CN-116295597-B - Whole-process state analysis method and system for grounding resistor

CN116295597BCN 116295597 BCN116295597 BCN 116295597BCN-116295597-B

Abstract

The invention discloses a whole-process state analysis method of a grounding resistor, which comprises the following steps that S1, a grounding resistor state acquisition device acquires real-time operation working condition data of the grounding resistor and transmits the real-time operation working condition data to an embedded processor, S2, the embedded processor stores and processes the real-time operation working condition data of the grounding resistor and uploads the real-time operation working condition data of the grounding resistor to a station end server, S3, a cloud end server performs offline analysis and test on the state of the grounding resistor to obtain state transition data of the grounding resistor and updates an offline database, and S4, the station end server performs real-time analysis on the state of the grounding resistor and updates the real-time database according to the real-time operation working condition data and the state transition data of the grounding resistor. The temperature evaluation is used for early warning of abnormal states, the resistance evaluation is used for judging whether the current state of the resistor is stable, the energy loss is used for judging the service life of the resistor, and the safety and stable operation of the power distribution network are improved.

Inventors

WU HONGHAO
Long Dajin
LI ZHONGMING
QI QIAN
WANG HUANAN
CHEN CHUANG
ZHANG RUIDONG

Assignees

广东电网有限责任公司广州供电局

Dates

Publication Date: 20260508
Application Date: 20221125

Claims (6)

1. The whole process state analysis method of the grounding resistor is characterized by comprising the following steps of: S1, a grounding resistor state acquisition device acquires real-time operation condition data of a grounding resistor and transmits the real-time operation condition data to an embedded processor; S2, the embedded processor stores and processes the real-time operation condition data of the grounding resistor, and uploads the real-time operation condition data of the grounding resistor to the station server; s3, the cloud server performs offline analysis and test on the state of the grounding resistor to obtain state transition data of the grounding resistor, and updates an offline database; s4, the station end server analyzes the state of the grounding resistor in real time according to the real-time operation condition data and the state transition data of the grounding resistor, and updates a real-time database; The real-time analysis of the state of the grounding resistor is divided into a state evaluation criterion based on the resistance value of the resistor, a state evaluation criterion based on the temperature value and a state evaluation criterion based on the energy loss value according to the time scale from small to large; the state evaluation criterion based on the resistance value of the resistor is specifically 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, A state evaluation model for the grounding resistor; the real-time resistance value of the resistor; Is the resistance change rate of the grounding resistor; The state evaluation of the resistance value of the grounding resistor is divided into the following three stages: the I level is defined as the real-time resistance of the resistor Early warning resistance value is less than or equal to Judging as a normal state; class II is defined as the real-time resistance of the resistor Not less than the early warning resistance value And rate of change of resistance Attention to the rate of change of resistance Judging the attention state, the system sends attention information to prompt the operation and maintenance personnel to make important rounds, As determined by experimentation; Class III is defined as the real-time resistance of the resistor Not less than the early warning resistance value Or rate of change of resistance value Not less than the early warning resistance change rate Judging the abnormal state, the system sends out early warning information, and an operation and maintenance person should immediately overhaul the grounding resistor, As determined by experimentation; the state evaluation criterion based on the temperature value is specifically: the temperature rise of the grounding resistor is a direct cause of burning out caused by the damage or even loss of the thermal stability of the grounding resistor, the operation state of the grounding resistor is indirectly evaluated according to the temperature rise and the duration of the grounding resistor, and the relation between the temperature rise and the zero sequence current and the duration of the grounding resistor is as follows: ; in the formula, For the temperature rise of the grounding resistor, namely the difference value between the temperature in the duration of the zero sequence current and the rated temperature, the rated temperature is consistent with the local temperature; for zero sequence current acting on the ground resistor; The duration of the zero sequence current; the state evaluation of the temperature value of the ground resistor is divided into the following two stages: Stage I is defined as the temperature rise of the grounding resistor Safety temperature rise limit value of grounding resistor Judging as a normal state; class II is defined as the temperature rise of the grounding resistor Greater than ground resistor safe temperature rise limit And rate of change of temperature rise Temperature rise change rate of the early warning is not less than Judging the abnormal state, sending early warning information by the system, and immediately overhauling the grounding resistor by operation and maintenance personnel; the state evaluation criterion based on the energy loss value is specifically: First, the The energy loss of the secondary intermittent ground fault grounding resistor is as follows: ; in the formula, Zero sequence voltage instantaneous value generated for zero sequence current flowing through the grounding resistor; is the effective value of zero sequence current flowing through the grounding resistor; is zero sequence current Duration of time; the number of intermittent zero sequence currents in a single ground fault; total energy consumption of ground resistor under secondary ground fault condition The method comprises the following steps: ; and (3) considering the energy loss accumulation effect, and further analyzing by combining with an offline tested resistor state probability transition matrix to obtain: ; ; ; ; Where n is the number of resistor state transitions, As a matrix of state probabilities, For the initial state matrix of the resistor, Is a resistor state probability matrix after state transition, For the probability of a transition of the resistor from state i to state j, For the probability of the final predicted state, An average energy loss for the state transition of the resistor occurs.
2. The method for analyzing the overall process state of the grounding resistor according to claim 1, wherein the off-line test is a basis for real-time analysis of the state of the equipment, a test environment is constructed through an external direct current power supply, the off-line test is divided into two stages, wherein the first stage is a destructive pressure test in a factory acceptance stage of the equipment resistance cabinet, the life, reliability parameters and state transition probability of the equipment are tested, and the second stage is a review test in an equipment overhaul stage, wherein the review test is to confirm the current state of the equipment under rated working conditions.
3. The method for analyzing the overall process state of the grounding resistor according to claim 2, wherein when the off-line test is performed by direct current, the influence of the non-periodic component of the short-circuit current is considered, and the alternating current and direct current are converted by adopting two modes, namely 1) short-term high-amplitude pulse current impact test, test of the short-circuit current peak impact grounding resistor, and cause the influence of state deterioration of part of the short-circuit current peak impact grounding resistor due to the problems of structure and materials, and 2) equivalent conversion is performed by adopting a current effective value, and the zero-sequence current is represented by direct current.
4. The method of claim 2, wherein the test indicators for off-line testing of the states of the ground resistor include a steady state value of resistance, a rate of change of resistance, a temperature, a rate of temperature rise, and a cumulative distribution of energy loss, and wherein the energy loss state transition matrix of the ground resistor is constructed by counting the energy loss values and the corresponding states of the ground resistor.
5. The grounding resistor whole process state analysis system is characterized by comprising 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, wherein the resistor cabinet is provided with a grounding resistor, the grounding resistor state acquisition device is used for acquiring real-time operation condition data of the grounding resistor, the grounding resistor state acquisition device, the data storage and signal processing device are respectively connected with the embedded processor, and the cloud server is connected with the station server; the embedded processor is used for receiving, storing and processing the real-time operation condition data of the grounding resistor, and uploading the real-time operation condition data of the grounding resistor to the station end server; The cloud server is used for carrying out offline analysis and test on the state of the grounding resistor, obtaining state transition data of the grounding resistor and updating an offline database; The station end server is used for analyzing the state of the grounding resistor in real time according to the real-time operation condition data and the state transition data of the grounding resistor and updating a real-time database.
6. The system according to claim 5, wherein the ground resistor state acquisition device comprises 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, and the data storage and signal processing device comprises a display unit, a keyboard unit, a clock circuit, a wireless sensor unit, a data storage unit, and a signal processing unit, wherein the zero sequence current sensor, the zero sequence voltage sensor, the temperature rise sensor, the temperature and humidity sensor, the auxiliary sensor, the alarm circuit, the display unit, the keyboard unit, the clock circuit, the wireless sensor unit, the data storage unit, and the signal processing unit are respectively connected with the embedded processor.

Description

Whole-process state analysis method and system for grounding resistor Technical Field The invention belongs to the technical field of novel power, and particularly relates to a method and a system for analyzing the overall process state of a grounding resistor in a power distribution network. Background At present, related manufacturers at home and abroad perform great improvement on the thermal stability of the grounding resistor around materials, structures and improved working environments, and early warning of extreme working conditions is performed by monitoring the temperature of the grounding resistor, the parameters such as zero sequence current and the like. The extreme working conditions of the temperature limit value and the zero sequence current limit value of the grounding resistor are considered, good results are achieved, but under the current situation that the operation modes are changeable, the actual operation state of the grounding resistor is more and more difficult to reflect, and the state early warning of the grounding resistor is possibly excessive or insufficient. Particularly when intermittent nonmetallic high-resistance ground faults occur, the operation condition of the resistor is converted from short-time and intense power receiving to a long-time, multiple and gentle recessive process. The resistor body is in a high-consumption state, the usability of the resistor body gradually decreases along with the time, and the resistor body is not provided with using elasticity. The accident that the resistor burns out happens sometimes, and the safety and the stable operation of the small-resistance grounding power distribution network are seriously threatened. Disclosure of Invention The invention aims to solve the defects of the prior art, and provides a whole-process state analysis method for a grounding resistor, which is convenient for a production operation unit to maintain the grounding resistor and improves the safety and stable operation performance of a power distribution network. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: A method for analyzing the overall process state of a grounding resistor, comprising the steps of: S1, a grounding resistor state acquisition device acquires real-time operation condition data of a grounding resistor and transmits the real-time operation condition data to an embedded processor; S2, the embedded processor stores and processes the real-time operation condition data of the grounding resistor, and uploads the real-time operation condition data of the grounding resistor to the station server; s3, the cloud server performs offline analysis and test on the state of the grounding resistor to obtain state transition data of the grounding resistor, and updates an offline database; s4, the station end server analyzes the state of the grounding resistor in real time according to the real-time operation condition data and the state transition data of the grounding resistor, and updates a real-time database. The off-line test is based on real-time analysis of the state of the equipment, a test environment is built through an external direct current power supply, the off-line test is divided into two stages, wherein the first stage is to conduct destructive pressure test in the delivery acceptance stage of the resistance cabinet of the equipment to test the service life, reliability parameters and state transition probability of the equipment, and the second stage is to conduct recheck test in the equipment overhaul stage to confirm the current state of the equipment under the rated working condition. Further, when the off-line test is performed by DC, the influence of the non-periodic component of the short-circuit current is considered, and the AC/DC conversion adopts two modes, namely 1) the short-term high-amplitude pulse current impact test is adopted, the short-circuit current peak impact grounding resistor is tested, the influence of state deterioration of the local part of the short-circuit current peak impact grounding resistor due to the problems of structure and materials is caused, 2) the equivalent conversion is performed by adopting the current effective value, and the zero sequence current is represented by the DC. Further, the test indexes of the off-line test of the state of the grounding resistor comprise a resistance steady state value, a resistance change rate, temperature, a temperature rise rate and energy loss accumulation distribution, and the energy loss state transition matrix of the grounding resistor can be constructed by counting the energy loss value and the corresponding state of the grounding resistor. Further, the real-time analysis of the state of the grounding resistor can be classified into a state evaluation criterion based on the resistance value of the resistor, a state evaluation criterion based on the temperature value and a state evaluation criterion based