GIS isolation switch and grounding knife switch opening and closing loop state real-time monitoring method

Abstract

The invention discloses a real-time monitoring method for the state of an opening and closing loop of a GIS isolating switch and a grounding knife-switch, belongs to the technical field of high-voltage switch equipment monitoring, and aims to solve the problems of low monitoring reliability, high false alarm rate and insufficient operation safety in the prior art. The method comprises the steps that double-relay monitoring hardware is deployed, and independent monitoring is achieved by adding a closing loop monitoring relay KHJ and an opening loop monitoring relay KTJ in series; static and dynamic combined opening and closing loop state monitoring logic is constructed, loop integrity is statically monitored, and a relay state and a contactor feedback signal are dynamically compared; a series alarm signal is output to form an AND logic alarm loop, so that the alarm accuracy is ensured; remote and local operation modes are compatible, electrical interlocking is implemented, and the operation safety is improved; data such as operation time and relay states are recorded in real time, logs are generated, remote retrieval is supported, the reliability and safety of a monitoring system are improved, and the system is suitable for intelligent operation and maintenance management of high-voltage switchgear.

Description

Technical Field

[0001] This invention relates to the field of monitoring and protection technology for high-voltage switchgear in power systems, and particularly to a method for real-time monitoring of the opening and closing circuit status of GIS disconnectors and grounding switches. Background Technology

[0002] In power systems, 500kV GIS (Gas Insulated Metal Enclosed Switchgear) is a critical piece of equipment, and its stable operation is essential for ensuring the safety and reliability of power supply. However, traditional GIS disconnector maintenance methods, such as opening and closing tests on the non-energized side and voltage measurement on the energized side by opening the grounding switch, have significant limitations. These methods cannot achieve real-time monitoring of the GIS equipment's operating status and are insufficient to detect potential faults such as poor contact or deterioration in insulation performance during operation. If these potential faults are not detected and addressed in a timely manner, they may lead to operational failures at critical moments, potentially causing widespread power outages and posing a serious threat to the stable operation of the power system.

[0003] Currently, several monitoring devices and methods for disconnecting switches exist in the prior art. For example, one online monitoring device and method for disconnecting switches uses a high-frequency power supply circuit and a loop resistance measurement circuit to obtain the change curve of the contact resistance of the contact points, thereby enabling the monitoring of faults in the disconnecting switch loop. However, this method suffers from problems such as complex measurement principles and high implementation costs. Furthermore, it relies on a large amount of pre-stored temperature-resistance correlation data, and the data varies significantly for disconnecting switches of different models and under different operating environments, making data acquisition and updating laborious. Once the operating environment changes, the original correlation may no longer be applicable, leading to unreliable measurement results and affecting the accurate judgment of the disconnecting switch's operating status.

[0004] In addition, there is another method for diagnosing faults in GIS disconnect switches, which uses infrared imaging to obtain an infrared temperature distribution map and combines it with the collected parameters to determine the fault level. However, this method is mainly aimed at local hot spot faults caused by increased contact resistance. It may not be able to accurately detect and diagnose other complex electrical faults such as electrical insulation faults and incorrect wiring in secondary circuits. At the same time, the real-time performance of infrared imaging detection is relatively insufficient, making it difficult to meet the needs of real-time monitoring of GIS equipment. Therefore, it may be inadequate in dealing with sudden faults.

[0005] Specifically, CN113484741A discloses a device and method for monitoring the operating status of a GIS disconnector. This method uses an open-type current transformer to obtain the current value changing over time during the operation of the drive motor of the GIS disconnector's operating mechanism, indirectly determining the operating status of the disconnector's disconnecting switch. Simultaneously, it uses an angular displacement sensor to obtain the rotational displacement value changing over time of the drive motor of the GIS disconnector's operating mechanism, determining the position status of the disconnector's disconnecting switch. However, the real-time performance of this method is still limited, relying on historical data for estimation, and it is highly dependent on sensors. If the sensors malfunction or the data is inaccurate, it will directly affect the judgment result of the disconnector's operating status.

[0006] Furthermore, CN115879044A discloses a method and device for detecting the opening and closing status current of GIS based on a CNN network. This method achieves accurate judgment of the opening and closing status of GIS by constructing and optimizing a CNN (Convolutional Neural Network). However, the implementation process of this method is relatively complex, requiring preprocessing of the collected current data, construction of a training set for the network, and optimization of the CNN network parameters using a particle swarm optimization algorithm. The data preprocessing and model training optimization involved in this process are time-consuming, making it difficult to meet the urgent needs of power systems for real-time monitoring. Therefore, in practical applications, the real-time performance and efficiency of this method may be limited to some extent.

[0007] In summary, in view of the problems and shortcomings of the existing technology, this invention proposes a more efficient, reliable and real-time monitoring scheme for the working status of GIS disconnect switches, aiming to improve the accuracy and real-time performance of monitoring the working status of GIS equipment, thereby ensuring the safe and stable operation of the power system. Summary of the Invention

[0008] The technical problem to be solved by this invention is to provide a real-time monitoring method for the status of the opening and closing circuits of GIS disconnectors and grounding switches, which solves the technical problems of low reliability, high false alarm rate and insufficient operational safety in the status monitoring of the opening and closing circuits of GIS disconnectors and grounding switches in the field of high-voltage switchgear. It overcomes the specific limitations of the existing technology, such as the susceptibility of single relay monitoring to interference, lack of dynamic monitoring, unreliable alarm logic, poor compatibility of operation modes and insufficient data recording and analysis functions, and improves the stability, safety and intelligence level of the monitoring system.

[0009] To achieve the above objectives, the present invention employs the following technical solution: a method for real-time monitoring of the opening and closing circuit status of GIS disconnect switches and grounding switches, comprising the following steps: Step 1: Deploy dual relay monitoring hardware Step 1.1: A closing circuit monitoring relay KHJ and a tripping circuit monitoring relay KTJ are added in series in the closing and tripping control circuit, and independent monitoring is achieved through parallel high-resistance components. KHJ and KTJ adopt a DIN rail mounting structure, with a rated voltage of 24V or 48V, and contact capacity meeting the 500kV circuit breaking requirements. The high-resistance component is a metal film resistor, with a resistance value 50-100 times that of the original circuit contactor coil, ensuring that the relay resistance value is much greater than the original circuit contactor coil resistance value and avoiding mutual interference. The closing and tripping control circuit consists of remote control contacts, local transfer switch contacts, contactor coils, and auxiliary contacts connected in series. KHJ is connected in parallel across the closing contactor coil HC, and KTJ is connected in parallel across the tripping contactor coil TC, forming a dual-relay independent monitoring circuit.

[0010] Step 1.2: Through the above hardware deployment, independent and reliable monitoring of the closing circuit and the opening circuit is achieved, providing basic data support for subsequent status judgment.

[0011] Step 2: Construct the status monitoring logic for the opening and closing circuits. Step 2.1: During the static monitoring phase, the integrity of the closing circuit is checked using a KHJ when the disconnecting switch is opened, and the integrity of the opening circuit is checked using a KTJ when the grounding switch is opened. If the relay status is abnormal (such as the normally closed contact being closed), it indicates that there is an open circuit or poor contact fault in the corresponding circuit.

[0012] Step 2.2: Dynamic monitoring phase. During closing and opening operations, the relay status and contactor feedback signals are compared in real time. During closing operations, the HC contactor is triggered via the remote closing contact Y1; during opening operations, the TC contactor is triggered via the remote tripping contact Y2. If the contactor fails to engage after the command is triggered and the relay remains energized for more than a set value (e.g., 200ms), a circuit fault is identified. The relay status signal is uploaded to the monitoring system via optocoupler isolation to ensure interference resistance in signal transmission.

[0013] Step 3: Output series alarm signal The normally closed contacts of KHJ and KTJ are connected in series to the monitoring backend to form an AND logic alarm loop. The alarm signal is disconnected only when both loops are normal; an alarm is triggered if either loop malfunctions, avoiding missed alarms due to single-point faults. The alarm module adopts a hardware redundancy design, with a monitoring delay less than a preset value (e.g., 10ms), ensuring timely fault alarms. The alarm signal is simultaneously uploaded to the dispatch master station and the local display terminal, and supports remote access via the IEC 61850 protocol or Modbus protocol, enabling multi-level, multi-terminal alarm information sharing.

[0014] Step 4: Ensure compatibility with both remote and local operation modes and implement electrical interlocking. Step 4.1: The operation mode supports remote mode (monitoring system command) and local mode (transfer switch trigger) to meet the operation needs of different scenarios. In remote mode, the operation command is sent to the equipment through the communication network; in local mode, the operator directly triggers the opening and closing operation through the local transfer switch.

[0015] Step 4.2: During the electrical interlocking phase, monitor in real time the status of the grounding switch, the position of the disconnector, and at least one of the five-prevention interlocking logic conditions. If the condition is not met (e.g., the grounding switch is not open, the disconnector is in the wrong position, or the five-prevention interlocking logic conflicts), operation is prohibited and an abnormal alarm is sent. The electrical interlocking signal is connected to the control circuit via hardwiring, and the interlocking condition judgment logic is implemented using a programmable logic controller (PLC) to ensure operational safety and compliance.

[0016] Step 5: Data Recording and Analysis The system records the opening and closing operation time, relay status, contactor action signals, and fault alarm information in real time, generating an operation log and storing it in non-volatile memory for a period of no less than the required value (e.g., 12 months). The operation log supports uploading to the upper-level management system via the IEC 61850 protocol or Modbus protocol, and supports retrieval and statistical analysis by time, equipment type, and fault type, providing data support for equipment operation and maintenance.

[0017] The present invention provides a method for real-time monitoring of the opening and closing circuit status of GIS disconnect switches and grounding switches, which has the following beneficial effects: 1. This invention effectively solves the technical problems of low reliability, high false alarm rate, and insufficient operational safety in the status monitoring of GIS disconnecting switches and grounding switches in the field of high-voltage switchgear. It successfully overcomes the specific limitations of existing technologies, such as susceptibility to interference from single relay monitoring, lack of dynamic monitoring, unreliable alarm logic, poor compatibility of operating modes, and insufficient data recording and analysis functions. It significantly improves the stability, safety, and intelligence level of the monitoring system, and realizes a leap from "passive perception" to "active decision-making" in the field of GIS equipment status monitoring. It has significant technological advancement and engineering application value.

[0018] 2. Focusing on the field of 500kV GIS equipment, this invention systematically solves three core pain points of existing technologies: lack of real-time performance, limited monitoring range, and high implementation costs. Existing solutions rely on periodic testing or indirect parameter detection, which cannot perceive the integrity of the circuit in real time. The circuit status monitoring delay of this invention is less than 10ms, which is three orders of magnitude better than existing technologies. Existing solutions can only cover a single type of fault, while this invention covers nine typical faults, including control circuit disconnection, auxiliary contact faults, and power loss, increasing the fault detection rate from 40% to over 95%. High-frequency signal measurement and other technologies are costly, but the hardware cost of a single set of equipment in this invention is controlled within 2,000 yuan, which is more than 60% lower than similar solutions, and the long-term operation and maintenance costs are close to zero.

[0019] 3. This invention reduces the false alarm rate of the monitoring system to below 0.1% through a combination design of independent monitoring by dual relays and dual monitoring logic (static + dynamic) (verified by laboratory comparative testing). It effectively solves the problems of single relays being susceptible to interference and lack of dynamic monitoring. At the same time, hardware redundancy improves system reliability and avoids monitoring failure caused by a single relay failure.

[0020] 4. This invention employs a series alarm logic and hardware redundancy design to ensure timely and reliable fault alarms and avoid operational risks; it introduces electrical interlocking functions to standardize operating procedures, improving equipment operation safety by more than 30% (based on on-site operation data statistics); it achieves full tracking of the operation process, changing the traditional solution's lag in "faults can only be discovered after operation failure," allowing for early fault detection; and it can automatically adjust equipment status under extreme weather conditions, such as coping with the impact of strong winds on equipment in wind farms, thus improving equipment operation safety.

[0021] 5. This invention supports both remote and local operation modes, is compatible with multiple communication protocols (IEC 61850, Modbus), reduces system integration costs, and its modular design facilitates functional expansion; it enables long-term storage and remote access to operation logs, supports conditional retrieval and statistical analysis, and provides data-driven decision support for operation and maintenance; it generates equipment operation heatmaps through clustering algorithms to assist in the formulation of maintenance plans, thereby improving operation and maintenance efficiency and intelligence.

[0022] 6. This invention breaks through the traditional monitoring method that relies solely on the auxiliary contacts of the contactor. It introduces a high-resistance element connected in parallel across the two ends of the contactor coil to detect the circuit integrity. This solves the problem that the auxiliary contacts cannot provide feedback on the true status when the contactor contacts are stuck or the coil is broken, and fills the gap in monitoring "hidden faults" (such as contactor contact oxidation).

[0023] 7. This invention integrates multi-dimensional data to achieve autonomous interlocking control, breaking through the limitation of traditional interlocking that only relies on the location of the equipment; it introduces a fault self-healing mechanism, which automatically executes a "reclosing-opening" test and analyzes the fault type when the opening operation fails, reducing the need for manual intervention and improving the automation level of equipment operation.

[0024] 8. This invention transforms "post-event maintenance" into "predictive maintenance" by using an LSTM neural network model to predict the remaining lifespan of the contactor and send replacement reminders in advance, which significantly reduces the risk of unplanned equipment downtime.

[0025] 9. This invention is specially designed for wind farm scenarios, integrating wind speed signals into the PLC to achieve specific functions; it adopts a new method for obtaining operation permissions and communication methods, breaking through the limitations of traditional key management, improving operation and maintenance efficiency and reducing the risk of misoperation.

[0026] 10. This invention has been piloted in a 500kV substation, successfully providing an early warning of a grounding switch control circuit disconnection fault 3 hours in advance, thus avoiding a bus power outage accident caused by misoperation, fully demonstrating its engineering practicality and economy. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the opening and closing circuit of the original disconnecting switch and grounding switch; Figure 2 A schematic diagram of the monitoring relay circuit is added to this invention; Figure 3 This is a schematic diagram of the alarm circuit of the present invention. Detailed Implementation

[0028] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments: Example 1 like Figures 1 to 3 As shown in the figure, this embodiment provides a method for real-time monitoring of the opening and closing status of GIS disconnect switches and grounding switches, including the following steps: Step 1: Deploy dual relay monitoring hardware 1.1 Hardware Selection and Installation In the opening and closing control circuit, a closing circuit monitoring relay KHJ and an opening circuit monitoring relay KTJ are added in series. They adopt a rail mounting structure, with a rated voltage of 24V or 48V and a contact capacity that meets the 500kV circuit breaking requirements (e.g., rated current ≥ 5A). The opening and closing control circuit consists of remote control contacts, local changeover switch contacts, contactor coils HC / TC and auxiliary contacts connected in series. KHJ is connected in parallel across the two ends of the closing contactor coil HC, and KTJ is connected in parallel across the two ends of the tripping contactor coil TC, forming a dual-relay independent monitoring circuit. High-resistance component configuration: Connect a metal film resistor in series in the parallel branch of KHJ / KTJ and contactor coil. The resistance value should be 50 to 100 times the resistance value of the original circuit contactor coil (e.g., if the coil resistance is 100Ω, select a high-resistance component of 5kΩ to 10kΩ) to ensure that the relay monitors the current independently of the main circuit.

[0029] 1.2 Loop Integrity Design The contact status of KHJ / KTJ is uploaded to the monitoring system through an optocoupler isolation module to avoid electromagnetic interference; the relay coil power supply is independently taken from the DC bus of the control circuit to prevent monitoring failure due to shared power supply.

[0030] Step 2: Construct the status monitoring logic for the opening and closing circuits. 2.1 Static Monitoring Closing circuit detection: When the disconnecting switch is in the open state, the KHJ coil is energized and its normally open contact is closed; if the contact is open, the integrity of the closing circuit is determined to be abnormal (such as contactor coil open circuit or loose wiring). Tripping circuit detection: When the grounding switch is in the tripped state, the KTJ coil is energized and its normally open contact is closed; if the contact is open, the tripping circuit integrity is determined to be abnormal.

[0031] 2.2 Dynamic monitoring Closing operation: The remote closing contact Y1 triggers the HC contactor to close, and the status of KHJ is monitored synchronously. If the KHJ contact does not close or the HC auxiliary contact does not provide a closing signal within 200ms after Y1 closes, it is determined to be a closing fault (such as contactor jamming or mechanical interlock failure). Tripping operation: Remote tripping contact Y2 triggers the TC contactor to close, and the KTJ status is monitored synchronously. If the KTJ contact does not close or the TC auxiliary contact does not provide a closing signal within 200ms after Y2 closes, it is determined to be a tripping fault; Signal transmission: The relay status signal is isolated by an optocoupler and then uploaded to the PLC or monitoring backend as a level signal (such as 24V high level), with a sampling period of ≤50ms.

[0032] Step 3: Output series alarm signal 3.1 Alarm Circuit Design Connect the normally closed contacts of KHJ and KTJ in series to the monitoring backend to form an AND logic alarm loop: the alarm signal is disconnected only when both loops are normal (normally closed contacts are open); the alarm is triggered when either loop is abnormal (normally closed contacts are closed). Hardware redundancy: The alarm module adopts a dual-channel design with automatic switching between primary and backup channels, and the monitoring delay is ≤10ms; the alarm signal is simultaneously uploaded to the dispatch master station (IEC 61850 protocol) and the local display terminal (Modbus protocol), supporting remote access.

[0033] 3.2 Alarm Classification and Handling Level 1 alarm: Abnormal circuit integrity (such as KHJ / KTJ contact disconnection) triggers an audible and visual alarm and pushes a notification to the maintenance personnel's mobile APP. Level 2 alarm: Operational malfunction (such as dynamic monitoring timeout) triggers an emergency sound and locks operation permissions, which must be manually reset to be restored.

[0034] Step 4: Ensure compatibility with both remote and local operation modes and implement electrical interlocking. 4.1 Switching between operating modes Remote mode: Commands are sent through the monitoring system, and operation permissions are locked by the dispatch master station; the local switching switch is invalid. Local mode: Triggered by a switch in the control cabinet, operation is limited to local use, and the monitoring system records the operation time and personnel information.

[0035] 4.2 Electrical Interlocking Logic Interlocking conditions: Real-time monitoring of grounding switch status (position contact), disconnector switch position (auxiliary contact), and five-prevention interlocking logic (such as "closing grounding switch while energized" interlocking); Hardware implementation: The interlock signal is hardwired into the input module of the PLC (Programmable Logic Controller). The PLC outputs interlock contacts (such as K1 / K2) based on the logic judgment, which are connected in series in the opening and closing control circuit. Example: If the grounding switch is not tripped, the PLC disconnects contact K1 to block the closing circuit and prevent misoperation.

[0036] Abnormal handling: When the interlocking conditions are not met, the PLC triggers an alarm and prohibits operation, while displaying the specific reason for the interlocking on the local display terminal (such as "grounding switch not open, closing is prohibited").

[0037] Step 5: Data Recording and Traceability 5.1 Operation Log Storage Records the opening and closing operation time (accurate to milliseconds), relay status, contactor action signals, and fault alarm information in real time, generates structured logs, and stores them in non-volatile memory [such as SD (Secure Digital Card) cards or industrial-grade SSDs (Solid State Drives)], with a storage period of ≥12 months.

[0038] 5.2 Data Retrieval and Analysis Supports searching logs by time range (e.g., the last 24 hours), equipment type (e.g., disconnector / grounding switch), and fault type (e.g., circuit break / operation timeout); Upload data to the upper-level management system via IEC 61850 or Modbus protocol to generate operation statistics reports (such as monthly failure rate and operation success rate).

[0039] 6. Methodological Advantages (1) High reliability: Dual relay independent monitoring + hardware redundancy design, false alarm rate ≤0.1%; (2) Strong safety: Electrical interlocking hard isolation + five-proof logic to eliminate the risk of misoperation; (3) Full traceability: Millisecond-level data recording + multi-dimensional retrieval to meet the needs of power system operation and maintenance audit.

[0040] This method has been verified through type testing and is applicable to GIS equipment with voltage levels of 500kV and below. It can significantly improve operation and maintenance efficiency and reduce the risk of unplanned outages. Compared with traditional solutions, it has the following advantages, as shown in Table 1: Table 1. Technical Comparison Between the Invention and Traditional Solutions

[0041] Example 2 In another preferred embodiment, based on the above embodiment 1, such as Figure 2 As shown, this embodiment provides a method for real-time monitoring of the opening and closing circuit status of GIS disconnect switches and grounding switches. A specific embodiment is implemented using a 500kV substation GIS equipment monitoring system. The method and its implementation steps are explained in conjunction with actual engineering scenarios and technical details: 1. Project Background like Figure 1 As shown, the GIS equipment of a 500kV substation cannot detect latent faults in the opening and closing circuits in real time using traditional monitoring methods, resulting in multiple unplanned outages caused by contactor coil burnout. This method needs to be deployed to achieve full circuit status awareness. Figure 2 and Figure 3 As shown.

[0042] 2. Implementation Steps Step 1: Hardware Deployment (1) Relay selection: KHJ closing monitoring relay: DIN rail mounting, rated voltage 48V, contact capacity 10A / 250V (meets 500kV circuit breaking requirements); KTJ: Same model, connected in parallel with KHJ and installed independently in the control cabinet.

[0043] (2) High-resistivity component configuration: The closing contactor coil HC resistor is 80Ω, and a metal film resistor (resistance value 5kΩ, power 1W) is connected in parallel. The TC resistor of the trip contactor coil is 120Ω, and a metal film resistor (8kΩ, 1W power) is connected in parallel.

[0044] (3) Circuit modification: KHJ is connected in parallel across the HC coil, and KTJ is connected in parallel across the TC coil. The relay coil power supply is taken from the DC bus of the control circuit (+220V / -220V). The remote control closing contact Y1 and tripping contact Y2 are connected to the PLC input terminals through an optocoupler isolation module (model TLP521).

[0045] Step 2: Monitoring Logic Implementation (1) Static monitoring: When the disconnecting switch is opened, the KHJ coil is energized and its normally open contact closes; if the monitoring backend does not receive a closing signal (lasting 5 seconds), an alarm for "abnormal closing circuit integrity" is triggered.

[0046] (2) Dynamic monitoring During the closing operation, after Y1 is closed, a timer (200ms) is started. If the KHJ contact is not closed or the HC auxiliary contact does not provide a closing signal, it is determined to be a fault and the operation is locked. The alarm information is uploaded to the dispatch master station via the IEC 61850 protocol, and at the same time, the fault screen pops up on the local display terminal (HMI).

[0047] Step 3: Electrical Interlocking and Operation Mode (1) Interlocking conditions: The grounding switch position contact (S1), the disconnector auxiliary contact (S2), and the five-prevention interlocking logic (such as "the grounding switch on the bus side is not open, and the disconnector is prohibited from closing") are connected to the PLC via hardwiring. PLC logic example: If S1 is closed (grounding switch closed), then the output interlocking contact K1 is opened, blocking the closing circuit.

[0048] (2) Operation mode Remote mode: The dispatching master station sends instructions, the local switch is locked in the "remote" position, and the operation permission is controlled by the monitoring system; Local mode: Triggered by the control cabinet switch. When operating, the operation requires the input of the maintenance personnel's authorization password (such as 6 digits + fingerprint recognition).

[0049] Step 4: Data Recording and Analysis (1) Log storage: Industrial-grade SSDs are used to store operation logs, and the recorded fields include: operation time (milliseconds), KHJ / KTJ status, HC / TC action signal, and fault code (such as E001 indicating closing timeout). (2) Remote access: The upper-level management system reads logs through the Modbus TCP (Transmission Control Protocol) protocol and generates monthly fault statistics reports (such as "3 closing failures this month, all due to contactor jamming"). 3. Implementation Results Within 6 months of deployment, two potential overheating risks of contactor coils were successfully detected, preventing equipment burnout; the response time for maintenance personnel was reduced from an average of 30 minutes to 5 minutes, and the number of unplanned outages was reduced by 80%.

[0050] Example 3 In another preferred embodiment, based on the above embodiments 1 and 2, in order to further demonstrate the practicality and flexibility of the present invention, this embodiment takes the intelligent transformation of GIS equipment in a 220kV wind farm as an example to illustrate how to adjust the temperature control strategy according to the material characteristics.

[0051] 1. Project Background Because the GIS equipment of a certain 220kV wind farm is located in a remote area, traditional manual inspection is inefficient. This method is needed to achieve unattended status monitoring and autonomous interlocking.

[0052] 2. Implementation Steps Step 1: Hardware Optimization Design (1) Relay selection: KHJ / KTJ uses a rated voltage of 24V and a contact capacity of 5A / 125V (suitable for low-voltage control circuits in wind farms). The relay is installed inside the local control box of the GIS unit, with a protection rating of IP65 (dustproof and waterproof).

[0053] (2) High-resistivity component configuration: The HC coil has a resistance of 150Ω and is connected in parallel with a metal film resistor (resistance value of 10kΩ, power of 0.5W). The TC coil has a resistance of 200Ω and is connected in parallel with a metal film resistor (resistance value of 15kΩ, power of 0.5W).

[0054] Step 2: Monitoring Logic and Communication (1) Static monitoring: The integrity of the tripping circuit is detected by KTJ. If the KTJ contact does not close after the grounding switch trips (for 10 seconds), the local buzzer alarm is triggered and pushed to the operation and maintenance APP. (2) Dynamic monitoring: During the tripping operation, if the KTJ contact does not close within 200ms after Y2 is closed, the PLC will automatically perform a "reclosing-tripping" test (up to 3 times). If it still fails, the equipment will be locked and a fault will be reported. (3) Communication protocol: The monitoring backend and dispatch master station adopt the IEC 61850-90-5 protocol and communicate with the wind farm SCADA (Supervisory Control And Data Acquisition) system via the Modbus RTU protocol.

[0055] Step 3: Electrical Interlocking and Autonomous Control (1) Interlocking conditions: Real-time monitoring of wind speed signals (connected to PLC via an anemometer). If the wind speed is >15m / s and the disconnector is in the closed state, the tripping operation is automatically triggered and the closing circuit is locked (to prevent phase-to-phase short circuit caused by wind deviation). (2) Operation mode: Local mode: Obtain operation permission by scanning a QR code via mobile APP (valid for 10 minutes), and support Bluetooth near field communication (NFC) to trigger opening and closing of the circuit breaker.

[0056] Step 4: Data Application and Decision Support (1) Fault prediction: Based on historical logs (stored for 24 months), the lifespan of the contactor is predicted using machine learning algorithms [such as LSTM (Long Short-Term Memory) neural network], and a replacement reminder is pushed out 30 days in advance; (2) Operation and maintenance optimization: Generate operation heatmaps (e.g., "A certain disconnector switch is operated 50 times a month, it is recommended to add backup equipment") to assist in the development of maintenance plans.

[0057] 3. Implementation Results This enables unmanned operation of GIS equipment in wind farms, reducing annual maintenance costs by 600,000 yuan; and through wind speed interlocking, it avoids two equipment damage accidents caused by strong winds.

[0058] 4. A comparative summary of Examples 2 and 3 is shown in Table 2: Table 2 Comparison Summary of Examples 2 and 3

[0059] Both embodiments verify the universality and scalability of this method, which allows for flexible adjustment of hardware parameters and logic strategies according to different scenario requirements.

[0060] In the preferred embodiment, KHJ and KTJ in step 1.1 adopt a rail-mounted structure with a rated voltage of 24V or 48V. The above settings ensure that the equipment can operate stably under different voltage environments. At the same time, the rail-mounted structure facilitates later maintenance and upgrades, improves the system's flexibility and maintainability, and lays a solid foundation for the implementation of the overall solution.

[0061] In a preferred embodiment, the high-resistance element is a metal film resistor with a resistance value of 50 to 100 times that of the original circuit contactor coil resistance. This setting ensures that even if the contactor contacts stick together under high-resistance conditions, the current passing through the high-resistance element is significantly limited, effectively preventing overheating and damage, while ensuring the safe and stable operation of the system.

[0062] In the preferred embodiment, the opening and closing control circuit in step 1.1 is composed of remote control contacts, local transfer switch contacts, contactor coils, and auxiliary contacts connected in series, and the contact capacity of KHJ and KTJ meets the 500kV circuit breaking requirements. The above settings ensure the reliability of the opening and closing control circuit during remote and local operation. At the same time, the high-capacity contacts of KHJ (closing relay) and KTJ (tripping relay) effectively resist arc erosion in the 500kV high-voltage environment, improving the overall safety performance of the system.

[0063] In the preferred embodiment, during the dynamic monitoring in step 2.2, the HC contactor is triggered via the remote closing contact Y1 during the closing operation, and the TC contactor is triggered via the remote tripping contact Y2 during the opening operation. The relay status signal is uploaded to the monitoring system through optocoupler isolation. The above settings ensure the accurate transmission and execution of operation commands, while improving the electrical isolation and anti-interference capabilities of the system, ensuring the real-time performance and reliability of monitoring data, and providing solid technical support for the stable operation of the power system.

[0064] In the preferred embodiment, step 3 includes: connecting the normally closed contacts of KHJ and KTJ in series to the monitoring backend to form an AND logic alarm loop; disconnecting the alarm signal only when both loops are normal; and using hardware redundancy in the alarm module to ensure monitoring delay is less than a preset value (e.g., 10ms). These settings ensure high reliability and rapid response capability of the system. When any loop is abnormal, an alarm is triggered immediately, and hardware redundancy improves fault detection efficiency, ensuring the stable operation of the overall system.

[0065] In the preferred embodiment, the alarm signal is simultaneously uploaded to the dispatch master station and the local display terminal, and supports remote access via the IEC 61850 protocol or the Modbus protocol. These settings ensure that monitoring personnel can quickly obtain alarm information whether at the master station or on-site, improving the flexibility and timeliness of fault response. At the same time, the compatible communication protocol broadens the application scope of system integration and enhances the system's compatibility and scalability.

[0066] In the preferred embodiment, the electrical interlock signal in step 4.2 is connected to the control circuit via hard-wiring, and the interlock condition judgment logic is implemented using a programmable logic controller (PLC). The above settings ensure reliable transmission and rapid response of the electrical interlock signal, while the flexible programming capability of the PLC makes the interlock condition judgment more accurate, facilitating later maintenance and functional expansion.

[0067] In a preferred embodiment, the method further includes: step 5, the data recording step, which records the opening and closing operation time, relay status, contactor action signal, and fault alarm information in real time, generates an operation log, and stores it in a non-volatile memory for a period of not less than (e.g., 12 months). The above settings ensure the integrity and traceability of the system's historical data, facilitating subsequent fault analysis and maintenance. At the same time, the system has an automatic function to clean up expired logs to maintain effective utilization of storage space and optimize system performance.

[0068] In the preferred embodiment, the operation log in step 5 supports uploading to the upper-level management system via the IEC 61850 protocol or the Modbus protocol, and supports retrieval and statistical analysis by time, equipment type, and fault type. The above settings greatly improve the efficiency of operation and maintenance, ensuring that managers can quickly locate problems and take timely countermeasures. At the same time, the system is compatible with multiple communication protocols, making it easy to integrate into the existing management system and achieve seamless connection and data sharing.

[0069] In summary, this invention proposes a real-time monitoring method for the opening and closing circuit status of GIS disconnect switches and grounding switches, which effectively solves the problems of low reliability, high false alarm rate, and insufficient operational safety in this type of monitoring in the field of high-voltage switchgear. It successfully overcomes the limitations of existing technologies in terms of monitoring methods, alarm logic, compatibility of operating modes, and data functions, and significantly improves the stability, safety, and intelligence level of the monitoring system.

[0070] At the hardware level, this invention introduces high-resistance components (such as metal film resistors) in parallel across the contactor coil for the first time in GIS equipment, breaking through the traditional monitoring method that relies on auxiliary contacts of the contactor. It can accurately detect the integrity of the circuit and solve the problem that auxiliary contacts cannot provide feedback on the true status. At the same time, the closing monitoring relay KHJ and the opening monitoring relay KTJ are deployed independently. Through hardware redundancy, the monitoring failure caused by the failure of a single relay is avoided, thereby improving the reliability of the system.

[0071] Logically, by sensing the physical connection integrity of the circuit in real time through the relay contact status, the monitoring gap for "hidden faults" (such as contactor contact oxidation) is filled; by combining remote control contact signals with relay action timing, the entire operation process can be tracked, avoiding the lag of "faults can only be discovered after operation failure" in traditional solutions; by integrating multi-dimensional data and realizing autonomous interlocking control through PLC logic, the limitation of traditional interlocking relying solely on equipment location is broken; when the tripping operation fails, the "reclosing-tripping" test is automatically executed and the fault type is analyzed, introducing a fault self-healing mechanism into the control circuit of GIS (Gas Insulated Switchgear) equipment, reducing manual intervention.

[0072] In terms of data, based on historical operation logs, an LSTM neural network model is used to predict the remaining life of contactors, enabling "predictive maintenance" and reducing the risk of unplanned equipment downtime. For wind farm scenarios, wind speed signals are integrated into the PLC to achieve special functions, improving equipment operational safety. Operation permissions are obtained by scanning codes with a mobile app or using NFC near-field communication, combined with Bluetooth communication to achieve local control, improving operation and maintenance efficiency. Multiple protocols are supported to achieve seamless integration with multiple systems, providing data support for operation and maintenance decisions. Equipment operation heatmaps are generated based on historical operation data to assist in the formulation of maintenance plans and enhance data value.

[0073] This invention achieves a leap from "passive perception" to "proactive decision-making" in the field of GIS equipment status monitoring through hardware, logic, and data innovation. It achieves breakthroughs in core functions such as technology integration and scenario adaptation, fault self-healing, predictive maintenance, and cross-level data interaction, demonstrating significant technological advancement and engineering application value.

Claims

1. A method for real-time monitoring of the opening and closing circuit status of GIS disconnect switches and grounding switches, characterized in that, Includes the following steps: Step 1: Deploy dual-relay monitoring hardware; Step 2: Construct the status monitoring logic for the opening and closing circuits; Step 3: Output a series alarm signal; Step 4: Ensure compatibility with both remote and local operation modes and implement electrical interlocking.

2. The method for real-time monitoring of the opening and closing circuit status of GIS disconnect switches and grounding switches according to claim 1, characterized in that, Step 1 includes: Step 1.1: Add a closing circuit monitoring relay KHJ and a opening circuit monitoring relay KTJ in series in the opening and closing control circuit, and achieve independent monitoring by connecting high resistance components in parallel, and the resistance value of the relay is much greater than the resistance value of the original circuit contactor coil. Step 1.2: Connect KHJ in parallel to the two ends of the closing contactor coil HC, and connect KTJ in parallel to the two ends of the tripping contactor coil TC to form a dual-relay independent monitoring circuit.

3. The method for real-time monitoring of the opening and closing circuit status of GIS disconnect switches and grounding switches according to claim 2, characterized in that: In step 1.1, KHJ and KTJ adopt a rail mounting structure with a rated voltage of 24V or 48V.

4. The method for real-time monitoring of the opening and closing circuit status of GIS disconnect switches and grounding switches according to claim 3, characterized in that: The high-resistance element is a metal film resistor, and its resistance value is 50 to 100 times the resistance value of the original circuit contactor coil.

5. The method for real-time monitoring of the opening and closing circuit status of GIS disconnect switches and grounding switches according to claim 4, characterized in that: In step 1.1, the opening and closing control circuit is composed of remote control contacts, local transfer switch contacts, contactor coils and auxiliary contacts connected in series, and the contact capacity of KHJ and KTJ meets the 500kV circuit breaking requirements.

6. The method for real-time monitoring of the opening and closing circuit status of GIS disconnect switches and grounding switches according to claim 1, characterized in that, Step 2 includes: Step 2.1: Static monitoring. When the disconnecting switch is opened, the integrity of the closing circuit is detected by KHJ. When the grounding switch is opened, the integrity of the opening circuit is detected by KTJ. Step 2.2: Dynamic monitoring: In the opening and closing operation, compare the relay status with the contactor feedback signal in real time. If the contactor does not engage after the command is triggered and the relay remains energized for more than the set value, it is determined to be a circuit fault.

7. The method for real-time monitoring of the opening and closing circuit status of GIS disconnect switches and grounding switches according to claim 6, characterized in that: In step 2.2 dynamic monitoring, during the closing operation, the HC contactor is triggered by the remote closing contact Y1, and during the opening operation, the TC contactor is triggered by the remote tripping contact Y2. The relay status signal is uploaded to the monitoring system through optocoupler isolation.

8. The method for real-time monitoring of the opening and closing circuit status of GIS disconnect switches and grounding switches according to claim 1, characterized in that, Step 3 includes: connecting the normally closed contacts of KHJ and KTJ in series to the monitoring backend to form an AND logic alarm loop. The alarm signal is disconnected only when both loops are normal. At the same time, the alarm module adopts a hardware redundancy design, and the monitoring delay is less than a preset value.

9. The method for real-time monitoring of the opening and closing circuit status of GIS disconnect switches and grounding switches according to claim 8, characterized in that: The alarm signal is simultaneously uploaded to the dispatch master station and the local display terminal, and can be remotely accessed via the IEC 61850 protocol or the Modbus protocol.

10. The method for real-time monitoring of the opening and closing circuit status of GIS disconnect switches and grounding switches according to claim 1, characterized in that, Step 4 includes: Step 4.1: Operation mode, supporting remote mode and local mode; Step 4.2: Electrical interlocking. Monitor at least one interlocking condition in the following categories in real time: grounding switch status, disconnector position, and five-prevention interlocking logic. If the condition is not met, operation is prohibited and an abnormal alarm is sent.

11. The method for real-time monitoring of the opening and closing circuit status of GIS disconnectors and grounding switches according to claim 10, characterized in that: In step 4.2, the electrical interlock signal is connected to the control circuit through hard wiring, and the interlock condition judgment logic is implemented by a programmable logic controller (PLC).

12. The method for real-time monitoring of the opening and closing circuit status of GIS disconnect switches and grounding switches according to claim 1, characterized in that, The method further includes: step 5, data recording step, which records the opening and closing operation time, relay status, contactor action signal and fault alarm information in real time, generates an operation log and stores it in a non-volatile memory, with a storage period of not less than the required value.

13. The method for real-time monitoring of the opening and closing circuit status of GIS disconnect switches and grounding switches according to claim 12, characterized in that: In step 5, the operation log can be uploaded to the upper-level management system via the IEC 61850 protocol or the Modbus protocol, and can be retrieved and statistically analyzed by time, device type, and fault type.

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