CN113624519A - Parameter calculation and test method for resonance voltage resistance of high-voltage high-capacity equipment - Google Patents
Parameter calculation and test method for resonance voltage resistance of high-voltage high-capacity equipment Download PDFInfo
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Abstract
The invention discloses a parameter calculation and test method for resonance withstand voltage of high-voltage high-capacity equipment, which comprises the following steps of: 1) acquiring a device parameter C to be tested, and determining a target test voltage value and an expected alternating current frequency range; 2) generating an optional solution set by the total number of available test reactors; 3) calculating the resonant frequency and the quality factor of each test arrangement scene in the solution set; 4) rejecting the situation that the resonant frequency value in the calculated scene does not meet the requirement according to the limit of the test frequency condition; 5) calculating the current flowing through each reactor; 6) the best trial solution is selected in the configuration to obtain the current solution set. The invention can be used for guiding the calculation and test configuration of the field alternating current withstand voltage parameters of high-voltage and high-capacity equipment, thereby ensuring the safe and stable operation of the equipment level of the power system.
Description
Technical Field
The invention belongs to the technical field of electric equipment resonance voltage-withstanding field tests, and particularly relates to a parameter calculation and test method for resonance voltage-withstanding of high-voltage large-capacity equipment.
Background
Based on the existing common series resonance principle, the optimal quality factor Q of the system is obtained under the frequency modulation, and the voltage which is Q times of the excitation transformer high-voltage side is generated on a tested product. However, it should be noted that when the circuit is not in the resonance state or the preferred resonance frequency is difficult to modulate, the resultant inductive reactive power and capacitive reactive power in the system is not zero, and the partial power needs to flow through the excitation transformer, the reactor and the variable frequency power supply, which increases the capacity requirement of these devices. In consideration of the characteristics of parallel resonance, in recent years, series-parallel resonance is also used in the resonance withstand voltage test of large-capacity equipment, and a parallel branch in a series-parallel circuit is used for reducing the current of a full circuit. However, under the influence of the parallel branch, the calculation of the resonance point and the quality factor of the original system also changes. The calculation of the resonant frequency and the quality factor of the series-parallel resonant circuit is obvious if the deviation of the resistance to the quality factor is not considered, and the error influences the configuration result of each branch reactor. The main working modes of the current frequency modulation type test power supply, namely sine type output and square wave pulse type output, are not discussed at present about the influence on the test characteristic parameters.
The development of the field alternating current test of the high-voltage large-capacity equipment is a 'consumption' type test, which is used for reducing the consumption of transportation and field assembly and placement of the high-voltage test equipment frequently and needs scientific and correct theoretical guidance. From the engineering application angle of a resonance voltage withstand test (including conventional series resonance and series-parallel resonance), key characteristic parameters are summarized and deduced, and resonance parameter calculation is analyzed in a real-time manner by utilizing a laboratory-level dynamic simulation experiment, a field case of a field large-capacity submarine cable and PSCAD simulation.
Disclosure of Invention
In order to overcome the technical problems, the invention provides a parameter calculation and test method for resonance withstand voltage of high-voltage large-capacity equipment, which can pre-calculate the resonance frequency and quality factor of key parameters of a test before the test, so that whether the test frequency meets the requirements of regulations is judged by guiding test arrangement and scheme formulation, the pre-calculation of the quality factor is used for assisting in judging whether the test source capacity can meet the requirements, and the optimal configuration is used for determining a test scheme and guiding a test site.
In order to achieve the purpose, the invention adopts the technical scheme that:
a parameter calculation and test method for resonance voltage resistance of high-voltage large-capacity equipment comprises the following steps;
1) obtaining a device parameter C to be tested, and determining a target test voltage value and an expected alternating current frequency range (for example, the frequency section of the alternating current withstand voltage of the cable is 30 Hz-300 Hz);
2) generating an optional solution set M { [ N ] of the total number N of available test reactors1,n2]|n1+n2N is not more than N and N2>0} where n is1The number of parallel reactors of the parallel branch in the series-parallel resonance is; n is2The number of the parallel reactors of the series branch in the pure series resonance or the series-parallel resonance;
3) calculating the resonant frequency and the quality factor of each test arrangement scene in the solution set M;
4) rejecting the situation that the resonant frequency value in the calculated scene does not meet the requirement according to the limit of the test frequency condition;
5) according to n1,n2Calculating the current flowing through each reactor according to the value of the reference voltage and the target test voltage value, rejecting the scene if the current exceeds the rated current value of a single reactor, judging whether the capacity of the excitation transformer for the test and the power supply capacity meet the limit, and judging whether the target withstand voltage value can be met or not according to the calculated quality factor Q value and the maximum voltage of the excitation transformer and rejecting the scene which does not meet the condition;
6) in the configuration of obtaining the current solution set, an optimal test scheme is selected according to the condition that the 'minimum number of reactors' is better than the condition that the 'maximum Q value' is obtained.
The parameters of the test equipment in the step 1) comprise a tested sample capacitance parameter C; inductance L and resistance of test reactorR and the total number N of available test reactors; equivalent resistance R of excitation variable high-voltage windingtEquivalent leakage inductance L of excitation high voltage windingtAnd exciting a variable rated voltage.
M in the step 2) is realized by the following codes:
where N is the total number of available test reactors, M is a two-dimensional array whose first column represents N in the model1The second column represents n in the model2。
The specific operation of the step 3) is as follows: calculating the resonant frequency and the quality factor of each test arrangement scene in the solution set M;
(1) when n is1When the resonance frequency is 0, the calculation formula of the resonance frequency under the pure series resonance is as follows:
if so, LtThe approximate calculation formula can be obtained by carrying formula (1) when the value is 0:
(2) when n is1>At 0, the calculation formula of the resonance frequency under the series-parallel resonance is
Wherein,
to obtain in the formula (3)
There are two cases of the symbol of (2), when
The sign of the series-parallel system is positive, the resonance is a global resonance point, namely the series-parallel system obtains a series resonance point after the n2 branch is subjected to under-compensation; when in use
The sign of the test point is negative, the resonance is a local resonance point, namely the parallel connection system obtains a parallel connection type resonance point after the n2 branch and the test sample branch generate full resonance, and the test should be carried out in the test
The sign of the voltage is positive, so that the alternating current withstand voltage requirement can be met;
if R is equal to 0, R is equal to 0, LtWhen the compound is taken in formulas (3) to (5) as 0, it can be obtained:
obtaining the resonant frequency f' which is simply calculated at the moment and has a similar calculation structure with the formula (2), wherein the resonant frequency is determined after the use number of the test reactors is determined;
(3) one equation for figure of merit that is suitable for field calculations is
The formula is suitable for series equivalent test conditions and needs to be calculated under a resonance frequency point, and the Q value and the parameter R, L, C, Rt、LtIn this connection, it should be noted that in the field, there may be some situations where the test measures are not in place, such as poor grounding, severe corona, etc., and the Q value may be affected.
And 4) eliminating, namely calculating the resonance frequency of each reactor combination condition in the solution set M if the acceptable range of the test frequency band is between 20Hz and 300Hz, and eliminating the combination condition in the solution set M if the frequency band does not meet the range of the frequency band.
The step 5) specifically comprises the following operations:
n1the current flowing through a single reactor in the branch is calculated according to the following formula:
n2the current flowing through a single reactor in the branch is calculated according to the following formula:
n2the total current of the branch can be used for judging whether the capacity of the excitation transformer and the power supply capacity meet the limit, the product of the rated voltage of the high voltage side of the excitation transformer and the Q value is compared with the target withstand voltage value, and the range limit of the lowest Q value is screened.
The invention has the beneficial effects that:
the invention can calculate parameters of pure series resonance and series-parallel resonance, and can calculate resonance frequency and quality factor before test, and can be used for guiding on-site test configuration.
Drawings
Fig. 1 is a schematic diagram of a general wiring of the resonance withstand voltage of the present invention.
FIG. 2 is a simulation model diagram of the resonant withstand voltage of the present invention.
Detailed Description
The present invention will be described in further detail with reference to examples.
As shown in fig. 1 and 2: the invention relates to a parameter calculation and test method for resonance withstand voltage of high-voltage large-capacity equipment, which comprises the following steps of:
1) obtaining the capacitance parameter of the test article to be testedC; the inductance L and the resistance R of the test reactor and the total number N of the available test reactors; equivalent resistance R of excitation variable high-voltage windingtEquivalent leakage inductance L of excitation high voltage windingtAnd excitation variable rated voltage; and determining a target test voltage value and an expected ac frequency range.
2) According to the test model shown in fig. 1, generating an optional solution set M { [ N ] of the total number N of available test reactors1,n2]|n1+n2N is not more than N and N2>0} where n is1The number of parallel reactors of the parallel branch in the series-parallel resonance is; n is2The number of the parallel reactors of the series branch in the pure series resonance or the series-parallel resonance. Wherein M is implemented by:
where N is the total number of available test reactors, M is a two-dimensional array whose first column represents N in the model1The second column represents n in the model2。
3) And (4) calculating the resonance frequency and the quality factor of each experimental arrangement scene in the solution set M.
(1) When n is1When the resonance frequency is 0, the calculation formula of the resonance frequency under the pure series resonance is as follows:
if so, LtThe approximate calculation formula can be obtained by carrying formula (1) when the value is 0:
(2) when n is1>At 0, the calculation formula of the resonance frequency under the series-parallel resonance is
Wherein,
it can be seen that the theoretical calculation of the resonance frequency is quite complex. In the formula (3)
There are two cases of the symbol of (1). When in use
The sign of the series-parallel system is positive, the resonance is a global resonance point, namely the series-parallel system obtains a series resonance point after the n2 branch is subjected to under-compensation; when in use
The sign of the test sample is negative, the resonance is a local resonance point, namely the parallel connection system obtains a parallel connection type resonance point after the n2 branch and the test sample branch generate full resonance. In the test should be
The sign of the voltage-resistant resistor is positive, so that the alternating current voltage-resistant requirement can be met.
If R is equal to 0, R is equal to 0, LtWhen the compound is taken in formulas (3) to (5) as 0, it can be obtained:
it can be found that the resonant frequency f' of the simplified calculation at this time has a similar calculation structure to that of the formula (2), and the resonant frequency is determined after the number of the test reactors is determined.
(3) One equation for figure of merit that is suitable for field calculations is
The formula is suitable for series equivalent test conditions and needs to be calculated under a resonance frequency point, and the Q value and the parameter R, L, C, Rt、LtAnd (4) correlating. In addition, it should be noted that in the field, the test measures are not in place, and the Q value is also affected by poor grounding, severe corona and the like.
4) The condition that the resonant frequency value in the calculated scene does not meet the requirement needs to be eliminated according to the limit of the experimental frequency condition. Namely, if the acceptable range of the test frequency band is between 20Hz and 300Hz, the resonance frequency of each reactor combination condition in the solution set M is calculated, and if the frequency band range is not satisfied, the combination condition is deleted in the solution set M.
5) According to n1,n2And calculating the current flowing through each reactor according to the value of the voltage and the target test voltage value, and rejecting the scene if the current exceeds the rated current value of a single reactor.
n1The current flowing through a single reactor in the branch is calculated according to the following formula:
n2the current flowing through a single reactor in the branch is calculated according to the following formula:
n2the total current of the branch can be used for judging whether the capacity of the excitation transformer and the power supply capacity meet the limit, the product of the rated voltage of the high voltage side of the excitation transformer and the Q value is compared with the target withstand voltage value, and the range limit of the lowest Q value is screened.
6) In the configuration of obtaining the current solution set, an optimal test scheme is selected according to the condition that the 'minimum number of reactors' is better than the condition that the 'maximum Q value' is obtained.
Example 1
For the correctness of derivation, a test loop supported by a pure sine power supply is built in the PSCAD, the parameters of the rest parts are kept consistent, only the voltage amplitude of the power supply module is adjusted until the voltage of a test position meets the requirement, and a simulation model is shown in figure 2.
1) Variable frequency power supply:
rated input voltage: 380V
Rated output voltage: 480V
Rated capacity: 50kW
2) Testing reactance:
rated capacity: 66kVar
Rated voltage: 30kV
Rated inductance: 43H
The reactor direct resistance: 192 omega
3) Test excitation change:
rated capacity: 18kVA
Rated transformation ratio: 500V/8kV
High-pressure side direct resistance: 90 omega
No-load voltage: 0.71 percent
4) Nominal test capacitance:
rated voltage: 20kV
Rated capacitance: 0.15uF
A target voltage withstanding value is designed according to the rated voltage of a nominal test capacitor, the frequency qualified range is 20 Hz-300 Hz, and six reactors are respectively combined to simulate various series-harmonic and series-parallel resonance test scenes. The comparison between the obtained simulation results and the calculated values is shown in table 1. The value of Us in the table is derived from the value of the power supply voltage, and Ub represents the measured voltage on the high-voltage side of the excitation transformer.
TABLE 1 quality factor review and simulation results
Example 2
This example demonstrates a comparison of the results of field testing, which was performed on a 110kV crosslinked polyethylene submarine cable in the field, while performing test analysis by field testing. 4 test reactances with rated voltage of 300kV inductance of 19.1H are adopted in the test, and the combination mode is as follows: 2 series circuits are used for series branches, 2 parallel circuits are used for parallel branches, the equivalent capacitance of the submarine cable is 4.62uF, the tested object is applied with a relatively low 128kV alternating current withstand voltage, the acceptable frequency range of the test is 20-300 Hz, and the sine wave type output is adopted by the field variable frequency power supply cabinet.
In order to keep the field test combination mode consistent with the test structure, the parameters of the two reactors are reduced to be single, and the original combination is equivalent to a 38.2H reactor 1 in series-parallel connection with 4. The numerical equivalence does not affect the experimental procedure in question, and the results of the calculations and field data are shown in table 2. Theoretical calculation and field data verify the correctness of the derivation of the key parameters of the resonance voltage resistance and provide a theoretically optimal combination scheme.
TABLE 2 comparison of field tests with theory
Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.
Claims (6)
1. A parameter calculation and test method for resonance withstand voltage of high-voltage large-capacity equipment is characterized by comprising the following steps;
1) acquiring a device parameter C to be tested, and determining a target test voltage value and an expected alternating current frequency range;
2) generating an optional solution set M { [ N ] of the total number N of available test reactors1,n2]|n1+n2N is not more than N and N2>0} where n is1The number of parallel reactors of the parallel branch in the series-parallel resonance is; n is2The number of the parallel reactors of the series branch in the pure series resonance or the series-parallel resonance;
3) calculating the resonant frequency and the quality factor of each test arrangement scene in the solution set M;
4) rejecting the situation that the resonant frequency value in the calculated scene does not meet the requirement according to the limit of the test frequency condition;
5) according to n1,n2Calculating the current flowing through each reactor according to the value of the reference voltage and the target test voltage value, rejecting the scene if the current exceeds the rated current value of a single reactor, judging whether the capacity of the excitation transformer for the test and the power supply capacity meet the limit, and judging whether the target withstand voltage value can be met or not according to the calculated quality factor Q value and the maximum voltage of the excitation transformer and rejecting the scene which does not meet the condition;
6) in the configuration of obtaining the current solution set, an optimal test scheme is selected according to the condition that the 'minimum number of reactors' is better than the condition that the 'maximum Q value' is obtained.
2. The method for calculating and testing the parameters of the resonance withstand voltage of the high-voltage large-capacity equipment according to claim 1, wherein the parameters of the equipment tested in the step 1) comprise a tested product capacitance parameter C; the inductance L and the resistance R of the test reactor and the total number N of the available test reactors; equivalent resistance R of excitation variable high-voltage windingtEquivalent leakage inductance L of excitation high voltage windingtAnd exciting a variable rated voltage.
3. The method for calculating and testing the parameters of the resonance withstand voltage of the high-voltage large-capacity equipment according to claim 1, wherein M in the step 2) is realized by the following codes:
i＝0；ii＝0；
while N>0
while N-ii>0
aM(ii+1)＝[N-ii]；
M(i+1,:)＝[aM(ii+1),N-aM(ii+1)]；
i＝i+1；ii＝ii+1；
end
N＝N-1；ii＝0；
end
n1＝M(:,1)；
n2＝M(:,2)；
where N is the total number of available test reactors, M is a two-dimensional array whose first column represents N in the model1The second column represents n in the model2。
4. The parameter calculation and test method for the resonance withstand voltage of the high-voltage large-capacity equipment according to claim 1, wherein the specific operation of the step 3) is as follows: calculating the resonant frequency and the quality factor of each test arrangement scene in the solution set M;
(1) when n is1When the resonance frequency is 0, the calculation formula of the resonance frequency under the pure series resonance is as follows:
if so, LtThe approximate calculation formula can be obtained by carrying formula (1) when the value is 0:
(2) when n is1>At 0, the calculation formula of the resonance frequency under the series-parallel resonance is
Wherein,
to obtain in the formula (3)
There are two cases of the symbol of (2), when
The sign of the series-parallel system is positive, the resonance is a global resonance point, namely the series-parallel system obtains a series resonance point after the n2 branch is subjected to under-compensation; when in use
The sign of the test point is negative, the resonance is a local resonance point, namely the parallel connection system obtains a parallel connection type resonance point after the n2 branch and the test sample branch generate full resonance, and the test should be carried out in the test
The sign of the voltage is positive, so that the alternating current withstand voltage requirement can be met;
if R is equal to 0, R is equal to 0, LtWhen the compound is taken in formulas (3) to (5) as 0, it can be obtained:
obtaining the resonant frequency f' which is simply calculated at the moment and has a similar calculation structure with the formula (2), wherein the resonant frequency is determined after the use number of the test reactors is determined;
(3) one equation for figure of merit that is suitable for field calculations is
The formula is suitable for series equivalent test conditions and needs to be at harmonicCalculation of Q value and parameter R, L, C, R at vibration frequency pointt、LtIn this connection, it should be noted that in the field, there may be some situations where the test measures are not in place, such as poor grounding, severe corona, etc., and the Q value may be affected.
5. The parameter calculation and test method for the resonance withstand voltage of the high-voltage large-capacity equipment according to claim 1, wherein the operation of eliminating in the step 4) is to calculate the resonance frequency of each reactor combination condition in the solution set M if the acceptable range of the test frequency band is between 20Hz and 300Hz, and eliminate the combination condition in the solution set M if the frequency band range is not satisfied.
6. The parameter calculation and test method for the resonance withstand voltage of the high-voltage large-capacity equipment according to claim 1, wherein the step 5) specifically comprises the following operations:
n1the current flowing through a single reactor in the branch is calculated according to the following formula:
n2the current flowing through a single reactor in the branch is calculated according to the following formula:
n2the total current of the branch can be used for judging whether the capacity of the excitation transformer and the power supply capacity meet the limit, the product of the rated voltage of the high voltage side of the excitation transformer and the Q value is compared with the target withstand voltage value, and the range limit of the lowest Q value is screened.
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| CN114397537A (en) * | 2021-12-02 | 2022-04-26 | 中国大唐集团科学技术研究院有限公司火力发电技术研究院 | Method for optimizing portability of withstand voltage test of offshore 66kV submarine cable |
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| CN105548833A (en) * | 2015-12-09 | 2016-05-04 | 天津二十冶建设有限公司 | High-voltage cable frequency conversion series resonance voltage withstand debugging method |
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| CN105548833A (en) * | 2015-12-09 | 2016-05-04 | 天津二十冶建设有限公司 | High-voltage cable frequency conversion series resonance voltage withstand debugging method |
| CN108445357A (en) * | 2018-03-19 | 2018-08-24 | 河海大学 | A kind of long cable voltage testing equipment parameter preferred method |
Non-Patent Citations (1)
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| CN114397537A (en) * | 2021-12-02 | 2022-04-26 | 中国大唐集团科学技术研究院有限公司火力发电技术研究院 | Method for optimizing portability of withstand voltage test of offshore 66kV submarine cable |
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