Automatic Tuning Method and Testing Device for Admittance Plane Loss-of-Excitation Protection

Abstract

The present application relates to an automatic setting method and inspection device for admittance plane loss-of-excitation protection, including: first, obtaining the maximum allowable leading power factor depth of the target generator according to the static stability limit PQ curve of the target generator; then, obtaining the loss-of-excitation protection admittance characteristic value of the target generator according to the maximum allowable leading power factor depth, the rated parameters of the target generator, and the terminal voltage of the target generator; finally, determining the loss-of-excitation protection setting characteristic curve for the target generator to perform loss-of-excitation protection according to the loss-of-excitation protection admittance characteristic value. By using this method, the loss-of-excitation protection setting characteristic curve of the generator can be obtained according to the maximum allowable leading power factor depth of the generator in the static stability limit PQ curve, thereby improving the reliability of the generator loss-of-excitation protection.

Description

Technical Field

[0001] This application relates to the technical field of generator loss-of-excitation protection, and particularly to an automatic setting method and inspection device for admittance-plane loss-of-excitation protection. Background Art

[0002] The emergency diesel generator in a nuclear power plant is the last line of defense for the power supply safety of the entire nuclear power plant. Its reliable, safe and stable operation is related to the nuclear safety of the entire nuclear power plant. When the generator loses its excitation due to a fault in the excitation system, the loss-of-excitation protection acts, such as tripping or shutting down, which can not only protect the generator itself but also protect the stable operation of the entire system.

[0003] Currently, the setting value of the loss-of-excitation protection for the emergency diesel generator in a nuclear power plant is based on the empirical values given by the manufacturer or set according to the protection method of large steam turbine generators. Moreover, the conventional setting method of admittance-plane loss-of-excitation protection is not applicable to generators with a relatively small direct-axis reactance, which is likely to cause the loss-of-excitation protection to refuse to operate, making the loss-of-excitation protection unreliable and affecting the stability of the generator operation. Summary of the Invention

[0004] Based on this, it is necessary to provide an automatic setting method and inspection device for admittance-plane loss-of-excitation protection with reliable loss-of-excitation protection for the above technical problems.

[0005] In a first aspect, this application provides an automatic setting method for admittance-plane loss-of-excitation protection. The method includes:

[0006] Obtaining the allowable maximum leading power factor depth of the target generator according to the static stability limit PQ curve of the target generator; obtaining the loss-of-excitation protection admittance characteristic value of the target generator according to the allowable maximum leading power factor depth, the rated parameters of the target generator, and the terminal voltage of the target generator; determining the loss-of-excitation protection setting characteristic curve according to the loss-of-excitation protection admittance characteristic value, where the loss-of-excitation protection setting characteristic curve is used for the target generator to perform loss-of-excitation protection according to the loss-of-excitation protection setting characteristic curve.

[0007] In one embodiment, obtaining the loss-of-excitation protection admittance characteristic value of the target generator according to the allowable maximum leading power factor depth, the rated parameters of the target generator, and the terminal voltage of the target generator includes: obtaining the per-unit value of the primary-side susceptance of the target generator according to the allowable maximum leading power factor depth, the rated parameters, and the terminal voltage; performing secondary-side conversion on the per-unit value of the primary-side susceptance to obtain the per-unit value of the secondary-side susceptance of the target generator; and obtaining the loss-of-excitation protection admittance characteristic value according to the per-unit value of the secondary-side susceptance.

[0008] In one embodiment, the rated parameters include the rated capacity of the target generator and the rated voltage of the target generator. According to the allowable maximum leading power factor depth, the rated parameters, and the terminal voltage, the per-unit value of the primary-side susceptance of the target generator is obtained, including: calculating a first ratio of the allowable maximum leading power factor depth to the rated capacity; calculating a second ratio of the terminal voltage to the rated voltage, and squaring the second ratio to obtain a squared value; and taking the ratio of the first ratio to the squared value as the per-unit value of the primary-side susceptance.

[0009] In one embodiment, the rated parameters include the rated current of the target generator and the primary rated current of the current transformer of the target generator. The per-unit value of the secondary-side susceptance of the target generator is obtained by performing a secondary-side conversion on the per-unit value of the primary-side susceptance, including: calculating a third ratio of the rated current to the primary rated current; and taking the product of the per-unit value of the primary-side susceptance and the third ratio as the per-unit value of the secondary-side susceptance.

[0010] In one embodiment, according to the per-unit value of the secondary-side susceptance, the admittance characteristic value of the loss-of-excitation protection is obtained, including: taking the product of the per-unit value of the secondary-side susceptance and the reliability coefficient as the admittance characteristic value of the loss-of-excitation protection.

[0011] In one embodiment, the loss-of-excitation protection setting characteristic curve includes a first curve, a second curve, and a third curve. Determining the loss-of-excitation protection setting characteristic curve according to the admittance characteristic value of the loss-of-excitation protection includes: determining the first curve according to the admittance characteristic value of the loss-of-excitation protection; determining the second curve according to k times the admittance characteristic value of the loss-of-excitation protection, where the value range of k is greater than 0 and less than 1; and determining the third curve according to p times the admittance characteristic value of the loss-of-excitation protection, where the value range of p is greater than 1 and less than 2.

[0012] In one embodiment, after determining the loss-of-excitation protection setting characteristic curve according to the admittance characteristic value of the loss-of-excitation protection, the method further includes: applying current and voltage to the protection system of the target generator in a test environment so that the target generator performs a protection action in response to the current and voltage. Performing the protection action includes at least one of the following: performing a loss-of-excitation protection action according to the loss-of-excitation protection setting characteristic curve; performing a stator overcurrent protection action; and determining whether the loss-of-excitation protection setting characteristic curve meets the conditions for application in an actual production environment according to the protection action performed by the protection system of the target generator.

[0013] In one embodiment, determining whether the loss-of-excitation protection setting characteristic curve meets the conditions applicable to the actual production environment according to the protection actions performed by the target generator protection system includes: if the current and voltage trigger the loss of excitation of the target generator and the loss-of-excitation protection action takes precedence over the stator overcurrent protection action, it is determined that the loss-of-excitation protection setting characteristic curve meets the conditions applicable to the actual production environment; if the current and voltage trigger the loss of excitation of the target generator and the loss-of-excitation protection does not act or the loss-of-excitation protection action occurs after the stator overcurrent protection action, it is determined that the loss-of-excitation protection setting characteristic curve does not meet the conditions applicable to the actual production environment.

[0014] In one embodiment, the method further includes: if the loss-of-excitation protection setting characteristic curve does not meet the conditions applicable to the actual production environment, correcting the loss-of-excitation protection setting characteristic curve.

[0015] In a second aspect, the present application also provides an admittance-plane loss-of-excitation protection automatic setting device. The device includes:

[0016] An acquisition module: used to obtain the allowable maximum leading power factor depth of the target generator according to the static stability limit PQ curve of the target generator;

[0017] A calculation module, configured to obtain the loss-of-excitation protection admittance characteristic value of the target generator according to the allowable maximum leading power factor depth, the rated parameters of the target generator, and the terminal voltage of the target generator;

[0018] A determination module, configured to determine the loss-of-excitation protection setting characteristic curve according to the loss-of-excitation protection admittance characteristic value, where the loss-of-excitation protection setting characteristic curve is used for the target generator to perform loss-of-excitation protection according to the loss-of-excitation protection setting characteristic curve.

[0019] In one embodiment, the calculation module is specifically configured to obtain the per-unit value of the primary-side susceptance of the target generator according to the allowable maximum leading power factor depth, the rated parameters, and the terminal voltage; perform secondary-side conversion on the per-unit value of the primary-side susceptance to obtain the per-unit value of the secondary-side susceptance of the target generator; and obtain the loss-of-excitation protection admittance characteristic value according to the per-unit value of the secondary-side susceptance.

[0020] In one embodiment, the rated parameters include the rated capacity of the target generator and the rated voltage of the target generator. The calculation module is specifically configured to calculate the first ratio of the allowable maximum leading power factor depth to the rated capacity; calculate the second ratio of the terminal voltage to the rated voltage and square the second ratio to obtain the squared value; and use the ratio of the first ratio to the squared value as the per-unit value of the primary-side susceptance.

[0021] In one embodiment, the rated parameters include the rated current of the target generator and the primary rated current of the target generator current transformer. The calculation module is specifically configured to calculate a third ratio of the rated current to the primary side rated current; and use the product of the per-unit value of the primary side susceptance and the third ratio as the per-unit value of the secondary side susceptance.

[0022] In one embodiment, the calculation module is specifically configured to use the product of the per-unit value of the secondary side susceptance and the reliability coefficient as the admittance characteristic value of the loss-of-excitation protection.

[0023] In one embodiment, the loss-of-excitation protection setting characteristic curve includes a first curve, a second curve, and a third curve. The first determination module is specifically configured to determine the first curve according to the admittance characteristic value of the loss-of-excitation protection; determine the second curve according to k times the admittance characteristic value of the loss-of-excitation protection, where the value range of k is greater than 0 and less than 1; and determine the third curve according to p times the admittance characteristic value of the loss-of-excitation protection, where the value range of p is greater than 1 and less than 2.

[0024] In one embodiment, the device further includes a second determination module. The second determination module is configured to apply current and voltage to the target generator protection system in a test environment, so that the target generator performs protection actions in response to the current and voltage. Performing the protection actions includes at least one of the following: performing a loss-of-excitation protection action according to the loss-of-excitation protection setting characteristic curve; performing a stator overcurrent protection action; and determining whether the loss-of-excitation protection setting characteristic curve meets the conditions for application to the actual production environment according to the protection actions performed by the target generator protection system.

[0025] In one embodiment, the device further includes a third determination module. The third determination module is configured to determine that the loss-of-excitation protection setting characteristic curve meets the conditions for application to the actual production environment if the loss-of-excitation protection action takes precedence over the stator overcurrent protection action when the current and voltage trigger the loss of excitation of the target generator; and determine that the loss-of-excitation protection setting characteristic curve does not meet the conditions for application to the actual production environment if the loss-of-excitation protection does not act or the loss-of-excitation protection action occurs after the stator overcurrent protection action when the current and voltage trigger the loss of excitation of the target generator.

[0026] In one embodiment, the device further includes a correction module. The correction module is configured to correct the loss-of-excitation protection setting characteristic curve if the loss-of-excitation protection setting characteristic curve does not meet the conditions for application to the actual production environment.

[0027] In a third aspect, the present application further provides an automatic tuning and verification device for admittance plane loss-of-excitation protection. The device includes:

[0028] An automatic tuning module, which is used to obtain the maximum allowable leading power factor depth of the target generator according to the static stability limit PQ curve of the target generator; is used to obtain the admittance characteristic value of the loss-of-excitation protection of the target generator according to the maximum allowable leading power factor depth, the rated parameters of the target generator, and the terminal voltage of the target generator; is used to determine the loss-of-excitation protection tuning characteristic curve according to the admittance characteristic value of the loss-of-excitation protection, wherein the loss-of-excitation protection tuning characteristic curve is used for the target generator to perform loss-of-excitation protection according to the loss-of-excitation protection tuning characteristic curve.

[0029] An inspection module, which is used to check whether the loss-of-excitation protection tuning characteristic curve meets the conditions for application in the actual production environment according to the protection actions performed by the protection system of the target generator. The inspection module can automatically sample the real-time operating parameters of the generator through methods such as transmitters or signal communication transmission, and then check the loss-of-excitation protection tuning characteristic curve and the overcurrent protection action characteristic.

[0030] In a fourth aspect, the present application also provides a computer device. The computer device includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the admittance plane loss-of-excitation protection automatic tuning method as described in any one of the first aspects above.

[0031] In a fifth aspect, the present application also provides a computer-readable storage medium. The computer-readable storage medium stores a computer program thereon, and when the computer program is executed by a processor, it implements the admittance plane loss-of-excitation protection automatic tuning method as described in any one of the first aspects above.

[0032] For the above admittance plane loss-of-excitation protection automatic tuning method and inspection device, first, according to the static stability limit PQ curve of the target generator, the maximum allowable leading power factor depth of the target generator is obtained; then, according to the maximum allowable leading power factor depth, the rated parameters of the target generator, and the terminal voltage of the target generator, the admittance characteristic value of the loss-of-excitation protection of the target generator is obtained; finally, according to the admittance characteristic value of the loss-of-excitation protection, the loss-of-excitation protection tuning characteristic curve for the target generator to perform loss-of-excitation protection is determined. In this way, the loss-of-excitation protection tuning characteristic curve of the generator is obtained according to the maximum allowable leading power factor depth of the generator in the static stability limit PQ curve of the generator. This method avoids the problem that when the generator has exceeded the maximum value of the allowable leading power factor depth, the loss-of-excitation protection still does not act, resulting in the leading power factor depth of the generator exceeding the safe area of the static stability limit and affecting the operation stability of the generator. Therefore, the reliability of the loss-of-excitation protection is higher. Description of the Drawings

[0033] Figure 1 It is a PQ curve diagram of the static stability limit of the generator in an embodiment;

[0034] Figure 2Schematic flow chart of the automatic setting method for the admittance plane loss-of-excitation protection in an embodiment;

[0035] Figure 3 Generator stator current motion trajectory diagram in another embodiment;

[0036] Figure 4 Schematic flow chart of the automatic setting method for the admittance plane loss-of-excitation protection in another embodiment;

[0037] Figure 5 Schematic flow chart of the automatic setting method for the admittance plane loss-of-excitation protection in another embodiment;

[0038] Figure 6 Schematic flow chart of the automatic setting method for the admittance plane loss-of-excitation protection in another embodiment;

[0039] Figure 7 Schematic diagram of the joint inspection between generator protections in another embodiment;

[0040] Figure 8 Schematic flow chart of the automatic setting method for the admittance plane loss-of-excitation protection in another embodiment;

[0041] Figure 9 Structure block diagram of the automatic setting device for the admittance plane loss-of-excitation protection in an embodiment;

[0042] Figure 10 Internal structure diagram of a computer device in an embodiment. Specific embodiments

[0043] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0044] The nuclear power plant emergency diesel generator is the last line of defense for the power safety guarantee of the entire nuclear power plant, and its reliable, safe and stable operation is related to the nuclear safety of the entire nuclear power plant. When the generator loses excitation due to a fault in the excitation system, the loss-of-excitation protection will act, such as tripping and shutting down, which can not only protect the generator itself, but also protect the stable operation of the entire system.

[0045] During the first grid connection and load test of a nuclear power plant's nuclear emergency diesel generator, the unit lost excitation due to a fault in the excitation system, and the loss-of-excitation protection did not act correctly, resulting in the generator being deeply in the leading phase and causing the generator stator overcurrent protection to trip. The specific reasons for this problem are analyzed as follows:

[0046] The existing loss-of-excitation protection setting values are as follows:

[0047] Characteristic λ1: per-unit susceptance value of 1.18, inclination angle of 80°, delay of 10 s, and output modes of alarm, trip, and shutdown;

[0048] Characteristic λ2: per-unit susceptance value of 1.06, inclination angle of 90°, delay of 10 s, and output modes of alarm, trip, and shutdown;

[0049] Characteristic λ3: per-unit susceptance value of 2.00, inclination angle of 110°, delay of 1.5 s, and output modes of alarm, trip, and shutdown.

[0050] Among them, the setting of the loss-of-excitation characteristic λ1 is the key to the loss-of-excitation protection setting. According to the direct-axis reactance X of the generator Gd and the system reactance X s of the total reactance X dΣ for calculation, the total reactance expression is X dΣ = X Gd + X s . Therefore, the calculation formula for the static stability characteristic of the generator loss-of-excitation protection is as follows:

[0051] λ1 = k × (1 / X dΣ ) × (I N / U n ) × (U N.VTprim / I N.CTprim )

[0052] Among them, k is the reliability coefficient, taking 1.05, I N is the rated current of the generator, taking 577 A, U n is the rated voltage of the generator, 10 kV, U N.VTprim is the primary rated voltage of the generator, 10 kV, I N.CTprim is the primary-side rated current of the generator CT current transformer, 800 A. Because the emergency diesel generator is connected to the 10 kV nuclear power plant auxiliary power system, compared with the external power grid system, its system reactance can be ignored, X dΣ ≈ X Gd . By checking the generator parameter table, the direct-axis reactance X Gd is 0.64. After substituting the above parameters into the calculation formula for the static stability characteristic of the loss-of-excitation protection, we get: Characteristic λ1 = 1.05 × (1 / 0.64) × (577 / 10) × (10 / 800) = 1.18. From λ1, the three characteristic curves corresponding to the above loss-of-excitation protection setting values can be obtained. When the admittance value during the generator fault falls within the action range of the characteristic curve, after a delay, the loss-of-excitation protection acts, such as alarm, trip, or shutdown.

[0053] For the analysis of the generator stator overcurrent protection action, assuming that the magnetic flux does not consider the saturation effect, the electromagnetic power P e and the output electric power P are both constant, and the terminal voltage U remains unchanged after grid connection. Then, from the power calculation formula, we know:

[0054] P e =(3E0U / X t )×sinθ = constant

[0055] P = 3UIcosα = constant

[0056] E0sinθ / X t = Icosα = constant

[0057] This constant is represented by the straight line AB in Figure 1 . As the generator operates under different conditions, its stator current I will also move along this straight line; as the generator starts to operate in the leading power factor region, the excitation current decreases, and the generator electromotive force E0 will move along the straight line CD. When the power angle θ reaches the maximum of 90°, the generator will reach the stable operation limit. If the excitation current is further decreased, the generator will lose synchronization, and at this time, E0 is at point C. Among them, X t is the generator reactance, I is the generator stator current, E0 is the generator electromotive force, θ is the generator power angle (the angle between E0 and U), and α is the generator power factor angle (the angle between I and U).

[0058] From the generator electromotive force calculation formula:

[0059] E0 = U + jIX t

[0060] it can be seen that the generator terminal voltage U remains unchanged, and the generator reactance X t is also fixed. As the excitation current decreases, E0 will also decrease. The generator goes from the lagging power factor region to the leading power factor region. At this time, the generator stator current will also change accordingly. As the excitation current decreases, the generator electromotive force gradually moves from E 01 along the straight line to the static stability boundary E 04 , and the generator stator current will also gradually move from I1 along the straight line to I4.

[0061] From Figure 1 it is easy to know that the generator enters the leading power factor region where the stator current I leads the generator terminal voltage U from the lagging power factor region. The change of the stator current is a process from large to small and then to large. Therefore, as the generator operates deeper into the leading power factor region, the stator current will gradually increase until the generator stator overcurrent protection operates.

[0062] As can be seen from the above analysis, the occurrence of the above problems, that is, the under-excitation protection fails to operate correctly, ultimately causing the generator to operate in deep leading phase and triggering the stator overcurrent protection of the generator to trip, affecting the stability of the generator, is because the current setting value of the under-excitation protection for the emergency diesel generator in nuclear power plants is based on the empirical values given by the manufacturer or set according to the protection method of large steam turbines. This setting method is not applicable to generators with a relatively small direct-axis reactance. At the same time, the correctness of the action logic coordination between various protections is not considered.

[0063] In view of this, the embodiment of the present application proposes an automatic setting method for the under-excitation protection of the generator's admittance plane. According to the maximum allowable leading phase depth of the generator in the static stability limit PQ curve of the generator, the under-excitation protection setting characteristic curve of the generator is obtained. This method avoids the problem that when the generator has exceeded the maximum allowable leading phase depth value, the under-excitation protection still fails to operate, affecting the operation stability of the generator. Therefore, the reliability of the under-excitation protection is higher.

[0064] In one embodiment, as Figure 2 shown, an automatic setting method for the under-excitation protection of the admittance plane is provided. Taking the application of this method to a terminal as an example for illustration, it can be understood that this method can also be applied to a server, and can also be applied to a system including a terminal and a server, and is implemented through the interaction between the terminal and the server. This method includes the following steps:

[0065] Step 201, the terminal obtains the maximum allowable leading phase depth of the target generator according to the static stability limit PQ curve of the target generator.

[0066] Among them, the static stability limit PQ curve of the target generator is determined by the production specifications of the target generator and provided by the generator manufacturer. To avoid the problem of excessive leading phase depth and excessive stator current of the target generator, the calculation of the setting value of the under-excitation protection of the target generator is carried out through the maximum allowable leading phase depth allowed by the static stability limit of the target generator. For example, as Figure 3 shown, the maximum allowable leading phase depth of the target generator is that when the active power P is 0, the maximum reactive power Q is -5000 kVar. 0.8 PF and 0.95 PF in the figure correspond to different power factors.

[0067] Step 202, the terminal obtains the under-excitation protection admittance characteristic value of the target generator according to the maximum allowable leading phase depth, the rated parameters of the target generator, and the terminal voltage of the target generator.

[0068] The under-excitation protection admittance characteristic value is the threshold for the under-excitation protection of the target generator and is calculated from the maximum allowable leading phase depth, the rated parameters of the target generator, and the terminal voltage of the target generator.

[0069] Step 203: The terminal determines the loss-of-excitation protection setting characteristic curve according to the loss-of-excitation protection admittance characteristic value.

[0070] The loss-of-excitation protection setting characteristic curve is used for the target generator to perform loss-of-excitation protection according to the loss-of-excitation protection setting characteristic curve. Optionally, during actual operation, when the actual admittance value calculated by the target generator based on the actual leading power factor depth, rated parameters, and actual terminal voltage exceeds the loss-of-excitation protection setting characteristic curve, the target generator needs to perform loss-of-excitation protection and take corresponding actions according to the preset loss-of-excitation protection action export mode to protect the stability of the system operation.

[0071] In the above admittance plane loss-of-excitation protection automatic setting method, first, according to the static stability limit PQ curve of the target generator, the allowable maximum leading power factor depth of the target generator is obtained; then, according to the allowable maximum leading power factor depth, the rated parameters of the target generator, and the terminal voltage of the target generator, the loss-of-excitation protection admittance characteristic value of the target generator is obtained; finally, according to the loss-of-excitation protection admittance characteristic value, the loss-of-excitation protection setting characteristic curve for the target generator to perform loss-of-excitation protection is determined. In this way, the loss-of-excitation protection setting characteristic curve of the generator is obtained based on the allowable maximum leading power factor depth in the static stability limit PQ curve of the generator. This method avoids the problem that when the loss-of-excitation protection setting value set according to the empirical value causes the loss-of-excitation protection not to act when the generator has exceeded the maximum allowable leading power factor depth, resulting in the leading power factor depth of the generator exceeding the safe area of the static stability limit and affecting the operation stability of the generator. Therefore, the reliability of the loss-of-excitation protection is higher.

[0072] In an optional embodiment, the loss-of-excitation protection admittance characteristic value is determined by the parameters of the target generator itself. The specific calculation steps are as Figure 4 shown, including:

[0073] Step 401: The terminal obtains the per-unit value of the primary-side susceptance of the target generator according to the allowable maximum leading power factor depth, rated parameters, and terminal voltage.

[0074] The per-unit value is a commonly used numerical marking method in power system analysis and engineering calculations, representing the relative values of various physical quantities and parameters. The rated parameters include the rated capacity of the target generator and the rated voltage of the target generator. The calculation steps for the per-unit value of the primary-side susceptance of the target generator are as follows:

[0075] (1) Calculate the first ratio of the allowable maximum leading power factor depth and the rated capacity.

[0076] A = -Q / S n

[0077] where A is the first ratio, Q is the allowable maximum leading power factor depth under the safe operation of the target generator, and S n is the rated capacity of the target generator.

[0078] (2) Calculate the second ratio of the terminal voltage of the computer to the rated voltage, and square the second ratio to obtain a squared value.

[0079] C = (U / U n ) 2

[0080] where C is the squared value, U is the terminal voltage of the target generator, and U n is the rated voltage of the target generator.

[0081] (3) Take the ratio of the first ratio to the squared value as the per-unit value of the primary-side susceptance.

[0082] B [p.u] = A / C = (-Q / S n ) / (U / U n ) 2

[0083] where B [p.u] is the per-unit value of the primary-side susceptance.

[0084] Optionally, please continue to refer to Figure 3 , allowing the maximum leading power factor depth, that is, when the active power P is 0, the corresponding reactive power Q value is -5000 kVar. Taking the rated parameters of the target generator of a certain nuclear power plant with the above problems as an example for calculation, substituting the maximum value of the above maximum leading power factor depth, B [p.u] = (-5000 / 10000) / (10 / 10) 2 , calculating to obtain B [p.u] The per-unit value of conductance is -0.5.

[0085] Step 402, the terminal performs a secondary-side conversion on the per-unit value of the primary-side susceptance to obtain the per-unit value of the secondary-side susceptance of the target generator.

[0086] The primary side of the generator is the high voltage and high current during actual operation. The secondary side is converted into an analog quantity of low voltage and low current through a current transformer. The loss-of-excitation protection device collects the secondary-side analog quantity for operation. Therefore, it is necessary to convert the per-unit value of the susceptance calculated on the primary side to the secondary side of the target generator to obtain the per-unit value of the secondary-side susceptance of the target generator. Among them, the rated parameters include the rated current of the target generator and the primary rated current of the current transformer of the target generator. The specific calculation steps of the per-unit value of the secondary-side susceptance include:

[0087] (1) Calculate the third ratio of the rated current to the primary-side rated current.

[0088] D = I N / I N.CTprim

[0089] Among them, D is the third ratio, and I N is the rated current of the target generator, and I N.CTprim is the rated primary current of the CT current transformer of the target generator.

[0090] (2) Take the product of the per-unit value of the primary susceptance and the third ratio as the per-unit value of the secondary susceptance.

[0091] B* = B [p.u] × D = B [p.u] × I N / I N.CTprim

[0092] Among them, B* is the per-unit value of the secondary susceptance.

[0093] Optionally, taking the rated parameters of the target generator of a certain nuclear power plant with the above problems as an example for calculation, after substituting the rated current and the rated primary current value, B* = 0.5 × 577 / 800, and it is calculated that the per-unit value of the secondary susceptance B* is 0.36.

[0094] Step 403, the terminal obtains the admittance characteristic value of the loss-of-excitation protection according to the per-unit value of the secondary susceptance.

[0095] Among them, in order to ensure the reliability of the setting value and prevent misoperation, a reliability coefficient can also be added on the basis of the per-unit value of the secondary susceptance, that is, take the product of the per-unit value of the secondary susceptance and the reliability coefficient as the admittance characteristic value of the loss-of-excitation protection.

[0096] λ1 = k × B*

[0097] Among them, λ1 is the admittance characteristic value of the loss-of-excitation protection. Taking the reliability coefficient k = 1.05 as an example and substituting it into the numerical calculation, λ1 ≈ 0.38. Optionally, the specific value of the reliability coefficient can be adjusted according to the actual test process.

[0098] In the above embodiment, the admittance characteristic value of the loss-of-excitation protection of the generator is calculated according to the maximum allowable in-phase depth of the generator in the static stability limit PQ curve of the generator. The calculation process takes into account the parameters and limitation characteristics of the generator set itself, making up for the deficiencies of the existing conventional loss-of-excitation protection setting methods.

[0099] In one embodiment, the loss-of-excitation protection setting characteristic curve includes a first curve, a second curve, and a third curve. As Figure 5 shown, to determine the loss-of-excitation protection setting characteristic curve according to the admittance characteristic value of the loss-of-excitation protection, the steps include:

[0100] Step 501, the terminal determines the first curve according to the admittance characteristic value of the loss-of-excitation protection.

[0101] Optionally, according to the value of the admittance characteristic value λ1 calculated above, which is 0.38, and taking the inclination angle as 80°, the first curve is determined. Optionally, the delay can be 10 seconds. When the admittance value calculated in real time by the target generator exceeds the first curve, after a 10-second delay, the loss-of-excitation protection is performed, and the outlet modes of the loss-of-excitation protection action are alarm, trip, and shutdown.

[0102] Step 502, the terminal determines the second curve according to k times the admittance characteristic value of the loss-of-excitation protection.

[0103] Optionally, the value range of k is greater than 0 and less than 1, and generally 0.9 is taken. Given that the value of λ1 is 0.38, then λ2 = 0.38 * 0.9 = 0.34. Optionally, taking the inclination angle as 90°, the second curve is determined. Optionally, the delay can be 10 seconds. When the admittance value calculated in real time by the target generator exceeds the second curve, after the delay, the loss-of-excitation protection is performed, and the outlet modes of the loss-of-excitation protection action are alarm, trip, and shutdown.

[0104] Step 503, the terminal determines the third curve according to p times the admittance characteristic value of the loss-of-excitation protection.

[0105] Optionally, the value range of p is greater than 1 and less than 2. In this embodiment, p is taken as 1.9. Given that the value of λ1 is 0.38, then λ3 = 0.38 * 1.9 = 0.72. Optionally, taking the inclination angle as 110°, the third curve is determined. Optionally, the delay can be 1 second. When the admittance value calculated in real time by the target generator exceeds the third curve, after the delay, the loss-of-excitation protection is performed, and the outlet modes of the loss-of-excitation protection action are alarm, trip, and shutdown.

[0106] In an optional embodiment, after determining the loss-of-excitation protection setting characteristic curve and before applying the loss-of-excitation protection setting characteristic curve to practice, the effectiveness of the loss-of-excitation protection setting curve is evaluated, as Figure 6 shown. The specific steps of the evaluation method include:

[0107] Step 601, in a test environment, current and voltage are applied to the protection system of the target generator so that the target generator performs a protection action in response to the current and voltage.

[0108] Among them, performing the protection action includes at least one of the following: performing a loss-of-excitation protection action according to the loss-of-excitation protection setting characteristic curve; performing a stator overcurrent protection action. The stator overcurrent protection and the loss-of-excitation protection of the target generator are tested simultaneously to check whether the action logic coordination between the two protections is reasonable. Optionally, the target generator is tested by a relay protection tester. Current and voltage are applied to the protection system of the target generator, the angle between the current and the voltage is fixed, and the current value is gradually changed to trigger the target generator to perform a protection action in response to the current and voltage.

[0109] Step 602, detect the protection action behavior of the target generator.

[0110] Optionally, the real-time operating parameters of the generator can be automatically sampled through methods such as transmitters or signal communication transmission to detect the protection action behavior.

[0111] Step 603, determine whether the loss-of-excitation protection setting characteristic curve meets the conditions for application in the actual production environment according to the protection actions performed by the target generator protection system.

[0112] Optionally, there are two cases to judge whether the loss-of-excitation protection setting characteristic curve meets the conditions for application in the actual production environment:

[0113] In the first case, if the current and voltage trigger the loss of excitation of the target generator and the loss-of-excitation protection action takes precedence over the stator overcurrent protection action, it is determined that the loss-of-excitation protection setting characteristic curve meets the conditions for application in the actual production environment.

[0114] Optionally, fix the angle between the current and voltage applied to the target generator, and then gradually change the current value to trigger the loss of excitation of the target generator. At this time, the loss-of-excitation protection action takes precedence over the stator overcurrent protection action and will not cause the in-phase depth of the generator to exceed the maximum allowable in-phase depth. Therefore, it is determined that the loss-of-excitation protection setting characteristic curve meets the conditions for application in the actual production environment at this time.

[0115] In the second case, if the current and voltage trigger the loss of excitation of the target generator and the loss-of-excitation protection does not act or the loss-of-excitation protection action occurs after the stator overcurrent protection action, it is determined that the loss-of-excitation protection setting characteristic curve does not meet the conditions for application in the actual production environment.

[0116] If the angle between the fixed applied current and voltage is fixed and then the current value is gradually changed to trigger the loss of excitation of the target generator. At this time, the loss-of-excitation protection does not act, or the stator overcurrent protection acts first and then the loss-of-excitation protection acts. This situation indicates that the in-phase depth of the generator is already too deep, resulting in too large stator current and thus the stator overcurrent protection action occurs. At this time, the generator has entered the non-safe area from the safe area of the static stability limit curve, thus affecting the stability of the generator operation. In this case, the loss-of-excitation protection setting characteristic curve does not meet the conditions for application in the actual production environment.

[0117] Optionally, the specific process is as Figure 7As shown, the overcurrent protection and loss-of-excitation protection of the generator stator are tested simultaneously. Current and voltage are applied separately through the neutral point current input of the generator and the terminal voltage input of the generator. After the protection action is triggered, judgment is made based on the actually measured results. If the judgment result is the first case above, the conditions of the actual production environment are met and it can be applied in actual applications. If the judgment result is the second case above, it does not meet the conditions of the actual production environment, and the protection setting value needs to be corrected. Then, after correction, the inspection is continued until it meets the conditions of the production environment and can be used in actual applications.

[0118] In the above embodiment, the loss-of-excitation protection and stator overcurrent protection of the target generator are inspected simultaneously, which can conduct a joint debugging test on whether the action logic coordination between the loss-of-excitation protection and overcurrent protection of the generator is reasonable, thereby solving the problem of unreasonable action logic coordination between various protections.

[0119] Optionally, if the setting characteristic curve of the loss-of-excitation protection does not meet the conditions for application in the actual production environment, the setting characteristic curve of the loss-of-excitation protection is corrected.

[0120] The setting characteristic curve of the loss-of-excitation protection can be corrected by adjusting the value of the reliability coefficient k, or when obtaining the allowable maximum leading power factor depth according to the static stability limit PQ curve of the generator, instead of choosing the limit value, a smaller leading power factor depth value is selected to improve the reliability of the setting characteristic curve of the loss-of-excitation protection so that it meets the conditions for application in the actual production environment.

[0121] In the embodiment of the present application, please refer to Figure 8 , which shows a flowchart of an automatic setting method for loss-of-excitation protection in the admittance plane provided by the embodiment of the present application. The automatic setting method for loss-of-excitation protection in the admittance plane includes the following steps:

[0122] Step 801, the terminal obtains the allowable maximum leading power factor depth of the target generator according to the static stability limit PQ curve of the target generator.

[0123] Step 802, the terminal obtains the per-unit value of the primary side susceptance of the target generator according to the allowable maximum leading power factor depth, rated parameters, and terminal voltage.

[0124] Step 803, the terminal performs secondary side conversion on the per-unit value of the primary side susceptance to obtain the per-unit value of the secondary side susceptance of the target generator.

[0125] Step 804, the terminal obtains the loss-of-excitation protection admittance characteristic value according to the per-unit value of the secondary side susceptance.

[0126] Step 805, the terminal determines the first curve according to the loss-of-excitation protection admittance characteristic value.

[0127] Step 806, the terminal determines the second curve according to k times of the loss-of-excitation protection admittance characteristic value.

[0128] Step 807, the terminal determines a third curve according to p times the admittance characteristic value of the loss-of-excitation protection.

[0129] Step 808, in a test environment, current and voltage are applied to the target generator protection system so that the target generator performs a protection action in response to the current and voltage.

[0130] Step 809, detect the protection action behavior of the target generator.

[0131] Step 810, determine whether the loss-of-excitation protection setting characteristic curve meets the conditions for application in the actual production environment according to the protection action performed by the target generator protection system.

[0132] In the first case, if the current and voltage trigger the loss of excitation of the target generator and the loss-of-excitation protection action takes precedence over the stator overcurrent protection action, it is determined that the loss-of-excitation protection setting characteristic curve meets the conditions for application in the actual production environment.

[0133] In the second case, if the current and voltage trigger the loss of excitation of the target generator and the loss-of-excitation protection does not act or the loss-of-excitation protection action occurs after the stator overcurrent protection action, it is determined that the loss-of-excitation protection setting characteristic curve does not meet the conditions for application in the actual production environment.

[0134] An example of the generator loss-of-excitation protection method of the present application is given. The comparison between the new and old setting values after the optimization setting method of the loss-of-excitation protection is shown in Table 1.

[0135] Fixed value category Original design fixed value Fixed value after optimization <![CDATA[Characteristic curve λ1]]> λ = 1.18; α = 80°; T = 10s λ = 0.38; α = 80°; T = 10s <![CDATA[Characteristic curve λ2]]> λ = 1.06; α = 90°; T = 10s λ = 0.34; α = 90°; T = 10s <![CDATA[Characteristic curve λ3]]> λ = 2; α = 110°; T = 1.5s λ = 0.72; α = 110°; T = 1s

[0136] It can be seen from the data in the above table that the protection setting value has changed greatly after the improvement of the setting method. It is applied to the above-mentioned generator set with problems for actual full-load inspection, and the implementation effect is obvious:

[0137] (1) According to the static stability limit PQ curve of the generator, the maximum allowable leading power factor depth of the generator should be when the active power P is 0, the maximum reactive power Q is -5000 kVar, and the generator terminal voltage U is 10 kV. After calculation, the terminal current I at the static stability limit of the generator is calculated as follows: U = 10 kV, P = 0, Q = -5000 kvar, S 2 = P 2 + Q 2, after substituting the above data, the apparent power \(S = 5000\ kVA\) can be obtained. Since \(I=\frac{S}{1.732U}\), substituting the voltage amplitude and apparent power values, the terminal current at the static stability limit of the generator is approximately \(290\ A\). Therefore, according to the setting value calculated in this way, when the loss-of-excitation protection occurs, the terminal current is much less than the existing stator overcurrent protection setting value of \(808\ A\), and the stator overcurrent protection will not operate. At the same time, in the original setting method, the in-phase depth at the generator fault moment is \(15000\ kVar\), and it becomes \(4500\ kVar\) after adopting the optimized setting method. It enters the safe area from the non-safe area of the static stability limit PQ curve of the generator and enters the normal operation area of the allowable in-phase operation of the generator from the deep in-phase area. This avoids the damage of the generator body caused by deep in-phase operation and ensures the stability of the nuclear power plant auxiliary power system and nuclear safety.

[0138] (2) If a loss-of-excitation protection failure occurs again when the excitation system fails, the loss-of-excitation protection will act reliably prior to the stator overcurrent protection, and it will not cause the abnormal situation that the loss-of-excitation protection fails during the excitation system failure and the stator overcurrent protection cuts off the fault. This avoids the project schedule delay caused by the unit trip during the unit startup and grid connection with load due to the failure of important components of the excitation system, as well as the delay of the power main line commissioning schedule before the heat test caused by replacing equipment, changing protection setting values, and restoring the unit state for restart. It can shorten the startup test duration of a single nuclear emergency diesel generator, save the manpower input of each specialty in installation, design, and commissioning, and greatly reduce the project construction cost. For example, applying the loss-of-excitation protection setting value obtained by the method of this application to a single nuclear-grade power diesel generator set, the original manpower input was 36 person-years, and it was reduced to 25 person-years after applying this innovative technical achievement. Calculated at a unit man-hour cost of 5 million per person-year, the total savings in the commissioning labor cost of 3 diesel generators is: \(3\times(36 - 25)\times5\ million=16.5\ million\). In summary, the total direct economic benefit is: 16.5 million yuan.

[0139] It should be understood that although the steps in the flowcharts involved in the above-described embodiments are sequentially shown according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless there is a clear indication in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-described embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily executed at the same moment, but can be executed at different moments. The execution order of these steps or stages is not necessarily sequential, but can be executed alternately or in turn with at least a part of other steps or steps or stages in other steps.

[0140] Based on the same inventive concept, an embodiment of this application further provides an automatic setting device for admittance plane loss-of-excitation protection for implementing the above-mentioned automatic setting method for admittance plane loss-of-excitation protection. The solution provided by this device to solve the problem is similar to the solution described in the above method. Therefore, the specific limitations in one or more embodiments of the automatic setting device for admittance plane loss-of-excitation protection provided below can refer to the limitations on the automatic setting method for admittance plane loss-of-excitation protection in the above text, and will not be elaborated here.

[0141] In one embodiment, as Figure 9 shown, an automatic setting device 900 for admittance plane loss-of-excitation protection is provided, including: an acquisition module 901, a calculation module 902, and a first determination module 903, where:

[0142] The acquisition module 901: is used to obtain the allowable maximum leading power factor depth of the target generator according to the static stability limit PQ curve of the target generator;

[0143] The calculation module 902 is used to obtain the loss-of-excitation protection admittance characteristic value of the target generator according to the allowable maximum leading power factor depth, the rated parameters of the target generator, and the terminal voltage of the target generator;

[0144] The first determination module 903 is used to determine the loss-of-excitation protection setting characteristic curve according to the loss-of-excitation protection admittance characteristic value, where the loss-of-excitation protection setting characteristic curve is used for the target generator to perform loss-of-excitation protection according to the loss-of-excitation protection setting characteristic curve.

[0145] In one of the embodiments, the calculation module 902 is specifically used to obtain the per-unit value of the primary side susceptance of the target generator according to the allowable maximum leading power factor depth, the rated parameters, and the terminal voltage; perform secondary side conversion on the per-unit value of the primary side susceptance to obtain the per-unit value of the secondary side susceptance of the target generator; and obtain the loss-of-excitation protection admittance characteristic value according to the per-unit value of the secondary side susceptance.

[0146] In one of the embodiments, the rated parameters include the rated capacity of the target generator and the rated voltage of the target generator. The calculation module 902 is specifically used to calculate the first ratio of the allowable maximum leading power factor depth and the rated capacity; calculate the second ratio of the terminal voltage and the rated voltage, and square the second ratio to obtain the squared value; and use the ratio of the first ratio and the squared value as the per-unit value of the primary side susceptance.

[0147] In one of the embodiments, the rated parameters include the rated current of the target generator and the primary rated current of the current transformer of the target generator. The calculation module 902 is specifically used to calculate the third ratio of the rated current and the primary side rated current; and use the product of the per-unit value of the primary side susceptance and the third ratio as the per-unit value of the secondary side susceptance.

[0148] In one embodiment, the computing module 902 is specifically configured to use the product of the per-unit value of the secondary susceptance and the reliability coefficient as the admittance characteristic value of the loss-of-excitation protection.

[0149] In one embodiment, the loss-of-excitation protection setting characteristic curve includes a first curve, a second curve, and a third curve. The first determination module 903 is specifically configured to determine the first curve according to the admittance characteristic value of the loss-of-excitation protection; determine the second curve according to k times the admittance characteristic value of the loss-of-excitation protection, where the value range of k is greater than 0 and less than 1; determine the third curve according to p times the admittance characteristic value of the loss-of-excitation protection, where the value range of p is greater than 1 and less than 2.

[0150] In one embodiment, the device further includes a second determination module, which is configured to apply current and voltage to the target generator protection system in a test environment, so that the target generator performs protection actions in response to the current and voltage. Performing the protection actions includes at least one of the following: performing a loss-of-excitation protection action according to the loss-of-excitation protection setting characteristic curve; performing a stator overcurrent protection action; determining whether the loss-of-excitation protection setting characteristic curve meets the conditions for application in the actual production environment according to the protection actions performed by the target generator protection system.

[0151] In one embodiment, the device further includes a third determination module, which is configured to determine that the loss-of-excitation protection setting characteristic curve meets the conditions for application in the actual production environment if the loss-of-excitation protection action takes precedence over the stator overcurrent protection action when the current and voltage trigger the loss of excitation of the target generator; determine that the loss-of-excitation protection setting characteristic curve does not meet the conditions for application in the actual production environment if the loss-of-excitation protection does not act or the loss-of-excitation protection action occurs after the stator overcurrent protection action when the current and voltage trigger the loss of excitation of the target generator.

[0152] In one embodiment, the device further includes a correction module, which is configured to correct the loss-of-excitation protection setting characteristic curve if the loss-of-excitation protection setting characteristic curve does not meet the conditions for application in the actual production environment.

[0153] Each module in the above admittance-plane loss-of-excitation protection automatic setting device can be implemented in whole or in part by software, hardware, and their combination. The above modules can be embedded in the processor of the computer device in hardware form or independent of it, or stored in the memory of the computer device in software form, so that the processor can call and execute the operations corresponding to the above modules.

[0154] In one embodiment, an admittance-plane loss-of-excitation protection automatic setting and verification device is provided, and the device includes:

[0155] An automatic tuning module, which is used to obtain the maximum allowable in-phase depth of the target generator according to the static stability limit PQ curve of the target generator; is used to obtain the admittance characteristic value of the loss-of-excitation protection of the target generator according to the maximum allowable in-phase depth, the rated parameters of the target generator, and the terminal voltage of the target generator; is used to determine the loss-of-excitation protection tuning characteristic curve according to the admittance characteristic value of the loss-of-excitation protection, where the loss-of-excitation protection tuning characteristic curve is used for the target generator to perform loss-of-excitation protection according to the loss-of-excitation protection tuning characteristic curve.

[0156] A verification module, which is used to verify whether the loss-of-excitation protection tuning characteristic curve meets the conditions for application in the actual production environment according to the protection actions performed by the protection system of the target generator. Optionally, the verification module can automatically sample the real-time operating parameters of the generator through methods such as transmitters or signal communication transmission, and then verify the loss-of-excitation protection tuning characteristic curve and the overcurrent protection action characteristic.

[0157] In one embodiment, a computer device is provided. The computer device can be a terminal, and its internal structure diagram can be as Figure 10 shown. The computer device includes a processor, a memory, a communication interface, a display screen, and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, a mobile cellular network, NFC (Near Field Communication), or other technologies. When the computer program is executed by the processor, it implements a method for automatic tuning of loss-of-excitation protection in the admittance plane. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a button, a trackball, or a touchpad provided on the housing of the computer device, or an external keyboard, touchpad, or mouse, etc.

[0158] Those skilled in the art can understand that Figure 10 the structure shown in

[0159] is only a block diagram of some structures related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements.

[0159] In one embodiment, a computer device is provided, including a memory and a processor. A computer program is stored in the memory, and when the processor executes the computer program, it implements the method for automatic tuning of loss-of-excitation protection in the admittance plane provided in the above method embodiments.

[0160] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the automatic setting method for admittance plane loss-of-excitation protection provided in each of the above method embodiments is implemented.

[0161] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0162] Those of ordinary skill in the art can understand that all or part of the processes in the above method embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the above method embodiments. Among them, any reference to a memory, database, or other medium used in each of the embodiments provided in this application can include at least one of non-volatile and volatile memories. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The databases involved in each of the embodiments provided in this application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in each of the embodiments provided in this application can be general-purpose processors, central processors, graphics processors, digital signal processors, programmable logic devices, data processing logics based on quantum computing, etc., without limitation.

[0163] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0164] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims

1. An automatic setting method for admittance plane loss-of-excitation protection, characterized in that, The method includes: Obtaining the allowable maximum leading power factor depth of the target generator according to the static stability limit PQ curve of the target generator; The rated parameters of the target generator include the rated capacity and the rated voltage of the target generator. Calculate the first ratio of the allowable maximum leading power factor depth to the rated capacity; Calculate the second ratio of the terminal voltage of the target generator to the rated voltage, and square the second ratio to obtain a squared value; Use the ratio of the first ratio to the squared value as the per-unit value of the primary susceptance; The rated parameters further include the rated current of the target generator and the primary rated current of the current transformer of the target generator. Calculate the third ratio of the rated current to the primary rated current; Use the product of the per-unit value of the primary susceptance and the third ratio as the per-unit value of the secondary susceptance; Obtain the admittance characteristic value of the loss-of-excitation protection according to the per-unit value of the secondary susceptance; Determine the loss-of-excitation protection setting characteristic curve according to the admittance characteristic value of the loss-of-excitation protection, where the loss-of-excitation protection setting characteristic curve is used for the target generator to perform loss-of-excitation protection according to the loss-of-excitation protection setting characteristic curve.

2. The method according to claim 1, wherein The obtaining the admittance characteristic value of the loss-of-excitation protection according to the per-unit value of the secondary susceptance includes: Use the product of the per-unit value of the secondary susceptance and the reliability coefficient as the admittance characteristic value of the loss-of-excitation protection.

3. The method according to any one of claims 1 to 2, characterized in that The loss-of-excitation protection setting characteristic curve includes a first curve, a second curve, and a third curve. The determining the loss-of-excitation protection setting characteristic curve according to the admittance characteristic value of the loss-of-excitation protection includes: Determine the first curve according to the admittance characteristic value of the loss-of-excitation protection; Determine the second curve according to k times the admittance characteristic value of the loss-of-excitation protection, where the value range of k is greater than 0 and less than 1; Determine the third curve according to p times the admittance characteristic value of the loss-of-excitation protection, where the value range of p is greater than 1 and less than 2.

4. The method according to any one of claims 1 to 2, characterized in that After determining the loss-of-excitation protection setting characteristic curve according to the admittance characteristic value of the loss-of-excitation protection, the method further includes: In a test environment, apply current and voltage to the protection system of the target generator so that the target generator performs protection actions in response to the current and the voltage. The performing the protection actions includes at least one of the following: performing loss-of-excitation protection actions according to the loss-of-excitation protection setting characteristic curve, performing stator overcurrent protection actions; Determine whether the loss-of-excitation protection setting characteristic curve meets the conditions for application in the actual production environment according to the protection actions performed by the protection system of the target generator.

5. The method according to claim 4, wherein The determining whether the loss-of-excitation protection setting characteristic curve meets the conditions for application in the actual production environment according to the protection actions performed by the protection system of the target generator includes: If the current and the voltage trigger the loss of excitation of the target generator and the loss-of-excitation protection action takes precedence over the stator overcurrent protection action, determine that the loss-of-excitation protection setting characteristic curve meets the conditions for application in the actual production environment; If the current and the voltage trigger the loss of excitation of the target generator, and the loss-of-excitation protection does not operate or the loss-of-excitation protection operates after the stator overcurrent protection, it is determined that the setting characteristic curve of the loss-of-excitation protection does not meet the conditions for application in the actual production environment.

6. The method according to claim 5, wherein The method further includes: If the setting characteristic curve of the loss-of-excitation protection does not meet the conditions for application in the actual production environment, the setting characteristic curve of the loss-of-excitation protection is corrected.

7. The method according to claim 6, wherein The correction of the setting characteristic curve of the loss-of-excitation protection includes: Adjusting the value of the reliability coefficient to correct the setting characteristic curve of the loss-of-excitation protection.

8. The method according to claim 4, characterized in that The outlet modes of the loss-of-excitation protection action include alarm, trip, or shutdown.

9. An admittance plane field loss protection automatic setting and inspection device, characterized in that, The device includes: An automatic setting module, configured to obtain the allowable maximum leading power factor depth of the target generator according to the static stability limit PQ curve of the target generator; the rated parameters of the target generator include the rated capacity of the target generator and the rated voltage of the target generator, and are used to calculate the first ratio of the allowable maximum leading power factor depth and the rated capacity; calculate the second ratio of the terminal voltage of the target generator and the rated voltage, and square the second ratio to obtain a squared value; use the ratio of the first ratio and the squared value as the per-unit value of the primary-side susceptance; the rated parameters further include the rated current of the target generator and the primary-side rated current of the current transformer of the target generator, and calculate the third ratio of the rated current and the primary-side rated current; use the product of the per-unit value of the primary-side susceptance and the third ratio as the per-unit value of the secondary-side susceptance; obtain the loss-of-excitation protection admittance characteristic value according to the per-unit value of the secondary-side susceptance; and is configured to determine the setting characteristic curve of the loss-of-excitation protection according to the loss-of-excitation protection admittance characteristic value, where the setting characteristic curve of the loss-of-excitation protection is used for the target generator to perform loss-of-excitation protection according to the setting characteristic curve of the loss-of-excitation protection; An inspection module, configured to inspect whether the setting characteristic curve of the loss-of-excitation protection meets the conditions for application in the actual production environment according to the protection actions performed by the protection system of the target generator.

10. The device according to claim 9, characterized in that, The automatic setting module is configured to use the product of the per-unit value of the secondary-side susceptance and the reliability coefficient as the loss-of-excitation protection admittance characteristic value.

11. The device according to any one of claims 9 to 10, characterized in that, The setting characteristic curve of the loss-of-excitation protection includes a first curve, a second curve, and a third curve. The automatic setting module is configured to determine the first curve according to the loss-of-excitation protection admittance characteristic value; determine the second curve according to k times the loss-of-excitation protection admittance characteristic value, where the value range of k is greater than 0 and less than 1; and determine the third curve according to p times the loss-of-excitation protection admittance characteristic value, where the value range of p is greater than 1 and less than 2.

12. A computer device, comprising a memory and a processor, the memory storing a computer program, characterized in that, When the processor executes the computer program, the steps of the method according to any one of claims 1 to 8 are implemented.

13. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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