceed to step 6.

[0028] Step 6: Adjust the voltage correction coefficient K according to the following formula (5) u and current correction factor K i The voltage correction iteration coefficient K is obtained by iterative update. u and current correction iteration coefficient K i

[0029] (5);

[0030] In equation (5), minJ is the minimization iterative function; and These are the voltage correction factor and current correction factor from the previous iteration, respectively; λ u and λ i These are the voltage regularization factor and the current regularization factor, λ. u >0, λ i >0;

[0031] The voltage correction coefficient K in formula (4) of step 5 is... u and current correction factor K i Replace with voltage correction iteration coefficient K u and current correction iteration coefficient K iThe true values ​​of each electrical parameter of the circuit under test are then recalculated.

[0032] 7. Further, the reference values ​​of each electrical parameter in step 5 are the electrical parameter values ​​of the historical line after it was wired in an interference-free environment.

[0033] The beneficial effects of this invention are as follows: by constructing a difference vector from multi-dimensional differences and fusing it into voltage and current correction coefficients, the electrical parameters of the line measured under de-energized conditions are corrected, achieving synchronous correction of amplitude and phase errors under strong electromagnetic induction conditions. Compared to existing measurement techniques that rely solely on amplitude filtering or manual experience correction, this invention improves the measurement accuracy and stability of the suspended line under non-stop operation conditions of adjacent lines, enabling precise measurement of the electrical parameters of the suspended line. Detailed Implementation

[0034] Example

[0035] This embodiment of a method for measuring the parameters of a suspended line under strong electromagnetic induction conditions includes the following steps:

[0036] Step 1: Connect the wire to be tested and measure it to obtain the first measurement parameter;

[0037] The first measurement parameters include the first induced voltage phasor u1 and the first induced current phasor i1 of the line under test, the first operating voltage amplitude U1, the first operating voltage phase θU1, the first operating current amplitude I1, the first operating current phase θI1 of the adjacent lines of the line under test, the first active power P1, the first reactive power Q1, the apparent power S, and the first power frequency F1.

[0038] Step 2: Power on the circuit under test and simultaneously measure to obtain the second measurement parameter;

[0039] The second measurement parameters include the second induced voltage phasor u2 and the second induced current phasor i2 of the line under test, the second operating voltage amplitude U2, the second operating voltage phase θU2, the second operating current amplitude I2, the second operating current phase θI2, the second active power P2, the second reactive power Q2, and the second power frequency F2 of the adjacent lines of the line under test.

[0040] Step 3: Calculate the voltage correction factor and current correction factor based on the first measurement parameter and the second measurement parameter;

[0041] Specifically: Step 3.1: Construct the difference vector M according to the following formula (1)

[0042] (1);

[0043] In equation (1), K UIt is the voltage amplitude difference; K θU Voltage phase difference; K I Current amplitude difference, K θI It is the current phase difference; K P It is the difference in active power; K Q It is the reactive power difference; K F It is the power frequency difference; K L It is a normalized change in spatial structure and environment, consisting of the parallel length of the measured line and adjacent lines, line spacing, conductor height, soil resistivity, grounding resistance, and phase sequence difference before and after power-on; T is transpose; ε is a positive number to prevent the denominator from being zero; wrap(•) indicates that the phase difference is converted to [-π,π].

[0044] Step 3.2: Calculate the voltage correction factor K according to the following formula (2). u and current correction factor K i

[0045] (2);

[0046] In equation (2), It is the voltage sensing amplitude sensitivity vector; It is the voltage-induced phase amplitude sensitivity vector; is the current-induced amplitude sensitivity vector; is the current-induced phase sensitivity vector; j is the imaginary unit, j²=-1.

[0047] Step 4: Calculate the true values ​​of each electrical parameter of the circuit under test based on the voltage correction factor and the current correction factor;

[0048] Specifically, the true values ​​of each electrical parameter of the circuit under test are calculated according to the following formula (3).

[0049] (3);

[0050] In equation (3), U is the voltage phasor, I is the current phasor, φ is the true value of phase difference, Z is the true value of impedance, R is the true value of resistance, X is the true value of reactance, Y is the true value of admittance, G is the true value of conductance, B is the true value of susceptance, and C is the true value of capacitance. (•) is the real part function of the complex number; Im (•) is the imaginary part function of the complex number; ω is the power frequency angular frequency.

[0051] Example 2

[0052] The method for measuring line parameters under strong electromagnetic induction conditions in this embodiment is basically the same as that in Embodiment 1, except that after step 4, step 5 is performed: setting the error threshold q and the reference values ​​of each electrical parameter, and normalizing the difference between the actual values ​​of each electrical parameter obtained in step 4 and the corresponding reference values ​​of the electrical parameters to obtain the impedance error eZ, resistance error eR, reactance error eX, capacitance error eC, and phase difference error eφ.

[0053] In this embodiment, the reference values ​​of each electrical parameter are adopted from the electrical parameter values ​​of the historical line after it was wired in an interference-free environment.

[0054] Step 5.1: Calculate the total error E using the following formula (4).

[0055] (4);

[0056] In equation (4), γ1~γ5 are all error weights, and the sum of all error weights is 1;

[0057] If E≤q, the true values ​​of each electrical parameter obtained in step 4 are determined to meet the accuracy requirements.

[0058] If E > q, determine that the true values ​​of each electrical parameter obtained in step 4 do not meet the accuracy requirements, and proceed to step 6.

[0059] Step 6: Adjust the voltage correction coefficient K according to the following formula (5) u and current correction factor K i Perform iterative updates

[0060] (5);

[0061] In equation (5), minJ is the minimization iterative function; and These are the voltage correction factor and current correction factor from the previous iteration, respectively; λ u and λ i These are the voltage regularization factor and the current regularization factor, λ. u >0, λ i >0;

[0062] The voltage correction coefficient K in formula (3) of step 5 is... u and current correction factor K i Replace with voltage correction iteration coefficient K u and current correction iteration coefficient K i The true values ​​of each electrical parameter of the circuit under test are then recalculated.

[0063] The above description is only a preferred embodiment of the present invention, but the present invention is not limited thereto. All equivalent substitutions or modifications made to the concepts and technical solutions of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for measuring the parameters of a suspended line under strong electromagnetic induction conditions, characterized in that... The steps include the following: Step 1: Connect the wire to be tested and measure it to obtain the first measurement parameter; Step 2: Power on the circuit under test and simultaneously measure to obtain the second measurement parameter; Step 3: Calculate the voltage correction factor and the current correction factor based on the first measurement parameter and the second measurement parameter; Step 4: Calculate the true values ​​of each electrical parameter of the circuit under test based on the voltage correction factor and the current correction factor.

2. The method for measuring the parameters of a suspended line under strong electromagnetic induction environment according to claim 1, characterized in that: The first measurement parameters in step 1 include the first induced voltage phasor u1 and the first induced current phasor i1 of the line under test, the first operating voltage amplitude U1, the first operating voltage phase θU1, the first operating current amplitude I1, the first operating current phase θI1 of the adjacent lines of the line under test, the first active power P1, the first reactive power Q1, the apparent power S, and the first power frequency F1.

3. The method for measuring the parameters of a suspended line under strong electromagnetic induction environment according to claim 1, characterized in that: The second measurement parameters in step 2 include the second induced voltage phasor u2 and the second induced current phasor i2 of the line under test, the second operating voltage amplitude U2, the second operating voltage phase θU2, the second operating current amplitude I2, the second operating current phase θI2, the second active power P2, the second reactive power Q2, and the second power frequency F2 of the adjacent lines of the line under test.

4. The method for measuring the parameters of a suspended line under strong electromagnetic induction environment according to claim 1, characterized in that: The voltage correction factor and current correction factor in step 3 are calculated through the following steps: Step 3.1: Construct the difference vector M according to the following formula (1) （1）； In equation (1), K U It is the voltage amplitude difference; K θU Voltage phase difference; K I Current amplitude difference, K θI It is the current phase difference; K P It is the difference in active power; K Q It is the reactive power difference; K F It is the power frequency difference; K L It is a normalized change in spatial structure and environment, consisting of the parallel length of the measured line and adjacent lines, line spacing, conductor height, soil resistivity, grounding resistance, and the difference in phase sequence before and after energization; T is transpose. ε is a positive number to prevent the denominator from being zero; wrap(•) indicates that the phase difference is converted to [-π,π]. Step 3.2: Calculate the voltage correction factor K according to the following formula (2). u and current correction factor K i （2）； In equation (2), It is the voltage sensing amplitude sensitivity vector; It is the voltage-induced phase amplitude sensitivity vector; is the current-induced amplitude sensitivity vector; is the current-induced phase sensitivity vector; j is the imaginary unit, j²=-1.

5. The method for measuring the parameters of a suspended line under strong electromagnetic induction environment according to claim 1, characterized in that: In step 4, the true values ​​of each electrical parameter of the circuit under test are calculated according to formula (3). （3）； In equation (3), U is the voltage phasor, I is the current phasor, φ is the true value of phase difference, Z is the true value of impedance, R is the true value of resistance, X is the true value of reactance, Y is the true value of admittance, G is the true value of conductance, B is the true value of susceptance, and C is the true value of capacitance. (•) is the real part function of the complex number; Im (•) is the imaginary part function of the complex number; ω is the power frequency angular frequency.

6. The method for measuring the parameters of a suspended line under strong electromagnetic induction environment according to claim 1, characterized in that: Following step 4, step 5 is executed: An error threshold q and reference values ​​for each electrical parameter are set. The actual values ​​of each electrical parameter obtained in step 4 are then normalized with their corresponding reference values ​​to obtain impedance error eZ, resistance error eR, reactance error eX, capacitance error eC, and phase difference error eφ. Step 5.1: Calculate the total error E using the following formula (4). （4）； In equation (4), γ1~γ5 are all error weights, and the sum of all error weights is 1; If E≤q, the true values ​​of each electrical parameter obtained in step 4 are determined to meet the accuracy requirements. If E > q, determine that the true values ​​of each electrical parameter obtained in step 4 do not meet the accuracy requirements, and proceed to step 6. Step 6: Adjust the voltage correction coefficient K according to the following formula (5) u and current correction factor K i The voltage correction iteration coefficient K is obtained by iterative update. u and current correction iteration coefficient K i （5）； In equation (5), minJ is the minimization iterative function; and These are the voltage correction factor and current correction factor from the previous iteration, respectively; λ u and λ i These are the voltage regularization factor and the current regularization factor, λ. u >0, λ i >0; The voltage correction coefficient K in formula (4) of step 5 is... u and current correction factor K i Replace with voltage correction iteration coefficient K u and current correction iteration coefficient K i The true values ​​of each electrical parameter of the circuit under test are then recalculated.

7. The method for measuring the parameters of a suspended line under strong electromagnetic induction environment according to claim 6, characterized in that: In step 5, the reference values ​​for each electrical parameter are the values ​​of each electrical parameter after the historical line was wired in an interference-free environment.

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