A protection method and device for generator circuit breakers of a large generator with contact resistance

Abstract

The present invention discloses a protection method and a device for generator circuit breakers of a large, contact-resistive generator and relates to a technical field of equipment protection, wherein the method comprises: obtaining the monitoring data from the generator circuit breaker of a large generator; determining the overall specific heat capacity of the generator circuit breaker and knife breaker according to the material and quality of the generator circuit breaker and knife breaker; calculating, based on the overall specific heat capacity, the alarm threshold for the temperature rise rate of the generator circuit breaker and / or the tripping threshold for the temperature rise rate of the generator circuit breaker according to the temperature of the generator circuit breaker under the influence of the maximum load current;Determining the alarm threshold for the maximum SF6 pressure and / or the trip threshold for the maximum SF6 pressure according to the SF6 gas pressure equation; analyzing the monitoring data and determining the condition types based on the alarm and / or trip thresholds met by the monitoring data; determining the alarm and / or trip protection procedure based on the met condition type. Therefore, if the generator circuit breaker operates abnormally, the alarm or trip procedure is initiated in a timely manner, thus ensuring the monitoring and protection of the generator circuit breaker.

Description

Technical field

[0001] The present invention relates to the technical field of equipment protection and in particular to a protection method and a device for generator circuit breakers of a large generator with contact resistance. Background technology

[0002] Currently, the generator circuit breaker of large generators is insulated by SF6 gas. The SF6 gas exchanges heat with the surrounding cold air through the cooler, dissipating the heat generated by the generator circuit breaker. During normal operation, the amount of heat generated and the amount of heat dissipated by the SF6 gas cooling can maintain a dynamic equilibrium. However, if the operating mechanism of the generator circuit breaker and the contactor malfunction, resulting in improper operation, poor contact, and increased contact resistance, the generator circuit breaker will overheat under the load current. This can burn out the contactor, exacerbating the vicious cycle of increased contact resistance and further heat generation.Based on this, monitoring and protecting the generator circuit breaker is an urgent problem that needs to be solved. Content of the invention

[0003] The present invention provides a protection method and a device for generator circuit breakers of a large generator with contact resistance, in order to monitor and protect the generator circuit breaker.

[0004] To this end, the present invention proposes a protection method for the generator circuit breaker of a large generator with contact resistance. Based on the monitoring data of the generator circuit breaker, the condition type to which the monitoring data corresponds can be determined based on the alarm thresholds and / or the tripping thresholds, so that in the event of a fault in the generator circuit breaker, the alarm or tripping process can be carried out in a timely manner, thereby realizing the monitoring and protection of the generator circuit breaker.

[0005] Another object of the present invention is to propose a device for generator circuit breakers of a large generator with contact resistance.

[0006] To solve the above problem, one aspect of the present invention proposes a protection method for generator circuit breakers of a large generator with contact resistance, the method comprising the following: Receiving monitoring data from the generator circuit breaker of a large generator, the monitoring data including SF6 gas pressure and temperature of the generator circuit breaker; Determining the total specific heat capacity of the generator circuit breaker and knife switch according to the material and quality of the generator circuit breaker and knife switch; Calculate based on the comprehensive specific heat capacity of the alarm threshold for the temperature rise rate of the generator circuit breaker and / or the tripping threshold for the temperature rise rate of the generator circuit breaker according to the temperature of the generator circuit breaker under the influence of the maximum load current; Determining the alarm threshold for the maximum SF6 pressure and / or the trigger threshold for the maximum SF6 pressure according to the SF6 gas pressure according to the SF6 gas state parameter equation; Data analysis of the monitoring data and determination of the condition types based on the alarm and / or trigger thresholds that are met by the monitoring data; Determining the alarm and / or trigger protection process based on the fulfilled condition type; where determining the overall specific heat capacity of the generator circuit breaker and knife switch according to the material and quality of the generator circuit breaker and knife switch comprises: The overall specific heat capacity of the generator circuit breaker and knife switch is determined by a first formula according to the material and quality of the generator circuit breaker and knife switch, wherein the first formula is: C=λ1C1+λ2C2+λ3C3+λ4C4+…+λnCn where C i the specific heat capacity of the i-th metal and λ i the mass ratio of the i-th metal; where the calculation based on the comprehensive specific heat capacity of the alarm threshold for the temperature rise rate of the generator circuit breaker and / or the tripping threshold for the temperature rise rate of the generator circuit breaker according to the temperature of the generator circuit breaker under the influence of the maximum load current comprises the following: Calculating based on the comprehensive specific heat capacity of the alarm threshold for the temperature rise rate of the generator circuit breaker and / or the tripping threshold for the temperature rise rate of the generator circuit breaker according to the temperature of the generator circuit breaker under the influence of the maximum load current using the second formula, wherein the second formula is: ΔTset=I2Rset / mC where I is the maximum load current, R set where m is the contact resistance, m is the total mass of the generator circuit breaker and the knife switch, and C is the overall specific heat capacity of the generator circuit breaker and the knife switch; the SF6 gas state parameter equation includes the following: P=[0.58×10−3pT(1+B(p)−ρA(ρ))]×9.8×10−3 A(ρ)=0.764×10 -3 (1-0.727×10- 3 ρ), B(p)=2.51×10 -3 ρ (1-0.846×10 -3 ρ), where p is the absolute pressure of SF6 gas, ρ is the density of SF6 gas and T is the thermodynamic temperature of SF6 gas.

[0007] The protection method for a generator circuit breaker of a large generator with contact resistance according to an embodiment of the present invention may also have the following additional technical features: In one embodiment of the present invention, the monitoring data includes contact resistance, current, knife switch temperature and SF6 gas temperature. In one embodiment of the present invention, data analysis of the monitoring data and determination of the condition types based on the alarm and / or trigger thresholds fulfilled by the monitoring data comprise the following: Determining the temperature rise rate of the generator circuit breaker based on the temperature of the generator circuit breaker; Determining the SF6 gas temperature rise rate and the SF6 gas pressure change rate based on the SF6 gas temperature or the SF6 gas pressure; Determine, based on the alarm threshold, the alarm condition types that are met by the monitoring data; Determine, based on the trigger threshold, the type of trigger conditions that are met by the monitoring data.

[0008] In an embodiment of the present invention, determining the alarm condition types based on the alarm threshold, which are fulfilled by the monitoring data, comprises: If the monitoring value of the contact resistance is greater than or equal to the alarm threshold of the contact resistance, and the trend monitoring value of the contact resistance is greater than or equal to the alarm threshold of the contact resistance and persists for a certain period of time, then it is determined that the monitoring data meets the first alarm condition type; If the SF6 gas temperature rise rate is greater than or equal to an alarm threshold for SF6 gas temperature rise rates, and the SF6 gas pressure change rate is greater than or equal to an alarm threshold for gas pressure change rate, and the SF6 gas pressure is greater than or equal to the alarm threshold for maximum SF6 pressure for a second period of time, then it is determined that the monitoring data meet the second alarm condition type; If the temperature of the generator circuit breaker is greater than or equal to the alarm threshold temperature of the generator circuit breaker, or the knife switch temperature is greater than or equal to the alarm threshold of the knife switch temperature, and the temperature rise rate of the generator circuit breaker is greater than or equal to the alarm threshold of the temperature rise rate of the generator circuit breaker, and persists for a third period of time, then it is determined that the monitoring data meet the third alarm condition type; if the contact resistance monitoring value is greater than or equal to the contact resistance alarm threshold, and the contact resistance trend monitoring value is greater than or equal to the contact resistance alarm threshold and persists for a fourth time, and if the SF6 gas temperature rise rate is greater than or equal to the SF6 gas temperature rise rate alarm threshold, and the pressure change rate is greater than or equal to the SF6 pressure change rate alarm threshold, and the SF6 gas pressure is greater than or equal to the SF6 maximum pressure alarm threshold and persists for a fifth time, and if the generator circuit breaker temperature is greater than or equal to the generator circuit breaker temperature alarm threshold or the knife breaker temperature alarm threshold,and the temperature rise rate of the generator circuit breaker is greater than or equal to the alarm threshold of the temperature rise rate of the generator circuit breaker and persists for a sixth period of time, then it is determined that the monitoring data meet the fourth alarm condition type.

[0009] In one embodiment of the present invention, determining the type of triggering conditions based on the trigger threshold includes the following, which are fulfilled by the monitoring data: If the monitoring value of the contact resistance is greater than or equal to the trip threshold of the contact resistance, and the trend monitoring value of the contact resistance is greater than or equal to the trip threshold of the contact resistance and lasts for a seventh period, then it is determined that the monitoring data meet the first trip condition type; If the SF6 gas temperature rise rate is greater than or equal to a trigger threshold for SF6 gas temperature rise rates, and the SF6 gas pressure change rate is greater than or equal to a trigger threshold for gas pressure change rate, and the SF6 gas pressure is greater than or equal to the trigger threshold for maximum SF6 pressure for an eighth period of time, then it is determined that the monitoring data meet the second trigger condition type; If the temperature of the generator circuit breaker is greater than or equal to the temperature of the generator circuit breaker trip threshold, or the knife breaker temperature is greater than or equal to the trip threshold of the knife breaker temperature, and the temperature rise rate of the generator circuit breaker is greater than or equal to the trip threshold of the temperature rise rate of the generator circuit breaker, and persists for a ninth time, then it is determined that the monitoring data meet the third trip condition type; if the monitoring value of the contact resistance is greater than or equal to the trip threshold of the contact resistance, and the trend monitoring value of the contact resistance is greater than or equal to the trip threshold of the contact resistance and lasts for a tenth time, and the SF6 gas temperature rise rate is greater than or equal to the trip threshold of the SF6 gas temperature rise rate, and the SF6 gas pressure change rate is greater than or equal to the trip threshold of the pressure change rate, and the SF6 gas pressure is greater than or equal to the trip threshold of the SF6 maximum pressure and lasts for an eleventh time,and if the generator circuit breaker temperature is greater than or equal to the generator circuit breaker temperature trip threshold, or the knife breaker temperature is greater than or equal to the knife breaker temperature trip threshold and the generator circuit breaker temperature rise rate is greater than or equal to the generator circuit breaker temperature rise rate trip threshold and lasts for a twelfth time, then it is determined that the monitoring data meet the fourth trip condition type.

[0010] In one embodiment of the present invention, the alarm protection process comprises a first alarm protection process and a second alarm protection process, and the trip protection process comprises a first trip protection process and a second trip protection process; wherein the method determines, based on the fulfilled condition type, to execute the alarm protection process and / or the trip protection process of the generator circuit breaker, including: If the fulfilled condition type is the first, second, or third tripping condition type, then it is determined that the first alarm protection operation of the generator circuit breaker is executed; If the fulfilled condition type is the fourth trip condition type, then it is determined that the first trip protection operation of the generator circuit breaker is carried out; If the fulfilled condition type is the first, second, or third tripping condition type, then it is determined that the second alarm protection operation of the generator circuit breaker is executed; If the fulfilled condition type is the fourth trip condition type, then it is determined that the second trip protection operation of the generator circuit breaker is carried out.

[0011] To solve the above problem, a further aspect of the present invention proposes a protective device for generator circuit breakers of a large generator with contact resistance, wherein the device comprises the following: a data acquisition module for acquiring monitoring data of a generator circuit breaker from the large generator, wherein the monitoring data includes SF6 gas pressure and temperature of the generator circuit breaker; a first determination module for determining the overall specific heat capacity of the generator circuit breaker and knife switch according to the material and quality of the generator circuit breaker and knife switch; a calculation module for calculating, based on the comprehensive specific heat capacity, the alarm threshold for the temperature rise rate of the generator circuit breaker and / or the tripping threshold for the temperature rise rate of the generator circuit breaker according to the temperature of the generator circuit breaker under the influence of the maximum load current; a second determination module for determining the alarm threshold for the SF6 maximum pressure and / or the trigger threshold for the SF6 maximum pressure according to the SF6 gas pressure according to the SF6 gas state parameter equation; a third determination module for data analysis of the monitoring data and determination of the type of conditions based on the alarm and / or trigger thresholds that are met by the monitoring data; an execution module for determining the alarm and / or trigger protection process based on the fulfilled condition type;

[0012] Another object of the present invention is to provide an electronic device comprising the following: at least one processor; and a memory that is communicatively connected to at least one processor; wherein The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to implement the procedure according to any aspect such as above.

[0013] Another objective of the present invention is to propose a computer storage medium wherein the computer storage medium stores computer-executable instructions which, after being executed by a processor, cause a computer to carry out the method according to one of the foregoing aspects.

[0014] To this end, the exemplary embodiment of the present invention proposes a protection method and a device for the generator circuit breaker of the contact-resistance large generator. Based on the monitoring data of the generator circuit breaker, the condition type to which the monitoring data corresponds can be determined based on the alarm thresholds and / or the tripping thresholds, so that in the event of a fault in the generator circuit breaker, the alarm or tripping process can be carried out in a timely manner, thereby realizing the monitoring and protection of the generator circuit breaker.

[0015] Further aspects and advantages of the present invention are partly mentioned in the following description, partly they result from the following description or are recognized through the practice of the invention. Illustration of the attached drawings

[0016] The aforementioned and / or additional aspects and advantages of the present invention will become apparent and easily understandable from the following description of the embodiments in conjunction with the accompanying drawings, wherein: Fig. Figure 1 is a flowchart of a protection method for a generator circuit breaker of a large generator with contact resistance according to an embodiment of the present invention; Fig. Figure 2 is a schematic representation of an alarm logic for a generator circuit breaker of a large generator with contact resistance according to an embodiment of the present invention; Fig. Figure 3 is a schematic representation of a tripping logic for a generator circuit breaker of a large generator with contact resistance according to an embodiment of the present invention; Fig. Figure 4 is a structural diagram of a protective device for a generator circuit breaker of a large generator with contact resistance according to an embodiment of the present invention. Specific embodiments

[0017] It should be noted that the embodiments and features of the embodiments in the invention can be combined without conflicting with one another. The invention is described in more detail below with reference to the accompanying drawings and in conjunction with exemplary embodiments.

[0018] To enable personnel in the technical field to better understand the scheme of the invention, the following is combined with the drawings of the embodiment of the invention to clearly and completely describe the technical scheme in that embodiment. Obviously, the described embodiment is only a part of the embodiment of the invention, not the entire embodiment. Based on the embodiment in the present invention, all other methods of implementation obtained by ordinary technical personnel in the field without creative work are within the scope of protection of the present invention.

[0019] A protection method and a protection device for generator circuit breakers of a large generator with contact resistance according to an embodiment of the present invention are described below with reference to the accompanying drawings.

[0020] Fig. Figure 1 is a flowchart of a protection method for a generator circuit breaker of a large generator with contact resistance according to an embodiment of the present invention;

[0021] As in Fig. As shown in 1, the procedure includes: S1: Receiving monitoring data from the generator circuit breaker for large generators;

[0022] In one embodiment of the invention, the monitoring data described above can include contact resistance, current, generator circuit breaker temperature, knife switch temperature, SF6 gas temperature, and SF6 gas pressure. Furthermore, in one embodiment of the present invention, the other pressures and temperatures of the respective SF6 phases can be monitored separately by SF6 gas temperature and pressure sensors.

[0023] S2: Determining the overall specific heat capacity of the generator circuit breaker and knife switch according to the material and quality of the generator circuit breaker and knife switch

[0024] In particular, in one embodiment of the present invention, the overall specific heat capacity of the generator circuit breaker and the knife switch can be determined by a first formula according to the material and quality of the generator circuit breaker and the knife switch, wherein the first formula is: C=λ1C1+λ2C2+λ3C3+λ4C4+…+λnCn

[0025] This includes C i the specific heat capacity of the i-th metal and λ i the mass ratio of the i-th metal.

[0026] S3: Calculate, based on the comprehensive specific heat capacity, the alarm threshold for the temperature rise rate of the generator circuit breaker and / or the tripping threshold for the temperature rise rate of the generator circuit breaker according to the temperature of the generator circuit breaker under the influence of the maximum load current.

[0027] In one embodiment of the present invention, under the influence of the maximum load current, assuming that all the heat generated by the contact resistance is absorbed by the generator circuit breaker and the knife switch and there is no other heat dissipation path, i.e., the heat only affects the temperature rise of the body of the generator circuit breaker, then the alarm threshold of the temperature rise rate of the generator circuit breaker and the tripping threshold of the temperature rise rate of the generator circuit breaker can be determined by the second formula, wherein the second formula is: ΔTset=I2Rset / mC

[0028] Among these, I is the maximum load current, R set the contact resistance, m the total mass of the generator circuit breaker and the knife switch (47 kg) and C the total specific heat capacity of the generator circuit breaker and knife switch.

[0029] In one embodiment of the present invention, if the alarm threshold of the temperature rise rate of the generator circuit breaker is determined by the second formula above, R set = 12 µΩ (alarm threshold of the contact resistance) can be substituted into the second formula above to obtain an alarm threshold for the temperature rise rate of the generator circuit breaker of 0.091 K / s; if the tripping threshold for the temperature rise rate of the generator circuit breaker is determined by the second formula above, R can be set = 18 µΩ (trip threshold of the contact resistance) can be substituted into the second formula above to obtain a trip threshold of the temperature rise rate of the generator circuit breaker of 0.136K / s.

[0030] S4: Determining the alarm threshold for the maximum SF6 pressure and / or the trigger threshold for the maximum SF6 pressure according to the SF6 gas pressure according to the SF6 gas state parameter equation;

[0031] In one embodiment of the present invention, the alarm threshold for the maximum SF6 pressure and / or the trigger threshold for the maximum SF6 pressure is determined according to the SF6 gas pressure according to the SF6 gas state parameter equation, wherein the SF6 gas state parameter equation is: P=[0.58×10−3pT(1+B(p)−ρA(ρ))]×9.8×10−3 where A(ρ)=0.764×10 -3 (1-0.727×10- 3 ρ), B(p)=2.51×10- 3 ρ (1-0.846×10 -3 ρ), where p is the absolute pressure of SF6 gas, ρ is the density of SF6 gas and T is the thermodynamic temperature (K °C) of SF6 gas.

[0032] In one embodiment of the present invention, the alarm threshold for the SF6 maximum pressure of 0.95 MPa and / or the trigger threshold for the SF6 maximum pressure of 1.05 MPa is determined according to the SF6 gas pressure according to the SF6 gas state parameter equation: In one embodiment of the present invention, alarm thresholds and / or trip thresholds corresponding to each of the data in the other monitoring data can also be determined according to different operating conditions of the generator circuit breaker.

[0033] In particular, in one embodiment of the present invention, the alarm threshold of the contact resistance and / or the tripping threshold of the contact resistance applicable to the contact resistance can be set to a maximum permissible contact resistance in accordance with the technical requirements of the generator circuit breaker. The alarm threshold of the contact resistance can be 12 µΩ and the tripping threshold of the contact resistance can be 18 µΩ.

[0034] In one embodiment of the invention, the temperature alarm threshold of the generator circuit breaker and / or the temperature trip threshold of the generator circuit breaker, which is applicable to the temperature of the generator circuit breaker, can be set according to the material of the generator circuit breaker. Among these materials, the generator circuit breaker material mainly contains copper, and according to the relevant specifications, the temperature of the electrical copper terminals does not exceed 95 °C. Based on this, the temperature alarm threshold of the generator circuit breaker can be 90 °C and the temperature trip threshold of the generator circuit breaker can be 95 °C.

[0035] In one embodiment of the invention, the temperature alarm threshold of the knife switch and / or the temperature trip threshold of the knife switch, which is applicable to the temperature of the knife switch, can be set according to the material of the knife switch. Among these materials, the material of the knife switch can include aluminum (such as an aluminum-titanium alloy). According to the relevant specifications, the temperature of the electrical aluminum terminals does not exceed 75 °C. Based on this, the temperature alarm threshold of the knife switch can be 80 °C and the temperature trip threshold of the knife switch can be 85 °C.

[0036] Furthermore, in one embodiment of the present invention, the overall specific heat capacity of the generator circuit breaker and the knife switch can be determined according to the material and quality of the generator circuit breaker and the knife switch, and the alarm threshold of the corresponding temperature rise rate of the generator circuit breaker and the tripping threshold of the temperature rise rate of the generator circuit breaker under the influence of the maximum load current can be calculated on the basis of the overall specific heat capacity.

[0037] Furthermore, in one embodiment of the present invention, according to the analysis of the results caused by the large increase in contact resistance, the temperature of the SF6 gas increases simultaneously with the temperature of the generator circuit breaker and the knife breaker, and based on this, the temperature rise rate and the pressure change rate of the SF6 gas are increased. Specifically, under the influence of the maximum load current and the most unfavorable conditions, i.e., when the heat generated by the contact resistance is absorbed by the SF6 gas, the alarm threshold for the SF6 gas temperature rise rate is 0.2288 K / s and the alarm threshold for the pressure change rate is 0.84 kPa / s; the trip threshold for the SF6 gas temperature rise rate is 0.3432 K / s and the trip threshold for the pressure change rate is 1.26 kPa / s.

[0038] In one embodiment of the present invention, the alarm threshold and the trigger threshold can be set according to the requirements for the protection sensitivity, and triggering can be allowed after the alarm action, which not only ensures the protection sensitivity but also improves the reliability of the protection.

[0039] S5: Data analysis of the monitoring data and determination of the condition types based on the alarm and / or trigger thresholds that are met by the monitoring data.

[0040] In one embodiment of the present invention, after obtaining the monitoring data by the above steps, it is necessary to perform a data analysis on the monitoring data in order to obtain a rate of change of a part of the data corresponding to a unit of time, in order to subsequently determine the type of condition to be fulfilled using the alarm threshold and / or the trigger threshold.

[0041] In particular, in one embodiment of the present invention, the determination of a temperature rise rate of the generator circuit breaker is carried out based on the temperature of the generator circuit breaker, and the determination of the SF6 gas temperature rise rate and the SF6 gas pressure change rate are carried out based on the SF6 gas temperature and the SF6 gas pressure, respectively;

[0042] And in an embodiment of the present invention, the above method may further comprise, prior to data analysis of the contact resistance, monitoring the heat generation and heat dissipation of the generator circuit breaker in real time and determining the compensation value of the contact resistance when the heat generation and heat dissipation are in a dynamic equilibrium state and the current satisfies the compensation conditions; and compensating the monitored contact resistance based on the compensation value and determining the contact resistance as the compensated contact resistance.

[0043] In particular, in one embodiment of the present invention, the current that satisfies the compensation condition can have a current step value of less than 0.2 I Nor a current change amount that exceeds a current threshold during shutdown or startup, or a system fault that exceeds a time threshold, wherein I N a nominal current.

[0044] In one embodiment of the present invention, if the aforementioned current fulfills different compensation conditions, the corresponding method for determining the compensation value of the contact resistance also differs. In particular, in one embodiment of the present invention, if the current change rate is less than 0.2 I N The compensation value of the contact resistance is determined using an integral derivation method.

[0045] In particular, in one embodiment of the present invention, during the aforementioned generator circuit breaker operation, when the unit participates in frequency modulation, small current fluctuations occur which affect the calculation of the contact resistance. After analysis and verification, the compensation amount of the contact resistance can be determined using the algorithm function R = Q / I 2 The compensation amount is derived from: R' = -2Q * I Δ If the current I Δ When this changes, the measuring resistance-2I increases. Δ , which can partially compensate for the problem of the "offset" measurement of contact resistance caused by rapid current changes and slow temperature changes.

[0046] And if, in an embodiment of the present invention, the magnitude of the current change exceeds the current threshold during shutdown or startup; or if the system disturbance exceeds the time threshold, the current sample value can assume a plurality of sets of data-weighted average algorithms, introducing a comparison with historical values ​​(e.g., data from 120 seconds ago) to effectively suppress the effect of the current change.

[0047] Furthermore, in one embodiment of the present invention, a failure time strategy can be added: During the failure time process, when the current reduction is less than 0.1 I N If the value is greater than 0.1 I, the data from before the outage (before the current change) will be retained as valid measurement data until normal measurement calculation resumes, when the current restoration is greater than 0.1 I. NThis is demonstrated through experiments that the current processing method uses the weighted average of the first 15 samples as the measured current value, thereby effectively reducing the error in contact resistance calculation caused by current changes. Simultaneously, if the monitored current is less than 0.1 I N The measured value before the first load reduction is maintained until the next boat power recovery is greater than 0.1 I N is.

[0048] Furthermore, in one embodiment of the present invention, the above-described method for determining the fulfilled alarm condition types based on the alarm threshold / trigger threshold of the alarm condition types may include: determining, based on the alarm threshold of the alarm condition types that are fulfilled by the monitoring data, or determining, based on the trigger threshold, the type of trigger conditions that are fulfilled by the monitoring data.

[0049] In one embodiment of the present invention, the method for determining, based on the alarm threshold, the alarm condition types that are fulfilled by the monitoring data may comprise the following steps: S51: If the monitoring value of the contact resistance is greater than or equal to the alarm threshold of the contact resistance, and the trend monitoring value of the contact resistance is greater than or equal to the alarm threshold of the contact resistance and persists for a certain period of time, then the monitoring data is determined to meet the first alarm condition type; S52: If the SF6 gas temperature rise rate is greater than or equal to an alarm threshold for SF6 gas temperature rise rates, and the SF6 gas pressure change rate is greater than or equal to an alarm threshold for gas pressure change rate, and the SF6 gas pressure is greater than or equal to the alarm threshold for maximum SF6 pressure for a second period of time, then it is determined that the monitoring data meet the second alarm condition type; S53: If the generator circuit breaker temperature is greater than or equal to the generator circuit breaker alarm threshold temperature, or the knife breaker temperature is greater than or equal to the knife breaker temperature alarm threshold, and the generator circuit breaker temperature rise rate is greater than or equal to the generator circuit breaker temperature rise rate alarm threshold and persists for a third period of time, then the monitoring data shall be determined to satisfy the third alarm condition type; S54: if the contact resistance monitoring value is greater than or equal to the contact resistance alarm threshold, and the contact resistance trend monitoring value is greater than or equal to the contact resistance alarm threshold and persists for a fourth time, and if the SF6 gas temperature rise rate is greater than or equal to the SF6 gas temperature rise rate alarm threshold, and the pressure change rate is greater than or equal to the SF6 pressure change rate alarm threshold, and the SF6 gas pressure is greater than or equal to the SF6 maximum pressure alarm threshold and persists for a fifth time, and if the generator circuit breaker temperature is greater than or equal to the generator circuit breaker temperature alarm threshold or the knife breaker temperature alarm threshold,and the temperature rise rate of the generator circuit breaker is greater than or equal to the alarm threshold of the temperature rise rate of the generator circuit breaker and persists for a sixth period of time, then it is determined that the monitoring data meet the fourth alarm condition type.

[0050] And in one embodiment of the present invention, the above-described method for determining the trigger condition type fulfilled by the monitoring data, based on the trigger threshold, may comprise the following steps: Step 1: If the monitoring value of the contact resistance is greater than or equal to the trip threshold of the contact resistance, and the trend monitoring value of the contact resistance is greater than or equal to the trip threshold of the contact resistance and persists for a seventh time, then it is determined that the monitoring data meets the first trip condition type; Step 2: If the SF6 gas temperature rise rate is greater than or equal to an alarm threshold for SF6 gas temperature rise rates, and the SF6 gas pressure change rate is greater than or equal to a trigger threshold for gas pressure change rate, and the SF6 gas pressure is greater than or equal to the trigger threshold for maximum SF6 pressure for a second period of time, then it is determined that the monitoring data meet the second trigger condition type; Step 3: If the generator circuit breaker temperature is greater than or equal to the generator circuit breaker trip threshold temperature, or the knife breaker temperature is greater than or equal to the knife breaker temperature trip threshold, and the generator circuit breaker temperature rise rate is greater than or equal to the generator circuit breaker temperature rise rate trip threshold and persists for a ninth time, then the monitoring data is determined to meet the third trip condition type; Step 4: If the contact resistance monitoring value is greater than or equal to the contact resistance trip threshold, and the contact resistance trend monitoring value is greater than or equal to the contact resistance trip threshold and persists for a tenth time, and the SF6 gas temperature rise rate is greater than or equal to the SF6 gas temperature rise rate trip threshold, and the SF6 gas pressure change rate is greater than or equal to the pressure change rate trip threshold, and the SF6 gas pressure is greater than or equal to the SF6 maximum pressure trip threshold and persists for an eleventh time,and if the generator circuit breaker temperature is greater than or equal to the generator circuit breaker temperature trip threshold, or the knife breaker temperature is greater than or equal to the knife breaker temperature trip threshold and the generator circuit breaker temperature rise rate is greater than or equal to the generator circuit breaker temperature rise rate trip threshold and lasts for a twelfth time, then it is determined that the monitoring data meet the fourth trip condition type.

[0051] It should be noted that in one embodiment of the present invention, the first time, second time, third time, fourth time, fifth time, sixth time, seventh time, eighth time, ninth time, tenth time, eleventh time, and twelfth time may be the same or different. Furthermore, in one embodiment of the invention, the aforementioned first time, second time, third time, fourth time, fifth time, sixth time, seventh time, eighth time, ninth time, tenth time, eleventh time, and twelfth time may be set by experiment or expert experience. For example, in one embodiment of the invention, the aforementioned first time may be 30 seconds.

[0052] Furthermore, in one embodiment of the present invention, the first, second, third, and fourth alarm condition types described above can be determined through experimentation or expert experience. For example, if the real-time contact resistance measurement is greater than or equal to 12 µΩ and the historical contact resistance measurement is greater than or equal to 12 µΩ and persists for the first time, then it is determined that the monitoring data fulfills the first alarm condition type, wherein the first alarm condition type can be a fault alarm of the generator circuit breaker's contact resistance.

[0053] Furthermore, in one embodiment of the present invention, the first, second, third, and fourth tripping condition types described above can be obtained through experimentation or expert experience. For example, if the real-time contact resistance measurement is greater than or equal to 18 µΩ, and the historical contact resistance measurement is greater than or equal to 18 µΩ, and the seventh time period is observed, then it is determined that the monitoring data meet the first tripping condition type, where the first tripping condition type can be the high-value alarm of the generator circuit breaker's contact resistance.

[0054] S6: Determine the alarm and / or trigger protection process based on the fulfilled condition type.

[0055] In one embodiment of the present invention, after obtaining the condition type fulfilled by the monitoring data through the above steps, the alarm protection process and / or the executed trip protection process can be determined based on the fulfilled condition type, wherein the alarm protection process can comprise a first alarm protection process and a second alarm protection process, and the trip protection process can comprise a first trip protection process and a second trip protection process.

[0056] In particular, in one embodiment of the present invention, a method for determining the alarm and / or trip protection operation based on the fulfilled condition type may comprise the following steps: S61: If the fulfilled condition type is the first, second, or third alarm condition type, then it is determined that the first alarm protection operation of the generator circuit breaker is performed;

[0057] In one embodiment of the present invention, if the fulfilled condition type is the first, second, or third tripping condition type, the operating state of the generator circuit breaker is abnormal at that time, but the danger limit has not been reached, and it is then determined that the first alarm protection operation of the generator circuit breaker is performed to sound the alarm.

[0058] Among these, the first alarm protection action mentioned above can consist of notifying the person via the system, SMS, or email to trigger appropriate alarms. In the example, if the above-mentioned condition type is the first alarm condition type, the generator circuit breaker contact resistance alarm can be triggered; if the above-mentioned condition type is the second alarm condition type, the SF6 fault alarm can be triggered; if the above-mentioned condition type is the third alarm condition type, the generator circuit breaker temperature fault alarm can be triggered.

[0059] S62: If the fulfilled condition type is the fourth trip condition type, then it is determined that the first trip protection operation of the generator circuit breaker is carried out;

[0060] In one embodiment of the present invention, if the aforementioned condition type is the fourth alarm condition type, the generator circuit breaker contact resistance fault alarm, the generator circuit breaker temperature fault alarm, and the SF6 fault alarm can be implemented. Based on this, the first tripping protection operation of the generator circuit breaker can be performed to protect the generator circuit breaker.

[0061] Among them, the first trip protection operation may include the authorization of the generator circuit breaker trip, i.e., the generator circuit breaker trip authorization operation may be released at this time so that personnel can perform the generator circuit breaker trip authorization operation in a timely manner to protect the generator circuit breaker.

[0062] S63: If the fulfilled condition type is the first, second, or third tripping condition type, then it is determined that the second alarm protection operation of the generator circuit breaker is executed;

[0063] In one embodiment of the present invention, if the fulfilled condition type is the first, second, or third tripping condition type, the operating state of the generator circuit breaker is abnormal at that time, but the danger limit has not been approached or reached, and it is then determined that the second alarm protection operation of the generator circuit breaker is carried out to sound the alarm.

[0064] Among these, the aforementioned second alarm protection procedure can consist of notifying the person via the buzzer or system, or by SMS or email, to trigger appropriate alarms. For example, if the condition type met above is the first tripping condition type, the generator circuit breaker contact resistance high-value alarm can be triggered; if the aforementioned condition type is the second tripping condition type, the SF6 fault high-value alarm can be triggered; if the aforementioned condition type is the third tripping condition type, then the generator circuit breaker fault high-temperature alarm can be triggered.

[0065] S64: If the fulfilled condition type is the fourth trip condition type, then it is determined that the second trip protection operation of the generator circuit breaker is carried out.

[0066] In one embodiment of the present invention, if the condition type fulfilled above is the fourth tripping condition type, the generator circuit breaker contact resistance high-value alarm, the generator circuit breaker fault high-temperature alarm, and the SF6 fault high-value alarm can be executed. Based on this, the second tripping protection operation of the generator circuit breaker can be executed to protect the generator circuit breaker.

[0067] Among them, the second trip protection operation may include tripping the generator circuit breaker, i.e., the generator circuit breaker is tripped at this time to protect the generator circuit breaker.

[0068] In one embodiment of the present invention, the operating conditions of the generator circuit breaker can be monitored in real time. If the operation of the generator circuit breaker is abnormal and jeopardizes the safety of the device, the generator circuit breaker can be monitored and protected by issuing an alarm or tripping fault in a timely manner and sending a corresponding signal.

[0069] It should be noted that in one embodiment of the present invention, the invention consists of three variable states: the contact resistance of the generator circuit breaker, the temperature of the generator circuit breaker, and the SF6 gas, and represents an output action logic. Based on the alarm threshold or trip threshold, an alarm or trip can be triggered as required by a "two out of three variables" or "three out of three variables" approach, respectively, to achieve the protective function of the generator circuit breaker.

[0070] In one embodiment of the present invention, monitoring data of a generator circuit breaker of a large generator are obtained, wherein the monitoring data include the SF6 gas pressure and temperature of the generator circuit breaker; determining the overall specific heat capacity of the generator circuit breaker and knife switch according to the material and quality of the generator circuit breaker and knife switch; calculating, based on the overall specific heat capacity, the alarm threshold for the temperature rise rate of the generator circuit breaker and / or the tripping threshold for the temperature rise rate of the generator circuit breaker according to the temperature of the generator circuit breaker under the influence of the maximum load current; determining the alarm threshold for the maximum SF6 pressure and / or the tripping threshold for the maximum SF6 pressure according to the SF6 gas state parameter equation;Data analysis of the monitoring data and determination of the type of conditions based on the alarm and / or trip thresholds met by the monitoring data; determination of the alarm and / or trip protection operation based on the fulfilled condition type. Therefore, according to the generator circuit breaker monitoring data, it is possible to determine the condition type that meets the monitoring data based on the alarm threshold and / or trip threshold in order to execute the alarm or trip operation in a timely manner if the generator circuit breaker is operating abnormally, thus realizing the monitoring and protection of the generator circuit breaker.

[0071] Based on the above, the protection method and a device for generator circuit breakers of a large generator with contact resistance are explained by way of example.

[0072] Fig. Figure 2 is a schematic diagram of the alarm logic used for the generator circuit breaker of a contact-resistance large generator in the embodiment of the present disclosure, as shown in the figure: If the real-time contact resistance measurement is greater than or equal to 12 µΩ and the waveform contact resistance measurement is greater than or equal to 12 µΩ, the contact resistance fault alarm of the generator circuit breaker is executed for t0; if the SF6 pressure is greater than or equal to 0.95 MPa and the SF6 pressure change rate is greater than or equal to 0.84 kPa / s and the SF6 temperature rise rate is greater than or equal to 0.2288 k / s and lasts for t2, the SF6 fault alarm is executed;If the temperature of the generator circuit breaker is greater than or equal to 90 °C or the temperature of the knife switch is greater than or equal to 80 °C and the temperature rise rate of the generator circuit breaker is greater than or equal to 0.091 k / s and lasts for t4, the temperature fault alarm of the generator circuit breaker is executed;If the real-time contact resistance measurement is greater than or equal to 12 µΩ and the trend measurement of the contact resistance is greater than or equal to 12 µΩ and lasts for t1 and the SF6 pressure is greater than or equal to 0.95 MPa and the SF6 pressure change rate is greater than or equal to 0.84 kPa / s and the SF6 temperature rise rate is greater than or equal to 0.2288 k / s and lasts for t3 and the generator circuit breaker temperature is greater than or equal to 90 °C or the knife switch temperature is greater than or equal to 80 °C and the generator circuit breaker temperature rise rate is greater than or equal to 0.091 k / s and lasts for t5, then tripping of the generator circuit breaker is permitted.

[0073] Fig. Figure 3 is a schematic diagram of the tripping logic used for the generator circuit breaker of a contact-resistance large generator in the embodiment of the present disclosure, as shown in the figure: If the real-time contact resistance reading is greater than or equal to 18 µΩ and the waveform contact resistance reading is greater than or equal to 18 µΩ and lasts for t6, the high-value alarm of the generator circuit breaker's contact resistance is triggered; if the SF6 pressure is greater than or equal to 1.05 MPa and the SF6 pressure change rate is greater than or equal to 1.26 kPa / s and the SF6 temperature rise rate is greater than or equal to 0.3432 k / s and lasts for t8, then the SF6 fault high-value alarm is triggered;is the temperature of the generator circuit breaker greater than or equal to 95 °C or the temperature of the knife switch greater than or equal to 85 °C and the temperature rise rate of the generator circuit breaker greater than or equal to 0.136 k / s and lasts for t; 10 , then the generator circuit breaker temperature fault high-value alarm is triggered; if the real-time contact resistance reading is greater than or equal to 18 µΩ and the waveform contact resistance reading is greater than or equal to 18 µΩ and lasts for t7, and the SF6 pressure is greater than or equal to 1.05 MPa and the SF6 pressure change rate is greater than or equal to 1.26 kPa / s and the SF6 temperature rise rate is greater than or equal to 0.3432 k / s and lasts for t9, and the generator circuit breaker temperature is greater than or equal to 95 °C or the knife switch temperature is greater than or equal to 85 °C and the generator circuit breaker temperature rise rate is greater than or equal to 0.136 k / s and lasts for t11 , the generator circuit breaker will be tripped.

[0074] To realize the above embodiment, as shown in Fig. As shown in Figure 4, in this embodiment a protective device 10 for generator circuit breakers of a large generator with contact resistance is also provided, comprising a detection module 401, a first determination module 402, a calculation module 403, a second determination module 404, a third determination module 405 and an execution module 406; a 401 acquisition module for acquiring monitoring data of a generator circuit breaker from the large generator, wherein the monitoring data include SF6 gas pressure and temperature of the generator circuit breaker; a first determination module 402 for determining the overall specific heat capacity of the generator circuit breaker and knife switch according to the material and quality of the generator circuit breaker and knife switch; a calculation module 403 for calculating, based on the comprehensive specific heat capacity, the alarm threshold for the temperature rise rate of the generator circuit breaker and / or the tripping threshold for the temperature rise rate of the generator circuit breaker according to the temperature of the generator circuit breaker under the influence of the maximum load current; a second determination module 404 for determining the alarm threshold for the SF6 maximum pressure and / or the trigger threshold for the SF6 maximum pressure according to the SF6 gas pressure according to the SF6 gas state parameter equation; a third determination module 405 for data analysis of the monitoring data and determination of the type of conditions based on the alarm and / or trigger thresholds that are met by the monitoring data; an execution module 406 for determining the alarm and / or trigger protection process based on the fulfilled condition type;

[0075] Furthermore, the monitoring data includes contact resistance, current, knife switch temperature, and SF6 gas pressure.

[0076] Furthermore, the third determination module 405 described above is specifically intended for the following: Determining the temperature rise rate of the generator circuit breaker based on the temperature of the generator circuit breaker; Determining the SF6 gas temperature rise rate and the SF6 gas pressure change rate based on the SF6 gas temperature or the SF6 gas pressure; Determine, based on the alarm threshold, the alarm condition types that are met by the monitoring data; Determine, based on the trigger threshold, the type of trigger conditions that are met by the monitoring data.

[0077] Furthermore, the third determination module 405 described above is specifically intended for the following: If the monitoring value of the contact resistance is greater than or equal to the alarm threshold of the contact resistance, and the trend monitoring value of the contact resistance is greater than or equal to the alarm threshold of the contact resistance and persists for a certain period of time, then it is determined that the monitoring data meets the first alarm condition type; If the SF6 gas temperature rise rate is greater than or equal to an alarm threshold for SF6 gas temperature rise rates, and the SF6 gas pressure change rate is greater than or equal to an alarm threshold for gas pressure change rate, and the SF6 gas pressure is greater than or equal to the alarm threshold for maximum SF6 pressure for a second period of time, then it is determined that the monitoring data meet the second alarm condition type; If the temperature of the generator circuit breaker is greater than or equal to the alarm threshold temperature of the generator circuit breaker, or the knife switch temperature is greater than or equal to the alarm threshold of the knife switch temperature, and the temperature rise rate of the generator circuit breaker is greater than or equal to the alarm threshold of the temperature rise rate of the generator circuit breaker, and persists for a third period of time, then it is determined that the monitoring data meet the third alarm condition type; if the contact resistance monitoring value is greater than or equal to the contact resistance alarm threshold, and the contact resistance trend monitoring value is greater than or equal to the contact resistance alarm threshold and persists for a fourth time, and if the SF6 gas temperature rise rate is greater than or equal to the SF6 gas temperature rise rate alarm threshold, and the pressure change rate is greater than or equal to the SF6 pressure change rate alarm threshold, and the SF6 gas pressure is greater than or equal to the SF6 maximum pressure alarm threshold and persists for a fifth time, and if the generator circuit breaker temperature is greater than or equal to the generator circuit breaker temperature alarm threshold or the knife breaker temperature alarm threshold,and the temperature rise rate of the generator circuit breaker is greater than or equal to the alarm threshold of the temperature rise rate of the generator circuit breaker and persists for a sixth period of time, then it is determined that the monitoring data meet the fourth alarm condition type.

[0078] Furthermore, the third determination module 405 described above is specifically intended for the following: If the monitoring value of the contact resistance is greater than or equal to the trip threshold of the contact resistance, and the trend monitoring value of the contact resistance is greater than or equal to the trip threshold of the contact resistance and lasts for a seventh period, then it is determined that the monitoring data meet the first trip condition type; If the SF6 gas temperature rise rate is greater than or equal to an alarm threshold for SF6 gas temperature rise rates, and the SF6 gas pressure change rate is greater than or equal to a trigger threshold for gas pressure change rate, and the SF6 gas pressure is greater than or equal to the trigger threshold for maximum SF6 pressure for a second period of time, then it is determined that the monitoring data meet the second trigger condition type; If the temperature of the generator circuit breaker is greater than or equal to the temperature of the generator circuit breaker trip threshold, or the knife breaker temperature is greater than or equal to the trip threshold of the knife breaker temperature, and the temperature rise rate of the generator circuit breaker is greater than or equal to the trip threshold of the temperature rise rate of the generator circuit breaker, and persists for a ninth time, then it is determined that the monitoring data meet the third trip condition type; if the monitoring value of the contact resistance is greater than or equal to the trip threshold of the contact resistance, and the trend monitoring value of the contact resistance is greater than or equal to the trip threshold of the contact resistance and lasts for a tenth time, and the SF6 gas temperature rise rate is greater than or equal to the trip threshold of the SF6 gas temperature rise rate, and the SF6 gas pressure change rate is greater than or equal to the trip threshold of the pressure change rate, and the SF6 gas pressure is greater than or equal to the trip threshold of the SF6 maximum pressure and lasts for an eleventh time,and if the generator circuit breaker temperature is greater than or equal to the generator circuit breaker temperature trip threshold, or the knife breaker temperature is greater than or equal to the knife breaker temperature trip threshold and the generator circuit breaker temperature rise rate is greater than or equal to the generator circuit breaker temperature rise rate trip threshold and lasts for a twelfth time, then it is determined that the monitoring data meet the fourth trip condition type.

[0079] Furthermore, the alarm protection process includes a first alarm protection process and a second alarm protection process, and the trigger protection process includes a first trigger protection process and a second trigger protection process.

[0080] Furthermore, the execution module 406 described above is specifically intended for the following: If the fulfilled condition type is the first, second, or third alarm condition type, then it is determined that the first alarm protection operation of the generator circuit breaker is executed; If the fulfilled condition type is the fourth trip condition type, then it is determined that the first trip protection operation of the generator circuit breaker is carried out; If the fulfilled condition type is the first, second, or third tripping condition type, then it is determined that the second alarm protection operation of the generator circuit breaker is executed; If the fulfilled condition type is the fourth trip condition type, then it is determined that the second trip protection operation of the generator circuit breaker is carried out.

[0081] Furthermore, the device described above is specifically designed for the following: Monitoring the heat generation and heat dissipation of the generator circuit breaker in real time and determining the compensation value of the contact resistance when the heat generation and heat dissipation are in a dynamic equilibrium state and the current meets the compensation conditions; Based on the compensation value, the monitored contact resistance is compensated and the compensated contact resistance is determined.

[0082] To this end, the exemplary embodiment of the present invention proposes a protective device for the generator circuit breaker of the large, contact-resistance generator. Based on the monitoring data of the generator circuit breaker, the device can determine the condition type to which the monitoring data corresponds, based on the alarm thresholds and / or the tripping thresholds, so that in the event of a fault in the generator circuit breaker, the alarm or tripping process can be carried out in a timely manner, thereby realizing the monitoring and protection of the generator circuit breaker.

[0083] In the description of this specification, the terms “one embodiment”, “some embodiments”, “embodiments”, “examples”, “exemplary”, “specific examples”, or “some examples” refer to the specific features, structures, materials, or properties described in connection with the embodiment or examples and included in at least one embodiment or example of the disclosure. In this description, the schematic expressions of the above terms need not refer to the same embodiment or example. Furthermore, the described specific features, structures, materials, or properties may be combined appropriately in one or more embodiments or examples.Furthermore, the person skilled in the art can combine the various embodiments or examples described in this description and the features of the various embodiments or examples without contradicting each other.

[0084] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be interpreted as indicating or implying a relative meaning, or as an implicit indication of the number of technical features referred to. Thus, a feature designated as "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the invention, unless otherwise specified, "multiple" means at least two, e.g., two or three.

Claims

[1] The present invention discloses a protection method and a device for generator circuit breakers of a large generator with contact resistance, characterized by , that the procedure includes: Acquisition of monitoring data from a generator circuit breaker of the large generator, wherein the monitoring data includes SF6 gas pressure and temperature of the generator circuit breaker; Determining the total specific heat capacity of the generator circuit breaker and knife switch according to the material and quality of the generator circuit breaker and knife switch; Calculate based on the comprehensive specific heat capacity of the alarm threshold for the temperature rise rate of the generator circuit breaker and / or the tripping threshold for the temperature rise rate of the generator circuit breaker according to the temperature of the generator circuit breaker under the influence of the maximum load current; Determining the alarm threshold for the maximum SF6 pressure and / or the trigger threshold for the maximum SF6 pressure according to the SF6 gas pressure according to the SF6 gas state parameter equation; Data analysis of the monitoring data and determination of the condition types based on the alarm and / or trigger thresholds that are met by the monitoring data; Determining the alarm and / or trigger protection process based on the fulfilled condition type; where determining the overall specific heat capacity of the generator circuit breaker and knife switch according to the material and quality of the generator circuit breaker and knife switch comprises: The overall specific heat capacity of the generator circuit breaker and knife switch is determined by a first formula according to the material and quality of the generator circuit breaker and knife switch, wherein the first formula is: C=λ1C1+λ2C2+λ3C3+λ4C4+…+λnCn where C i the specific heat capacity of the i-th metal and λ i the mass ratio of the i-th metal; where the calculation based on the comprehensive specific heat capacity of the alarm threshold for the temperature rise rate of the generator circuit breaker and / or the tripping threshold for the temperature rise rate of the generator circuit breaker according to the temperature of the generator circuit breaker under the influence of the maximum load current comprises the following: Calculating based on the comprehensive specific heat capacity of the alarm threshold for the temperature rise rate of the generator circuit breaker and / or the tripping threshold for the temperature rise rate of the generator circuit breaker according to the temperature of the generator circuit breaker under the influence of the maximum load current using the second formula, wherein the second formula is: ΔTset=I2Rset / mC where I is the maximum load current, R set where m is the contact resistance, m is the total mass of the generator circuit breaker and the knife switch, and C is the overall specific heat capacity of the generator circuit breaker and the knife switch; the SF6 gas state parameter equation includes the following: P=[0.58×10−3pT(1+B(p)−ρA(ρ))]×9.8×10−3 A(ρ)=0.764×10 -3 (1-0.727×10 3 ρ), B(p)= 2.51×10 -3 ρ (1-0.846×10 -3 ρ), where p is the absolute pressure of SF6 gas, p is the density of SF6 gas and T is the thermodynamic temperature of SF6 gas. [2] A method according to claim 1, characterized by that the monitoring data also includes contact resistance, current, knife switch temperature, and SF6 gas temperature. [3] A method according to claim 2, characterized by, that data analysis of the monitoring data and determination of the condition types are performed based on the alarm and / or trigger thresholds that are met by the monitoring data and include the following: Determining the temperature rise rate of the generator circuit breaker based on the temperature of the generator circuit breaker; Determining the SF6 gas temperature rise rate and the SF6 gas pressure change rate based on the SF6 gas temperature or the SF6 gas pressure; Determine, based on the alarm threshold, the alarm condition types that are met by the monitoring data; Determine, based on the trigger threshold, the type of trigger conditions that are met by the monitoring data. [4] A method according to claim 3, characterized by, that data analysis of the monitoring data and determination of the condition types are performed based on the alarm thresholds that are met by the monitoring data and include the following: If the monitoring value of the contact resistance is greater than or equal to the alarm threshold of the contact resistance, and the trend monitoring value of the contact resistance is greater than or equal to the alarm threshold of the contact resistance and persists for a certain period of time, then it is determined that the monitoring data meets the first alarm condition type; If the SF6 gas temperature rise rate is greater than or equal to an alarm threshold for SF6 gas temperature rise rates, and the SF6 gas pressure change rate is greater than or equal to an alarm threshold for gas pressure change rate, and the SF6 gas pressure is greater than or equal to the alarm threshold for maximum SF6 pressure for a second period of time, then it is determined that the monitoring data meet the second alarm condition type; If the temperature of the generator circuit breaker is greater than or equal to the alarm threshold temperature of the generator circuit breaker, or the knife switch temperature is greater than or equal to the alarm threshold of the knife switch temperature, and the temperature rise rate of the generator circuit breaker is greater than or equal to the alarm threshold of the temperature rise rate of the generator circuit breaker, and persists for a third period of time, then it is determined that the monitoring data meet the third alarm condition type; if the contact resistance monitoring value is greater than or equal to the contact resistance alarm threshold, and the contact resistance trend monitoring value is greater than or equal to the contact resistance alarm threshold and persists for a fourth time, and if the SF6 gas temperature rise rate is greater than or equal to the SF6 gas temperature rise rate alarm threshold, and the pressure change rate is greater than or equal to the SF6 pressure change rate alarm threshold, and the SF6 gas pressure is greater than or equal to the SF6 maximum pressure alarm threshold and persists for a fifth time, and if the generator circuit breaker temperature is greater than or equal to the generator circuit breaker temperature alarm threshold or the knife breaker temperature alarm threshold,and the temperature rise rate of the generator circuit breaker is greater than or equal to the alarm threshold of the temperature rise rate of the generator circuit breaker and persists for a sixth period of time, then it is determined that the monitoring data meet the fourth alarm condition type. [5] A method according to claim 3, characterized by , that the determination of condition types is performed based on the trigger thresholds that are met by the monitoring data includes the following: If the monitoring value of the contact resistance is greater than or equal to the trip threshold of the contact resistance, and the trend monitoring value of the contact resistance is greater than or equal to the trip threshold of the contact resistance and lasts for a seventh period, then it is determined that the monitoring data meet the first trip condition type; If the SF6 gas temperature rise rate is greater than or equal to a trigger threshold for SF6 gas temperature rise rates, and the SF6 gas pressure change rate is greater than or equal to a trigger threshold for gas pressure change rate, and the SF6 gas pressure is greater than or equal to the trigger threshold for maximum SF6 pressure for an eighth period of time, then it is determined that the monitoring data meet the second trigger condition type; If the temperature of the generator circuit breaker is greater than or equal to the temperature of the generator circuit breaker trip threshold, or the knife breaker temperature is greater than or equal to the trip threshold of the knife breaker temperature, and the temperature rise rate of the generator circuit breaker is greater than or equal to the trip threshold of the temperature rise rate of the generator circuit breaker, and persists for a ninth time, then it is determined that the monitoring data meet the third trip condition type; if the monitoring value of the contact resistance is greater than or equal to the trip threshold of the contact resistance, and the trend monitoring value of the contact resistance is greater than or equal to the trip threshold of the contact resistance and lasts for a tenth time, and the SF6 gas temperature rise rate is greater than or equal to the trip threshold of the SF6 gas temperature rise rate, and the SF6 gas pressure change rate is greater than or equal to the trip threshold of the pressure change rate, and the SF6 gas pressure is greater than or equal to the trip threshold of the SF6 maximum pressure and lasts for an eleventh time,and if the generator circuit breaker temperature is greater than or equal to the generator circuit breaker temperature trip threshold, or the knife breaker temperature is greater than or equal to the knife breaker temperature trip threshold and the generator circuit breaker temperature rise rate is greater than or equal to the generator circuit breaker temperature rise rate trip threshold and lasts for a twelfth time, then it is determined that the monitoring data meet the fourth trip condition type. [6] A method according to claim 1, characterized by, that the alarm protection process comprises a first alarm protection process and a second alarm protection process, and the trip protection process comprises a first trip protection process and a second trip protection process; wherein the method determines, based on the fulfilled condition type, to execute the alarm protection process and / or the trip protection process of the generator circuit breaker, including: If the fulfilled condition type is the first, second, or third alarm condition type, then it is determined that the first alarm protection operation of the generator circuit breaker is executed; If the fulfilled condition type is the fourth trip condition type, then it is determined that the first trip protection operation of the generator circuit breaker is carried out; If the fulfilled condition type is the first, second, or third tripping condition type, then it is determined that the second alarm protection operation of the generator circuit breaker is executed; If the fulfilled condition type is the fourth trip condition type, then it is determined that the second trip protection operation of the generator circuit breaker is carried out. [7] A method according to claim 2, wherein the method further comprises: Monitoring the heat generation and heat dissipation of the generator circuit breaker in real time and determining the compensation value of the contact resistance when the heat generation and heat dissipation are in a dynamic equilibrium state and the current meets the compensation conditions; Compensation of the monitored contact resistance based on the compensation value and determination of the contact resistance as the compensated contact resistance. [8] A protective device for generator circuit breakers of a large generator with contact resistance, characterized by , that the device comprises the following: a data acquisition module for acquiring monitoring data of a generator circuit breaker from the large generator, wherein the monitoring data includes SF6 gas pressure and temperature of the generator circuit breaker; a first determination module for determining the overall specific heat capacity of the generator circuit breaker and knife switch according to the material and quality of the generator circuit breaker and knife switch; a calculation module for calculating, based on the comprehensive specific heat capacity, the alarm threshold for the temperature rise rate of the generator circuit breaker and / or the tripping threshold for the temperature rise rate of the generator circuit breaker according to the temperature of the generator circuit breaker under the influence of the maximum load current; a second determination module for determining the alarm threshold for the SF6 maximum pressure and / or the trigger threshold for the SF6 maximum pressure according to the SF6 gas pressure according to the SF6 gas state parameter equation; a third determination module for data analysis of the monitoring data and determination of the type of conditions based on the alarm and / or trigger thresholds that are met by the monitoring data; an execution module for determining the alarm and / or trigger protection process based on the fulfilled condition type; wherein the first determination module for determining the overall specific heat capacity of the generator circuit breaker and knife switch according to the material and quality of the generator circuit breaker and knife switch; C=λ1C1+λ2C2+λ3C3+λ4C4+…+λnCn where C i the specific heat capacity of the i-th metal and λ ithe mass ratio of the i-th metal; wherein the calculation module is particularly suitable for calculating, based on the comprehensive specific heat capacity, the alarm threshold for the temperature rise rate of the generator circuit breaker and / or the tripping threshold for the temperature rise rate of the generator circuit breaker according to the temperature of the generator circuit breaker under the influence of the maximum load current, using the second formula, wherein the second formula is: ΔTset=I2Rset / mC where I is the maximum load current, R set where m is the contact resistance, m is the total mass of the generator circuit breaker and the knife switch, and C is the overall specific heat capacity of the generator circuit breaker and the knife switch; the SF6 gas state parameter equation includes the following: P=[0.58×10−3pT(1+B(p)−ρA(ρ))]×9.8×10−3 A(ρ)=0.764×10 3 (1-0.727×103 ρ), B(p)= 2.51×10 -3 ρ (1-0.846×10 3 ρ), where p is the absolute pressure of SF6 gas, p is the density of SF6 gas and T is the thermodynamic temperature of SF6 gas. [9] An electronic device comprising the following: at least one processor; and a memory that is communicatively connected to at least one processor; wherein The memory stores instructions that can be executed by the at least one processor, such that the instructions are executed by the at least one processor in order to enable the at least one processor to perform the method according to any one of claims 1-7. [10] A computer storage medium, wherein the computer storage medium stores computer-executable instructions; after the computer-executable instructions have been executed by a processor, the method according to any one of claims 1-7 can be implemented.

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