Grounding resistor whole-process state analysis method and system

Abstract

The application discloses a kind of whole process state analysis methods of grounding resistor, comprising the following steps: S1.grounding resistor state acquisition device collects the real-time running condition data of grounding resistor, and the real-time running condition data is transmitted to embedded processor;S2.embedded processor stores and processes the real-time running condition data of grounding resistor, and the real-time running condition data of grounding resistor is uploaded to station end server;S3.cloud server carries out offline analysis and test to the state of grounding resistor, obtains the state transition data of grounding resistor, and updates offline database;S4.according to the real-time running condition data of grounding resistor and state transition data, the state of grounding resistor is analyzed in real time by station end server, and real-time database is updated.Temperature evaluation is used for early warning of abnormal state, resistance value evaluation is used to determine whether the current state of resistor is stable, energy loss is used to determine the service life of resistor, to improve the safe and stable operation of distribution network.

Description

Technical Field

[0001] This invention belongs to the field of new power technology, specifically, it relates to a method and system for analyzing the entire state of grounding resistors in a power distribution network. Background Technology

[0002] Currently, domestic and international manufacturers have made significant improvements to the thermal stability of grounding resistors in terms of materials, structure, and working environment. They monitor parameters such as grounding resistor temperature and zero-sequence current to provide early warnings for extreme operating conditions. While considering extreme operating conditions with grounding resistor temperature and zero-sequence current limits has yielded good results, the current dynamic operating modes make it increasingly difficult to reflect the actual operating status of the grounding resistor, potentially leading to over- or under-warnings. This is especially true during intermittent non-metallic high-resistance grounding faults, where the resistor's operating condition changes from a short-term, intense surge to a long-term, repeated, and gradual implicit process. The resistor itself is under high consumption, and its availability gradually decreases over time, losing its flexibility. Resistor burnout accidents occur frequently, posing a serious threat to the safe and stable operation of low-resistance grounding distribution networks. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies by proposing a method for analyzing the entire state of grounding resistors, which facilitates maintenance of grounding resistors by production and operation units and improves the safety and stability of power distribution networks.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A method for full-process state analysis of a grounding resistor includes the following steps:

[0006] S1. The grounding resistor status acquisition device collects real-time operating condition data of the grounding resistor and transmits the real-time operating condition data to the embedded processor.

[0007] S2. The embedded processor stores and processes the real-time operating condition data of the grounding resistor, and uploads the real-time operating condition data of the grounding resistor to the station server;

[0008] S3. The cloud server performs offline analysis and testing on the state of the grounding resistor, obtains the state transition data of the grounding resistor, and updates the offline database;

[0009] S4. The station server analyzes the status of the grounding resistor in real time based on the real-time operating condition data and status transition data of the grounding resistor, and updates the real-time database.

[0010] Furthermore, offline testing is the foundation for real-time equipment status analysis. The test environment is constructed by connecting an external DC power supply. Offline testing is divided into two stages. The first stage is a destructive stress test conducted during the factory acceptance of the equipment resistor cabinet to test the equipment's lifespan, reliability parameters, and state transition probability. The second stage is a re-inspection test conducted during the equipment maintenance stage to confirm the current status of the equipment under rated operating conditions.

[0011] Furthermore, when offline testing is simulated using DC, the influence of the aperiodic component of the short-circuit current is considered. Two methods are used for AC-DC conversion: 1) Short-term high-amplitude pulse current impact test, which tests the impact of the peak short-circuit current on the grounding resistor, causing the local condition to deteriorate due to structural and material problems; 2) Equivalent conversion using the effective value of the current, using DC current to represent the zero-sequence current.

[0012] Furthermore, the test indicators for offline testing of grounding resistor status include steady-state resistance value, resistance change rate, temperature, temperature rise rate, and cumulative energy loss distribution. By statistically analyzing the energy loss value and the corresponding grounding resistor status, a grounding resistor energy loss state transition matrix can be constructed.

[0013] Furthermore, the real-time analysis of the grounding resistor status can be divided into three categories according to the time scale, from smallest to largest: status evaluation criteria based on resistor value, status evaluation criteria based on temperature value, and status evaluation criteria based on energy loss value.

[0014] Furthermore, the state evaluation criteria based on the resistor value are as follows:

[0015] Under the action of zero-sequence current, the grounding resistance state evaluation model based on resistance state variables is as follows:

[0016] Z p =F(R) w k r )

[0017] k r =dR w /

[0018] In the formula, Z p Grounding resistor condition evaluation model; R w k is the real-time resistance value of the resistor. r This represents the rate of change of the grounding resistance value.

[0019] The condition evaluation of the grounding resistor value is divided into the following three levels:

[0020] Level I is defined as: the real-time resistance value R of the resistor. w ≤ Warning resistance value R yj This is considered a normal state.

[0021] Class II is defined as: the real-time resistance value R of the resistor. w ≥ Warning resistance value R yj (1x1%), and the resistance change rate k r ≥Note the rate of change of resistance kr zy If the system determines that the status is under alert, it will send an "Attention" message to prompt maintenance personnel to conduct key inspections. The percentage of cases under this status will be determined by testing.

[0022] Class III is defined as: the real-time resistance value R of the resistor. w ≥ Warning resistance value R yj (1x2%), or the rate of change of resistance k r ≥ Rate of change of warning resistance kr yj If the system determines that the condition is abnormal, it will issue an "early warning" message. Maintenance personnel should immediately inspect the grounding resistor. The percentage of x2% is determined by testing.

[0023] Furthermore, the state evaluation criteria based on temperature values ​​are as follows:

[0024] Temperature rise in grounding resistors is the direct cause of damage or even loss of thermal stability, leading to burnout. The operating status of a grounding resistor can be indirectly evaluated based on its temperature rise and duration. The relationship between temperature rise, zero-sequence current, and duration is as follows:

[0025] T W =f(i0,t) cx )

[0026] In the formula, T W The temperature rise of the grounding resistor is the difference between the temperature during the duration of the zero-sequence current and the rated temperature, where the rated temperature is the same as the local temperature; i0 is the zero-sequence current acting on the grounding resistor; t cx The duration of the zero-sequence current;

[0027] The condition evaluation of the temperature value of the grounding resistor is divided into the following two levels:

[0028] Class I is defined as: temperature rise T of the grounding resistor. W ≤ Safety temperature rise limit of grounding resistor T aq This is considered a normal state.

[0029] Class II is defined as: the temperature rise T of the grounding resistor. W Greater than the safe temperature rise limit T of the grounding resistor aq And the rate of change of temperature dT w / dt≥the rate of change of the warning temperature rise kt yj If the condition is abnormal, the system will issue an early warning, and maintenance personnel should immediately inspect the grounding resistor.

[0030] Furthermore, the state evaluation criteria based on energy loss values ​​are as follows:

[0031] The energy loss of the grounding resistance during the j-th intermittent grounding fault is:

[0032]

[0033] In the formula, u 0i i is the instantaneous value of the zero-sequence voltage generated by the zero-sequence current flowing through the grounding resistor; 0i The effective value of the zero-sequence current flowing through the grounding resistor; Δt i For zero-sequence current i 0i Duration; m is the number of intermittent zero-sequence currents within a single ground fault;

[0034] The total energy consumption E of the grounding resistor under N grounding fault conditions is:

[0035]

[0036] Considering the cumulative effect of energy loss, and combining it with the resistor state probability transition matrix from offline testing, further analysis yields the following:

[0037] S n =S0P n

[0038]

[0039] S p =max(S) n )

[0040] n = E / P i

[0041] In the formula, n is the number of resistor state transitions, and S n Let S0 be the state probability matrix, and P be the initial state matrix of the resistor. n Let S be the resistor state probability matrix after the state transition, where P(i,j) is the transition probability of the resistor from state i to state j, and S is the resistor state probability matrix after the state transition. p P is the probability of the final predicted state. i This represents the average energy loss during the state transition of the resistor.

[0042] A grounding resistor full-process state analysis system, employing any of the above-mentioned grounding resistor full-process state analysis methods, includes: a resistor cabinet, a grounding resistor state acquisition device, an embedded processor, a data storage and signal processing device, a station server, and a cloud server. The resistor cabinet is equipped with a grounding resistor. The grounding resistor state acquisition device is used to acquire real-time operating condition data of the grounding resistor. The grounding resistor state acquisition device and the data storage and signal processing device are respectively connected to the embedded processor, and the cloud server is connected to the station server.

[0043] The embedded processor is used to receive, store, and process the real-time operating condition data of the grounding resistor, and upload the real-time operating condition data of the grounding resistor to the station server.

[0044] The cloud server is used to perform offline analysis and testing of the grounding resistor status, obtain the state transition data of the grounding resistor, and update the offline database;

[0045] The station-side server is used to analyze the status of the grounding resistor in real time based on the real-time operating condition data and status transition data of the grounding resistor, and update the real-time database.

[0046] Furthermore, the grounding resistor status acquisition device includes a zero-sequence current sensor, a zero-sequence voltage sensor, a temperature rise sensor, a temperature and humidity sensor, an auxiliary sensor, and an alarm circuit. The data storage and signal processing device includes a display unit, a keyboard unit, a clock circuit, a wireless sensing unit, a data storage unit, and a signal processing unit. The zero-sequence current sensor, zero-sequence voltage sensor, temperature rise sensor, temperature and humidity sensor, auxiliary sensor, alarm circuit, display unit, keyboard unit, clock circuit, wireless sensing unit, data storage unit, and signal processing unit are respectively connected to the embedded processor.

[0047] Compared with existing technologies, the grounding resistor full-process state analysis method of this invention, in practical applications, focuses on early warning of abnormal states of grounding resistors based on temperature state quantities. Temperature exceeding the limit will accelerate resistor wear, and the temperature rise rate can reflect the severity of the fault, making it easy to attract the attention of the operation and maintenance party in a timely manner. The evaluation criteria based on resistance state quantities can be used to directly determine whether the current state of the resistor is stable or whether a sudden change has occurred that leads to damage. The energy loss criterion uses the concept of energy to quantify the life of the resistor. Through the cumulative change of energy loss, the remaining life and failure probability of the equipment can be probabilistically assessed. The combined use of several evaluation methods can ensure that the resistor is well maintained at different time scales and improve the safety and stability of the power distribution network. Attached Figure Description

[0048] Figure 1 This is a flowchart illustrating the method for analyzing the entire state of a grounding resistor.

[0049] Figure 2 a) is a schematic diagram of offline detection of grounding resistor value, and b) is a schematic diagram of grounding resistor temperature monitoring.

[0050] Figure 3 This is a state transition diagram for resistor energy loss.

[0051] Figure 4 This is a schematic diagram for resistor condition evaluation and early warning.

[0052] Figure 5 This is a diagram of the grounding resistor condition monitoring architecture. Detailed Implementation

[0053] The following description, in conjunction with the accompanying drawings and specific embodiments, further illustrates the method and system for analyzing the entire state of the grounding resistor according to the present invention.

[0054] Please see Figure 1 This invention discloses a method for analyzing the entire state of a grounding resistor, comprising the following steps:

[0055] S1. The grounding resistor status acquisition device collects real-time operating condition data of the grounding resistor and transmits the real-time operating condition data to the embedded processor.

[0056] S2. The embedded processor stores and processes the real-time operating condition data of the grounding resistor and uploads the real-time operating condition data of the grounding resistor to the station server.

[0057] S3. The cloud server performs offline analysis and testing on the state of the grounding resistor, obtains the state transition data of the grounding resistor, and updates the offline database.

[0058] S4. The station server analyzes the status of the grounding resistor in real time based on the real-time operating condition data and status transition data of the grounding resistor, and updates the real-time database.

[0059] In this embodiment, the sensor data is conditioned and stored in an embedded processor to form a grounding resistor dataset identified by site, time, and different electrical types. The dataset supports multiple communication methods, including wired and wireless, facilitating subsequent data analysis and online monitoring. The state analysis of the grounding resistor can be divided into two dimensions: offline analysis and real-time analysis.

[0060] Offline analysis and testing of grounding resistor status

[0061] Offline testing is fundamental to real-time equipment status analysis. An external DC power supply can be used to create a test environment to test the thermal stability characteristics of specific types of resistors. Offline testing consists of two phases. The first phase is conducted during the factory acceptance testing of the resistor cabinet. This phase primarily involves destructive stress testing to assess equipment lifespan, reliability parameters, and state transition probability. This phase requires high-current flow testing using specialized instruments. The second phase is a follow-up inspection during equipment maintenance. This follow-up test confirms the current state of the equipment under rated operating conditions. Since short-circuit faults are relatively low-probability events, performing a follow-up inspection of resistors under rated operating conditions is a safer maintenance method.

[0062] The specific principles of offline analysis are as follows: Figure 2 As shown, a commercially available single-phase current booster or a secondary tester with voltage regulation can be used as the DC power supply. Complex operating conditions can be simulated by adjusting the resistor current and the voltage across it. During offline testing, the isolating switch QS should be opened to separate the resistor from grounding transformers and other electrical equipment, and a spare resistor should be connected. If the operating mode allows, a power outage for maintenance can also be performed. After QS is disconnected, the DC power supply should be reconnected for offline analysis.

[0063] Offline testing methods need to consider the impact of AC / DC conversion, since normal operation is under AC conditions. When simulating with DC, the influence of the aperiodic component of the short-circuit current should be considered. Two methods can be used for conversion: 1) Short-term high-amplitude pulse current impact test. This tests the impact of the short-circuit current peak on the resistor, causing localized deterioration due to structural and material issues; 2) Equivalent conversion using the effective value of the current, representing the zero-sequence current with DC current.

[0064] The offline test indicators are shown in Table 1, which mainly reflect the indicator values ​​of resistors with different materials and structures under four states: normal, moderate, severe, and fault. Considering the differences in resistor materials, the mild and moderate states of some resistors can be combined.

[0065] Table 1 Offline Test Metrics

[0066]

[0067] By statistically analyzing the energy loss values ​​and their corresponding resistor states, a resistor energy loss state transition matrix P can be constructed. Detailed state transitions are as follows: Figure 3 As shown. S represents the operating state, with values ​​of 0 indicating normal operation, 1 indicating slight loss, 2 indicating moderate loss, and 3 indicating a fault state. λ0, λ1, λ2, and λ3 represent the probabilities of the resistor maintaining the corresponding numerical state. m,m+1Let be the probability that the resistor deteriorates from state m to state m+1. Assuming the energy of a momentary single-phase-to-ground short circuit is used as the quantification unit, offline analysis can measure the statistical data of state transitions after multiple short-circuit impacts on the resistor. This includes the probability of the resistor transitioning from a normal state to various abnormal and fault states, as well as the cumulative energy loss. Dividing the cumulative energy loss from a normal state to a fault state by the total number of short-circuit impact tests yields the average energy loss P of the resistor during state transitions. i This allows for real-time analysis and prediction of the resistor's state using average energy loss.

[0068] Real-time analysis of grounding resistor status

[0069] Please see Figure 1 and Figure 4 Real-time analysis of grounding resistors is categorized by time scale from smallest to largest, and evaluation criteria can be divided into three categories: resistance, temperature, and energy loss. Resistance is the smallest time-scale criterion, directly reflecting the resistor's current physical state. When the resistor transitions from a normal to a faulty state, its resistance typically exhibits a significant jump. Resistance value ranges effectively distinguish the health status of the grounding resistor. Temperature, on the other hand, requires a certain amount of time to stabilize; the operating condition of the resistor can be comprehensively judged by combining static temperature and temperature rise rate. Temperature can serve as an auxiliary criterion for alarms and subsequent protective measures. Energy loss is the largest time-scale criterion, reflecting the thermal stability loss of the grounding resistor under different operating conditions through long-term cumulative analysis. Energy loss requires offline analysis models for equipment status evaluation. The three online analysis indicators are as follows:

[0070] The state evaluation criteria based on resistor values ​​are as follows:

[0071] Under the action of zero-sequence current, the grounding resistance state evaluation model based on resistance state variables can be described as follows:

[0072] Z p =F(R) w k r (1)

[0073] k r =dR w / dt (2)

[0074] In the formula, Z p Grounding resistor condition evaluation model; R w k is the real-time resistance value of the resistor. r Rate of change of grounding resistance.

[0075] The condition evaluation of the grounding resistor value is divided into the following three levels:

[0076] Level I is defined as: the real-time resistance value R of the resistor. w ≤ Warning resistance value R yj This is considered a normal state.

[0077] Class II is defined as: the real-time resistance value R of the resistor. w ≥ Warning resistance value R yj (1+x1%), and the rate of change of resistance k r ≥Note the rate of change of resistance kr zy If the system determines that the status is under alert, it will send an "Attention" message to prompt maintenance personnel to conduct key inspections. The percentage of cases under this status will be determined by testing.

[0078] Class III is defined as: the real-time resistance value R of the resistor. w ≥ Warning resistance value R yj (1+x2%), or the rate of change of resistance k r ≥ Rate of change of warning resistance kr yj If the system determines that the condition is abnormal, it will issue an "early warning" message. Maintenance personnel should immediately inspect the grounding resistor. The percentage of x2% is determined by testing.

[0079] The grounding resistance status evaluation criterion based on temperature value is as follows:

[0080] Temperature rise in a grounding resistor is a direct cause of damage to or even loss of its thermal stability, leading to burnout. Therefore, the operating condition of a grounding resistor can be indirectly evaluated based on its temperature rise and duration. The relationship between grounding resistor temperature rise and zero-sequence current and duration can be described as follows:

[0081] T W =f(i0,t) cx (3)

[0082] In the formula, T W The temperature rise of the grounding resistor is the difference between the temperature during the duration of the zero-sequence current and the rated temperature, where the rated temperature is the same as the local temperature; i0 is the zero-sequence current acting on the grounding resistor; t cx The duration of the zero-sequence current. The grounding resistance state evaluation model based on temperature rise state variables can be described by the rate of change of temperature rise over time.

[0083] Z p =dT w / dt (4)

[0084] The condition evaluation of the temperature value of the grounding resistor is divided into the following two levels:

[0085] Class I is defined as: temperature rise T of the grounding resistor. w ≤ Safety temperature rise limit of grounding resistor T aq This is considered a normal state.

[0086] Class II is defined as: the temperature rise T of the grounding resistor. w Greater than the safe temperature rise limit T of the grounding resistor aq And the rate of change of temperature dT w / dt≥the rate of change of the warning temperature rise kt yj If the condition is abnormal, the system will issue an early warning, and maintenance personnel should immediately inspect the grounding resistor.

[0087] The condition evaluation criterion for grounding resistors based on energy loss is as follows:

[0088] The energy loss criterion primarily uses the cumulative zero-sequence energy passing through the resistor over a long period. It objectively reflects the fault impact experienced by the resistor, and using energy as a criterion can further predict the equipment reliability of the resistor. Compared to temperature and resistance criteria, energy loss is more suitable for reflecting the equipment state of the resistor after experiencing multiple fault currents. Assume the energy loss of the grounding resistor during the j-th intermittent grounding fault is:

[0089]

[0090] In the formula, u 0i i is the instantaneous value of the zero-sequence voltage generated by the zero-sequence current flowing through the grounding resistor; 0i The effective value of the zero-sequence current flowing through the grounding resistance (greater than the critical zero-sequence current); Δt i For zero-sequence current i 0i Duration; m is the number of intermittent zero-sequence currents within a single ground fault.

[0091] The total energy consumption E of the grounding resistor under N grounding fault conditions is:

[0092]

[0093] Since the cumulative effect of energy loss may lead to the failure of the grounding resistor after N grounding faults, the state evaluation model of the grounding resistor considering the cumulative effect of energy loss can be further analyzed by combining the resistor state probability transition matrix obtained from offline testing, resulting in:

[0094] S n =S0P n (7)

[0095]

[0096] S p =max(S) n (9)

[0097] n = E / P i (10) Where n is the number of resistor state transitions, Sn Let S0 be the state probability matrix, and S0 be the resistor initial state matrix, which is a four-state row vector. n Let S be the resistor state probability matrix after the state transition, where P(i,j) is the transition probability of the resistor changing from state i to state j. The resistor state can be verified by an external DC power supply during operation and maintenance. p P represents the probability of the final predicted state, which is the maximum value of the state probability matrix, and the corresponding state is the predicted state of the current resistor. i The average energy loss during the state transition of the resistor is obtained from offline analysis.

[0098] Please see Figure 5 This invention also discloses a system for analyzing the full-process status of a grounding resistor, employing any of the aforementioned methods for analyzing the full-process status of a grounding resistor. The system includes: a resistor cabinet, a grounding resistor status acquisition device, an embedded processor, a data storage and signal processing device, a station server, and a cloud server. The resistor cabinet houses a grounding resistor. The grounding resistor status acquisition device is used to acquire real-time operating condition data of the grounding resistor. The grounding resistor status acquisition device and the data storage and signal processing device are respectively connected to the embedded processor. The cloud server is connected to the station server. The embedded processor receives, stores, and processes the real-time operating condition data of the grounding resistor and uploads the data to the station server. The cloud server performs offline analysis and testing of the grounding resistor status, obtains state transition data of the grounding resistor, and updates the offline database. The station server performs real-time analysis of the grounding resistor status based on the real-time operating condition data and state transition data of the grounding resistor and updates the real-time database.

[0099] The grounding resistor status acquisition device includes a zero-sequence current sensor, a zero-sequence voltage sensor, a temperature rise sensor, a temperature and humidity sensor, an auxiliary sensor, and an alarm circuit. The data storage and signal processing device includes a display unit, a keyboard unit, a clock circuit, a wireless sensing unit, a data storage unit, and a signal processing unit. The zero-sequence current sensor, zero-sequence voltage sensor, temperature rise sensor, temperature and humidity sensor, auxiliary sensor, alarm circuit, display unit, keyboard unit, clock circuit, wireless sensing unit, data storage unit, and signal processing unit are all connected to the embedded processor.

[0100] In this embodiment, a zero-sequence current sensor, a zero-sequence voltage sensor, a temperature rise sensor, a temperature and humidity sensor, and auxiliary sensors are added to the traditional resistor cabinet, and these sensors are connected to an embedded processor along with an alarm circuit. The embedded processor is mainly responsible for data acquisition and storage, signal processing, and local operation. Data is then wirelessly transmitted to the station server for data processing and real-time analysis.

[0101] The station-side server connects to the cloud server periodically to update the device's basic data, including the device's state transition matrix, reliability parameters, and failure probability distribution. Based on the basic data and real-time collected data, resistor status evaluation calculations are performed. Alarm logic is then applied based on the indicator results to issue warnings regarding the current resistor status and failure probability.

[0102] In summary, the grounding resistor full-process state analysis method of this invention, in practical applications, focuses on early warning of abnormal states of grounding resistors based on temperature state quantities. Temperature exceeding the limit will accelerate resistor wear, and the temperature rise rate can reflect the severity of the fault, making it easy to attract the attention of the operation and maintenance party in a timely manner. The evaluation criteria based on resistance state quantities can be used to directly determine whether the current state of the resistor is stable or whether a sudden change has occurred leading to damage. The energy loss criterion uses the concept of energy to quantify the life of the resistor. Through the cumulative change of energy loss, the remaining life and failure probability of the equipment can be probabilistically assessed. The combined use of several evaluation methods can ensure that the resistor is well maintained at different time scales, thereby improving the safety and stability of the power distribution network.

[0103] The above description is a detailed description of the preferred embodiments of the present invention. However, the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modifications made under the technical spirit disclosed in the present invention should fall within the patent scope covered by the present invention.

Claims

1. A method for analyzing the entire state of a grounding resistor, characterized in that, Includes the following steps: S1. The grounding resistor status acquisition device collects real-time operating condition data of the grounding resistor and transmits the real-time operating condition data to the embedded processor. S2. The embedded processor stores and processes the real-time operating condition data of the grounding resistor, and uploads the real-time operating condition data of the grounding resistor to the station server; S3. The cloud server performs offline analysis and testing on the state of the grounding resistor, obtains the state transition data of the grounding resistor, and updates the offline database; S4. The station server analyzes the status of the grounding resistor in real time based on the real-time operating condition data and status transition data of the grounding resistor, and updates the real-time database accordingly. The real-time analysis of the grounding resistor status is divided into three categories according to the time scale, from smallest to largest: status evaluation criteria based on resistor value, status evaluation criteria based on temperature value, and status evaluation criteria based on energy loss value. The state evaluation criteria based on resistor values ​​are as follows: Under the action of zero-sequence current, the state evaluation model of the grounding resistor based on the resistance state quantity is as follows: ； ； In the formula, For the condition evaluation model of grounding resistors; This is the real-time resistance value of the resistor; This represents the rate of change of the grounding resistor value. The condition evaluation of the grounding resistor value is divided into the following three levels: Level I is defined as: the real-time resistance value of the resistor. ≤Warning resistance value This is considered a normal state. Class II is defined as: the real-time resistance value of the resistor. ≥ Warning resistance value and the rate of change of resistance ≥Note the rate of change of resistance If the system detects a "pay attention" status, it sends a "pay attention" message to alert maintenance personnel to conduct focused inspections. Determined by experiment; Class III is defined as: the real-time resistance value of the resistor. ≥ Warning resistance value or resistance change rate ≥ Rate of change of warning resistance If the system detects an abnormal state, it will issue a "warning" message. Maintenance personnel should immediately inspect the grounding resistor. Determined by experiment; The condition assessment criteria based on temperature values ​​are as follows: Temperature rise in grounding resistors is the direct cause of damage or even loss of thermal stability, leading to burnout. The operating status of grounding resistors can be indirectly evaluated based on their temperature rise and duration. The relationship between temperature rise, zero-sequence current, and duration is as follows: ； In the formula, The temperature rise of the grounding resistor is the difference between the temperature during the duration of the zero-sequence current and the rated temperature, which is consistent with the local temperature. This refers to the zero-sequence current acting on the grounding resistor. The duration of the zero-sequence current; The condition evaluation of the temperature value of the grounding resistor is divided into the following two levels: Class I is defined as: temperature rise of the grounding resistor. ≤Safe temperature rise limit of grounding resistor This is considered a normal state. Class II is defined as: temperature rise of the grounding resistor. Greater than the safe temperature rise limit of the grounding resistor And the rate of change of temperature rise ≥ Warning temperature change rate If the condition is abnormal, the system will issue an early warning, and maintenance personnel should immediately inspect the grounding resistor. The state evaluation criteria based on energy loss values ​​are as follows: No. The energy loss of the grounding resistor during intermittent grounding faults is: ； In the formula, The instantaneous value of the zero-sequence voltage generated by the zero-sequence current flowing through the grounding resistor; This is the effective value of the zero-sequence current flowing through the grounding resistor; Zero-sequence current Duration; The number of intermittent zero-sequence currents within a single ground fault; Total energy consumption of grounding resistor under secondary grounding fault conditions for: ； Considering the cumulative effect of energy loss, and combining it with the resistor state probability transition matrix from offline testing, further analysis yields the following: ； ； ； ； In the formula, n represents the number of resistor state transitions. The state probability matrix, Here is the initial state matrix of the resistor. This is the resistor state probability matrix after the state transition. Let be the transition probability of the resistor from state i to state j. The probability of the final predicted state. This represents the average energy loss during the state transition of the resistor.

2. The method for analyzing the entire state of a grounding resistor according to claim 1, characterized in that, Offline testing is the foundation for real-time equipment status analysis. The test environment is constructed by connecting an external DC power supply. Offline testing is divided into two stages. The first stage is to conduct destructive stress testing during the factory acceptance of the equipment resistor cabinet to test the equipment life, reliability parameters, and state transition probability. The second stage is the re-inspection and testing during the equipment maintenance phase. The re-inspection and testing is to confirm the current status of the equipment under rated operating conditions.

3. The method for analyzing the entire state of a grounding resistor according to claim 2, characterized in that, When offline testing is simulated using DC, the influence of the non-periodic component of the short-circuit current is considered. Two methods are used for AC-DC conversion: 1) Short-term high-amplitude pulse current impact test, which tests the impact of the peak short-circuit current on the grounding resistor, causing local deterioration of its condition due to structural and material problems; 2) Equivalent conversion using the effective value of the current, using DC current to represent the zero-sequence current.

4. The method for analyzing the entire state of a grounding resistor according to claim 2, characterized in that, The test indicators for offline testing of grounding resistor status include steady-state resistance value, resistance change rate, temperature, temperature rise rate, and cumulative energy loss distribution. By statistically analyzing the energy loss value and the corresponding grounding resistor status, an energy loss state transition matrix for the grounding resistor is constructed.

5. A system for analyzing the entire state of a grounding resistor, employing the method for analyzing the entire state of a grounding resistor as described in any one of claims 1 to 4, characterized in that, include: The system includes a resistor cabinet, a grounding resistor status acquisition device, an embedded processor, a data storage and signal processing device, a station server, and a cloud server. The resistor cabinet is equipped with a grounding resistor. The grounding resistor status acquisition device is used to collect real-time operating condition data of the grounding resistor. The grounding resistor status acquisition device and the data storage and signal processing device are respectively connected to the embedded processor, and the cloud server is connected to the station server. The embedded processor is used to receive, store, and process the real-time operating condition data of the grounding resistor, and upload the real-time operating condition data of the grounding resistor to the station server. The cloud server is used to perform offline analysis and testing of the grounding resistor status, obtain the state transition data of the grounding resistor, and update the offline database; The station-side server is used to analyze the status of the grounding resistor in real time based on the real-time operating condition data and status transition data of the grounding resistor, and update the real-time database.

6. The grounding resistor full-process state analysis system according to claim 5, characterized in that, The grounding resistor status acquisition device includes a zero-sequence current sensor, a zero-sequence voltage sensor, a temperature rise sensor, a temperature and humidity sensor, an auxiliary sensor, and an alarm circuit. The data storage and signal processing device includes a display unit, a keyboard unit, a clock circuit, a wireless sensing unit, a data storage unit, and a signal processing unit. The zero-sequence current sensor, zero-sequence voltage sensor, temperature rise sensor, temperature and humidity sensor, auxiliary sensor, alarm circuit, display unit, keyboard unit, clock circuit, wireless sensing unit, data storage unit, and signal processing unit are all connected to the embedded processor.

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