阅读说明：本技术 一种用于高压大容量设备谐振耐压的参数计算及试验方法 (Parameter calculation and test method for resonance voltage resistance of high-voltage high-capacity equipment ) 是由 雷阳 何信林 王团结 李春丽 张鹏 杨世强 史振利 于 2021-08-19 设计创作，主要内容包括：本发明公开了一种用于高压大容量设备谐振耐压的参数计算及试验方法,包括以下步骤：1)获取待试验的设备参数C,确定目标试验电压值和预期的交流频率范围；2)将可用试验电抗器的总数量生成一个可选的解集；3)对解集中每一种试验布置场景进行谐振频率、品质因数计算；4)根据试验频率条件限制将所计算的场景中谐振频率值不满足要求的情况剔除；5)计算流过每一台电抗器的电流；6)在获取当前解集的配置中选择最佳试验方案。本发明能够用于指导高电压、大容量设备现场交流耐压参数计算及试验配置,从而保证电力系统设备级的安全稳定运行。(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.)

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 winding_tEquivalent leakage inductance L of excitation high voltage winding_tAnd 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, L_tThe 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 the content of the first and second substances,

to obtain in the formula (3)There are two cases of the symbol of (2), whenThe 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 useThe 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 testThe 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, L_tWhen 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 point_t、L_tIn 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.

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 winding_tEquivalent leakage inductance L of excitation high voltage winding_tAnd 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, L_tThe 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 the content of the first and second substances,

to obtain in the formula (3)There are two cases of the symbol of (2), whenThe 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 useThe 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 testThe 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, L_tWhen 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, R_t、L_tIn 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 winding_tEquivalent leakage inductance L of excitation high voltage winding_tAnd 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, L_tThe 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 the content of the first and second substances,

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 useThe 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 useThe 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 beThe 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, L_tWhen 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, R_t、L_tAnd (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.