Dynamic stability current sharing test method and system for high-capacity dry-type air-core reactor

Abstract

The invention discloses a dynamic stability current sharing test method and system for a high-capacity dry-type air-core reactor. The method comprises the following steps: constructing a multi-layer encapsulation test object group for testing the high-capacity dry-type air-core reactor; determining dynamic thermal stability test equipment; carrying out N times of tests on the encapsulated test object by using voltage and current sensors, and collecting N groups of test data in total; minimizing the difference between the actually measured current value and the estimated current value in each group of test data; calculating equivalent resistance and equivalent inductance encapsulated in the corresponding test based on the difference; calculating according to the equivalent resistance and the equivalent inductance to obtain active and reactive components; and calculating the corresponding parallel equivalent resistance, parallel equivalent inductance, parallel active component and parallel reactive component, calculating the relative deviation with the estimated value, and if the relative deviation is lower than a threshold value, determining that the uniformity meets the requirement. According to the invention, the collection of the uniform current among different encapsulated coils can be realized, and data support is provided for analyzing the heating condition in the encapsulation.

Description

Technical Field

[0001] The present invention belongs to the technical field of current uniformity of air-core reactors, and particularly relates to a dynamic stability current sharing test method and system for large-capacity dry-type air-core reactors. Background Art

[0002] In the 500kV receiving-end power grid in East China of our country, due to the dense grid and concentrated load, the short-circuit current in hub substations generally exceeds the breaking capacity of circuit breakers. Although traditional methods such as line disconnection and bus splitting can reduce the short-circuit current, they will damage the integrity of the power grid and lead to a decline in power supply reliability. Series current-limiting reactors are connected in series to the 500kV bus or outgoing line. By using the inductive impedance characteristic, the short-circuit current can be limited to the allowable range of the circuit breaker during a fault, while maintaining the full connection operation of the main ring network and avoiding grid fragmentation. Therefore, connecting series current-limiting reactors in series has become the core means for short-circuit current control in the 500kV power grid.

[0003] The 500kV series current-limiting reactor adopts a multi-packet parallel structure with a high rated capacity and large current, which causes the problem that the inductance deviation of each winding is relatively large during rated operation, resulting in uneven current distribution. Usually, it is necessary to optimize winding transposition and current sharing reactance compensation, and carry out dynamic and thermal stability tests under power frequency conditions to indirectly ensure that the current uniformity between packets meets the engineering requirements. In order to ensure the dynamic stability performance of the reactor under the short-circuit peak current, in the conventional scheme, it is necessary to conduct dozens of large-capacity power frequency voltage tests on the scaled-down model of the reactor. If there is no obvious abnormality in the packet after operation, it means that the test passes.

[0004] However, the design complexity of the latest 500kV series current-limiting reactor has been significantly improved, the overall size and the number of packet layers have increased, the rated capacity has reached the GVar level, and the number of packet layers is as high as 30 layers. Although the conventional scheme can control the overall performance, it can only indirectly ensure the current uniformity between packets, and lacks the actual measurement verification of the internal parameters and heating uniformity of each packet. At the same time, due to the large number of packets of the large series current-limiting reactor, the space at the star connection of its windings is relatively narrow, and only small current measurements can be carried out. Under approximate rated conditions, the current in the 500kV series current-limiting reactor can reach dozens of kiloamperes, and the corresponding current sensor size increases, so the measurement layout is difficult. At the same time, the leakage inductance of the 500kV series current-limiting reactor is extremely strong, and the mutual inductance between packet coils is cumbersome. If the internal current is inconsistent with the simulation design result under the actual operating state, although the overall external inductance has little deviation, if there are obvious overcurrent nodes inside, serious heating will damage the coil insulation and cause serious power grid operation accidents. Summary of the Invention

[0005] To solve the deficiencies existing in the prior art, the present invention provides a dynamic stability current sharing test method and system for a large-capacity dry-type air-core reactor, which can accurately collect the uniformity current between different encapsulated coils without damaging the encapsulation structure, provide data support for analyzing the heating conditions in each encapsulation, and further effectively verify the design structure of the reactor. At the same time, by combining an optimization algorithm, the calculation of resistance and inductance parameters is accurately realized, providing a reliable basis for predicting the current parameters in each encapsulation during actual operation and ensuring the safe and stable operation of the power grid.

[0006] The present invention adopts the following technical solutions.

[0007] The present invention proposes a dynamic stability current sharing test method for a large-capacity dry-type air-core reactor, including: According to the large-capacity dry-type air-core reactor to be tested, construct a multi-layer encapsulated reduced-scale test sample group for the large-capacity dry-type air-core reactor test, with a total of N, which respectively include 1-layer encapsulation, 2-layer encapsulation,..., N-layer encapsulation; connect the dynamic and thermal stability test equipment to the test sample; connect the AC synchronous generator to the input end of the isolation transformer through a switch, and connect the output end of the isolation transformer to both ends of the test sample encapsulated winding; sequentially connect the 1st to Nth layer encapsulated reduced-scale test samples to the output end of the isolation transformer, apply the same voltage for the test, and collect the test data; Set the initial vectors of the resistance and inductance of the encapsulation in the corresponding test, and use the particle swarm optimization algorithm to iteratively optimize the resistance and inductance of each group of encapsulations. Take the minimization of the difference between the discrete value of the test current and the theoretical current discrete value calculated based on the iteratively optimized values of the resistance and inductance as the constraint condition for iteration. After reaching the convergence standard, obtain the final iteratively optimized values of the resistance and inductance of each group of encapsulations; use the iteratively optimized values of the resistance and inductance of the encapsulation in each group of tests as the equivalent resistance and equivalent inductance of the corresponding encapsulation in each group of tests, and calculate the active and reactive components of the encapsulation under the test voltage in each group of tests in combination with the discrete value of the test current; calculate the theoretical parallel equivalent resistance, parallel equivalent inductance, parallel active component, and parallel reactive component corresponding to each encapsulation, and calculate the relative deviation respectively with the corresponding measured values. If all relative deviations are lower than the threshold, the uniformity meets the requirements.

[0008] Further, the encapsulated reduced-scale test sample group refers to reducing the large-capacity dry-type air-core reactor to be tested in proportion, keeping the winding connection method and wire material unchanged, and reducing the wire diameter, encapsulation thickness, coil turns, coil length, etc. in proportion to obtain an encapsulated reduced-scale test sample group containing different numbers of encapsulation layers.

[0009] Further, during each test, the applied test voltage is the same, and the test voltage value is determined according to the wire diameter and encapsulation layer thickness of the reduced-scale test sample group.

[0010] Further, during each test, the test voltage value applied to the encapsulated reduction ratio specimen group is measured by a voltage divider, and the test current value of the encapsulated reduction ratio specimen group is measured by a current transformer.

[0011] Further, according to the coil parameters of each encapsulated specimen group, the corresponding encapsulated resistance initialization vector and the initialization vector of inductance are calculated by the following formula: ; ; where D is the coil diameter, H is the coil height, ρ is the resistivity of the coil, L is the coil length, and S is the cross-sectional area of the coil.

[0012] Further, for each encapsulated reduction ratio specimen group, based on the initial optimization parameters , the particle swarm optimization method is adopted, and the optimization equation is: ; where the superscripts k and k + 1 are the discrete moments of the particle running process during the particle swarm optimization process for the nth group of test data, k is an integer, k = 1, 2, 3…K, and are the velocities of the particle at the kth and k + 1th moments of the particle running process respectively, w is the inertia weight, is the individual optimal position of the particle at the kth moment of the particle running process, is the global optimal position of the particle at the kth moment of the particle running process, c1 and c2 are the individual learning factor and the global learning factor respectively, r1 and r2 are the individual random number and the global random number respectively, and are the positions of the particle at the kth and k + 1th moments of the particle running process respectively.

[0013] Further, the equivalent resistance and equivalent inductance for each test at each optimization iteration are obtained by using the particle swarm optimization algorithm, and the theoretical current discrete values corresponding to the resistance and inductance iteration optimization values obtained each time are calculated by using the test voltage; The corresponding encapsulated test current collected during the test process of the encapsulated reduction ratio specimen group is discretized to obtain the test current discrete value.

[0014] Further, combined with the theoretical current discrete value , the constraint condition formula at the discrete moment k of the particle running process is: ; where and They are the equivalent resistance and equivalent inductance after the k-th optimization iteration corresponding to the n-th group of tests, respectively, and h = 1,..., H, where H is the number of sampling points of the current test data. is the measured current value at the h-th sampling point at the k-th time of the optimization iteration corresponding to the n-th group of tests. is the measured current value at the h-th time at the k-th time of the optimization iteration corresponding to the n-th group of tests. After several rounds of iteration, when the constraint condition formula meets the convergence condition, the final iterative optimization values of the resistance and inductance for each group of tests can be obtained, and the final iterative optimization values of the resistance and inductance are used as the equivalent resistance and equivalent inductance for the corresponding tests.

[0015] Furthermore, the theoretical calculation formulas for the parallel equivalent resistance, parallel equivalent inductance, parallel active component, and parallel reactive component between different layers of encapsulation are as follows: ; ; ; ; Among them, Rn, Ln, Pn, and Qn are the theoretical parallel equivalent resistance, parallel equivalent inductance, parallel active component, and parallel reactive component of different encapsulation samples, respectively, and n, i, j ∈ [1, N], i, j < n, In represents the effective value of the current passing through the encapsulation sample in the n-th test, and ω is the system electrical angular frequency; combining the physical parameters of the dry-type air-core reactor, Ri, Li, Lj, and Mij of each layer of encapsulation are obtained according to the finite element method.

[0016] Furthermore, using the equivalent resistance and equivalent inductance corresponding to different layers of encapsulation, the active and reactive components of each group of encapsulation under the test voltage are calculated by combining the discrete values of the test current; The relative deviations between the corresponding theoretical values Rn, Ln, Pn, and Qn and the corresponding equivalent resistance, equivalent inductance, and active and reactive components are calculated. If they are all lower than the threshold, the uniformity meets the requirements; the calculation formula for the relative deviation is: ; Among them, is the relative deviation between the theoretical values Rn, Ln, Pn, and Qn obtained in the n-th time and the corresponding equivalent resistance, equivalent inductance, and active and reactive components. When the indicators 、 、 and are less than the corresponding thresholds, it means that the uniformity of the reactor meets the requirements.

[0017] The present invention also provides a dynamic stability current sharing test system for large-capacity dry-type air-core reactors, including a test sample group construction module, a test equipment connection module, a data acquisition module, an equivalent parameter calculation module, and a uniformity verification module: The test sample group construction module constructs a reduced-scale test sample group for multi-layer large-capacity dry-type air-core reactor tests; The test equipment connection module, when the switch is closed, connects the encapsulated test sample to the AC synchronous generator through an isolation transformer. The current transformer is connected in series with the encapsulated test sample, and the voltage divider is installed at both ends of the encapsulated test sample; The data acquisition module conducts N tests on the encapsulated test sample and collects a total of N groups of test data, including the test current value; The equivalent parameter calculation module, based on the discrete values of the test current, obtains the equivalent resistance and equivalent inductance of the encapsulation in the corresponding test; optimizes the equivalent resistance and equivalent inductance in each group of tests to minimize the difference between the corresponding test current discrete value and the theoretical current discrete value; calculates the active and reactive components based on the equivalent resistance and equivalent inductance of each group of tests after the optimization, combined with the test current discrete value; The uniformity verification module calculates the parallel equivalent resistance, parallel equivalent inductance, parallel active component, and parallel reactive component corresponding to each encapsulation, calculates the relative deviation from the corresponding measured value. If it is lower than the threshold, the uniformity meets the requirements. Description of the Drawings

[0018] Figure 1 is the method flow chart of a dynamic stability current sharing test method for large-capacity dry-type air-core reactors of the present invention; Figure 2 is the schematic diagram of the reduced-scale test sample of a dynamic stability current sharing test method for large-capacity dry-type air-core reactors of the present invention; Figure 3 is the equipment connection diagram of a dynamic stability current sharing test method for large-capacity dry-type air-core reactors of the present invention.

[0019] Figure 4 is the power supply waveform diagram of a dynamic stability current sharing test method for large-capacity dry-type air-core reactors of the present invention. Detailed Embodiments

[0020] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the spirit of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

[0021] Embodiment 1 The present invention provides a dynamic stability current sharing test method and system for a large-capacity dry-type air-core reactor. The method flow chart is as shown in Figure 1 the following. The specific method steps are as follows: Construct a multi-layer encapsulated reduced-scale sample group for testing large-capacity dry-type air-core reactors, as shown in Figure 2 the following. There are a total of N samples, which respectively include 1-layer encapsulation, 2-layer encapsulation,..., N-layer encapsulation. Except for the number of encapsulation layers, the other structures are the same. The encapsulated reduced-scale sample group refers to an equal-proportion reduction of the 500 kV large-capacity dry-type air-core reactor to be tested, while keeping the winding connection method and wire material unchanged, and reducing the wire diameter, encapsulation thickness, number of coil turns, coil length, etc. in equal proportion to obtain an encapsulated reduced-scale sample group with different numbers of encapsulation layers.

[0022] Furthermore, connect the dynamic and thermal stability test equipment to the sample; the AC synchronous generator is connected to the input end of the isolation transformer through a switch, and the output end of the isolation transformer is connected to both ends of the sample encapsulated winding. As shown in Figure 3 the following, which is the equipment connection diagram of the present invention. Among them, when the switch S is closed, the encapsulated sample L is connected to the AC synchronous generator G through the isolation transformer T. After a short-time (about 500 ms) current is passed, the switch is disconnected. Among them, the current transformer is connected in series with the encapsulated sample, and the voltage divider is installed at both ends of the encapsulated sample. The connection structure of the current transformer, voltage divider, and encapsulated sample is called the test end in this embodiment. The voltage waveform applied to the encapsulated sample is a power-frequency sine component, as shown in Figure 4 the following. Furthermore, connect the 1st to Nth layer encapsulated reduced-scale samples to the output end of the isolation transformer in sequence, apply the same voltage for testing, and the wiring method of the sample is the same each time, that is, connect both ends of the sample to the test end. During each test, read the test data of the voltage uL and current iL through the voltage divider and current sensor. A total of N groups of test data are collected, as shown in Table 1. t ∈ [0, T], where T is the total duration of collecting test data.

[0023] Table 1 Test data

[0024] Discretize the data of each test. The total number of discretization points is H. Then the hth voltage and current discrete data of the nth test are respectively and .

[0025] Furthermore, set the initial vectors of the resistance and inductance of the encapsulation in the corresponding test, and use the particle swarm optimization algorithm to iteratively optimize the resistance and inductance of each group of encapsulations. Take the minimization of the difference between the discrete value of the test current and the theoretical current discrete value calculated based on the iteratively optimized values of the resistance and inductance as the constraint condition for iteration. After reaching the convergence standard, obtain the finally iteratively optimized values of the resistance and inductance of each group of encapsulations.

[0026] Specifically, according to the coil parameters of each encapsulated sample group, the corresponding initial vector of the encapsulated resistance is calculated by the following formula and the initial vector of the inductance as follows: ; ; where D is the coil diameter, H is the coil height, ρ is the resistivity of the coil, L is the coil length, and S is the cross-sectional area of the coil; For each encapsulated shrinkage test sample group, based on the initial optimization parameters , the particle swarm optimization method is adopted, and the optimization equation is: ; where the superscripts k and k + 1 are the discrete moments of the particle running process during the particle swarm optimization of the nth group of test data, k is an integer, k = 1, 2, 3...K, and are the velocities of the particle at the kth and (k + 1)th moments of the particle running process respectively, w is the inertia weight, is the individual optimal position of the particle at the kth moment of the particle running process, is the global optimal position of the particle at the kth moment of the particle running process, c1 and c2 are the individual learning factor and the global learning factor respectively, r1 and r2 are the individual random number and the global random number respectively, and are the positions of the particle at the kth and (k + 1)th moments of the particle running process respectively; After the kth round of optimization, the optimization parameter can be obtained. By using the optimization parameter and combining with the equivalent RLC circuit of the test platform and the actual voltage excitation waveform, and through discretization processing, the corresponding discrete theoretical current value can be obtained.

[0027] Furthermore, the equivalent resistance and equivalent inductance of the corresponding test at each optimization iteration are obtained by using the particle swarm optimization algorithm, and the discrete theoretical current value corresponding to the iterative optimized values of the resistance and inductance obtained each time is calculated by using the test voltage; The corresponding encapsulated test current collected during the test of the encapsulated shrinkage test sample group is discretized to obtain the discrete test current value.

[0028] Furthermore, combining the discrete theoretical current value , the constraint condition formula at the discrete moment k of the particle running process is: ; where and They are the equivalent resistance and equivalent inductance after the k-th optimization iteration corresponding to the n-th group of tests, respectively, and h = 1,..., H, where H is the number of sampling points of the current test data. is the measured current value at the h-th sampling point in the k-th optimization iteration corresponding to the n-th group of tests. is the measured current value at the h-th moment in the k-th optimization iteration corresponding to the n-th group of tests.

[0029] After several rounds of iteration, when the constraint condition formula meets the convergence condition, the final iterative optimization values of resistance and inductance for each group of tests can be obtained, and the final iterative optimization values of resistance and inductance are used as the equivalent resistance and equivalent inductance for the corresponding tests.

[0030] This constraint condition can closely optimize parameters around the test data. When calculating the equivalent resistance and inductance, it makes the optimization result more in line with the actual measurement situation, ensuring the reliability of the deduced equivalent resistance and inductance parameters. The parameters obtained in this way can more truly reflect the electrical characteristics of the reactor enclosure, help accurately evaluate the uniformity between enclosures, and provide key technical support for ensuring the safe and stable operation of the reactor.

[0031] Furthermore, taking the iterative optimization values of resistance and inductance of the enclosures in each group of tests as the equivalent resistance and equivalent inductance of the enclosures corresponding to each group of tests, and combining the discrete values of the test current, the active and reactive components of the enclosures under the test voltage in each group of tests are calculated, as shown in Table 2.

[0032] Table 2 Parameter Example

[0033] Calculate the theoretical parallel equivalent resistance, parallel equivalent inductance, parallel active component, and parallel reactive component corresponding to each enclosure, and calculate the relative deviation with the corresponding measured value respectively. If all relative deviations are lower than the threshold, the uniformity meets the requirements.

[0034] Specifically, the theoretical calculation formulas for the parallel equivalent resistance, parallel equivalent inductance, parallel active component, and parallel reactive component between enclosures with different numbers of layers are as follows: ; ; ; ; Among them, Rn, Ln, Pn, and Qn are respectively the theoretical parallel equivalent resistance, parallel equivalent inductance, parallel active component, and parallel reactive component of different encapsulated samples, and n, i, j ∈ [1, N], i, j < n. In represents the effective value of the current passing through the encapsulated sample in the nth test, and ω is the system electrical angular frequency; combining the physical parameters of the dry-type air-core reactor, Ri, Li, Lj, and Mij of each layer of encapsulation are obtained according to the finite element method.

[0035] Furthermore, using the equivalent resistance and equivalent inductance corresponding to different numbers of encapsulation layers, the active and reactive components of each group of encapsulation under the test voltage are calculated by combining the discrete values of the test current; The relative deviations are calculated between the corresponding theoretical values Rn, Ln, Pn, and Qn and the corresponding equivalent resistance, equivalent inductance, and active and reactive components. If all are lower than the threshold, the uniformity meets the requirements; the calculation formula for the relative deviation is: ; Among them, is the relative deviation between the theoretical values Rn, Ln, Pn, and Qn obtained in the nth time and the corresponding equivalent resistance, equivalent inductance, and active and reactive components. When the indicators , , and are less than the corresponding thresholds, it indicates that the uniformity of the reactor meets the requirements.

[0036] By calculating the parallel equivalent parameters, the electrical performance differences between different encapsulations can be intuitively compared. If the difference between the theoretical parallel equivalent parameters between encapsulations and the measured values is small, it indicates that the encapsulation uniformity is good; otherwise, there are problems. This helps to timely discover possible defects in the reactor design or manufacturing process, so as to optimize and improve the reactor and enhance its overall performance and operation reliability.

[0037] The present invention also proposes a dynamic stability current sharing test system for a large-capacity dry-type air-core reactor, including a test sample group construction module, a test equipment connection module, a data acquisition module, an equivalent parameter calculation module, and a uniformity verification module: The test sample group construction module constructs a multi-layer encapsulated reduced-scale test sample group for testing a large-capacity dry-type air-core reactor; The test equipment connection module, when the switch is closed, connects the encapsulated sample to the AC synchronous generator through an isolation transformer. The current transformer is connected in series with the encapsulated sample, and the voltage divider is installed at both ends of the encapsulated sample; The data acquisition module conducts N tests on the encapsulated sample and collects a total of N groups of test data, including the test current values; The equivalent parameter calculation module obtains the equivalent resistance and equivalent inductance of the enclosure in the corresponding test based on the discrete values of the test current; optimizes the equivalent resistance and equivalent inductance in each group of tests to minimize the difference between the corresponding discrete value of the test current and the discrete value of the theoretical current; calculates the active and reactive components based on the equivalent resistance and equivalent inductance of each group of tests after the optimization is completed, in combination with the discrete value of the test current. The uniformity verification module calculates the parallel equivalent resistance, parallel equivalent inductance, parallel active component, and parallel reactive component corresponding to each enclosure, calculates the relative deviation from the corresponding measured value. If it is lower than the threshold, the uniformity meets the requirements.

[0038] Embodiment 2 This embodiment makes further improvements on the basis of Embodiment 1.

[0039] In this embodiment, a test sample group of enclosures for multi-layer large-capacity dry-type air-core reactors is constructed. Considering cost issues, the number of layers of the scaled-down test sample group of enclosures can also be gradually increased to 2, 3, or other integers not greater than N / 2. The more the number of the scaled-down test sample groups of enclosures, the more obvious the uniformity verification effect. The number of layers of the enclosures can be, but is not limited to, this way: such as 1, 3, 5, 9, 12, etc., that is, the number of layers can be in a non-arithmetic progression manner.

[0040] In this embodiment, the specific steps for simulating and obtaining the equivalent resistance and equivalent inductance of the enclosure in the corresponding test are as follows: Taking the equivalent resistance and equivalent inductance corresponding to each group of tests as the optimization objects, an optimization equation is constructed; The constraint condition given for the optimization equation is to minimize the difference between the measured current value and the estimated current value in the test data.

[0041] Among them, the optimization algorithm can be, but is not limited to, the least squares method, the simulated annealing algorithm, and the genetic algorithm.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the specific implementation manners of the present invention can still be modified or equivalently replaced, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A large-capacity dry-type air-core reactor dynamic stability current sharing test method, characterized in that: include: According to the large-capacity dry-type air-core reactor to be tested, a multi-layer large-capacity dry-type air-core reactor test package reduction test sample group is constructed, with a total of N pieces, including 1 layer of package, 2 layers of package, ..., N layers of package; the dynamic thermal stability test equipment is connected to the test sample; The AC synchronous generator is connected to the input end of the isolation transformer through a switch, and the output end of the isolation transformer is connected to the two ends of the test sample encapsulation winding; 1 to N layers of encapsulation reduction ratio test samples are connected to the output end of the isolation transformer in sequence, the same voltage is applied for testing, and the test data is collected; Set the initialization vectors of the resistors and inductors encapsulated in the corresponding test, and use the particle swarm optimization algorithm to iteratively optimize the resistors and inductors of each group of encapsulations. Minimize the difference between the test current discrete value and the theoretical current discrete value calculated based on the iterative optimization value of the resistor and inductor as the iterative constraint condition. After reaching the convergence standard, obtain the final iterative optimization value of the resistor and inductor of each group of encapsulations. The iterative optimization values ​​of the resistance and inductance of the package in each group of tests are used as the equivalent resistance and equivalent inductance of the package corresponding to each group of tests, and the active and reactive components of the package under the test voltage in each group of tests are calculated in combination with the discrete value of the test current; The theoretical parallel equivalent resistance, parallel equivalent inductance, parallel active component and parallel reactive component corresponding to each package are calculated, and the relative deviations are calculated respectively with the corresponding measured values. If all relative deviations are lower than the threshold, the uniformity meets the requirements.

2. According to claim 1, a large-capacity dry-type air-core reactor dynamic stability current sharing test method is characterized in that: The encapsulation reduction test group refers to a large-capacity dry-type air-core reactor to be tested that is proportionally reduced, keeping the winding connection method and wire material unchanged, and reducing the wire diameter, encapsulation thickness, coil turns, and coil length in equal proportion to obtain an encapsulation reduction test group containing different numbers of encapsulation layers.

3. According to claim 1, a large-capacity dry-type air-core reactor dynamic stability current sharing test method is characterized in that: The test voltage applied is the same during each test, and the test voltage value is determined based on the wire diameter and the thickness of the encapsulation layer of the scaled test group.

4. A large-capacity dry-type air-core reactor dynamic stability current sharing test method according to claim 3, characterized in that: During each test, the test voltage value applied to the package shrinkage test group is measured by a voltage divider, and the test current value of the package shrinkage test group is measured by a current transformer.

5. According to claim 1, a large-capacity dry-type air-core reactor dynamic stability current sharing test method is characterized in that: According to the coil parameters of each encapsulated sample group, the corresponding encapsulation resistance initialization vector is calculated by the following formula: and the initialization vector of the inductor : ； ； Where D is the coil diameter, H is the coil height, ρ is the resistivity of the coil, L is the coil length, and S is the cross-sectional area of ​​the coil.

6. A large-capacity dry-type air-core reactor dynamic stability current sharing test method according to claim 5, characterized in that: For each package shrinkage ratio test group, based on the initial optimized parameters , using particle swarm optimization method, the optimization equation is: ； Among them, the superscript k and k+1 are the discrete moments of the particle operation process during the particle swarm optimization process of the nth group of test data, k is an integer, k=1,2,3…K, and are the speed of the particle at time k and time k+1 during the particle's running process, w is the inertia weight, is the optimal position of the individual particle at time k during the particle running process, is the optimal position of the particle group at time k during the particle operation process, c1 and c2 are the individual learning factor and the group learning factor, r1 and r2 are the individual random number and the group random number, and are the positions of the particle at time k and time k+1 during the particle's running process respectively.

7. A large-capacity dry-type air-core reactor dynamic stability current sharing test method according to claim 6, characterized in that: The particle swarm optimization algorithm is used to obtain the equivalent resistance and equivalent inductance of the corresponding test under each optimization iteration, and the test voltage is used to calculate the theoretical current discrete value corresponding to the iterative optimization value of resistance and inductance each time; The corresponding enclosed test current collected during the test of the enclosed shrinkage ratio sample group is discretized to obtain the discrete value of the test current.

8. A dynamic stability current sharing test method for a large-capacity dry-type air-core reactor according to claim 7, characterized in that: Combined with the theoretical current discrete value , the constraint formula at the discrete moment k of the particle running process is: ； in, and are the kth equivalent resistance and equivalent inductance of the optimization iteration corresponding to the nth group of tests, and h=1,...,H, where H is the number of sampling points of the current test data, is the measured current value of the sampling point number at the kth time of the optimization iteration corresponding to the nth group of tests, is the measured current value at the hth moment of the kth optimization iteration corresponding to the nth group of tests; After several rounds of iteration, when the constraint condition formula meets the convergence condition, the final iterative optimization values of the resistance and inductance of each group of tests can be obtained, and the final iterative optimization values of the resistance and inductance are used as the equivalent resistance and equivalent inductance of the corresponding test.

9. A dynamic stability current sharing test method for a large-capacity dry-type air-core reactor according to claim 1, characterized in that: The theoretical calculation formulas for the parallel equivalent resistance, parallel equivalent inductance, parallel active component, and parallel reactive component between different layers of enclosures are: ； ； ； ； Among them, Rn, Ln, Pn, and Qn are the theoretical parallel equivalent resistance, parallel equivalent inductance, parallel active component, and parallel reactive component of different enclosure samples respectively, and n, i, j ∈ [1, N], i, j < n, In represents the effective value of the current passing through the enclosure test sample in the nth test, and ω is the system electrical angular frequency; combined with the physical parameters of the dry-type air-core reactor, Ri, Li, Lj, and Mij of each layer of enclosure are obtained according to the finite element method.

10. A dynamic stability current sharing test method for a large-capacity dry-type air-core reactor according to claim 9, characterized in that: Using the equivalent resistance and equivalent inductance corresponding to different layers of enclosures, the active and reactive components of each group of enclosures under the test voltage are calculated in combination with the discrete value of the test current; The relative deviations of the corresponding theoretical values Rn, Ln, Pn, and Qn from the corresponding equivalent resistance, equivalent inductance, and active and reactive components are calculated respectively. If they are all lower than the threshold, the uniformity meets the requirements; the calculation formula for the relative deviation is: ； in, is the relative deviation between the theoretical values ​​Rn, Ln, Pn and Qn obtained for the nth time and the corresponding equivalent resistance, equivalent inductance, and active and reactive components. , , and If it is less than the corresponding threshold, it means that the uniformity of the reactor meets the requirements.

11. A dynamic stability current sharing test system for a large-capacity dry-type air-core reactor based on the method according to any one of claims 1-10, comprising a test sample group construction module, a test equipment connection module, a data acquisition module, an equivalent parameter calculation module, and a uniformity verification module, characterized in that: The test sample group construction module constructs a multi-layer enclosed shrinkage ratio sample group for testing a large-capacity dry-type air-core reactor; The test equipment connection module, when the switch is closed, the enclosed test sample is connected to the AC synchronous generator through an isolation transformer, the current transformer is connected in series with the enclosed test sample, and the voltage divider is installed at both ends of the enclosed test sample; The data acquisition module conducts N tests on the enclosed test sample and collects a total of N groups of test data, including the test current value; The equivalent parameter calculation module, based on the discrete value of the test current, obtains the equivalent resistance and equivalent inductance of the enclosure in the corresponding test; optimizes the equivalent resistance and equivalent inductance in each group of tests to minimize the difference between the corresponding discrete value of the test current and the theoretical discrete value of the current; according to the equivalent resistance and equivalent inductance of each group of tests after the optimization is completed, the active and reactive components are calculated in combination with the discrete value of the test current; The uniformity verification module calculates the parallel equivalent resistance, parallel equivalent inductance, parallel active component, and parallel reactive component corresponding to each enclosure, calculates the relative deviation from the corresponding measured value, and if it is lower than the threshold, the uniformity meets the requirements.

Images