Parameter confirmation method and device of fault current limiting and circuit breaking protection system, terminal equipment and computer readable storage medium

Abstract

The invention discloses a parameter confirmation method and device for a fault current limiting and circuit breaking protection system, terminal equipment and a computer readable storage medium, and the method comprises the steps: constructing a resistance type superconducting current limiter simulation model and a sulfur hexafluoride circuit breaker simulation model, and setting an initial strip length and an initial parallel resistance value; under the condition of the initial strip length and the initial parallel resistance value, fault simulation of preset maximum expected short-circuit current is carried out, and the maximum target unit resistance of room temperature resistance which does not exceed a preset proportion when the sulfur hexafluoride circuit breaker is opened is solved; determining a target strip length corresponding to the resistance type superconducting current limiter according to the maximum target unit resistance; and taking the target strip length as the final strip length of the resistance type superconducting current limiter in the fault current limiting and circuit breaking protection system. According to the invention, the damage risk of the resistance type superconducting current limiter can be reduced, and the material waste caused by the overlarge margin determined by human experience is avoided.

Description

Technical Field

[0001] The present invention relates to the field of superconducting current limiting, and in particular to a parameter confirmation method, device, terminal equipment and computer-readable storage medium for a fault current limiting and circuit breaker protection system. Background Art

[0002] With the continuous development of superconducting technology, the application of superconductivity in power systems is also constantly advancing, and superconducting power equipment such as superconducting current limiters, superconducting transformers, and superconducting cables have gradually emerged. Among them, the resistive superconducting current limiter has zero resistance in the superconducting state and can quickly change to the resistive state after quenching under short-circuit current. It has been widely studied to limit the short-circuit current of power systems.

[0003] The working principle of the resistive superconducting current limiter is that under normal conditions, the superconducting material inside is in a superconducting state, and the current passes through almost without loss. When a short circuit occurs in the system, the huge short-circuit current triggers the superconducting material to quench, and it quickly changes to a state with high resistance, thereby effectively limiting the size of the short-circuit current and protecting other components of the power system from damage. This feature greatly reduces the burden of DC circuit breakers in dealing with short-circuit currents, reduces the stringent requirements for the circuit breaker's breaking capacity, and simplifies the design and manufacturing process of DC circuit breakers.

[0004] However, although the resistive superconducting current limiter has significant advantages in limiting short-circuit current, the resistive superconducting current limiter cannot withstand short-circuit current for a long time. Its current limiting process is accompanied by a large amount of heat and temperature rise. When the temperature of the resistive superconducting current limiter reaches room temperature, the strip will be partially damaged and the critical current carrying capacity will also decrease. Therefore, it is necessary to cut off the resistive superconducting current limiter before its temperature reaches room temperature, so as to achieve the current limiting target while avoiding damage to the current limiter. In AC systems, resistive superconducting current limiters are mainly used together with sulfur hexafluoride circuit breakers, which are used to protect the resistive superconducting current limiters. The parameter design of the resistive superconducting current limiter mainly relies on experience and excessive margins, which not only increases the cost and volume of the superconducting current limiter, but also may reduce its efficiency in actual operation. Summary of the invention

[0005] The embodiments of the present invention provide a parameter confirmation method, apparatus, terminal equipment and computer-readable storage medium for a fault current limiting and circuit breaker protection system, which can reduce the damage risk of a resistive superconducting current limiter and avoid material waste caused by excessive margin determined by human experience.

[0006] An embodiment of the present invention provides a method for confirming parameters of a fault current limiting and circuit breaker protection system, comprising:

[0007] Construct a resistance-type superconducting current limiter simulation model and a sulfur hexafluoride circuit breaker simulation model, and set the initial strip length and initial parallel resistance value;

[0008] Under the conditions of the initial strip length and the initial parallel resistance value, a fault simulation of a preset maximum expected short-circuit current is performed, and the maximum target unit resistance of the room temperature resistance that does not exceed the preset ratio when the sulfur hexafluoride circuit breaker is opened is solved in the resistance-type superconducting current limiter simulation model, and then the target strip length corresponding to the resistance-type superconducting current limiter is determined according to the maximum target unit resistance;

[0009] The target tape length is taken as the final tape length of the resistive superconducting current limiter in the fault current limiting and circuit breaker protection system.

[0010] Furthermore, the parameter confirmation method of the fault current limiting and circuit breaker protection system also includes:

[0011] Under the conditions of the target strip length and the initial parallel resistance value, a fault simulation of a preset maximum expected short-circuit current is performed, a minimum target current limiting rate exceeding the preset current limiting rate is solved in the resistance-type superconducting current limiter simulation model, and then a target parallel resistance value of the parallel resistor is determined according to the minimum target current limiting rate;

[0012] The target parallel resistance value is used as the resistance value of the parallel resistor in the fault current limiting and circuit breaker protection system.

[0013] Furthermore, the simulation model of the resistive superconducting current limiter is as follows:

[0014]

[0015]

[0016] Among them, R YBCO The resistance of the superconducting layer of the resistive superconducting current limiter simulation model, E c Represents the critical electric field strength of the superconducting layer of the resistive superconducting current limiter simulation model, I YBCO Represents the current of the superconducting layer of the resistive superconducting current limiter simulation model, I c (T) represents the critical current of the superconducting layer of the resistive superconducting current limiter simulation model, R SFCL represents the total resistance of the resistance-type superconducting current limiter simulation model, R1 represents the resistance of other metal layers of the strip of the resistance-type superconducting current limiter simulation model, U represents the voltage across the strip of the resistance-type superconducting current limiter simulation model, T represents the temperature difference between the strip surface of the resistance-type superconducting current limiter simulation model and liquid nitrogen, h represents the heat transfer coefficient between the strip surface of the resistance-type superconducting current limiter simulation model and liquid nitrogen, A represents the surface area of ​​the strip of the resistance-type superconducting current limiter simulation model in contact with liquid nitrogen, ρ represents the strip density of the resistance-type superconducting current limiter simulation model, Heat variation representing the temperature rise per unit volume of the resistive superconducting current limiter simulation model.

[0017] Furthermore, under the conditions of the initial strip length and the initial parallel resistance value, a fault simulation of a preset maximum expected short-circuit current is performed, and the maximum target unit resistance of the room temperature resistance that does not exceed a preset proportion when the sulfur hexafluoride circuit breaker is opened is solved in the resistance-type superconducting current limiter simulation model, and then the target strip length corresponding to the resistance-type superconducting current limiter is determined according to the maximum target unit resistance, including:

[0018] The first simulation step: Under the conditions of the current strip length and the initial parallel resistance value, solving the current target unit resistance of the resistance-type superconducting current limiter when the sulfur hexafluoride circuit breaker is opened in the resistance-type superconducting current limiter simulation model; wherein the initial value of the current strip length is the initial strip length;

[0019] The first determination step: comparing the current target unit resistance with the preset ratio of room temperature resistance, if the current target unit resistance exceeds the preset ratio of room temperature resistance, then executing the step of increasing the strip length; if the current target unit resistance does not exceed the preset ratio of room temperature resistance, then executing the step of reducing the strip length;

[0020] Increasing the strip length step: multiplying the current strip length by a first preset threshold value to obtain an updated current strip length, and jumping to the first simulation step; wherein the first preset threshold value is greater than 1;

[0021] The step of reducing the strip length is as follows: multiplying the current strip length by a second preset threshold value to obtain an updated current strip length, and performing a second determination step; wherein the second preset threshold value is less than 1;

[0022] The second judgment step: under the conditions of the current strip length and the initial parallel resistance value, the current target unit resistance of the resistive superconducting current limiter when the sulfur hexafluoride circuit breaker is opened is solved in the resistive superconducting current limiter simulation model, and the current target unit resistance is compared with the room temperature resistance of the preset proportion. If the current target unit resistance exceeds the room temperature resistance of the preset proportion, the previous strip length is used as the final target strip length. If the current target unit resistance does not exceed the room temperature resistance of the preset proportion, jump to the step of reducing the strip length.

[0023] Further, under the conditions of the target strip length and the initial parallel resistance value, a fault simulation of a preset maximum expected short-circuit current is performed, and a minimum target current limiting rate exceeding the preset current limiting rate is solved in the resistance-type superconducting current limiter simulation model, and then a target parallel resistance value of the parallel resistor is determined according to the minimum target current limiting rate, including:

[0024] The second simulation step: Under the conditions of the target strip length and the current parallel resistance value, solving the current target current limiting rate of the resistance-type superconducting current limiter when the sulfur hexafluoride circuit breaker is opened in the resistance-type superconducting current limiter simulation model; wherein the initial value of the current parallel resistance value is the initial parallel resistance value;

[0025] The third determination step: comparing the current target current limiting rate with the preset current limiting rate, if the current target current limiting rate exceeds the preset current limiting rate, executing the step of reducing the parallel resistance, if the current target current limiting rate does not exceed the preset current limiting rate, executing the step of increasing the parallel resistance;

[0026] Reducing the parallel resistance step: multiplying the current parallel resistance value by the third preset threshold value to obtain an updated current parallel resistance value, and jumping to the second simulation step; wherein the third preset threshold value is less than 1;

[0027] Increasing the parallel resistance step: multiplying the current parallel resistance value by a fourth preset threshold value to obtain an updated current parallel resistance value, and executing a fourth determination step; wherein the fourth preset threshold value is greater than 1;

[0028] The fourth judgment step: under the conditions of the target strip length and the current parallel resistance value, solve the current target current limiting rate of the resistive superconducting current limiter when the sulfur hexafluoride circuit breaker is opened in the resistive superconducting current limiter simulation model, and compare the current target current limiting rate with the preset current limiting rate. If the current target current limiting rate exceeds the preset current limiting rate, the smallest parallel resistance value among all corresponding parallel resistance values ​​exceeding the preset current limiting rate is used as the final target parallel resistance value. If the current target current limiting rate does not exceed the preset current limiting rate, jump to the step of increasing the parallel resistance.

[0029] Furthermore, the current target current limiting rate is determined by:

[0030] In the simulation model of the resistive superconducting current limiter, the current peak value of the resistive superconducting current limiter is solved when the sulfur hexafluoride circuit breaker is opened;

[0031] The current target current limiting rate is obtained by dividing the current peak value by the preset current peak value.

[0032] Further, a fault current limiting and circuit breaker protection system includes: a resistive superconducting current limiter, a sulfur hexafluoride circuit breaker, and a parallel resistor;

[0033] The input end of the resistance-type superconducting current limiter is connected to the first end of the sulfur hexafluoride circuit breaker; the output end of the resistance-type superconducting current limiter is connected to the first end of the parallel resistor; and the second end of the sulfur hexafluoride circuit breaker is connected to the second end of the parallel resistor.

[0034] Based on the above method embodiment, the present invention provides a corresponding device embodiment, including: a simulation model building module, a target strip length determination module and a strip length configuration module;

[0035] A simulation model building module, used to build a resistance-type superconducting current limiter simulation model and a sulfur hexafluoride circuit breaker simulation model, and set an initial strip length and an initial parallel resistance value;

[0036] A target strip length determination module is used to perform a fault simulation of a preset maximum expected short-circuit current under the conditions of an initial strip length and an initial parallel resistance value, solve a maximum target unit resistance of a room temperature resistance not exceeding a preset ratio when a sulfur hexafluoride circuit breaker is opened in a resistance-type superconducting current limiter simulation model, and then determine a target strip length corresponding to the resistance-type superconducting current limiter according to the maximum target unit resistance;

[0037] The strip length configuration module is used for taking the target strip length as the final strip length of the resistive superconducting current limiter in the fault current limiting and circuit breaker protection system.

[0038] Based on the above-mentioned method embodiment, the present invention provides a corresponding terminal device embodiment, including: a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, the steps of the parameter confirmation method of the fault current limiting and circuit breaker protection system as described in the present invention are implemented.

[0039] Based on the above-mentioned method embodiment, the present invention provides a corresponding computer-readable storage medium embodiment, including: a stored computer program, which controls the device where the computer-readable storage medium is located to execute the steps of the parameter confirmation method of the fault current limiting and circuit breaker protection system as described in the present invention when the computer program is running.

[0040] Compared with the prior art, the beneficial effects of the embodiment of this solution are:

[0041] The present invention constructs a simulation model of a resistive superconducting current limiter and a simulation model of a sulfur hexafluoride circuit breaker, and sets an initial strip length and an initial parallel resistance value. The sulfur hexafluoride circuit breaker simulation model can lead the short-circuit circuit to the parallel resistance by opening the gate, thereby reducing the burden of the resistive superconducting current limiter and extending its service life. Then, in the fault simulation of the preset maximum expected short-circuit current, the strip length of the resistive superconducting current limiter is adjusted in the simulation model of the resistive superconducting current limiter to solve the maximum target unit resistance of the room temperature resistance that does not exceed the preset proportion when the sulfur hexafluoride circuit breaker is opened, and then the target strip length corresponding to the resistive superconducting current limiter is determined according to the solved maximum target unit resistance. The target unit resistance of the room temperature resistance that does not exceed the preset proportion can provide sufficient resistance to limit the short-circuit current, reduce the risk of partial damage, and reduce the risk of temperature rise and critical current capacity reduction of the superconducting current limiter. At the same time, the maximum target unit resistance is selected to avoid using too long strips, thereby reducing unnecessary material waste. Finally, the target tape length is used as the final tape length of the resistive superconducting current limiter in the fault current limiting and circuit breaker protection system, so as to accurately confirm the optimal tape parameters of the resistive superconducting current limiter, which not only ensures the optimal performance of the resistive superconducting current limiter, but also avoids the excessive margin determined by artificial experience.

[0042] In summary, the present invention determines the target strip length of the resistive superconducting current limiter according to the preset maximum expected short-circuit current by constructing a simulation model, so as to effectively control the temperature rise of the resistive superconducting current limiter during the current limiting process, thereby reducing the damage risk of the resistive superconducting current limiter, avoiding the waste of materials caused by excessive margin determined by human experience, and reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a flow chart of a parameter confirmation method of a fault current limiting and circuit breaker protection system provided by an embodiment of the present invention;

[0044] Figure 2 is an equivalent circuit diagram of a fault current limiting and circuit breaker protection system provided by an embodiment of the present invention;

[0045] Figure 3 is a curve diagram showing the relationship between the strip length and the unit resistance of the strip provided by an embodiment of the present invention;

[0046] Figure 4 is a curve diagram showing the relationship between the parallel resistance value and the current limiting peak value provided by an embodiment of the present invention;

[0047] Figure 5 It is a structural schematic diagram of a parameter confirmation device for a fault current limiting and circuit breaker protection system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features.

[0050] like Figure 1 As shown, an embodiment of the present invention provides a method for confirming parameters of a fault current limiting and circuit breaker protection system, the method comprising at least the following steps:

[0051] Step S1: constructing a resistance-type superconducting current limiter simulation model and a sulfur hexafluoride circuit breaker simulation model, and setting an initial strip length and an initial parallel resistance value;

[0052] For step S1, first, confirm the parameters of the fault current limiting and circuit breaker protection system, such as system voltage, line impedance, load impedance, short circuit occurrence time, sulfur hexafluoride circuit breaker opening time, the number of parallel roots of the resistance-type superconducting current limiter, the strip length of the resistance-type superconducting current limiter to be determined, and the parallel resistance value to be determined. Then, according to the structure of the fault current limiting and circuit breaker protection system and the above parameters, build a Figure 2 The equivalent circuit model shown in the figure is used to build a simulation model of a resistive superconducting current limiter R SFCL And the sulfur hexafluoride circuit breaker simulation model, and set the initial strip length L0 and the initial parallel resistance value R0.

[0053] In this embodiment, a 10kV / 630A power system is taken as an example. When a short circuit occurs in the system, the effective value of the power frequency component is expected to be 35kA, and the time constant of the short circuit current is 45ms. For such a system, the expected peak current limiting rate target is set to 80%. According to the relevant experience of current, the critical current of the parallel superconducting tapes should be 1.6 times the peak value of the rated current of the system, that is, 1425A. Three resistive superconducting tapes with a critical current of 500A can be connected in parallel.

[0054] Preferably, the fault current limiting and circuit breaker protection system comprises: a resistive superconducting current limiter, a sulfur hexafluoride circuit breaker and a parallel resistor;

[0055] The input end of the resistance-type superconducting current limiter is connected to the first end of the sulfur hexafluoride circuit breaker; the output end of the resistance-type superconducting current limiter is connected to the first end of the parallel resistor; and the second end of the sulfur hexafluoride circuit breaker is connected to the second end of the parallel resistor.

[0056] In a preferred embodiment, the simulation model of the resistive superconducting current limiter is specifically:

[0057]

[0058]

[0059] Among them, R YBCO The resistance of the superconducting layer of the resistive superconducting current limiter simulation model, E c Represents the critical electric field strength of the superconducting layer of the resistive superconducting current limiter simulation model, I YBCO Represents the current of the superconducting layer of the resistive superconducting current limiter simulation model, I c (T) represents the critical current of the superconducting layer of the resistive superconducting current limiter simulation model, R SFCL represents the total resistance of the resistance-type superconducting current limiter simulation model, R1 represents the resistance of other metal layers of the strip of the resistance-type superconducting current limiter simulation model, U represents the voltage across the strip of the resistance-type superconducting current limiter simulation model, T represents the temperature difference between the strip surface of the resistance-type superconducting current limiter simulation model and liquid nitrogen, h represents the heat transfer coefficient between the strip surface of the resistance-type superconducting current limiter simulation model and liquid nitrogen, A represents the surface area of ​​the strip of the resistance-type superconducting current limiter simulation model in contact with liquid nitrogen, ρ represents the strip density of the resistance-type superconducting current limiter simulation model, Heat variation representing the temperature rise per unit volume of the resistive superconducting current limiter simulation model.

[0060] For the simulation model of sulfur hexafluoride circuit breaker, the simulation model of sulfur hexafluoride circuit breaker can be established based on arc model formulas including but not limited to Mayr / Cassie / KEMA. When the sulfur hexafluoride circuit breaker is disconnected, due to the negative resistance characteristics of the gas arc, the arc voltage will increase as the arc current decreases, which can promote the rapid transfer of the current of the current limiter.

[0061] Step S2: Under the conditions of the initial strip length and the initial parallel resistance value, a fault simulation of a preset maximum expected short-circuit current is performed, and the maximum target unit resistance of the room temperature resistance that does not exceed the preset proportion when the sulfur hexafluoride circuit breaker is opened is solved in the resistance-type superconducting current limiter simulation model, and then the target strip length corresponding to the resistance-type superconducting current limiter is determined according to the maximum target unit resistance;

[0062] For step S2, in the AC power system, the resistance-type superconducting current limiter and the sulfur hexafluoride circuit breaker are commonly used in combination to protect circuits and equipment when a short circuit fault occurs. However, since the parameter design of the resistance-type superconducting current limiter, especially the parameters of the strip length and the parallel resistance, often relies on experience and a large design margin, this may lead to excessive equipment cost or poor performance. Therefore, in order to optimize the design of the resistance-type superconducting current limiter, especially to determine its strip length, the strip length of the resistance-type superconducting current limiter is determined by the following method:

[0063] First, under the conditions of the initial strip length and the initial parallel resistance value, the equivalent circuit model is simulated with a preset maximum expected short-circuit current. During the simulation, the unit resistance change of the resistive superconducting current limiter is calculated. When the sulfur hexafluoride circuit breaker is opened, the maximum target unit resistance of the room temperature resistance that does not exceed the preset ratio is solved. Then, based on the solved maximum target unit resistance, combined with the material properties and design parameters of the resistive superconducting current limiter, the corresponding target strip length can be determined. This length can provide sufficient resistance to limit the short-circuit current with the least material in practical applications, thereby improving its performance and reliability and reducing equipment costs.

[0064] It should be noted that in the simulation, in order to simplify the simulation time of superconductors and improve the stability of the model, the temperature of each layer of the superconducting tape is set equal, considering the thin layer structure of the superconducting tape and the high thermal conductivity of the metal. That is, the temperature rise of the superconducting tape is the heat generated by the tape minus the heat dissipated by liquid nitrogen.

[0065] Preferably, under the conditions of an initial strip length and an initial parallel resistance value, a fault simulation of a preset maximum expected short-circuit current is performed, and a maximum target unit resistance of a room temperature resistance not exceeding a preset ratio when the sulfur hexafluoride circuit breaker is opened is solved in a resistance-type superconducting current limiter simulation model, and then a target strip length corresponding to the resistance-type superconducting current limiter is determined according to the maximum target unit resistance, including:

[0066] The first simulation step: Under the conditions of the current strip length and the initial parallel resistance value, solving the current target unit resistance of the resistance-type superconducting current limiter when the sulfur hexafluoride circuit breaker is opened in the resistance-type superconducting current limiter simulation model; wherein the initial value of the current strip length is the initial strip length;

[0067] The first determination step: comparing the current target unit resistance with the preset ratio of room temperature resistance, if the current target unit resistance exceeds the preset ratio of room temperature resistance, then executing the step of increasing the strip length; if the current target unit resistance does not exceed the preset ratio of room temperature resistance, then executing the step of reducing the strip length;

[0068] Increasing the strip length step: multiplying the current strip length by a first preset threshold value to obtain an updated current strip length, and jumping to the first simulation step; wherein the first preset threshold value is greater than 1;

[0069] The step of reducing the strip length is as follows: multiplying the current strip length by a second preset threshold value to obtain an updated current strip length, and performing a second determination step; wherein the second preset threshold value is less than 1;

[0070] The second judgment step: under the conditions of the current strip length and the initial parallel resistance value, the current target unit resistance of the resistive superconducting current limiter when the sulfur hexafluoride circuit breaker is opened is solved in the resistive superconducting current limiter simulation model, and the current target unit resistance is compared with the room temperature resistance of the preset proportion. If the current target unit resistance exceeds the room temperature resistance of the preset proportion, the previous strip length is used as the final target strip length. If the current target unit resistance does not exceed the room temperature resistance of the preset proportion, jump to the step of reducing the strip length.

[0071] Specifically, the initial strip length L0=81.6m is set according to the system phase voltage peak value, the room temperature resistance of the resistive superconducting current limiter strip is 0.1Ω / m, and the initial parallel resistance value R0=0.836Ω. According to these conditions, simulation is performed to solve the current target unit resistance r of the resistive superconducting current limiter when the sulfur hexafluoride circuit breaker is opened. Then, the current target unit resistance r is compared with 80% of the room temperature resistance r1. When r>80%·r1, the strip length is increased by 20%, that is, the current strip length is multiplied by the first preset threshold value 120%, and the updated current strip length is obtained, that is, L=L·(1+20%), and then the first simulation step is returned to continue the fault simulation under short circuit, such as Figure 3 As shown, when a resistor of 0.836Ω is connected in parallel, as the strip length increases from 81.6m to 169.2m, the unit resistance of the strip at 50ms decreases from 127.3mΩ / m to 78.3mΩ / m, which is just less than 80% of the room temperature resistance.

[0072] Next, when r≤80%·r1, reduce the strip length by 5%, that is, multiply the current strip length by the second preset threshold value 95% to obtain the updated current strip length, that is, L=L·(1-5%). At this time, the strip length is reduced from 169.2m to 160.7m. Then, perform the first simulation step again. Under the conditions of the current strip length and the initial parallel resistance value, solve the current target unit resistance r of the resistive superconducting current limiter when the sulfur hexafluoride circuit breaker is opened. At this time, the target unit resistance r reaches 80.8mΩ / m. Compare the current target unit resistance r with 80% of the room temperature resistance r1. r>80%·r1, then take the previous strip length of 169.2m as the final target strip length L1, that is, the final target strip length L1=169.2m. If the current target unit resistance r of the resistive superconducting current limiter when the sulfur hexafluoride circuit breaker is opened is still less than 80% of the room temperature resistance r1, then continue to reduce the strip length by 5% until the maximum target unit resistance of the room temperature resistance that does not exceed the preset ratio is obtained.

[0073] Step S3: taking the target strip length as the final strip length of the resistive superconducting current limiter in the fault current limiting and circuit breaker protection system.

[0074] For step S3, the fault current limiting and circuit breaker protection system can promote the rapid transfer of short-circuit current through the combined action of sulfur hexafluoride gas arc and the quenching resistance of the resistance-type superconducting current limiter, thereby reducing the heating and temperature rise of the current limiter and effectively protecting the safety of the current limiter. The final target strip length L1=169.2m obtained by simulation in step S2 is used as the final strip length of the resistance-type superconducting current limiter in the fault current limiting and circuit breaker protection system, so as to provide sufficient resistance to limit the short-circuit current with the least material in practical applications, which can not only improve the performance and reliability of the resistance-type superconducting current limiter, but also reduce the cost of the equipment.

[0075] In a preferred embodiment, the parameter confirmation method of the fault current limiting and circuit breaker protection system further includes:

[0076] Under the conditions of the target strip length and the initial parallel resistance value, a fault simulation of a preset maximum expected short-circuit current is performed, a minimum target current limiting rate exceeding the preset current limiting rate is solved in the resistance-type superconducting current limiter simulation model, and then a target parallel resistance value of the parallel resistor is determined according to the minimum target current limiting rate;

[0077] The target parallel resistance value is used as the resistance value of the parallel resistor in the fault current limiting and circuit breaker protection system.

[0078] In one embodiment of the present invention, under the conditions of target strip length L1=169.2m and initial parallel resistance value, the equivalent circuit model is subjected to fault simulation of preset maximum expected short-circuit current. During the simulation process, the current limiting rate of the resistive superconducting current limiter is calculated. Then, when the sulfur hexafluoride circuit breaker is opened, the minimum target current limiting rate exceeding the preset current limiting rate is solved. Then, according to the solved minimum target current limiting rate, combined with the material properties and design parameters of the resistive superconducting current limiter, the target parallel resistance value corresponding to the parallel resistance can be determined. This target parallel resistance value can meet the current limiting under the preset current limiting rate when the system is short-circuited, while avoiding excessive design margin, which can effectively reduce the cost of the current limiter.

[0079] In a preferred embodiment, under the conditions of the target strip length and the initial parallel resistance value, a fault simulation of a preset maximum expected short-circuit current is performed, a minimum target current limiting rate exceeding the preset current limiting rate is solved in the resistance-type superconducting current limiter simulation model, and then a target parallel resistance value of the parallel resistor is determined according to the minimum target current limiting rate, including:

[0080] The second simulation step: Under the conditions of the target strip length and the current parallel resistance value, solving the current target current limiting rate of the resistance-type superconducting current limiter when the sulfur hexafluoride circuit breaker is opened in the resistance-type superconducting current limiter simulation model; wherein the initial value of the current parallel resistance value is the initial parallel resistance value;

[0081] The third determination step: comparing the current target current limiting rate with the preset current limiting rate, if the current target current limiting rate exceeds the preset current limiting rate, executing the step of reducing the parallel resistance, if the current target current limiting rate does not exceed the preset current limiting rate, executing the step of increasing the parallel resistance;

[0082] Reducing the parallel resistance step: multiplying the current parallel resistance value by the third preset threshold value to obtain an updated current parallel resistance value, and jumping to the second simulation step; wherein the third preset threshold value is less than 1;

[0083] Increasing the parallel resistance step: multiplying the current parallel resistance value by a fourth preset threshold value to obtain an updated current parallel resistance value, and executing a fourth determination step; wherein the fourth preset threshold value is greater than 1;

[0084] The fourth judgment step: under the conditions of the target strip length and the current parallel resistance value, solve the current target current limiting rate of the resistive superconducting current limiter when the sulfur hexafluoride circuit breaker is opened in the resistive superconducting current limiter simulation model, and compare the current target current limiting rate with the preset current limiting rate. If the current target current limiting rate exceeds the preset current limiting rate, the smallest parallel resistance value among all corresponding parallel resistance values ​​exceeding the preset current limiting rate is used as the final target parallel resistance value. If the current target current limiting rate does not exceed the preset current limiting rate, jump to the step of increasing the parallel resistance.

[0085] Specifically, according to the simulation result of the target strip length of the resistive superconducting current limiter, L1=169.2m, the room temperature resistance of the resistive superconducting current limiter strip is 0.1Ω / m, and the initial parallel resistance value R0=

[0086] 0.836Ω, and simulate according to these conditions to solve the current target current limiting rate X% of the resistive superconducting current limiter when the sulfur hexafluoride circuit breaker is opened.

[0087] Preferably, the current target flow limiting rate is determined by:

[0088] In the simulation model of the resistive superconducting current limiter, the current peak value of the resistive superconducting current limiter is solved when the sulfur hexafluoride circuit breaker is opened;

[0089] The current target current limiting rate is obtained by dividing the current peak value by the preset current peak value.

[0090] Next, the current target current limiting rate X% obtained by solving is compared with the preset current limiting rate X1%. When X%>X1%, the parallel resistance is reduced by 20%, that is, the current parallel resistance value is multiplied by the third preset threshold value 80%, and the updated current parallel resistance value is obtained, that is, R=R·(1-20%), and the second simulation step is returned to continue the fault simulation under short circuit, such as Figure 4 As shown in the figure, the first current limiting peak of the current limiting characteristics of the superconducting current limiter with different parallel impedances is obtained. When the parallel resistance is reduced from 0.836Ω to 0.535Ω, the first current peak value increases from 12.97kA to 17.71kA, which just meets the 80% peak current limiting rate. When it continues to decrease by 20% to 0.428Ω, the first current peak value is 20.71kA, which does not meet the current limiting requirements.

[0091] At this time, X%≤X1%, the parallel resistance is increased by 5%, that is, the current parallel resistance value is multiplied by the fourth preset threshold value 105%, and the updated current parallel resistance value is obtained, that is, R=R·(1+5%). Then, the second simulation step is performed again. Under the conditions of the target strip length and the current parallel resistance value, the current target current limiting rate of the resistive superconducting current limiter when the sulfur hexafluoride circuit breaker is opened is solved. At this time, the current target current limiting rate X% is still less than the preset current limiting rate X1%, then the resistance value is gradually increased at a rate of 5% until the current parallel resistance value is 0.546Ω, and the current peak value is 17.45kA, which meets the current limiting requirement. When the current limiting requirement is met, the smallest parallel resistance value R1=0.535Ω among all corresponding parallel resistance values ​​exceeding the preset current limiting rate is selected as the final target parallel resistance value.

[0092] In this embodiment, in the fault current limiting and circuit breaker protection system, the strip length of the resistive superconducting current limiter L1=169.2m and the parallel resistance R1=0.535Ω are selected. When the sulfur hexafluoride protection circuit breaker is disconnected after 50ms current limiting, the unit resistance of the resistive superconducting current limiter is 76.6mΩ / m, and the first peak value after current limiting is 17.71kA. While meeting the current limiting rate, it ensures that the impedance of the current limiter is lower than the set protection value, and there is no excessive margin. It can effectively reduce the cost of the current limiter and improve the safety and reliability of the equipment.

[0093] like Figure 5 As shown, based on the above method embodiment, a corresponding device embodiment is provided;

[0094] An embodiment of the present invention provides a parameter confirmation device for a fault current limiting and circuit breaker protection system, comprising: a simulation model building module, a target strip length determination module, and a strip length configuration module;

[0095] A simulation model building module, used to build a resistance-type superconducting current limiter simulation model and a sulfur hexafluoride circuit breaker simulation model, and set an initial strip length and an initial parallel resistance value;

[0096] A target strip length determination module is used to perform a fault simulation of a preset maximum expected short-circuit current under the conditions of an initial strip length and an initial parallel resistance value, solve a maximum target unit resistance of a room temperature resistance not exceeding a preset ratio when a sulfur hexafluoride circuit breaker is opened in a resistance-type superconducting current limiter simulation model, and then determine a target strip length corresponding to the resistance-type superconducting current limiter according to the maximum target unit resistance;

[0097] The strip length configuration module is used for taking the target strip length as the final strip length of the resistive superconducting current limiter in the fault current limiting and circuit breaker protection system.

[0098] In a preferred embodiment, the parameter confirmation device of the fault current limiting and circuit breaker protection system further includes: a target parallel resistance value determination module and a parallel resistance configuration module;

[0099] A target parallel resistance value determination module is used to perform a fault simulation of a preset maximum expected short-circuit current under the conditions of a target strip length and an initial parallel resistance value, solve a minimum target current limiting rate exceeding a preset current limiting rate in a resistance-type superconducting current limiter simulation model, and then determine a target parallel resistance value of the parallel resistor according to the minimum target current limiting rate;

[0100] The shunt resistor configuration module is used to set a target shunt resistor value as the resistance value of a shunt resistor in a fault current limiting and circuit breaker protection system.

[0101] In a preferred embodiment, the target strip length determination module includes: a first simulation unit, a first determination unit, a strip length increasing unit, a strip length reducing unit, and a second determination unit;

[0102] A first simulation unit is used for a first simulation step: under the conditions of a current strip length and an initial parallel resistance value, solving a current target unit resistance of the resistance-type superconducting current limiter when the sulfur hexafluoride circuit breaker is opened in a resistance-type superconducting current limiter simulation model; wherein the initial value of the current strip length is the initial strip length;

[0103] A first discrimination unit, used for a first discrimination step: comparing the current target unit resistance with the room temperature resistance of a preset ratio, and if the current target unit resistance exceeds the room temperature resistance of the preset ratio, executing a step of increasing the strip length; if the current target unit resistance does not exceed the room temperature resistance of the preset ratio, executing a step of reducing the strip length;

[0104] The strip length increasing unit is used for increasing the strip length step: multiplying the current strip length by the first preset threshold value to obtain the updated current strip length, and jumping to the first simulation step; wherein the first preset threshold value is greater than 1;

[0105] The strip length reduction unit is used to reduce the strip length step: multiply the current strip length by the second preset threshold to obtain the updated current strip length, and perform the second determination step; wherein the second preset threshold is less than 1;

[0106] The second discrimination unit is used for the second discrimination step: under the conditions of the current strip length and the initial parallel resistance value, the current target unit resistance of the resistance-type superconducting current limiter when the sulfur hexafluoride circuit breaker is opened is solved in the resistance-type superconducting current limiter simulation model, and the current target unit resistance is compared with the room temperature resistance of a preset proportion. If the current target unit resistance exceeds the room temperature resistance of the preset proportion, the previous strip length is used as the final target strip length. If the current target unit resistance does not exceed the room temperature resistance of the preset proportion, jump to the step of reducing the strip length.

[0107] In a preferred embodiment, the target parallel resistance value determination module includes: a second simulation unit, a third determination unit, a parallel resistance reduction unit, a parallel resistance increase unit and a fourth determination unit;

[0108] The second simulation unit is used for the second simulation step: under the conditions of the target strip length and the current parallel resistance value, solving the current target current limiting rate of the resistance-type superconducting current limiter when the sulfur hexafluoride circuit breaker is opened in the resistance-type superconducting current limiter simulation model; wherein the initial value of the current parallel resistance value is the initial parallel resistance value;

[0109] A third determination unit, used for a third determination step: comparing the current target current limiting rate with the preset current limiting rate, if the current target current limiting rate exceeds the preset current limiting rate, executing a step of reducing the parallel resistance, if the current target current limiting rate does not exceed the preset current limiting rate, executing a step of increasing the parallel resistance;

[0110] A parallel resistance reduction unit is used to reduce the parallel resistance step: multiply the current parallel resistance value by a third preset threshold value to obtain an updated current parallel resistance value, and jump to the second simulation step; wherein the third preset threshold value is less than 1;

[0111] The parallel resistance increasing unit is used for increasing the parallel resistance step: multiplying the current parallel resistance value by a fourth preset threshold value to obtain an updated current parallel resistance value, and performing a fourth determination step; wherein the fourth preset threshold value is greater than 1;

[0112] The fourth discrimination unit is used for the fourth discrimination step: under the conditions of the target strip length and the current parallel resistance value, solving the current target current limiting rate of the resistive superconducting current limiter when the sulfur hexafluoride circuit breaker is opened in the resistive superconducting current limiter simulation model, and comparing the current target current limiting rate with the preset current limiting rate. If the current target current limiting rate exceeds the preset current limiting rate, the smallest parallel resistance value among all corresponding parallel resistance values ​​exceeding the preset current limiting rate is used as the final target parallel resistance value. If the current target current limiting rate does not exceed the preset current limiting rate, jump to the step of increasing the parallel resistance.

[0113] It can be understood that the above-mentioned device item embodiments correspond to the method item embodiments of the present invention, and can implement the parameter confirmation method of the fault current limiting and circuit breaker protection system provided by any one of the above-mentioned method item embodiments of the present invention.

[0114] It should be noted that the device embodiments described above are merely illustrative, and some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment. In addition, in the accompanying drawings of the device embodiments provided by the present invention, the connection relationship between the modules indicates that there is a communication connection between them, which may be specifically implemented as one or more communication buses or signal lines. Those of ordinary skill in the art may understand and implement the present invention without creative work.

[0115] Based on the above-mentioned embodiment of the parameter confirmation method of the fault current limiting and circuit breaker protection system, another embodiment of the present invention provides a terminal device, which includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, the parameter confirmation method of the fault current limiting and circuit breaker protection system of any embodiment of the present invention is implemented.

[0116] Exemplarily, in this embodiment, the computer program may be divided into one or more modules, which are stored in the memory and executed by the processor to implement the present invention. The one or more module elements may be a series of computer program instruction segments capable of implementing specific functions, which are used to describe the execution process of the computer program in the terminal device.

[0117] The terminal device may be a computing device such as a desktop computer, a notebook, a PDA, a cloud server, etc. The terminal device may include, but is not limited to, a processor and a memory.

[0118] The processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc. The processor is the control center of the terminal device, and uses various interfaces and lines to connect various parts of the entire terminal device.

[0119] Based on the above method embodiment, another embodiment is provided: another embodiment of the present invention provides a computer-readable storage medium, including a stored computer program, wherein when the computer program is running, the device where the computer-readable storage medium is located is controlled to execute the parameter confirmation method of the fault current limiting and circuit breaker protection system described in any one of the above method embodiments of the present invention.

[0120] Wherein, the module / unit integrated in the parameter confirmation device / terminal device of the fault current limiting and circuit breaker protection system, if implemented in the form of a software functional unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on such an understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Wherein, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form, etc. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium, etc.

[0121] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for confirming parameters of a fault current limiting and circuit breaker protection system, characterized in that: include: Construct a resistance-type superconducting current limiter simulation model and a sulfur hexafluoride circuit breaker simulation model, and set the initial strip length and initial parallel resistance value; Under the conditions of the initial strip length and the initial parallel resistance value, a fault simulation of a preset maximum expected short-circuit current is performed, and a maximum target unit resistance of the room temperature resistance that does not exceed a preset proportion when the sulfur hexafluoride circuit breaker is opened is solved in the resistance-type superconducting current limiter simulation model, and then a target strip length corresponding to the resistance-type superconducting current limiter is determined according to the maximum target unit resistance; The target tape length is used as the final tape length of the resistive superconducting current limiter in the fault current limiting and circuit breaker protection system.

2. The parameter confirmation method of the fault current limiting and circuit breaker protection system according to claim 1, characterized in that: Also includes: Under the conditions of the target strip length and the initial parallel resistance value, a fault simulation of a preset maximum expected short-circuit current is performed, a minimum target current limiting rate exceeding the preset current limiting rate is solved in the resistance-type superconducting current limiter simulation model, and then a target parallel resistance value of the parallel resistor is determined according to the minimum target current limiting rate; The target parallel resistance value is used as the resistance value of the parallel resistor in the fault current limiting and circuit breaker protection system.

3. The parameter confirmation method of the fault current limiting and circuit breaker protection system according to claim 1, characterized in that: The simulation model of the resistive superconducting current limiter is specifically as follows: Among them, R YBCO The resistance of the superconducting layer of the resistive superconducting current limiter simulation model, E c Represents the critical electric field strength of the superconducting layer of the resistive superconducting current limiter simulation model, I YBCO Represents the current of the superconducting layer of the resistive superconducting current limiter simulation model, I c (T) represents the critical current of the superconducting layer of the resistive superconducting current limiter simulation model, R SFCL represents the total resistance of the resistance-type superconducting current limiter simulation model, R1 represents the resistance of other metal layers of the strip of the resistance-type superconducting current limiter simulation model, U represents the voltage across the strip of the resistance-type superconducting current limiter simulation model, T represents the temperature difference between the strip surface of the resistance-type superconducting current limiter simulation model and liquid nitrogen, h represents the heat transfer coefficient between the strip surface of the resistance-type superconducting current limiter simulation model and liquid nitrogen, A represents the surface area of ​​the strip of the resistance-type superconducting current limiter simulation model in contact with liquid nitrogen, ρ represents the strip density of the resistance-type superconducting current limiter simulation model, Heat variation representing the temperature rise per unit volume of the resistive superconducting current limiter simulation model.

4. The parameter confirmation method of the fault current limiting and circuit breaker protection system according to claim 3, characterized in that: Under the conditions of an initial strip length and an initial parallel resistance value, a fault simulation of a preset maximum expected short-circuit current is performed, and a maximum target unit resistance of a room temperature resistance not exceeding a preset ratio when a sulfur hexafluoride circuit breaker is opened is solved in a resistance-type superconducting current limiter simulation model, and then a target strip length corresponding to the resistance-type superconducting current limiter is determined according to the maximum target unit resistance, including: The first simulation step: Under the conditions of the current strip length and the initial parallel resistance value, solving the current target unit resistance of the resistance-type superconducting current limiter when the sulfur hexafluoride circuit breaker is opened in the resistance-type superconducting current limiter simulation model; wherein the initial value of the current strip length is the initial strip length; The first determination step: comparing the current target unit resistance with the preset ratio of room temperature resistance, if the current target unit resistance exceeds the preset ratio of room temperature resistance, then executing the step of increasing the strip length; if the current target unit resistance does not exceed the preset ratio of room temperature resistance, then executing the step of reducing the strip length; The step of increasing the strip length: multiplying the current strip length by a first preset threshold value to obtain an updated current strip length, and jumping to the first simulation step; wherein the first preset threshold value is greater than 1; The step of reducing the strip length: multiplying the current strip length by a second preset threshold to obtain an updated current strip length, and performing a second determination step; wherein the second preset threshold is less than 1; The second determination step is as follows: under the conditions of the current strip length and the initial parallel resistance value, the current target unit resistance of the resistance-type superconducting current limiter when the sulfur hexafluoride circuit breaker is opened is solved in the resistance-type superconducting current limiter simulation model, and the current target unit resistance is compared with the room temperature resistance of a preset proportion. If the current target unit resistance exceeds the room temperature resistance of the preset proportion, the previous strip length is used as the final target strip length. If the current target unit resistance does not exceed the room temperature resistance of the preset proportion, the process jumps to the step of reducing the strip length.

5. The parameter confirmation method of the fault current limiting and circuit breaker protection system according to claim 2, characterized in that: Under the conditions of the target strip length and the initial parallel resistance value, a fault simulation of a preset maximum expected short-circuit current is performed, a minimum target current limiting rate exceeding the preset current limiting rate is solved in the resistance-type superconducting current limiter simulation model, and then a target parallel resistance value of the parallel resistor is determined according to the minimum target current limiting rate, including: The second simulation step: under the conditions of the target strip length and the current parallel resistance value, solving the current target current limiting rate of the resistance-type superconducting current limiter when the sulfur hexafluoride circuit breaker is opened in the resistance-type superconducting current limiter simulation model; wherein the initial value of the current parallel resistance value is the initial parallel resistance value; The third determination step: comparing the current target current limiting rate with the preset current limiting rate, if the current target current limiting rate exceeds the preset current limiting rate, executing the step of reducing the parallel resistance, if the current target current limiting rate does not exceed the preset current limiting rate, executing the step of increasing the parallel resistance; The step of reducing the parallel resistance: multiplying the current parallel resistance value by a third preset threshold value to obtain an updated current parallel resistance value, and jumping to the second simulation step; wherein the third preset threshold value is less than 1; The step of increasing the parallel resistance: multiplying the current parallel resistance value by a fourth preset threshold value to obtain an updated current parallel resistance value, and executing a fourth determination step; wherein the fourth preset threshold value is greater than 1; The fourth determination step is: under the conditions of the target strip length and the current parallel resistance value, solving the current target current limiting rate of the resistive superconducting current limiter when the sulfur hexafluoride circuit breaker is opened in the resistive superconducting current limiter simulation model, and comparing the current target current limiting rate with the preset current limiting rate. If the current target current limiting rate exceeds the preset current limiting rate, the smallest parallel resistance value among all corresponding parallel resistance values ​​exceeding the preset current limiting rate is used as the final target parallel resistance value. If the current target current limiting rate does not exceed the preset current limiting rate, jump to the step of increasing the parallel resistance.

6. The parameter confirmation method of the fault current limiting and circuit breaker protection system according to claim 5, characterized in that: The current target current limiting rate is determined by: In the simulation model of the resistive superconducting current limiter, the current peak value of the resistive superconducting current limiter is solved when the sulfur hexafluoride circuit breaker is opened; The current target current limiting rate is obtained by dividing the current peak value by the preset current peak value.

7. The parameter confirmation method of the fault current limiting and circuit breaker protection system according to claim 1, characterized in that: The fault current limiting and circuit breaking protection system comprises: a resistance-type superconducting current limiter, a sulfur hexafluoride circuit breaker and a parallel resistor; The input end of the resistance-type superconducting current limiter is connected to the first end of the sulfur hexafluoride circuit breaker; the output end of the resistance-type superconducting current limiter is connected to the first end of the parallel resistor; the second end of the sulfur hexafluoride circuit breaker is connected to the second end of the parallel resistor.

8. A parameter confirmation device for a fault current limiting and circuit breaker protection system, characterized in that: include: A simulation model building module, a target strip length determination module, and a strip length configuration module; The simulation model building module is used to build a resistance-type superconducting current limiter simulation model and a sulfur hexafluoride circuit breaker simulation model, and set an initial strip length and an initial parallel resistance value; The target strip length determination module is used to perform a fault simulation of a preset maximum expected short-circuit current under the conditions of an initial strip length and an initial parallel resistance value, solve the maximum target unit resistance of the sulfur hexafluoride circuit breaker that does not exceed a preset ratio of room temperature resistance when the circuit breaker is opened in the resistance-type superconducting current limiter simulation model, and then determine the target strip length corresponding to the resistance-type superconducting current limiter according to the maximum target unit resistance; The strip length configuration module is used to use the target strip length as the final strip length of the resistive superconducting current limiter in the fault current limiting and circuit breaker protection system.

9. A terminal device, characterized in that: The method comprises a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, the method for confirming parameters of the fault current limiting and circuit breaker protection system according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium, characterized in that: include: A stored computer program, wherein when the computer program is running, the device where the computer-readable storage medium is located is controlled to execute the parameter confirmation method of the fault current limiting and circuit breaker protection system according to any one of claims 1 to 7.

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