CN111579976A - Loop parameter calculation method and system for high-voltage capacitive direct test - Google Patents

Abstract

The invention discloses a loop parameter calculation method and system for a high-voltage capacitive direct test. In the loop parameter calculation method of a single capacitor bank opening and closing test, the invention constructs the breakage voltage per unit value and time of the circuit breaker under test based on the test method. Calculate the K value under different amplitude coefficients, so as to calculate the parameters of the FM branch, so that the envelope of the initial part of the recovery voltage meets the standard requirements, the calculation process and calculation results are accurate, and no manual adjustment is required; in the back-to-back capacitor bank In the loop parameter calculation method of the opening and closing test, the standard recovery voltage peak value, the inrush current damping resistance and the standard inrush current peak value and frequency are taken into consideration. The calculation process and calculation results are accurate and do not require manual adjustment.

Description

A loop parameter calculation method and system for high-voltage capacitive direct test

technical field

The invention relates to a loop parameter calculation method and system for a high-voltage capacitive direct test, and belongs to the technical field of high-voltage tests.

Background technique

The capacitive current switching performance of an AC circuit breaker is one of its most important performances. my country began to study the capacitive current switching test of AC circuit breakers in the 1970s, and has been able to complete the full-pole capacitive current switching test of 550kV voltage level circuit breakers in the laboratory. Each laboratory at home and abroad selects direct or synthetic test methods that meet the standard requirements according to their own test loop parameters and equipment performance.

Due to equipment limitations, each test station conducts single-phase tests on circuit breakers with voltage levels of 72.5kV and above. The single-compatibility current switching test is the preferred direct test, that is, the voltage and current are provided by the same power supply. The capacitive switching test can be divided into three test methods: LC (line charging current switching test), CC (cable charging current switching test) and BC (capacitor bank current switching test) according to the type of breaking load. Most of the centralized capacitor banks are used to replace the line and cable loads, so when selecting the test circuit and calculating parameters, the test methods LC and CC can refer to the test method BC. The single-phase capacitor bank opening and closing test (BC) includes the opening and closing test of a single capacitor bank or a back-to-back capacitor bank.

See Figure 1(a) and Figure 1(b) for the circuit schematic diagram of the single capacitor bank opening and closing test. After the tested circuit breaker TB breaks the capacitive current, the recovery voltage borne by both ends should meet the requirements of Figure 3(a) and (b). The loop parameter calculation method mainly lies in the accurate calculation of the frequency modulation branch (R ₀ -C ₀ , R ₀ and C ₀ are the resistance and capacitance of the frequency modulation branch, respectively), so that the initial part of the expected recovery voltage remains from the origin to (t _1s , u _1s ) (see Figure 3(b)) below the line segment composed of points. The current calculation methods are: according to the test method and the amplitude coefficient K _af , calculate the actual initial recovery voltage envelope u ₁ -t ₁ and the undamped oscillation envelope L _s -C ₀ (L _s is the The ratio of the equivalent inductance) to obtain the oscillation frequency of L _s -C ₀ . Since L _s is known, the parameters of C ₀ and R ₀ can be calculated. However, the existing data only give the K value when K _af = 1.4, and the parameter calculation results still need manual fine-tuning.

The circuit schematic diagram of the back-to-back capacitor bank opening and closing test is shown in Figure 2(a) and Figure 2(b). When the tested circuit breaker TB closes the capacitive current, the current flowing through the TB should meet the requirements that the frequency is close to 4250Hz and the peak value reaches 20kA. (b) requirements. Due to the large capacitance of the inrush current branch, the initial part of the recovery voltage will automatically be kept below the envelope u _1s -t _1s , so the calculation method of the circuit parameters of the test is mainly based on the inrush current branch L ₁ -C ₁ (L ₁ , C ₁ are the inductance and capacitance of the inrush current branch, respectively) and the accurate calculation of the load branch R _d -L ₂ -C ₂ . The current calculation method for the inrush current branch is: by establishing the equations about the inrush current frequency, breaking current and loop principle, determine the load capacitance C ₂ , the load branch inductance L ₂ , the inrush current branch inductance C ₁ and the inrush current branch capacitance Parameters of _C1 . However, the standard recovery voltage peak value, inrush current damping resistance and standard inrush current peak value are not considered comprehensively, and need to be adjusted manually.

SUMMARY OF THE INVENTION

The present invention provides a loop parameter calculation method and system for a high-voltage capacitive direct test, which solves the problems disclosed in the background art.

In order to solve the above-mentioned technical problems, the technical scheme adopted in the present invention is:

A loop parameter calculation method for high-voltage capacitive direct test, including loop parameter calculation method for single capacitor bank opening and closing test and loop parameter calculation method for back-to-back capacitor bank opening and closing test;

The calculation method of circuit parameters for the opening and closing test of a single capacitor bank is as follows:

In response to the breaking of the tested circuit breaker, according to the test method, the relationship model between the per-unit value of the tested circuit breaker's breaking voltage and time is constructed;

Calculate the ratio K of the actual initial recovery voltage envelope to the envelope of the undamped oscillation according to the relational model, the straight line passing through the origin tangent to the curve corresponding to the relational model, and the horizontal line of the peak value of the overvoltage per unit value; The peak value is equal to the amplitude coefficient of the initial recovery voltage of the breaker under test;

According to the K value, calculate the parameters of the single capacitor bank opening and closing test loop;

The calculation method of circuit parameters for the back-to-back capacitor bank opening and closing test is as follows:

According to the breaking current of the tested circuit breaker, the peak value of the standard recovery voltage, the power frequency frequency and the standard inrush current frequency, the relationship model of the inrush current branch capacitance and the load branch capacitance is constructed;

According to the standard inrush current frequency, the standard inrush current peak value and the standard test voltage, calculate the sum L of the initial inrush current branch inductance and the load branch inductance;

Calculate the inrush current branch capacitance, load branch capacitance, equivalent power supply voltage of the test loop, inrush current damping resistance and actual inrush current peak value according to the relationship module, L. In response to the actual inrush current peak value not within the preset range, according to the preset step size Adjust L and repeat this step until the actual peak value of inrush current is within the preset range to obtain the parameters of the back-to-back capacitor bank opening and closing test loop.

The relationship model between the per-unit value of the fractured voltage of the tested circuit breaker and the time is:

Among them, ω ₀ is the undamped angular frequency, ω is the damped angular frequency, δ, β are the variables defined in the calculation process, u _{1_d} (t) is the per-unit value of the breaking voltage of the circuit breaker under test, t is the time, and R ₀ , C ₀ are the resistance and capacitance in the FM branch respectively, L _s is the equivalent inductance after the test loop is equivalent,

Among them, K _T is the transformation ratio between the high-voltage side and the low-voltage side of the boost-transformation, L _L and L _H are the loop inductance of the low-voltage side and the loop inductance of the high-voltage side of the boost-transformation before the test loop is equivalent, U _g is the power supply voltage, and f is the power supply voltage. frequency power supply frequency, K _c is the capacitive coefficient, U _r is the rated voltage of the circuit breaker under test, I _c is the breaking current of the circuit breaker under test, and k _type is the test mode.

Calculate the ratio K of the actual initial recovery voltage envelope to the undamped oscillation envelope according to the relational model, the straight line passing through the origin tangent to the corresponding curve of the relational model, and the horizontal line of the per-unit peak value of the overvoltage. The specific process is:

According to the relational model, calculate the time t _{d_p} when the voltage per unit value reaches the peak value;

Calculate the ratio K _P1 between t _{d_p} and the undamped oscillation half-cycle time;

Obtain the coordinates of the tangent point between the curve corresponding to the relational model and the line passing through the origin;

According to the coordinates of the tangent point, obtain the coordinates of the intersection point of the line passing through the origin and the horizontal line of the per-unit peak value of overvoltage;

Calculate the ratio K _P2 of the time corresponding to the intersection coordinates and t _{d_p} ;

According to K _P1 and K _P2 , calculate the ratio K of the actual initial recovery voltage envelope to the envelope of the undamped oscillation.

The test loop parameters include the resistance and capacitance in the FM branch, and the calculation formula is,

ω为有阻尼角频率，

为计算过程中定义的变量，t₁为实际的恢复电压起始部分包络线电压值对应的时间。Among them, L _s is the equivalent inductance after the test loop is equivalent, R ₀ and C ₀ are the resistance and capacitance in the frequency modulation branch, respectively.

ω is the damped angular frequency,

It is a variable defined in the calculation process, and t ₁ is the time corresponding to the envelope voltage value of the initial part of the actual recovery voltage.

The model formula of the relationship between the inrush current branch capacitance and the load branch capacitance is,

Among them, C ₂ and C ₁ are the load branch capacitance and inrush current branch capacitance, respectively, f is the power frequency frequency, L _s is the equivalent inductance after the test loop is equivalent, u _cs is the peak value of the standard recovery voltage, and I _c is the The breaking current of the test circuit breaker, f _ds is the standard inrush current frequency.

Test loop parameters include,

Adjust to the last L;

Bring the adjusted L into the relational model, and obtain the inrush current branch capacitance and load branch capacitance;

Bring the inrush current branch capacitance and load branch capacitance into the equivalent power supply calculation formula, and obtain the equivalent power supply voltage of the test loop;

Bring the adjusted L, inrush current branch capacitance and load branch capacitance into the inrush current damping calculation formula to obtain the inrush current damping resistance.

Equivalent power calculation formula,

U _s =U _A -U _A ·2πf·(C ₁ +C ₂ )·2πf·L _s

Among them, U _s is the equivalent power supply voltage of the test loop, C ₂ and C ₁ are the load branch capacitance and inrush current branch capacitance, respectively, f is the power frequency frequency, L _s is the equivalent inductance of the test loop after the equivalent, U _A is the inrush current branch voltage when the tested circuit breaker is closed;

The inrush damping formula is:

Among them, R _d is the inrush current damping resistance, K _d is the standard damping coefficient, parameter

A loop parameter calculation system for high-voltage capacitive direct test, including a loop parameter calculation system for a single capacitor bank opening and closing test and a loop parameter calculation system for back-to-back capacitor bank opening and closing tests;

The loop parameter calculation system for the opening and closing test of a single capacitor bank includes,

The first relationship model building module: in response to the opening of the circuit breaker under test, according to the test method, construct a relationship model between the per-unit value of the breakage voltage of the circuit breaker under test and the time;

K acquisition module: Calculate the ratio K of the actual initial recovery voltage envelope to the undamped oscillation envelope according to the relational model, the straight line passing through the origin tangent to the corresponding curve of the relational model, and the horizontal line of the per-unit peak value of the overvoltage; The per-unit peak value of the voltage is equal to the amplitude coefficient of the initial recovery voltage of the breaker under test;

Test loop parameter acquisition module: According to the K value, calculate the parameters of the single capacitor bank opening and closing test loop.

The loop parameter calculation system for the back-to-back capacitor bank opening and closing test includes,

The second relationship module building module: According to the breaking current of the tested circuit breaker, the peak value of the standard recovery voltage, the power frequency frequency and the standard inrush current frequency, the relationship model of the inrush current branch capacitance and the load branch capacitance is constructed;

Initial L acquisition module: Calculate the sum L of the initial inrush current branch inductance and load branch inductance according to the standard inrush current frequency, the standard inrush current peak value and the standard test voltage;

Adjust the calculation module: According to the relationship module, L, calculate the inrush current branch capacitance, load branch capacitance, the equivalent power supply voltage of the test circuit, the inrush current damping resistance and the actual inrush current peak value. In response to the actual inrush current peak value not within the preset range, according to The preset step length is adjusted to L, and this step is repeated until the actual inrush current peak value is within the preset range, and the back-to-back capacitor bank switching test loop parameters are obtained.

A computer-readable storage medium storing one or more programs comprising instructions that, when executed by a computing device, cause the computing device to perform loop parameter calculations for a high voltage capacitive direct test method.

A computing device comprising one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the The one or more programs include instructions for performing a loop parameter calculation method for high voltage capacitive direct testing.

The beneficial effects achieved by the present invention: in the method for calculating the loop parameters of the single capacitor bank opening and closing test, the present invention builds the relationship model between the per-unit value of the breakage voltage of the tested circuit breaker and the time based on the test method, and calculates the K under different amplitude coefficients. value, so as to calculate the parameters of the FM branch, so that the envelope of the initial part of the recovery voltage meets the standard requirements, the calculation process and calculation results are accurate, and no manual adjustment is required; in the loop parameter calculation method of the back-to-back capacitor bank switching test, the The standard recovery voltage peak value, inrush current damping resistance and standard inrush current peak value are taken into consideration, and the calculation process and calculation results are accurate and do not require manual adjustment.

Description of drawings

Figure 1(a) is the circuit diagram of a single capacitor bank before the opening and closing test circuit is equivalent;

Figure 1(b) is the circuit diagram of a single capacitor bank opening and closing test circuit after equivalent;

Figure 2(a) is the circuit diagram before the back-to-back capacitor bank opening and closing test circuit is equivalent;

Figure 2(b) is the circuit diagram after the back-to-back capacitor bank opening and closing test circuit is equivalent;

Figure 3(a) is the definition of u _cs , t _2s , u _1s , t _1s and the definitions of u _c and t ₂ that satisfy the conditions;

Figure 3(b) is the enlargement of the initial part of 3(a), which is the standard requirement for the initial recovery voltage of the breaker under test, that is, the initial recovery voltage of the breaker under test must be maintained from the origin to (t _1s , u _1s ) below the line segment composed of points;

Figure 4(a) is a schematic diagram of K _P1 calculation in the circuit parameter calculation method for the opening and closing test of a single capacitor bank;

Figure 4(b) is a schematic diagram of the calculation of K _P2 in the calculation method of the circuit parameters of a single capacitor bank opening and closing test;

Fig. 5 is the flow chart of the calculation method of loop parameters for the opening and closing test of a single capacitor bank;

Fig. 6 is the flow chart of the loop parameter calculation method of the back-to-back capacitor bank switching test;

Fig. 7 is a simulation calculation example of a single capacitor bank opening and closing test;

Figure 8 is a calculation example of the back-to-back capacitor bank switching test.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings. The following examples are only used to illustrate the technical solutions of the present invention more clearly, and cannot be used to limit the protection scope of the present invention.

A loop parameter calculation method for a high-voltage capacitive direct test includes a loop parameter calculation method for a single capacitor bank switching test and a loop parameter calculation method for back-to-back capacitor bank switching tests.

As shown in Figure 5, the calculation method of the circuit parameters for the opening and closing test of a single capacitor bank is as follows:

Step 1, in response to the breaking of the circuit breaker under test, according to the test method, build a relationship model between the per-unit value of the breakage voltage of the circuit breaker under test and the time.

The specific process of building a relational model is as follows:

According to the rated voltage U _r of the tested circuit breaker (TB), the breaking current I _c , the calculation coefficient k _type corresponding to the test method, and the initial recovery voltage amplitude coefficient K _af of the tested circuit breaker fracture, calculate the standard recovery voltage envelope parameters:

u _cs is the peak value of the standard recovery voltage:

t _2s is the time corresponding to the peak value of the standard recovery voltage:

t _2s = 8.7ms (50Hz) or 7.3ms (60Hz)

u _1s is the envelope voltage value of the initial part of the standard recovery voltage:

t _1s is the time corresponding to the envelope voltage value of the initial part of the standard recovery voltage:

t _1s = constant

Among them, K _c is the capacitive coefficient, and t _1s is a constant. According to the U _r check standard, the test method is BC1 (Test method 1 of BC, the breaking current I _c is 10-40% of the rated breaking current) k _type = 1.98, the test method is BC2 (Test method 2 of BC, the breaking current I _c is 100% or more of the rated breaking current) k _type =1.95.

u _cs and power supply voltage U _g should satisfy the following formula:

Among them, K _T is the transformation ratio of the high-voltage side to the low-voltage side of the boost-transformer T, L _L and L _H are the loop inductance of the low-voltage side and the loop inductance of the high-voltage side of the boost-transformer before the equivalent test loop, and f is the frequency of the power frequency power supply.

K _T and U _g are determined by the equipment parameters of the test station. Within the adjustable range of U _g , K _T should be as small as possible. After comprehensive consideration, K _T and U _g can be obtained, and then the equivalent power supply after the test loop can be calculated. Voltage U _s , equivalent inductance L _s , load capacitance C ₂ :

U _s =U _g ·K _T

where ω is the damped angular frequency.

Calculate the actual initial voltage envelope parameters as:

Among them, u ₁ is the actual envelope voltage value of the initial part of the recovery voltage, and t ₁ is the time corresponding to the actual envelope voltage value of the initial part of the recovery voltage.

After the TB is broken, the initial partial recovery voltage at both ends of the TB is determined by L _s and its voltage drop across the TB and the parameters of the frequency modulation branch (R ₀ -C ₀ ), and the relationship between the per-unit value of the breakage voltage of the tested circuit breaker and the time is derived. Model:

ω₀为无阻尼角频率，ω为有阻尼角频率，δ、β为计算过程中定义的变量，u_{1_d}(t)为被试断路器断口电压标幺值，t为时间，R₀、C₀分别为调频支路中的电阻和电容。in,

ω ₀ is the undamped angular frequency, ω is the damped angular frequency, δ and β are the variables defined in the calculation process, u _{1_d} (t) is the per-unit value of the breaker voltage under test, t is the time, R ₀ , C ₀ is the resistance and capacitance in the FM branch, respectively.

Step 2, according to the relational model, calculate the time t _{d_p} when the per-unit value reaches the peak value.

When ωt _{d_p} =2β, u _{1_d} =K _af , we can get:

Among them, t _{d_p} is the time when the per-unit value reaches the peak value.

范围内求取

的数值解m，即

β＝tan^-1(m)，则

Using the zeroin numerical algorithm to

get within the range

The numerical solution m of , namely

β=tan ^-1 (m), then

Step 3, calculate the ratio K _P1 of t _{d_p} and the undamped oscillation half-cycle time.

根据t_{d_p}可得K的第一部分，即because

The first part of K can be obtained according to t _{d_p} , namely

ω为有阻尼角频率，

为计算过程中定义的变量。where t _{0_p} is the undamped oscillation half-cycle time, and the parameter

ω is the damped angular frequency,

Variables defined in the calculation process.

Step 4: Obtain the coordinates of the tangent point between the curve corresponding to the relational model and the straight line passing through the origin.

Define a straight line line1 through the origin, line1 and u _{1_d} are tangent at time t _t , and the equation can be obtained by listing the equation:

代入上式并令θ＝ω·t_t，可得：It can be known from the calculation of m

Substituting into the above formula and setting θ=ω·t _t , we get:

Use the zeroin numerical algorithm to find the numerical solution n of θ in the range of θ∈(0,π), that is, θ=n, then we can get: t _t =n/ω, and the corresponding per-unit voltage at this time:

Step 5: According to the coordinates of the tangent point, obtain the coordinates of the intersection of the line passing through the origin and the horizontal line passing through the per-unit peak value.

即交点坐标为(t_c,K_af)。The per-unit peak value is equal to K _af . Specifically, as shown in Figure 4, the intersection time of the line passing the origin and the horizontal line passing the per-unit peak value is:

That is, the coordinates of the intersection point are (t _c , K _af ).

Step 6: Calculate the ratio of the time corresponding to the coordinates of the intersection to t _{d_p} to obtain the second part of K, denoted as K _P2 .

Among them, t _c , u _{1_d_t} are the time corresponding to the coordinates of the intersection point and the voltage per unit value corresponding to the coordinates of the tangent point, respectively.

Step 7, according to K _P1 and K _P2 , calculate the ratio K of the actual initial recovery voltage envelope to the undamped oscillation envelope, K=K _P1 ·K _P2 .

Step 8: Calculate the test loop parameters according to the K value.

The test loop parameters include the resistance and capacitance in the FM branch, and the calculation formula is:

ω为有阻尼角频率，

为计算过程中定义的变量，t₁为实际的恢复电压起始部分包络线电压值对应的时间。Among them, L _s is the equivalent inductance after the test loop is equivalent, R ₀ and C ₀ are the resistance and capacitance in the frequency modulation branch, respectively.

ω is the damped angular frequency,

It is a variable defined in the calculation process, and t ₁ is the time corresponding to the envelope voltage value of the initial part of the actual recovery voltage.

For the parameter calculation of the opening and closing test of a single capacitor bank, by combining the analytical calculation of the second-order circuit and the calculation method of the Zeroin numerical algorithm, the coefficient K under different amplitude coefficients is calculated, so as to calculate the parameters of the frequency modulation branch, so as to restore the packet of the initial part of the voltage. The network line meets the standard requirements. The calculation process and calculation results are accurate, no manual adjustment is required, and the parameter calculation can be quickly realized by programming.

For the parameter calculation of the opening and closing test of a single capacitor bank, the per-unit value of the voltage level is performed, and the search for the cut point can be independent of the voltage, but only depends on the R ₀ -L _s -C ₀ parameters and the amplitude coefficient.

As shown in Figure 6, the calculation method of the loop parameters of the back-to-back capacitor bank switching test is as follows:

S1) According to the breaking current of the tested circuit breaker, the peak value of the standard recovery voltage, the power frequency frequency and the standard inrush current frequency, the relationship model of the inrush current branch capacitance and the load branch capacitance is constructed.

The specific process of building a relational model is as follows:

According to the rated voltage U _r of the tested circuit breaker (TB), the breaking current I _c , the calculation coefficient k _type corresponding to the test method, and the initial recovery voltage amplitude coefficient K _af of the tested circuit breaker fracture, calculate the standard recovery voltage envelope parameters:

u _cs is the peak value of the standard recovery voltage:

t _2s is the time corresponding to the peak value of the standard recovery voltage:

t _2s = 8.7ms (50Hz) or 7.3ms (60Hz)

u _1s is the envelope voltage value of the initial part of the standard recovery voltage:

t _1s is the time corresponding to the envelope voltage value of the initial part of the standard recovery voltage:

t _1s = constant

Among them, K _c is the capacitive coefficient, and t _1s is a constant. According to the U _r check standard, the test method is BC1 (Test method 1 of BC, the breaking current I _c is 10-40% of the rated breaking current) k _type = 1.98, the test method is BC2 (Test method 2 of BC, the breaking current I _c is 100% or more of the rated breaking current) k _type =1.95.

u _cs and power supply voltage U _g should satisfy the following formula:

Among them, K _T is the transformation ratio of the high-voltage side to the low-voltage side of the boost-transformer T, L _L and L _H are the loop inductance of the low-voltage side and the loop inductance of the high-voltage side of the boost-transformer before the equivalent test loop, and f is the frequency of the power frequency power supply.

其中C₂、C₁分别为负载支路电容和涌流支路电容。K _T and U _g are determined by the equipment parameters of the test station. In the adjustable range of U _g , K _T is as small as possible. Comprehensive consideration can be drawn that K _T and U _g , C ₁ is relatively small compared to C ₂ , so generally it will not affect Choice of K _T. The equivalent inductance can be calculated

Among them, C ₂ and C ₁ are the load branch capacitance and the inrush current branch capacitance, respectively.

Determine the breaking current I _c , the peak value of the standard recovery voltage u _cs , and the power frequency f, and list the following equations:

U _A =U _s +U _A ·2πf·(C ₁ +C ₂ )·2πf·L _s

U _A′ =U _s +U _A′ ·2πf·C ₁ ·2πf·L _s

U _A ·ω ·C ₂ =I _c

Among them, U _A and U' _A are the inrush current branch voltages when the TB is closed and opened, respectively.

Solving the above equations can obtain the first equations of C ₂ and C ₁ :

According to the standard inrush current frequency f _ds , the second equation of C ₂ and C ₁ can be obtained:

即

which is

L为涌流支路电感L₁与负载支路电感L₂之和，即L＝L₁+L₂。Among them, the parameter

L is the sum of the inrush current branch inductance L ₁ and the load branch inductance L ₂ , that is, L=L ₁ +L ₂ .

The first equation and the second equation form a relationship model of the inrush branch capacitance and the load branch capacitance.

S2) Calculate the sum L of the initial inrush current branch inductance and the load branch inductance according to the standard inrush current frequency, the standard inrush current peak value and the standard test voltage.

I_f_ds为标准涌流峰值。Among them, the standard test voltage

I_f _ds is the standard peak inrush current.

S3) According to the relationship module, L, calculate the inrush current branch capacitance, load branch capacitance, equivalent power supply voltage of the test circuit, inrush current damping resistance and actual inrush current peak value. In response to the actual inrush current peak value not within the preset range, according to the preset Adjust the step size L, repeat this step until the actual peak value of inrush current is within the preset range, and obtain the parameters of the back-to-back capacitor bank opening and closing test loop.

Bring L into the relational model to solve C ₁ , use C ₁ to solve C ₂ , use C ₂ , C ₁ to solve U _A , U′ _A , test loop equivalent power supply voltage U _s , inrush current damping resistance and the actual peak inrush current, as follows:

U _s =U _A -U _A ·2πf·(C ₁ +C ₂ )·2πf·L _s

Among them, R _d is the inrush current damping resistance, K _d is the standard damping coefficient, and I_f _d is the actual inrush current peak value.

The preset range is (I_f _ds , 1.02I_f _ds ), so if I_f _d ≤I_f _ds , adjust L, that is, L=L-ΔL, ΔL is the preset step size, which can be adjusted as needed; if I_f _d ≥1.02· I_f _ds , then adjust L, that is, L=L+ΔL, and ΔL is a preset step size.

The final obtained test loop parameters include: 1. Adjust to the last L; 2. Bring the adjusted L into the relational model to obtain the inrush current branch capacitance and load branch capacitance; 3. Connect the inrush current branch capacitance and load Bring the branch capacitance into the calculation formula of the equivalent power supply, and obtain the equivalent power supply voltage of the test circuit; 4. Bring the adjusted L, inrush current branch capacitance and load branch capacitance into the inrush current damping calculation formula, and obtain the inrush current damping resistance. .

An example based on the above method: Figure 7 is a simulation calculation example of the opening and closing test of a single capacitor bank: U _r =252kV, I _c =900A, it can be seen from the calculation results that the recovery voltage satisfies the envelope u _cs -t _2s , and the recovery voltage The initial part (enlarged part) does not exceed u _1s -t _1s , which satisfies the requirement. Figure 8 shows the calculation example of the back-to-back capacitor bank switching test: U _r =252kV, I _c =1100A, peak inrush current I_f _d ≥I_f _ds (I_f _ds =20kA), inrush current frequency f _d =4348Hz (f _ds =4250Hz), satisfying Require.

Aiming at the parameter calculation of the back-to-back capacitor bank switching test, by establishing the equation system about inrush current frequency, breaking current, standard recovery voltage and loop principle, the expression about the relationship between C ₂ and C ₁ is obtained, and the obtained C ₂ , C ₁ can make the parameters meet the requirements of inrush current frequency and standard recovery voltage at the same time.

For the parameter calculation of the back-to-back capacitor bank opening and closing test, the initial L is given, which reduces the calculation range of I_f _d , shortens the calculation time and is beneficial to computer programming.

For the parameter calculation of the back-to-back capacitor bank switching test, the influence of R _d on the inrush current attenuation is simultaneously considered in the process of calculating the test parameters, and the calculation formula of the inrush current damping resistance is given, so that the calculated inrush current waveform automatically satisfies the standard damping coefficient K _d .

In summary, in the loop parameter calculation method of the single capacitor bank switching test, the relationship model between the per-unit value of the breakage voltage of the tested circuit breaker and time is constructed based on the test method, and the K value under different amplitude coefficients is calculated to calculate the frequency modulation branch. parameters, so that the envelope of the initial part of the recovery voltage meets the standard requirements, the calculation process and calculation results are accurate, and no manual adjustment is required; in the loop parameter calculation method of the back-to-back capacitor bank switching test, the standard recovery voltage peak value, inrush current damping The resistance and standard inrush current peak value and frequency are taken into consideration, the calculation process and calculation results are accurate, and no manual adjustment is required.

A loop parameter calculation system for high-voltage capacitive direct test, including a loop parameter calculation system for a single capacitor bank opening and closing test and a loop parameter calculation system for back-to-back capacitor bank opening and closing tests;

The loop parameter calculation system for the opening and closing test of a single capacitor bank includes,

The first relationship model building module: in response to the opening of the circuit breaker under test, according to the test method, construct a relationship model between the per-unit value of the breakage voltage of the circuit breaker under test and the time;

K acquisition module: Calculate the ratio K of the actual initial recovery voltage envelope to the undamped oscillation envelope according to the relational model, the straight line passing through the origin tangent to the corresponding curve of the relational model, and the horizontal line of the per-unit peak value of the overvoltage; The per-unit peak value of the voltage is equal to the amplitude coefficient of the initial recovery voltage of the breaker under test;

Test loop parameter acquisition module: According to the K value, calculate the parameters of the single capacitor bank opening and closing test loop.

The loop parameter calculation system for the back-to-back capacitor bank opening and closing test includes,

The second relationship module building module: According to the breaking current of the tested circuit breaker, the peak value of the standard recovery voltage, the power frequency frequency and the standard inrush current frequency, the relationship model of the inrush current branch capacitance and the load branch capacitance is constructed;

Initial L acquisition module: Calculate the sum L of the initial inrush current branch inductance and load branch inductance according to the standard inrush current frequency, the standard inrush current peak value and the standard test voltage;

Adjust the calculation module: According to the relationship module, L, calculate the inrush current branch capacitance, load branch capacitance, the equivalent power supply voltage of the test circuit, the inrush current damping resistance and the actual inrush current peak value. In response to the actual inrush current peak value not within the preset range, according to The preset step length is adjusted to L, and this step is repeated until the actual inrush current peak value is within the preset range, and the back-to-back capacitor bank switching test loop parameters are obtained.

A computer-readable storage medium storing one or more programs comprising instructions that, when executed by a computing device, cause the computing device to perform loop parameter calculations for a high voltage capacitive direct test method.

A computing device comprising one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the The one or more programs include instructions for performing a loop parameter calculation method for high voltage capacitive direct testing.

As will be appreciated by those skilled in the art, the embodiments of the present application may be provided as a method, a system, or a computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It will be understood that each flow and/or block in the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to the processor of a general purpose computer, special purpose computer, embedded processor or other programmable data processing device to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing device produce Means for implementing the functions specified in a flow or flow of a flowchart and/or a block or blocks of a block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory result in an article of manufacture comprising instruction means, the instructions The apparatus implements the functions specified in the flow or flow of the flowcharts and/or the block or blocks of the block diagrams.

These computer program instructions can also be loaded on a computer or other programmable data processing device to cause a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process such that The instructions provide steps for implementing the functions specified in the flow or blocks of the flowcharts and/or the block or blocks of the block diagrams.

The above are only examples of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention are included in the application for pending approval of the present invention. within the scope of the claims.

Claims (10)

1. a loop parameter calculation method of high-voltage capacitive direct test, it is characterized in that: comprise the loop parameter calculation method of single capacitor bank opening and closing test and the loop parameter calculation method of back-to-back capacitor bank opening and closing test; The calculation method of circuit parameters for the opening and closing test of a single capacitor bank is as follows: In response to the breaking of the tested circuit breaker, according to the test method, the relationship model between the per-unit value of the tested circuit breaker's breaking voltage and time is constructed; Calculate the ratio K of the actual initial recovery voltage envelope to the envelope of the undamped oscillation according to the relational model, the straight line passing through the origin tangent to the curve corresponding to the relational model, and the horizontal line of the peak value of the overvoltage per unit value; The peak value is equal to the amplitude coefficient of the initial recovery voltage of the breaker under test; According to the K value, calculate the parameters of the single capacitor bank opening and closing test loop; The calculation method of circuit parameters for the back-to-back capacitor bank opening and closing test is as follows: According to the breaking current of the tested circuit breaker, the peak value of the standard recovery voltage, the power frequency frequency and the standard inrush current frequency, the relationship model of the inrush current branch capacitance and the load branch capacitance is constructed; According to the standard inrush current frequency, the standard inrush current peak value and the standard test voltage, calculate the sum L of the initial inrush current branch inductance and the load branch inductance; Calculate the inrush current branch capacitance, load branch capacitance, equivalent power supply voltage of the test loop, inrush current damping resistance and actual inrush current peak value according to the relationship module, L. In response to the actual inrush current peak value not within the preset range, according to the preset step size Adjust L and repeat this step until the actual peak value of inrush current is within the preset range to obtain the parameters of the back-to-back capacitor bank opening and closing test loop. 2. The circuit parameter calculation method of a high-voltage capacitive direct test according to claim 1, wherein the relationship model between the per-unit value of the breakage voltage of the tested circuit breaker and the time is,

Among them, ω ₀ is the undamped angular frequency, ω is the damped angular frequency, δ, β are the variables defined in the calculation process, u _{1_d} (t) is the per-unit value of the breaking voltage of the circuit breaker under test, t is the time, and R ₀ , C ₀ are the resistance and capacitance in the FM branch respectively, L _s is the equivalent inductance after the test loop is equivalent,

Among them, K _T is the transformation ratio between the high-voltage side and the low-voltage side of the boost-transformation, L _L and L _H are the loop inductance of the low-voltage side and the loop inductance of the high-voltage side of the boost-transformation before the test loop is equivalent, U _g is the power supply voltage, and f is the power supply voltage. frequency power supply frequency, K _c is the capacitive coefficient, U _r is the rated voltage of the circuit breaker under test, I _c is the breaking current of the circuit breaker under test, and k _type is the coefficient of the test mode. 3. The loop parameter calculation method of a high-voltage capacitive direct test according to claim 1, characterized in that: according to the relational model, the straight line crossing the origin that is tangent to the corresponding curve of the relational model, and the horizontal line of the per-unit peak value of overvoltage , calculate the ratio K of the actual initial recovery voltage envelope to the undamped oscillation envelope. The specific process is: According to the relational model, calculate the time t _{d_p} when the voltage per unit value reaches the peak value; Calculate the ratio K _P1 between t _{d_p} and the undamped oscillation half-cycle time; Obtain the coordinates of the tangent point between the curve corresponding to the relational model and the line passing through the origin; According to the coordinates of the tangent point, obtain the coordinates of the intersection point of the line passing through the origin and the horizontal line of the per-unit peak value of overvoltage; Calculate the ratio K _P2 of the time corresponding to the intersection coordinates and t _{d_p} ; According to K _P1 and K _P2 , the ratio K of the actual initial recovery voltage envelope to the envelope of the undamped oscillation is calculated. 4. The loop parameter calculation method of a high-voltage capacitive direct test according to claim 1, wherein the test loop parameter comprises the resistance and the capacitance in the frequency modulation branch, and the calculation formula is,

Among them, L _s is the equivalent inductance after the test loop is equivalent, R ₀ and C ₀ are the resistance and capacitance in the frequency modulation branch, respectively.

ω is the damped angular frequency,

It is a variable defined in the calculation process, and t ₁ is the time corresponding to the envelope voltage value of the initial part of the actual recovery voltage. 5. The loop parameter calculation method of a high-voltage capacitive direct test according to claim 1, characterized in that: the relationship model formula of the inrush current branch capacitance and the load branch capacitance is,

Among them, C ₂ and C ₁ are the load branch capacitance and inrush current branch capacitance, respectively, f is the power frequency frequency, L _s is the equivalent inductance after the test loop is equivalent, u _cs is the peak value of the standard recovery voltage, and I _c is the The breaking current of the test circuit breaker, f _ds is the standard inrush current frequency. 6. The loop parameter calculation method for a high-voltage capacitive direct test according to claim 1, wherein the test loop parameters include: Adjust to the last L; Bring the adjusted L into the relational model, and obtain the inrush current branch capacitance and load branch capacitance; Bring the inrush current branch capacitance and load branch capacitance into the equivalent power supply calculation formula, and obtain the equivalent power supply voltage of the test loop; Bring the adjusted L, inrush current branch capacitance and load branch capacitance into the inrush current damping calculation formula to obtain the inrush current damping resistance. 7. The loop parameter calculation method of a high-voltage capacitive direct test according to claim 6, characterized in that: the equivalent power calculation formula, U _s =U _A −U _A ·2πf·(C ₁ +C ₂ )·2πf·L _s Among them, U _s is the equivalent power supply voltage of the test loop, C ₂ and C ₁ are the load branch capacitance and inrush current branch capacitance, respectively, f is the power frequency frequency, L _s is the equivalent inductance of the test loop after the equivalent, U _A is the inrush current branch voltage when the circuit breaker under test is closed; The inrush damping formula is:

Among them, R _d is the inrush current damping resistance, K _d is the standard damping coefficient, parameter

8. A loop parameter calculation system for a high-voltage capacitive direct test, characterized in that: a loop parameter calculation system including a single capacitor bank opening and closing test and a back-to-back capacitor bank opening and closing test loop parameter calculation system; The loop parameter calculation system for the opening and closing test of a single capacitor bank includes, The first relationship model building module: in response to the opening of the circuit breaker under test, according to the test method, construct a relationship model between the per-unit value of the breakage voltage of the circuit breaker under test and the time; K acquisition module: Calculate the ratio K of the actual initial recovery voltage envelope to the undamped oscillation envelope according to the relational model, the straight line passing through the origin tangent to the corresponding curve of the relational model, and the horizontal line of the per-unit peak value of the overvoltage; The per-unit peak value of the voltage is equal to the amplitude coefficient of the initial recovery voltage of the breaker under test; Test loop parameter acquisition module: According to the K value, calculate the parameters of the single capacitor bank opening and closing test loop. The loop parameter calculation system for the back-to-back capacitor bank opening and closing test includes, The second relationship module building module: According to the breaking current of the tested circuit breaker, the peak value of the standard recovery voltage, the power frequency frequency and the standard inrush current frequency, the relationship model of the inrush current branch capacitance and the load branch capacitance is constructed; Initial L acquisition module: Calculate the sum L of the initial inrush current branch inductance and load branch inductance according to the standard inrush current frequency, the standard inrush current peak value and the standard test voltage; Adjust the calculation module: According to the relationship module, L, calculate the inrush current branch capacitance, load branch capacitance, the equivalent power supply voltage of the test circuit, the inrush current damping resistance and the actual inrush current peak value. In response to the actual inrush current peak value not within the preset range, according to The preset step length is adjusted to L, and this step is repeated until the actual inrush current peak value is within the preset range, and the back-to-back capacitor bank switching test loop parameters are obtained. 9. A computer-readable storage medium storing one or more programs, characterized in that the one or more programs comprise instructions that, when executed by a computing device, cause the computing device to perform according to the claims Any of the methods described in 1 to 7. 10. A computing device, characterized in that: comprising, one or more processors, a memory, and one or more programs stored in the memory and configured to be executed by the one or more processors, the one or more programs including Instructions for performing any of the methods of claims 1 to 7.

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