Isolation switch updating and transforming method

Abstract

The invention relates to the technical field of disconnecting link maintenance and transformation, in particular to an isolation disconnecting link updating and transformation method. The method comprises the following steps: S1, performing inspection and quantitative analysis, performing equipment evaluation and problem diagnosis, and identifying operation problems and function deficiency; s2, performing model selection and material optimization, and setting a standard isolation switch and an electric operation assembly; s3, defining a transformation range, dividing transformation units based on the main wiring diagram, and covering the isolation disconnecting link and the grounding disconnecting link; s4, implementing a safety locking structure, adding an electrified locking and five-prevention system, and accessing whole plant management to prevent misoperation; and S5, accessing a monitoring system, and connecting an LCU screen and a computer monitoring system to realize remote centralized control. The contact resistance and temperature rise of the contact reach the standard, ablation is completely eradicated, the operating force and time are greatly reduced, jamming is returned to zero, the five-prevention locking success rate is extremely high, the misoperation drill can reach the zero penetration level, and the on-site actual effects of mechanical zero jamming, five-prevention zero penetration, remote control zero delay and old and waste utilization are achieved.

Description

Technical Field

[0001] This invention relates to the field of disconnector maintenance and modification technology, and in particular to a method for updating and modifying disconnectors. Background Technology

[0002] With the deepening implementation of the "less staffed, remote centralized control" management model in hydropower plants, the 110kV substation isolating switches, as key primary equipment, directly affect the safe production and operation and maintenance efficiency of the power station due to their operational reliability, ease of operation, and level of intelligence. Currently, many 110kV outdoor isolating switches in China that have been in operation for more than 15 years generally use the GW5A-126DW / 630 or GW13-72.5G / 630 manual operation mechanisms, which have many prominent problems.

[0003] The mechanical performance of the manual mechanism has deteriorated significantly. Long-term exposure to the outdoor environment has caused corrosion and jamming of the base, transmission linkage, and operating mechanism. The operating work has increased to 1.5 to 2 times the original design. After closing, the contacts may not make proper contact, leading to increased contact resistance and the risk of overheating or even burning. The traditional CS17 manual mechanism only supports local operation and cannot be connected to the LCU or plant-wide monitoring system, thus failing to achieve the "four remote" functions and violating the requirements for unmanned operation. This results in high labor intensity for maintenance personnel. The 110kV busbars and outgoing line bays are generally not equipped with live line display interlocking devices. The prevention of misoperation mainly relies on manual program interlocking, which poses significant hidden dangers such as closing the grounding switch while energized and accidentally opening or closing the isolating switch.

[0004] Therefore, there is a need for a method to upgrade and retrofit isolating switches that comprehensively improves mechanical reliability and electrical conductivity, eliminates the risk of contact overheating and erosion, extends equipment life, enhances drive efficiency by utilizing servo motors, and achieves efficient remote centralized control while reducing labor costs to meet the needs of the current environment. Summary of the Invention

[0005] Therefore, the technical problem to be solved by this invention is that the mechanical performance of the manual mechanism is severely degraded, the contacts do not make proper contact after closing, the contact resistance increases, leading to the risk of overheating or even burning, it cannot be connected to the LCU or the whole plant monitoring system, it cannot realize the "four remote" functions, it violates the requirements of unmanned operation, the labor intensity of maintenance personnel is high, the line live display interlocking device is generally not configured, the prevention of misoperation mainly relies on manual program interlocking, and there are major hidden dangers such as closing the grounding switch under live conditions and accidentally opening or closing the isolating switch.

[0006] The above-mentioned technical problems are solved by the following technical solution: This invention proposes a method for upgrading and modifying isolating switches, which includes, S1, Inspection and quantitative analysis, conduct equipment assessment and problem diagnosis, identify operational problems and functional deficiencies; S2, selection and material optimization, setting up standard isolating switch and electric operation assembly; S3, Define the scope of the renovation, divide the renovation units based on the main wiring diagram, and cover the isolating switch and the grounding switch; S4, safety interlocking structure implementation, adding live interlocking and five-prevention system, and connecting to plant-wide management to prevent misoperation; S5 connects to the monitoring system, linking the LCU screen and the computer monitoring system to achieve remote centralized control.

[0007] In a preferred embodiment of the method for upgrading and modifying an isolating switch described in this invention: In the inspection and quantitative analysis process, Assess existing isolating switches, including checking the degree of corrosion of the operating linkage mechanism, the increase in operating power, the increase in contact resistance caused by incomplete contact of the closing contacts, and the lack of remote control function of the manual operating mechanism. Quantify corrosion and jamming issues to ensure diagnostic data accuracy is within ±5%.

[0008] In a preferred embodiment of the method for upgrading and modifying an isolating switch described in this invention: In the selection and material optimization process, Select a compliant isolating switch, with contacts and fingers made of copper and silver plating thickness of not less than 20μm. The rated power of the electric operating assembly is not less than 500W, and the integrated position sensor achieves a contact position feedback accuracy of ±1mm; The electric control assembly is equipped with a fault diagnosis module to analyze and detect motor stall or transmission jamming, and the fault signal is output to the monitoring system through dry contacts.

[0009] In a preferred embodiment of the method for upgrading and modifying an isolating switch described in this invention: In the process of defining the scope of the renovation, Based on the main wiring layout of the 110kV primary equipment, it covers the neutral grounding switch of the #1 and #2 main transformers, the isolating and grounding switches of the 16A and 16B switch bays, the isolating and grounding switches of the 161 and 162 switch bays, as well as the isolating and grounding switches of the 110kV bus PT bays, achieving full station coverage; The neutral point grounding switch of the main transformer adopts a single-pole grounding design, and the inrush current suppression resistor is increased to reduce the impact of grounding transient current on the system.

[0010] In a preferred embodiment of the method for upgrading and modifying an isolating switch described in this invention: In the implementation process of the safety interlocking structure, Add a live-line interlocking device, use voltage transformer signals to detect bus and outgoing line voltages, and set the voltage threshold to 90% of the rated voltage; When the actual voltage exceeds the voltage threshold, the line live-line interlocking device is triggered to lock out. The five-prevention system is integrated into the plant-wide five-prevention system to ensure that the interlock response time is less than 100ms; The five-prevention system integrates an audible and visual alarm device to provide malfunction detection. The live line interlocking device supports multiple inputs and is compatible with 110kV bus and outgoing line voltage signals.

[0011] In a preferred embodiment of the method for upgrading and modifying an isolating switch described in this invention: In the process of connecting to the monitoring system, The fault diagnosis module connects the disconnector status signal to the switch station LCU screen to achieve remote control and integrates it into the plant's computer monitoring system, with a transmission delay of less than 200ms. The disconnector status signal includes disconnector operating torque, disconnector temperature data, disconnector position, and disconnector fault status.

[0012] In a preferred embodiment of the method for upgrading and modifying an isolating switch described in this invention: After the monitoring process is modified, an equipment handover test will be conducted. Insulation resistance testing, contact resistance measurement, and operational cycle testing are conducted. In the insulation resistance test procedure, the threshold value of insulation resistance is set to 500MΩ, the threshold value of contact resistance is set to 50μΩ, and the threshold value of the number of operation cycle tests is set to 1000 times without failure. The actual resistance of the insulation is not less than 500MΩ, the actual resistance of the contact is not more than 50μΩ, and the equipment can be handed over to the secondary equipment after passing at least 1000 operation cycles without failure.

[0013] In a preferred embodiment of the method for upgrading and modifying an isolating switch described in this invention: In the secondary equipment handover test process, A verification test was conducted, simulating continuous operation under load conditions for 72 hours, and the temperature rise was monitored. When the temperature rise does not exceed 50K, the conditions for the handover test of the secondary equipment are met, and the acceptance is qualified.

[0014] The beneficial effects of this invention are as follows: contact resistance and temperature rise meet standards, eliminating erosion; operating force and time are significantly reduced; jamming is eliminated; the success rate of five-proof interlocking is extremely high; and the simulation of misoperation can achieve a zero-penetration level. Remote control of opening and closing can be completed within 30 seconds, saving 960 hours of on-site operation time per year. All indicators, including contact resistance, operating force, five-proof response, and remote control timeliness, exceed the requirements of the technical specifications, achieving the practical effect of "zero mechanical jamming, zero penetration of five-proof, zero delay of remote control, and zero waste of existing equipment". Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0016] Figure 1 A schematic diagram of the core steps of the isolating switch upgrade method of the present invention is shown.

[0017] Figure 2 A flowchart of the primary equipment handover test for the isolating switch upgrade and renovation method of the present invention is shown.

[0018] Figure 3 A flowchart of the secondary equipment handover test for the isolating switch upgrade and modification method of the present invention is shown. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0020] The terminology used in this invention refers to those general terms currently widely used in the art in consideration of the functionality of the invention; however, these terms may vary according to the intent of those skilled in the art, precedent, or new techniques. Furthermore, specific terms may be chosen independently, and in such cases, their detailed meanings will be described in the detailed description of the invention. Therefore, the terminology used in this specification should not be construed as simple names, but rather based on the meaning of the terms and the overall description of the invention.

[0021] Reference Figure 1 This embodiment provides a method for updating and upgrading isolation switches.

[0022] In the renovation and upgrading project of the isolating switches at the 110kV substation, a comprehensive inspection and quantitative analysis of the existing equipment was conducted first. This step was crucial for accurately understanding the actual condition of the equipment. The technical team went to the site and carefully observed the operating linkage mechanism of each set of switches. They discovered obvious signs of corrosion on the base and transmission parts, resulting in increased resistance during operation and occasional failure of the contacts to fully engage after closing, leading to unstable contact quality. Simultaneously, functional issues were tested. The original CS17 manual operating mechanism relied entirely on manual on-site operation, lacking any remote control interface and unable to connect to a monitoring system. This directly impacted the substation's transition to an unmanned operation mode. Through these inspections, the operational problems caused by mechanical corrosion and the lack of electric and remote functionality were clearly identified, providing a reliable basis for subsequent upgrades.

[0023] Next, equipment selection and material optimization were carried out. Isolating switches conforming to high-voltage AC disconnector standards were chosen, ensuring that the contacts and fingers used highly conductive copper, and that surface silver plating enhanced conductivity and oxidation resistance. Simultaneously, an electric operating assembly was equipped on the switch. This assembly is a servo motor-driven mechanism with a waterproof and dustproof design, and a built-in position sensor to provide feedback on the contact position.

[0024] During the selection process, priority was given to the equipment's applicability and reliability, ensuring a rational layout of the operating mechanism, easy interchangeability of parts, and convenient future maintenance. The control box is also equipped with an intelligent dehumidification device to keep the interior dry. These optimizations allow the new equipment to far surpass the performance of the original manual disconnect switch, ensuring safe operation.

[0025] The scope of the subsequent renovation was defined. Based on the main wiring diagram of the 110kV primary equipment of the power station, the renovation was divided into independent units based on the disconnector mechanism, covering the neutral grounding disconnectors of the #1 and #2 main transformers, the isolating disconnectors and grounding disconnectors of the 16A and 16B switch bays, multiple sets of isolating disconnectors and grounding disconnectors of the 161 and 162 switch bays, as well as the isolating disconnectors and grounding disconnectors of the 110kV bus PT bay, involving a total of 9 sets of disconnectors.

[0026] The neutral grounding switch of the main transformer was specially optimized, adopting a single-pole grounding design and adding an inrush current suppression resistor to mitigate the transient current impact during grounding. This ensures that the upgrade covers all critical parts of the station, avoiding any omissions.

[0027] During the implementation phase of the safety interlocking structure, a live-line interlocking device was added. This device uses voltage transformer signals to detect the voltage status of the busbars and outgoing lines. Once the voltage reaches a set threshold above the rated value, the interlocking is triggered. A five-prevention system was also integrated, implementing rules such as preventing live-line closing, preventing accidental closing / opening, and preventing load-bearing disconnection through electrical interlocking circuits. This system is connected to the plant's overall five-prevention management system. This system is equipped with audible and visual alarms, which immediately sound an alarm when potential misoperation is detected. These interlocking functions are connected to the power plant's management network via a fiber optic communication interface, ensuring that any operation is rigorously verified and completely preventing risks caused by human error.

[0028] Finally, the new disconnect switch was connected to the monitoring system. The status signals of the disconnect switch were connected to the LCU screen at the switchyard via an RS485 interface, enabling real-time transmission of location, fault, and operating mode information. Simultaneously, the system was integrated into the plant-wide computer monitoring system, utilizing protocols to ensure smooth data transmission and supporting telemetry, remote signaling, remote control, and remote adjustment functions. This enabled remote centralized control of the power plant. In unmanned operation mode, operators can directly monitor and control the disconnect switches from the central control center, significantly reducing on-site workload.

[0029] The entire upgrade process proceeded smoothly after the equipment arrived in October 2024. During the removal of the old equipment, the system switched to maintenance mode, using tools to remove the original disconnect switches and performing rust removal and painting on the brackets. The installation of the new equipment utilized the existing foundation and was securely fixed. During the commissioning phase, insulation resistance and contact resistance tests were conducted to ensure all indicators were normal. After 72 hours of trial operation, the equipment was stable and trouble-free, entering the warranty period. This upgrade not only improved the reliability of the disconnect switches but also provided support for the digital management of the power plant.

[0030] As one embodiment provided, such as Figures 1-2 , In the selection and material optimization process, an isolating switch conforming to DL / T486 and DL / T593 standards was selected. The contacts and contact fingers are made of copper, and a silver plating process is used to ensure that the plating thickness is not less than 20μm, in order to improve contact conductivity and oxidation resistance.

[0031] The disconnect switch is equipped with an electric operating assembly, which uses a servo motor with a rated power of no less than 500W and integrates a position sensor to achieve a contact position feedback accuracy of ±1mm. The electric operating assembly includes a fault diagnosis module that detects motor stall or transmission jamming through current waveform analysis, and the fault signal is output to the monitoring system via dry contacts. These selection measures ensure the reliability of the equipment and long-term spare parts support, meeting the performance requirements outlined in the retrofit principles.

[0032] The process for defining the scope of the renovation was established. Based on the main wiring layout of the 110kV primary equipment, the renovation will cover the neutral grounding switches of main transformers #1 and #2, the isolating and grounding switches of switch bays 16A and 16B, the isolating and grounding switches of switch bays 161 and 162, and the isolating and grounding switches of the 110kV busbar PT bays, achieving a comprehensive upgrade of the entire substation. Specifically, for the neutral grounding switches of the main transformers, a single-pole grounding design was adopted, and inrush current suppression resistors were added to reduce the impact of grounding transient currents on the system. This step ensured that the scope of the renovation matched the actual wiring diagram of the substation, avoiding any omissions in any bays, and incorporated the installation considerations for the five-proof devices.

[0033] In the implementation process of the safety interlock structure, a line power-on interlock device is added. The voltage transformer signal is used to detect the bus and outgoing line voltages. The voltage threshold is set to be above 90% of the rated voltage. When the actual voltage exceeds the threshold, the interlock is triggered. At the same time, the five-prevention system realizes rules such as preventing closing with power on, preventing misoperation of opening and closing, and preventing switching off with load through the electrical interlock circuit, and is connected to the whole-plant five-prevention management system to ensure that the interlock response time is less than 100 ms. This system is integrally connected to the audible and visual alarm device to provide an immediate alarm during misoperation detection. The line power-on interlock device supports multiple inputs and can be compatible with the 110 kV bus and outgoing line voltage signals, such as the Houdong Line and the Pinghou Line. The above measures strictly comply with standards such as GB1985 and DL / T593, and thoroughly improve the safety of operation.

[0034] Finally, the process of connecting to the monitoring system is carried out. The disconnector status signal is connected to the switchyard LCU panel by the fault diagnosis module to achieve remote control, and is integrated into the whole-plant computer monitoring system to ensure that the transmission delay is less than 200 ms. The disconnector status signal includes operating torque, temperature data, position, and fault status. This step realizes the "four remote" functions, supports remote centralized control in the unattended mode, and the operator can monitor and control the disconnector from the centralized control center, significantly reducing the operation and maintenance intensity.

[0035] In an embodiment provided, such as Figures 1-3 , After the monitoring process is transformed, it enters the equipment handover test stage. This step is to confirm that the newly installed isolating disconnector meets the design standards and operation requirements. First, a primary equipment handover test is carried out. The test is organized by the entrusted installation unit and participated in by the supplier's technical personnel, and is strictly carried out in accordance with GB50150 "Electrical Installation Engineering Electrical Equipment Handover Test Standard". The test items include insulation resistance test, contact resistance measurement, and operation cycle test.

[0036] In the insulation resistance test, an insulation resistance tester is used to measure the insulator, porcelain bushing, and flange connection part of the disconnector. After applying the specified voltage, the resistance value is read. The resistance value threshold of the insulation resistance is set to 500 MΩ. If the actual resistance value is not less than 500 MΩ, it is considered qualified. This threshold is based on DL / T486 and GB11022 standards to ensure that the equipment has no breakdown risk in the high-voltage environment and to avoid insulation failure caused by moisture or pollution. During the test process, the appearance of the equipment is also checked to ensure that the insulator is not damaged, the porcelain body has no cracks and scars, and the porcelain bushing is firmly connected to the flange.

[0037] The contact resistance is measured using a contact resistance tester to detect the contact surfaces of the contact tips and fingers. The measurement value threshold is set at 50 μΩ. If the actual resistance value is not higher than 50 μΩ, it is qualified. This threshold aims to control contact heating and prevent ablation or energy loss caused by excessive resistance during long-term operation. Clean the contact part before measurement, ensure that the connecting bolts are made of hot-dip galvanized material, the strength meets the requirements, flat gaskets and spring gaskets are complete, and the crimping is firm.

[0038] The operation cycle test verifies the mechanical reliability through repeated opening and closing operations. The number threshold is set at 1000 times. If there are no failures in at least 1000 times, it is qualified. The test simulates actual operating conditions, checks whether the operating linkage mechanism is smooth without jamming, the on-site manual operation is labor-saving and in place, and the interlocking function between each operating mode is normal. Status and fault signals are complete, and independent passive contacts are led out for use by the monitoring system. This test confirms that the electric operating mechanism has strong applicability, high reliability, good interchangeability of components, and is convenient for maintenance.

[0039] If the commissioning test of primary equipment meets the above conditions, that is, the insulation resistance is not lower than 500 MΩ, the contact resistance is not higher than 50 μΩ, and there are no failures in at least 1000 operation cycles, then the commissioning test process of secondary equipment is entered. The commissioning test of secondary equipment adopts a verification test. After the equipment is installed and debugged, it runs continuously for 72 hours under simulated load conditions, and the temperature rise value is monitored.

[0040] In the verification test, a temperature sensor is used to monitor the temperature changes of the switchblade contacts, the mechanism box body, and the transmission part in real time. The load simulates the normal operating current of the power station. The threshold of the temperature rise value is set not to exceed 50 K. If the actual rise value does not exceed 50 K, the condition is met and the acceptance is qualified. This threshold is based on the GB1985 and DL / T593 standards, ensuring that the equipment has no overheating risk during continuous operation and confirming that the equipment can operate safely and normally under continuous operation conditions.

[0041] Finally, it should be pointed out that the methods and equipment described in detail above are only examples, and those skilled in the art can modify these examples in different ways as long as they do not depart from the scope of the present invention.

Claims

1. A method for upgrading and modifying isolating switches, characterized in that: include, S1, Inspection and quantitative analysis, conduct equipment assessment and problem diagnosis, identify operational problems and functional deficiencies; S2, selection and material optimization, setting up standard isolating switch and electric operation assembly; S3, Define the scope of the renovation, divide the renovation units based on the main wiring diagram, and cover the isolating switch and the grounding switch; S4, safety interlocking structure implementation, adding live interlocking and five-prevention system, and connecting to plant-wide management to prevent misoperation; S5 connects to the monitoring system, linking the LCU screen and the computer monitoring system to achieve remote centralized control.

2. The method for upgrading and modifying isolating switches according to claim 1, characterized in that: In the inspection and quantitative analysis process, Assess existing isolating switches, including checking the degree of corrosion of the operating linkage mechanism, the increase in operating power, the increase in contact resistance caused by incomplete contact of the closing contacts, and the lack of remote control function of the manual operating mechanism. Quantify corrosion and jamming issues to ensure diagnostic data accuracy is within ±5%.

3. The method for upgrading and modifying isolating switches according to claim 1, characterized in that: In the selection and material optimization process, Select a compliant isolating switch, with contacts and fingers made of copper and silver plating thickness of not less than 20μm. The rated power of the electric operating assembly is not less than 500W, and the integrated position sensor achieves a contact position feedback accuracy of ±1mm; The electric control assembly is equipped with a fault diagnosis module to analyze and detect motor stall or transmission jamming, and the fault signal is output to the monitoring system through dry contacts.

4. The method for upgrading and modifying isolating switches according to claim 1, characterized in that: In the process of defining the scope of the renovation, Based on the main wiring layout of the 110kV primary equipment, it covers the neutral grounding switch of the #1 and #2 main transformers, the isolating and grounding switches of the 16A and 16B switch bays, the isolating and grounding switches of the 161 and 162 switch bays, as well as the isolating and grounding switches of the 110kV bus PT bays, achieving full station coverage; The neutral point grounding switch of the main transformer adopts a single-pole grounding design, and the inrush current suppression resistor is increased to reduce the impact of grounding transient current on the system.

5. The method for upgrading and modifying isolating switches according to any one of claims 1 to 4, characterized in that: In the implementation process of the safety interlocking structure, Add a live-line interlocking device, use voltage transformer signals to detect bus and outgoing line voltages, and set the voltage threshold to 90% of the rated voltage; When the actual voltage exceeds the voltage threshold, the line live-line interlocking device is triggered to lock out. The five-prevention system is integrated into the plant-wide five-prevention system to ensure that the interlock response time is less than 100ms; The five-prevention system integrates an audible and visual alarm device to provide malfunction detection. The live line interlocking device supports multiple inputs and is compatible with 110kV bus and outgoing line voltage signals.

6. The method for upgrading and modifying isolating switches according to claim 5, characterized in that: In the process of connecting to the monitoring system, The fault diagnosis module connects the disconnector status signal to the switch station LCU screen to achieve remote control and integrates it into the plant's computer monitoring system, with a transmission delay of less than 200ms. The disconnector status signal includes disconnector operating torque, disconnector temperature data, disconnector position, and disconnector fault status.

7. The method for upgrading and modifying isolating switches according to claim 6, characterized in that: After the monitoring process is modified, an equipment handover test will be conducted. Insulation resistance testing, contact resistance measurement, and operational cycle testing are conducted. In the insulation resistance test procedure, the threshold value of insulation resistance is set to 500MΩ, the threshold value of contact resistance is set to 50μΩ, and the threshold value of the number of operation cycle tests is set to 1000 times without failure. The actual resistance of the insulation is not less than 500MΩ, the actual resistance of the contact is not more than 50μΩ, and the equipment can be handed over to the secondary equipment after passing at least 1000 operation cycles without failure.

8. The method for upgrading and modifying isolating switches according to claim 7, characterized in that: In the secondary equipment handover test process, A verification test was conducted, simulating continuous operation under load conditions for 72 hours, and the temperature rise was monitored. When the temperature rise does not exceed 50K, the conditions for the handover test of the secondary equipment are met, and the acceptance is qualified.

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