A monitoring method for partial discharge of a switch cabinet

Abstract

The application provides a kind of monitoring method for partial discharge of switch cabinet, comprising, confirming the switch cabinet to be measured, calculating the residual working time value of each wireless sensor according to the real-time parameter data of each wireless sensor, and starting the wireless sensor with the maximum residual working time value to monitor the discharge condition of the switch cabinet to be measured, continuously monitoring according to the preset monitoring time, and obtaining the corresponding monitoring result;According to the monitoring result, judge whether the discharge condition of the switch cabinet to be measured meets the preset alarm standard, if it meets the preset alarm standard, generate a wake-up instruction and send the wake-up instruction to all wireless sensors through the data router;According to the wake-up instruction, start all wireless sensors, open the monitoring mode, and judge the partial discharge defect condition of the switch cabinet to be measured according to the received sensing data through the preset judgment standard.The application finds a balance between the precision and length of partial discharge defect monitoring through the power consumption optimization strategy and wake-up mechanism.

Description

Technical Field

[0001] This invention relates to the field of monitoring technology for partial discharge in switchgear, and in particular to a method for monitoring partial discharge in switchgear. Background Technology

[0002] In the current operation and maintenance inspection system for power distribution network equipment, a typical inspection cycle is set for 10kV switchgear equipment. If no serious partial discharge defects requiring immediate repair are found in the 10kV switchgear during the current inspection, a new inspection and assessment will only be conducted after one inspection cycle has elapsed. Therefore, a monitoring gap exists, preventing operation and management personnel from obtaining real-time information on the equipment's health status.

[0003] To address the above situation, a common solution is to install a 10kV switchgear real-time monitoring system in the ring main unit, distribution room, and transformer substation. This system transmits data 24 / 7 to monitor the health of the 10kV switchgear. However, this method has several drawbacks. First, the system deployment cost is high. In distribution networks, especially urban distribution networks, there are numerous 10kV switchgear units. Installing such a real-time monitoring system on every switchgear unit results in a low return on investment. Second, the system utilization rate is low. Generally, the partial discharge defect rate of 10kV switchgear equipment follows a bathtub curve with the commissioning time. The probability of problems occurring after entering a stable operating period is low, resulting in low utilization of the real-time monitoring system, which may even cause problems before the monitored switchgear. Third, the system occupies cabinet space. The internal space of ring main units, distribution rooms, and transformer substations is limited. Deploying a real-time monitoring system inevitably encroaches on operation or maintenance space, increasing operational risks. Summary of the Invention

[0004] The purpose of this invention is to propose a monitoring method for partial discharge in switchgear, and to solve the technical problem of how to achieve critical monitoring of partial discharge in 10kV switchgear through optimal strategies and wake-up mechanisms, thereby effectively improving equipment utilization and reducing equipment investment costs.

[0005] On the one hand, a method for monitoring partial discharge in a switchgear is provided, which is applied to the switchgear using a partial discharge monitoring system. The partial discharge monitoring system includes at least a wireless sensor installed in the switchgear, a data analysis terminal connected to the wireless sensor, and a data router connecting the wireless sensor and the data analysis terminal.

[0006] Identify the switch cabinet under test and obtain real-time parameter data from the wireless sensors installed on the switch cabinet under test;

[0007] The remaining working time of each wireless sensor is calculated based on the real-time parameter data of the wireless sensors. The wireless sensor with the largest remaining working time is activated to monitor the discharge status of the switch cabinet under test. The monitoring is carried out continuously for a preset monitoring time to obtain the corresponding monitoring results.

[0008] Based on the monitoring results, it is determined whether the discharge status of the switch cabinet under test meets the preset alarm standard. If the preset alarm standard is met, a wake-up command is generated and sent to all wireless sensors through the data router.

[0009] According to the wake-up command, all wireless sensors are activated and the monitoring mode is turned on. The data router receives the sensing data of all wireless sensors periodically according to the frequency setting and sends it to the data analysis terminal.

[0010] The data analysis terminal determines the partial discharge defect status of the switchgear under test based on the received sensor data and a preset judgment standard.

[0011] Preferably, the wireless sensor installed on the switch cabinet under test specifically includes:

[0012] A wireless high-frequency current sensor installed at the grounding wire of the switch cabinet under test;

[0013] UHF wireless magnetic sensor installed at the observation window of the switch cabinet under test;

[0014] Ground wave wireless magnetic sensors are installed on the front middle and lower cabinet doors and the upper and lower metal shells on the back of the switch cabinet under test.

[0015] Contact ultrasonic wireless magnetic sensors are installed on the front middle and lower cabinet doors and the upper and lower metal housings on the back of the switch cabinet under test.

[0016] Non-contact ultrasonic wireless magnetic sensors are installed in the gaps of the front door and the observation window of the switch cabinet under test.

[0017] Preferably, the calculation of the remaining operating time of each wireless sensor specifically includes:

[0018] The data router records the initial power consumption, rated operating power consumption, and rated standby power consumption of each wireless sensor;

[0019] The ratio between the initial power consumption of the wireless sensor and its rated operating power consumption is taken as the remaining operating time of the wireless sensor.

[0020] Preferably, it further includes:

[0021] If multiple wireless sensors have the same maximum remaining working time, one of them will be randomly selected to start monitoring.

[0022] Preferably, the preset listening time is specifically the difference between the maximum remaining working time value and the second largest remaining working time value among each wireless sensor.

[0023] Preferably, the preset alarm criteria include at least one of the following:

[0024] When the wireless sensor is listening, if the partial discharge detection signal is greater than the signal threshold set for each wireless sensor, the alarm standard is determined to be met.

[0025] When the wireless sensor is listening, if the growth rate of the partial discharge detection signal is greater than the signal growth rate threshold set for each wireless sensor, then the alarm standard is determined to be met.

[0026] Preferably, the signal thresholds set for each wireless sensor specifically include:

[0027] For UHF wireless magnetic sensors, the set signal threshold is -75dBm; for ground wave wireless magnetic sensors, the set signal threshold is 25dBmV; for contact ultrasonic wireless magnetic sensors, the set signal threshold is 15mV; for non-contact ultrasonic wireless magnetic sensors, the set signal threshold is 25dBμV; and for high-frequency current wireless sensors, the set signal threshold is 30dBmV.

[0028] Preferably, the signal growth threshold set for each wireless sensor specifically includes:

[0029] For ultra-high frequency wireless magnetic sensors, the signal growth threshold is set to 5 dBm / h; for ground wave wireless magnetic sensors, the signal growth threshold is set to 5 dBmV / h; for contact ultrasonic wireless magnetic sensors, the signal growth threshold is set to 3 mV / h; for non-contact ultrasonic wireless magnetic sensors, the signal growth threshold is set to 5 dBμV / h; and for high-frequency current wireless sensors, the signal growth threshold is set to 5 dBmV / h.

[0030] Preferably, it further includes:

[0031] If the discharge status of the switch cabinet under test does not meet the preset alarm standard, the monitoring will continue until the preset monitoring time ends, and the real-time power and remaining working time of each wireless sensor will be updated according to the real-time parameter data of the wireless sensor.

[0032] After updating the real-time power and remaining working time of each wireless sensor, the next round of monitoring begins. The wireless sensor with the largest remaining working time is restarted to monitor the discharge status of the switch cabinet under test. Monitoring continues according to the preset monitoring time to obtain the corresponding re-monitoring results.

[0033] Based on the re-monitoring results, it is determined whether the discharge status of the switch cabinet under test meets the preset alarm criteria. If the preset alarm criteria are met, a wake-up command is generated and sent to all wireless sensors through the data router.

[0034] According to the wake-up command, all wireless sensors are activated and the monitoring mode is turned on. The data router receives the sensing data of all wireless sensors periodically according to the frequency setting and sends it to the data analysis terminal.

[0035] The data analysis terminal determines the partial discharge defect status of the switchgear under test based on the received sensor data and a preset judgment standard.

[0036] In summary, implementing the embodiments of the present invention has the following beneficial effects:

[0037] The partial discharge monitoring method for switchgear provided by this invention, through the wireless and magnetic design of sensors, enables quick and convenient installation of various sensors. A complete 10kV switchgear partial discharge intensive care system can be deployed on-site within 5 minutes. It can be used in conjunction with inspection work, eliminating the need for pre-installation on every switchgear, effectively improving equipment utilization and reducing equipment investment costs. By designing an intelligent power consumption optimization strategy and wake-up mechanism, the system avoids the problem of low battery life caused by constant full-power operation, finding a balance between the accuracy and duration of partial discharge defect monitoring, allowing the monitoring system to operate on-site for extended periods. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0039] Figure 1 This is a schematic diagram of the main flow of a method for monitoring partial discharge in a switchgear according to an embodiment of the present invention.

[0040] Figure 2 This is a logic diagram of a method for monitoring partial discharge in a switchgear according to an embodiment of the present invention. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

[0042] like Figure 1 and Figure 2 The diagram shown is a schematic representation of an embodiment of a partial discharge monitoring method for switchgear provided by the present invention. In this embodiment, a partial discharge monitoring system is applied to the switchgear. The partial discharge monitoring system includes at least a wireless sensor installed in the switchgear, a data analysis terminal connected to the wireless sensor, and a data router connecting the wireless sensor and the data analysis terminal. It is understood that the wireless sensor includes a sensing element, a power module, and a wireless short-range communication module. The sensing element includes five types: ultra-high frequency (UHF) elements, ground wave elements, contact ultrasonic elements, non-contact ultrasonic elements, and high-frequency current elements. For wireless sensors with UHF, ground wave, contact, and non-contact ultrasonic sensing elements, a magnetic attraction design is adopted. Specifically, the sensing element is placed in the center of the sensor, and a magnetic lug component is added to each side of the sensor. The magnetic lug uses neodymium iron boron or ceramic magnets as the elements providing attraction force. The magnetic lug is fitted with a magnetic sleeve to reduce friction and wear between the magnet and the switchgear surface. The magnetic sleeve is made of a soft, elastic, and wear-resistant material, such as rubber or silicone. The sensor is integrally cast, with the magnetic lugs tightly connected to the sensing element, resulting in a more robust structure. The magnetic lugs are at least 10mm thick and at least 5mm wide. Therefore, wireless sensors with sensing elements of UHF, ground wave, contact ultrasonic, and non-contact ultrasonic types are also known as UHF wireless magnetic sensors, ground wave wireless magnetic sensors, contact ultrasonic wireless magnetic sensors, and non-contact ultrasonic wireless sensors.

[0043] The data router includes a wireless short-range communication module, a 4G communication module, and a processor. The data analysis terminal includes a 4G communication module, a data analysis module, and an intelligent analysis module. The wireless short-range communication module of the data router is connected to the wireless short-range communication module of the wireless sensor, and the 4G communication module is connected to the 4G communication module of the data analysis terminal. The aforementioned wireless sensor and the wireless short-range communication module of the data router include, but are not limited to, one of the following: Bluetooth Low Energy module, ZigBee module, Z-Wave module, or LoRa module. The 4G communication module of the aforementioned data router and data analysis terminal can also be replaced with a 5G communication module.

[0044] The method for monitoring partial discharge in the switchgear specifically includes:

[0045] Step S1: Confirm the switchgear under test and obtain real-time parameter data from the wireless sensors installed on the switchgear under test; understandably, confirm the switchgear under test. The switchgear under test is the switchgear found to have partial discharge defects during the inspection process. Sensors installed on the switchgear under test include wireless high-frequency current sensors, ultra-high frequency wireless magnetic sensors, ground wave wireless magnetic sensors, contact ultrasonic wireless magnetic sensors, and non-contact ultrasonic wireless magnetic sensors.

[0046] In a specific embodiment, the wireless sensor installed on the switch cabinet under test specifically includes:

[0047] A wireless high-frequency current sensor installed at the grounding wire of the switch cabinet under test;

[0048] UHF wireless magnetic sensor installed at the observation window of the switch cabinet under test;

[0049] Ground wave wireless magnetic sensors are installed on the front middle and lower cabinet doors and the upper and lower metal shells on the back of the switch cabinet under test.

[0050] Contact ultrasonic wireless magnetic sensors are installed on the front middle and lower cabinet doors and the upper and lower metal housings on the back of the switch cabinet under test.

[0051] Non-contact ultrasonic wireless magnetic sensors are installed in the gaps of the front door and the observation window of the switch cabinet under test.

[0052] Step S2: Calculate the remaining operating time of each wireless sensor based on the real-time parameter data of the wireless sensors, and activate the wireless sensor with the largest remaining operating time to monitor the discharge status of the switchgear under test. Continuously monitor for a preset monitoring time to obtain the corresponding monitoring result. Understandably, the data router records the initial power E of each wireless sensor. i Rated operating power consumption P i Rated standby power consumption P i And calculate the remaining work time T. i Where i = 1, ..., n, n is the number of sensors, and the current working state is set to listening state. The remaining working time T is then used to start the process. i The largest wireless sensor is used for listening, and the listening time is t.

[0053] In a specific embodiment, calculating the remaining working time of each wireless sensor specifically includes:

[0054] The data router records the initial power consumption, rated operating power consumption, and rated standby power consumption of each wireless sensor;

[0055] The ratio between the initial battery level of the wireless sensor and its rated operating power consumption is taken as the remaining operating time of the wireless sensor. As shown in the following formula:

[0056]

[0057] Initial charge E i The current remaining power of the power module for each wireless sensor.

[0058] In this embodiment, if multiple wireless sensors have the same maximum remaining working time, one of the wireless sensors is randomly selected to start monitoring.

[0059] Specifically, the preset listening time is the difference between the maximum remaining working time value and the second largest remaining working time value among all wireless sensors.

[0060] Step S3: Based on the monitoring results, determine whether the discharge status of the switch cabinet under test meets the preset alarm criteria. If the preset alarm criteria are met, generate a wake-up command and send the wake-up command to all wireless sensors through the data router. Understandably, when judging the local degradation situation, if the following conditions are met during monitoring, the system is woken up and the wireless sensor performing the monitoring sends a wake-up command to the data router; otherwise, continue monitoring until the end. After the monitoring ends, update the remaining working time and enter the next round of monitoring.

[0061] In a specific embodiment, the preset alarm criteria include at least one of the following:

[0062] When the wireless sensor is monitoring, if the partial discharge detection signal is greater than the signal threshold set for each wireless sensor, the alarm standard is determined to be met. Specifically, the signal threshold is -75dBm for the UHF wireless magnetic sensor, 25dBmV for the ground wave wireless magnetic sensor, 15mV for the contact ultrasonic wireless magnetic sensor, 25dBμV for the non-contact ultrasonic wireless magnetic sensor, and 30dBmV for the high-frequency current wireless sensor.

[0063] When the wireless sensor is monitoring, if the rate of increase of the partial discharge detection signal exceeds the signal rate of increase set for each wireless sensor, the alarm standard is deemed met. Specifically, the signal rate of increase threshold is 5 dBm / h for ultra-high frequency wireless magnetic sensors; 5 dBmV / h for ground wave wireless magnetic sensors; 3 mV / h for contact ultrasonic wireless magnetic sensors; 5 dBμV / h for non-contact ultrasonic wireless magnetic sensors; and 5 dBmV / h for high-frequency current wireless sensors.

[0064] Step S4: Activate all wireless sensors according to the wake-up command, start the monitoring mode, and the data router periodically receives the sensing data of all wireless sensors and sends it to the data analysis terminal according to the frequency setting.

[0065] In step S5, the data analysis terminal determines the partial discharge defect status of the switchgear under test based on the received sensor data and a preset judgment standard. Understandably, after receiving the wake-up command, the data router activates all wireless sensors and enters monitoring mode. In monitoring mode, the data router periodically receives sensor data from all wireless sensors according to the set frequency and sends it to the data analysis terminal. Based on the multi-parameter sensor data, the data analysis terminal activates the data analysis module and the intelligent analysis module, and outputs the partial discharge defect status of the switchgear under test.

[0066] In one specific embodiment, if the discharge status of the switch cabinet under test does not meet the preset alarm standard, the monitoring continues until the preset monitoring time ends, and the real-time power and remaining working time of each wireless sensor are updated according to the real-time parameter data of the wireless sensor.

[0067] After updating the real-time power and remaining working time of each wireless sensor, the next round of monitoring begins. The wireless sensor with the largest remaining working time is restarted to monitor the discharge status of the switch cabinet under test. Monitoring continues according to the preset monitoring time to obtain the corresponding re-monitoring results.

[0068] Based on the re-monitoring results, it is determined whether the discharge status of the switch cabinet under test meets the preset alarm criteria. If the preset alarm criteria are met, a wake-up command is generated and sent to all wireless sensors through the data router.

[0069] According to the wake-up command, all wireless sensors are activated and the monitoring mode is turned on. The data router receives the sensing data of all wireless sensors periodically according to the frequency setting and sends it to the data analysis terminal.

[0070] The data analysis terminal determines the partial discharge defect status of the switch cabinet under test based on the received sensor data and a preset judgment standard. The specific content of this monitoring process can be referred to the monitoring process described above, and will not be repeated here.

[0071] Specifically, for wireless sensors that initiate listening:

[0072] Update battery level E i :

[0073]

[0074] Update remaining work time T i :

[0075]

[0076] For wireless sensors in standby mode:

[0077] Update battery level E i :

[0078]

[0079] Update remaining work time T i :

[0080] In summary, implementing the embodiments of the present invention has the following beneficial effects:

[0081] The partial discharge monitoring method for switchgear provided by this invention, through the wireless and magnetic design of sensors, enables quick and convenient installation of various sensors. A complete 10kV switchgear partial discharge intensive care system can be deployed on-site within 5 minutes. It can be used in conjunction with inspection work, eliminating the need for pre-installation on every switchgear, effectively improving equipment utilization and reducing equipment investment costs. By designing an intelligent power consumption optimization strategy and wake-up mechanism, the system avoids the problem of low battery life caused by constant full-power operation, finding a balance between the accuracy and duration of partial discharge defect monitoring, allowing the monitoring system to operate on-site for extended periods.

[0082] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for monitoring partial discharge in a switchgear, wherein a partial discharge monitoring system is applied to the switchgear, the partial discharge monitoring system comprising at least a wireless sensor installed in the switchgear, a data analysis terminal connected to the wireless sensor, and a data router connecting the wireless sensor and the data analysis terminal, characterized in that, include: Identify the switch cabinet under test and obtain real-time parameter data from the wireless sensors installed on the switch cabinet under test; The remaining working time of each wireless sensor is calculated based on the real-time parameter data of the wireless sensors. The wireless sensor with the largest remaining working time is activated to monitor the discharge status of the switch cabinet under test. The monitoring is carried out continuously for a preset monitoring time to obtain the corresponding monitoring results. Based on the monitoring results, it is determined whether the discharge status of the switch cabinet under test meets the preset alarm standard. If the preset alarm standard is met, a wake-up command is generated and sent to all wireless sensors through the data router. According to the wake-up command, all wireless sensors are activated and the monitoring mode is turned on. The data router receives the sensing data of all wireless sensors periodically according to the frequency setting and sends it to the data analysis terminal. The data analysis terminal determines the partial discharge defect status of the switchgear under test based on the received sensor data and a preset judgment standard.

2. The method as described in claim 1, characterized in that, The wireless sensors installed on the switch cabinet under test specifically include: A wireless high-frequency current sensor installed at the grounding wire of the switch cabinet under test; UHF wireless magnetic sensor installed at the observation window of the switch cabinet under test; Ground wave wireless magnetic sensors are installed on the front middle and lower cabinet doors and the upper and lower metal shells on the back of the switch cabinet under test. Contact ultrasonic wireless magnetic sensors are installed on the front middle and lower cabinet doors and the upper and lower metal housings on the back of the switch cabinet under test. Non-contact ultrasonic wireless magnetic sensors are installed in the gaps of the front door and the observation window of the switch cabinet under test.

3. The method as described in claim 2, characterized in that, The calculation of the remaining operating time of each wireless sensor specifically includes: The data router records the initial power consumption, rated operating power consumption, and rated standby power consumption of each wireless sensor; The ratio between the initial power consumption of the wireless sensor and its rated operating power consumption is taken as the remaining operating time of the wireless sensor.

4. The method as described in claim 3, characterized in that, Also includes: If multiple wireless sensors have the same maximum remaining working time, one of them will be randomly selected to start monitoring.

5. The method as described in claim 4, characterized in that, The preset listening time is specifically the difference between the maximum remaining working time value and the second largest remaining working time value among each wireless sensor.

6. The method as described in claim 5, characterized in that, The preset alarm criteria include at least one of the following: When the wireless sensor is listening, if the partial discharge detection signal is greater than the signal threshold set for each wireless sensor, the alarm standard is determined to be met. When the wireless sensor is listening, if the growth rate of the partial discharge detection signal is greater than the signal growth rate threshold set for each wireless sensor, then the alarm standard is determined to be met.

7. The method as described in claim 6, characterized in that, The specific signal thresholds set for each wireless sensor include: For UHF wireless magnetic sensors, the set signal threshold is -75dBm; for ground wave wireless magnetic sensors, the set signal threshold is 25dBmV; for contact ultrasonic wireless magnetic sensors, the set signal threshold is 15mV; for non-contact ultrasonic wireless magnetic sensors, the set signal threshold is 25dBμV; and for high-frequency current wireless sensors, the set signal threshold is 30dBmV.

8. The method as described in claim 6, characterized in that, The specific signal growth thresholds set for each wireless sensor include: For ultra-high frequency wireless magnetic sensors, the signal growth threshold is set to 5 dBm / h; for ground wave wireless magnetic sensors, the signal growth threshold is set to 5 dBmV / h; for contact ultrasonic wireless magnetic sensors, the signal growth threshold is set to 3 mV / h; for non-contact ultrasonic wireless magnetic sensors, the signal growth threshold is set to 5 dBμV / h; and for high-frequency current wireless sensors, the signal growth threshold is set to 5 dBmV / h.

9. The method as described in claim 7 or 8, characterized in that, Also includes: If the discharge status of the switch cabinet under test does not meet the preset alarm standard, the monitoring will continue until the preset monitoring time ends, and the real-time power and remaining working time of each wireless sensor will be updated according to the real-time parameter data of the wireless sensor. After updating the real-time power and remaining working time of each wireless sensor, the next round of monitoring begins. The wireless sensor with the largest remaining working time is restarted to monitor the discharge status of the switch cabinet under test. Monitoring continues according to the preset monitoring time to obtain the corresponding re-monitoring results. Based on the re-monitoring results, it is determined whether the discharge status of the switch cabinet under test meets the preset alarm criteria. If the preset alarm criteria are met, a wake-up command is generated and sent to all wireless sensors through the data router. According to the wake-up command, all wireless sensors are activated and the monitoring mode is turned on. The data router receives the sensing data of all wireless sensors periodically according to the frequency setting and sends it to the data analysis terminal. The data analysis terminal determines the partial discharge defect status of the switchgear under test based on the received sensor data and a preset judgment standard.

Images