A method for preventing misoperation for single side maintenance working condition of power transmission line

Abstract

This invention provides a method for preventing misoperation during unilateral maintenance of transmission lines. The method includes: collecting operational data from a target substation; wherein the target substation is either an intelligent substation with a smart control system or a conventional substation without a smart control system; determining whether the target substation meets preset maintenance conditions based on the operational data; if so, initiating a timing program; and generating a valid line maintenance flag when the timing result meets a preset timing threshold; after generating the valid line maintenance flag, entering the maintenance phase and executing maintenance actions; and determining the maintenance status based on the execution result, wherein the maintenance status includes at least maintenance completion or an abnormality alarm. This invention addresses the common industry problem of unilateral line maintenance tripping errors by proposing a fully automatic anti-misoperation system, achieving self-adaptive and self-healing protection functions with zero manual intervention throughout the process.

Description

Technical Field

[0001] This invention relates to the field of power system automation technology, and in particular to a method for preventing misoperation during single-sided maintenance of transmission lines. Background Technology

[0002] In routine maintenance, protection debugging, and secondary circuit verification of transmission lines, an asymmetrical operation mode is commonly observed, where one side of the line is energized while the other side is cold standby / out of service for maintenance. Under this condition, the operating side operates normally with voltage, while the maintenance side performs routine maintenance work such as protection level adjustments, current flow tests, circuit transmission, and device point-to-point checks. Remote tripping protection (remote tripping protection) is a cross-site coordinated protection system. Its basic principle is as follows: when the local protection device detects a serious fault that cannot be handled locally alone (such as a bus fault or circuit breaker failure), it generates a remote tripping trigger signal. After encoding and verification, this signal is transmitted to the other side via a fiber optic channel, requesting the circuit breaker on the other side to operate and quickly isolate the fault. Upon receiving the remote tripping signal, the device on the other side needs to verify and confirm the signal multiple times before considering it reliable. After confirming the reliable signal, the output logic is determined based on the protection control word settings. Regulations clearly require that when a line is out of service and the corresponding switch on either side needs to be restored to operation, the remote tripping protection should be disabled to prevent erroneous tripping. However, many shortcomings still exist in actual operation.

[0003] In recent years, false tripping accidents caused by the improper disengagement of remote tripping pressure plates during single-sided line maintenance have become increasingly common. Case 1: False tripping of a 220kV bus differential protection system. After the replacement of the second 220kV bus differential protection system in a 220kV substation, a false tripping accident occurred on a 220kV line during circuit breaker transmission testing. The direct cause was that the opposite side mistakenly received a remote tripping signal, leading to the false tripping. The root cause was that the remote tripping pressure plate of the first line protection system was not disengaged during the verification of the second bus differential protection system, causing the remote tripping signal to be mistakenly transmitted to the opposite side through the first line protection system. Case 2: False tripping of a 110kV line fiber optic differential remote tripping protection system. During the replacement and upgrading of the 110kV bus differential protection system by a power supply company, when the relay protection personnel were debugging the secondary circuit between the bus differential protection and the line protection, the three-phase switch of the wind farm on the opposite side of the 110kV line tripped, and the protection action report showed a remote tripping output. This tripping was not caused by a line fault, but rather by a protection malfunction. The local protection device sent a "remote trip input" signal to the opposite side, causing the opposite switch to trip directly. This case demonstrates that remote protection malfunctions are not isolated incidents, but rather a long-standing and common problem plaguing the power safety industry.

[0004] Currently, the industry mainly relies on manual control, which has fundamental safety shortcomings: First, the risk of manual omissions is high. The deployment and removal of remote tripping control plates depends on the operator's memory and execution of operating procedures. Complex maintenance processes, fatigue from nighttime work, and interference from overlapping operations make it extremely easy to miss or forget to remove remote tripping control plates, with no technical backup guarantee. Second, traditional protection methods have poor reliability. Some teams use temporary fiber optic cable insertion / removal and disconnection of channel loops to isolate risks, which not only increases equipment wear and reduces the lifespan of fiber optic connectors but also poses long-term risks of incorrect or loose connections during restoration. Third, the device maintenance mode lacks specificity. The maintenance control plates built into the protection devices can only shield some remote signals and alarm changes, and cannot reliably block the transmission of remote tripping channel messages; the logic of devices from different manufacturers is inconsistent, resulting in varying protection effects, and they cannot be used as a specific anti-misoperation measure.

[0005] To achieve fully automated remote trip protection with error prevention, the first step is to solve the problem of accurately identifying the line maintenance status. Currently, the identification of transmission line operating conditions mainly relies on remote signaling of a single switch position or manual calibration. This cannot accurately distinguish between hot standby (disconnector closed) and cold standby / maintenance (disconnector open), cannot identify maintenance status, is susceptible to remote signaling jitter, and cannot handle maintenance-related additional testing scenarios (where voltage and current are artificially introduced with non-zero values). If the status is not accurately determined—either the operating state is misjudged as the maintenance state (leading to the remote trip protection being incorrectly deactivated), or the maintenance state is misjudged as the operating state (leading to the protective measures not being activated)—all subsequent protective measures cannot be reliably executed. Summary of the Invention

[0006] The purpose of this invention is to propose a method for preventing misoperation during single-sided maintenance of transmission lines, and to solve the technical problem of how to automatically identify the maintenance status of lines with high reliability, anti-interference, and full coverage of all operating conditions.

[0007] On the one hand, a method for preventing misoperation during unilateral maintenance of transmission lines is provided, including: Collect operational data from the target substation; the target substation is either an intelligent substation with an intelligent control system or a conventional substation without an intelligent control system. Based on the operational data, determine whether the target substation meets the preset maintenance conditions. If it does, start the timing program and generate a valid line maintenance flag when the timing result meets the preset timing threshold. Once a valid line maintenance flag is generated, the maintenance phase begins and maintenance actions are performed. The maintenance status is then determined based on the execution results, including at least maintenance completion or an abnormality alert alarm.

[0008] Preferably, the operating data of the target substation includes at least switch position information, disconnector position information, voltage telemetry information, current telemetry information, and maintenance switch information.

[0009] Preferably, the preset maintenance conditions include, Any one of the three phases of the switch is in the open position; Any one of the three phases of the disconnect switch is in the open position; If any one of the three phase voltages is less than the preset secondary voltage value; If any one of the three phase currents is less than the preset secondary current value.

[0010] Preferably, the preset maintenance conditions include, Any one of the three phases of the line-side disconnector is in the open position; Any one of the three phases of the busbar-side disconnector is in the open position; The maintenance pressure plate is in the "in operation" state or the maintenance sign is in the "valid" state.

[0011] Preferably, it also includes starting the corresponding timing when the preset maintenance conditions are met within the same program scan cycle; When the timing result reaches the preset timing threshold, a line maintenance validity flag is generated as a global read-only variable, and the line maintenance validity flag is sent to the line protection device through a preset protocol.

[0012] Preferably, the method further includes resetting the line maintenance validity flag to zero after the line resumes operation and the steady state is maintained for a preset steady state time; wherein, the line resumes operation when the switch is in the closed position, the disconnector is in the closed position, and there is voltage and current in the line.

[0013] Preferably, the entry into the maintenance phase includes sending two preset remote control commands to the line protection device within the same logic scan cycle via a remote control protocol: The protection device verifies the validity of the two preset commands respectively; if the verification passes, it returns a correct confirmation message; if the verification fails, it returns a negative confirmation message to the master station to terminate the subsequent execution operation. The legality of the two preset commands includes at least whether the operation permission meets the preset conditions, whether the interlocking conditions meet the preset conditions, whether the object exists, and whether the object can be remotely controlled.

[0014] Preferably, the maintenance action includes issuing a remote execution command after receiving confirmation of a correct return to school; After the protection device receives the execution command, it rewrites the parameter values ​​corresponding to the states of the two soft pressure plates to the corresponding values; when the execution is completed, it sends a status change message as the final confirmation result of the execution result. If any pressure plate fails to be remotely controlled, an alarm pop-up will immediately appear, prompting manual intervention; subsequent operations will be suspended and a complete error log will be recorded.

[0015] Preferably, the method further includes, after generating a valid line maintenance flag, simultaneously imposing access restrictions on the operation entry point; wherein, the access restriction on the operation entry point includes at least the following: the remote control button for sending / receiving the soft switch on the human-machine interface is automatically grayed out and cannot be clicked; the operator's remote control interface for the soft switch rejects any operation requests. When an operator attempts to engage a locked remote jump soft pressure plate, the system displays a corresponding locking prompt. If it is necessary to forcibly engage the remote jump plate during maintenance, a user with the corresponding permissions needs to enter an advanced authorization code to temporarily unlock the self-lock. Setting the temporary unlock triggers a network-wide audible and visual alarm and records it to the security audit log. If the line maintenance validity flag still exists after the self-locking is released, the system will automatically lock again after the preset safe time threshold is reached.

[0016] Preferably, it also includes, after the line maintenance valid indicator is cleared to zero, releasing the ash lock of the remote control button of the remote trip pressure plate and restoring normal remote control operation permission; Send a remote preset command to the protection device, and after receiving the correct confirmation of the return calibration of the two pressure plates, send a remote execution command. After the device completes the execution, send a status change message. The system compares the status of the pressure plate sent by the protection device with the instructions issued by the background. If they are all consistent, it outputs a recovery reminder message and generates a confirmation record of successful maintenance. If the command to engage fails, it immediately issues an alarm.

[0017] In summary, implementing the embodiments of the present invention has the following beneficial effects: This invention provides a method for preventing misoperation during single-sided maintenance of transmission lines. Addressing the industry-wide problem of erroneous remote tripping during single-sided line maintenance, it proposes a fully automated anti-misoperation system comprising "precise status identification—forced exit of soft pressure plate—rigid access control—automatic recovery." It constructs a multi-dimensional maintenance status determination method based on "three-dimensional fusion + dual-path parallelism + hierarchical anti-jitter." The innovative fully automated anti-misoperation mechanism of "forced exit of remote tripping transmission / reception soft pressure plate + self-locking of operation permissions" distinguishes it from traditional methods involving manual operation or temporary fiber optic cable insertion / removal. This achieves self-adaptive and self-healing protection functions with zero manual intervention throughout the entire process. Attached Figure Description

[0018] 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.

[0019] Figure 1 This is a schematic diagram of the main process of a method for preventing misoperation during single-sided maintenance of transmission lines in an embodiment of the present invention. Detailed Implementation

[0020] 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.

[0021] like Figure 1 The diagram shown is an embodiment of a method for preventing misoperation during unilateral maintenance of transmission lines provided by the present invention. In this embodiment, the method includes the following steps: Step S1: Collect the operating data of the target substation; wherein, the target substation is an intelligent substation with an intelligent control system or a conventional substation without an intelligent control system. Step S2: Determine whether the target substation meets the preset maintenance conditions based on the operating data. If it does, start the timing program and generate a valid line maintenance flag when the timing result meets the preset timing threshold. Step S3: After generating the valid line maintenance flag, the maintenance phase begins and maintenance actions are performed; and the maintenance status is determined based on the execution results, wherein the maintenance status includes at least maintenance completion or abnormal alarm.

[0022] In one embodiment, the operating data of the target substation includes at least switch position information, disconnector position information, voltage telemetry information, current telemetry information, and maintenance switch information. The data in the table below is collected in real time from the monitoring backend using the IEC 61850 MMS protocol (intelligent substation) or the IEC 60870-5-103 / 104 protocol (conventional substation).

[0023]

[0024] In one embodiment, the preset maintenance conditions are divided into two paths.

[0025] Firstly, the criteria for routine power outage inspection include: any one of the three phases of the switch is in the open position; any one of the three phases of the disconnect switch is in the open position; any one of the three phase voltages is less than the preset secondary voltage value; and any one of the three phase currents is less than the preset secondary current value.

[0026] Criterion Expression: Path 1 Condition = (Switch A phase = 1 minute) AND (Switch B phase = 1 minute) AND (Switch C phase = 1 minute) AND (Line-side disconnector three-phase = 1 minute) AND (Bus-side disconnector three-phase = 1 minute) AND (Ua < 0.5V) AND (Ub < 0.5V) AND (Uc < 0.5V) AND (Ia < 0.04A) AND (Ib < 0.04A) AND (Ic < 0.04A) The error prevention logic for each sub-condition: Three-phase switch open position: Any phase closed position is judged as non-maintenance state; Three-phase disconnect switch open position: Disconnect switch closed position means that primary and secondary equipment are not isolated; Three-phase voltage <0.5V (secondary value): Eliminates false judgment of "false liveness" caused by PT disconnection or contact adhesion; Three-phase current <0.04A (secondary value): Eliminates residual current of CT or induced interference.

[0027] Secondly, the determination of the increased quantity test / closed position maintenance includes: any one of the three phases of the line-side disconnector is in the open position; any one of the three phases of the bus-side disconnector is in the open position; and the maintenance pressure plate is in the engaged state or the maintenance sign is in the effective state.

[0028] Criterion expression: Path 2 condition = (Line-side disconnector three-phase = open) AND (Bus-side disconnector three-phase = open) AND (Maintenance pressure plate = in OR Maintenance flag = 1) In Path Two, the switch position is not subject to mandatory constraints (either open or closed is acceptable) to accommodate maintenance conditions when the switch is closed (such as mechanical characteristic tests or circuit resistance tests). The open position of the disconnect switch ensures isolation from the primary system, and the engagement of the maintenance pressure plate confirms that the system is currently in maintenance operation mode.

[0029] In one embodiment, when preset maintenance conditions are met within the same program scan cycle, the corresponding timing is initiated; when the timing result reaches a preset timing threshold, a line maintenance validity flag for a globally read-only variable is generated, and this flag is sent to the line protection device via a preset protocol. For graded anti-jitter fault tolerance and flag generation, when all sub-conditions of path one or path two are met within the same program scan cycle, the corresponding 30-second delay confirmation timer is initiated.

[0030] Tiered image stabilization strategies are shown in the table below.

[0031]

[0032] Flag generation and synchronization: After 30 seconds, the system generates a global read-only variable Line_Maintenance_Flag = 1 (valid flag for line maintenance) in the monitoring background, and synchronously sends it to the line protection device through the IEC 61850 MMS protocol or the IEC 60870-5-104 protocol to ensure that subsequent linkages have a unified time segment.

[0033] Furthermore, once the line resumes operation and maintains a steady state for a preset steady-state time, the line maintenance validity flag is cleared. This resumption of line operation is defined as the switch being closed, the disconnector being closed, and the line exhibiting voltage and current. The flag is cleared after the line resumes operation (switch closed, disconnector closed, voltage and current present) and maintains a steady state for 15 seconds, at which point the system automatically clears the Line_Maintenance_Flag.

[0034] In one embodiment, entering the maintenance phase includes sending two preset remote control commands to the line protection device within the same logical scan cycle via a remote control protocol. The protection device verifies the legality of each preset command. If the verification passes, it returns a correct confirmation message. If the verification fails, it returns a negative confirmation message to the master station to terminate subsequent operations. The legality of the two preset commands includes at least whether the operation permission meets preset conditions, whether the interlocking conditions meet preset conditions, whether the object exists, and whether the object is remotely controllable. The maintenance entry phase is actually a fully automatic exit of the remote trip soft pressure plate.

[0035] When Line_Maintenance_Flag changes from 0 to 1, the system automatically performs the following operations: Step 1: Issuance of Remote Preset Commands. The monitoring backend simultaneously issues two remote preset commands to the line protection device via the remote control protocol: Target object 1: [Long jump sending soft pressure plate], target value = 0 (exit) Target object 2: [Long jump receiving soft pressure plate], target value = 0 (exit) The two instructions are issued within the same logical scan cycle to ensure the synchronization of the exit action.

[0036] Step 2: Device Recalibration Confirmation. The protection device verifies the validity of the two preset commands (including operation permissions, interlocking conditions, object existence, and remote control capability). If the verification passes, a "Recalibration Correct" confirmation message is returned to the monitoring backend; if the verification fails, a negative confirmation is returned, and the main station terminates subsequent operations.

[0037] In one embodiment, the maintenance actions include: after receiving confirmation of correct calibration, issuing a remote control execution command; waiting for the protection device to receive the execution command and then rewriting the parameter values ​​corresponding to the states of the two soft pressure plates to their corresponding values; after execution is completed, sending a status change message as the final confirmation of the execution result; if remote control of any pressure plate fails, immediately displaying an alarm pop-up and reminding for manual intervention; pausing subsequent operations and recording a complete error log. After receiving confirmation of "correct calibration" for both commands, the backend issues a remote control execution command. After receiving the execution command, the device actually writes the states of the two soft pressure plates to 0. After execution, the device sends a status change message as the final confirmation of the execution result.

[0038] During error handling, if any remote control of a pressure plate fails (preset failure, execution failure, timeout, or negative confirmation return), the system will immediately: display an alarm pop-up window "Automatic exit failure of remote pressure plate check: [Failed pressure plate name], please intervene manually." Subsequent operations will be suspended. A complete error log (including the failure reason code) will be recorded.

[0039] The background database updates the pressure plate status, and the HMI synchronously displays the "Exit" status. The device panel also displays the updated status locally. An operation log is generated throughout the process, including: operation time (accurate to milliseconds), operation source (automatic system operation), names of the two pressure plates, status before operation, status after operation, return-to-calibration confirmation result, and operation result (success / failure).

[0040] In one embodiment, after a valid line maintenance flag is generated, access to the operation entry point is simultaneously locked. This access control includes at least the following: the remote control button for the remote tripping / receiving soft switch on the human-machine interface is automatically grayed out and cannot be clicked; the operator's remote control interface for the remote tripping soft switch rejects any operation requests; when an operator attempts to activate a locked remote tripping soft switch, the system displays a corresponding lock prompt; if it is necessary to forcibly activate the remote tripping soft switch during maintenance, a user with the corresponding permissions must enter an advanced authorization code to temporarily unlock the self-lock. This temporary unlocking triggers a network-wide audible and visual alarm and is recorded in the security audit log; if the valid line maintenance flag still exists after the self-lock is released, it will automatically re-lock after a preset safety time threshold is reached.

[0041] To prevent accidental recovery by human error, an operation permission self-locking mechanism is implemented. When Line_Maintenance_Flag = 1, in addition to automatically executing the soft clamp exit, the system simultaneously locks permissions for the following two operation entry points: The remote control button for sending / receiving soft pressure plates on the human-machine interface of the background monitoring system is automatically grayed out and cannot be clicked; the remote control operation interface for sending / receiving soft pressure plates on the operator workstation and engineer station rejects any operation requests.

[0042] When the operator attempts to activate the locked remote jump soft pressure plate, the system displays a prompt box: "The equipment is under maintenance, and the remote jump pressure plate activation permission has been automatically locked." If the remote tripping switch needs to be forcibly engaged during maintenance (e.g., for emergency power restoration, special testing requirements), a user with "administrator" privileges must enter an advanced authorization code to temporarily release the self-lock. This operation will trigger a network-wide audible and visual alarm and be recorded in the security audit log. After the self-lock is released, if Line_Maintenance_Flag is still 1, the system will automatically relock after a set time (e.g., 3 minutes).

[0043] In one embodiment, after the line maintenance validity flag is cleared, the remote control button of the remote trip pressure plate is unlocked and normal remote control operation permission is restored; a remote control preset command is sent to the protection device, and after receiving the correct confirmation of the return calibration of the two pressure plates, a remote control execution command is sent. After the device completes the execution, a status change message is sent up; the pressure plate status sent by the protection device is compared with the command sent by the background. If they are all consistent, a recovery reminder message is output and a confirmation record of successful maintenance is generated; if the command fails to be activated, an alarm is immediately triggered.

[0044] The maintenance exit phase actually involves the automatic reset of the remote jump soft pressure plate. Once Line_Maintenance_Flag is cleared, the system automatically executes the following process: The system automatically unlocks the remote control button on the remote jump pressure plate, restoring normal remote control operation privileges.

[0045] The dual-pressure plate synchronous remote control preset command is issued, and the monitoring backend issues the remote control preset command to the protection device: Target 1: [Long-jump transmission soft pressure plate], target value = 1 (investment) Target object 2: [Long jump receiving soft pressure plate], target value = 1 (investment) Upon receiving "Return to calibration correct" confirmations from the two pressure plates, the backend issues a remote execution command. After the device completes execution, it sends a status change message.

[0046] After status verification and successful activation confirmation, the system compares the status of the pressure plate sent by the protection device with the command issued by the background system. Once all are consistent, the background system displays "Line is running normally, remote tripping function fully restored" and generates a confirmation record of "Maintenance exited, soft pressure plate successfully restored".

[0047] In case of an error, if the command to activate fails, the system will immediately issue an alarm saying "Automatic activation of remote tripping pressure plate failed, please intervene manually" to prevent the remote tripping protection function from being lost after power is restored.

[0048] In a specific embodiment, the specific effects produced in the internal logic of the protection device after the remote jump sending soft pressure plate and the remote jump receiving soft pressure plate are exited are shown in the table below.

[0049]

[0050] Safety Assurance: One-click Emergency Activation / Deactivation: A soft control panel for "Overall Activation / Deactivation of Intelligent Prevention and Control Functions for Line Maintenance" is set in the monitoring backend. In case of unexpected situations, operators can disable all adaptive logic with one click, and the system will immediately revert to its pre-modification state. Full-Link Log Traceability: All automatic operations generate operation logs with timestamps (accurate to milliseconds), including status determination, remote control command issuance, return-to-work confirmation, and control panel status changes.

[0051] This invention constructs a fully automated error prevention system encompassing "precise status identification—forced exit via soft pressure plate—rigid access control—automatic reset and recovery." It comprises three core innovations.

[0052] Innovation Point 1: Constructing a multi-dimensional maintenance status determination method based on "three-dimensional fusion + dual-path parallelism + hierarchical anti-shake". Breaking away from the limitations of traditional single-criterion judgments, it deeply integrates information from three dimensions: Dimension 1 – Primary Equipment Location Conditions: Collect data on the three-phase open / closed positions of line switches, line-side disconnectors, and bus-side disconnectors. Disconnector positions are a key criterion for distinguishing between "cold standby / maintenance" and "hot standby" – disconnectors in open positions indicate that primary and secondary equipment are physically isolated.

[0053] Dimension Two – Electrical Quantity Verification Conditions (Preventing "False Data"): Collect remote measurement values ​​of three-phase voltage and three-phase current of the line, and confirm that the line is indeed in a de-energized state through no-voltage and no-current (voltage < 0.5V secondary value, current < 0.04A secondary value). Even if the position contacts of the primary equipment falsely report a disconnection due to reasons such as adhesion, the electrical quantity verification can still detect that the line is actually energized, thereby preventing false judgments.

[0054] Dimension 3 – Anti-jitter tolerance conditions: After all the above conditions are met, a 30-second delay confirmation timer is started. A maintenance flag is only generated if the steady state is maintained for more than 30 seconds, effectively filtering interference such as remote signal jitter and instantaneous signal flipping.

[0055] To address the limitation that a single decision path cannot cover all maintenance conditions, a dual-path parallel adaptive decision architecture is further proposed: Path 1 (Routine Power Outage Maintenance Path): Applicable to routine maintenance scenarios where the line is in cold standby mode and no additional testing has been performed. The judgment conditions are: (three-phase switch disconnection) AND (three-phase disconnection of both disconnectors) AND (no voltage and no current) AND (steady state for 30 seconds).

[0056] Path Two (Increased Quantity Test / Closed Position Maintenance Path): Applicable to special operating conditions such as increased quantity test (voltage and current are not zero) or switch body in closed position maintenance. The judgment condition is: (three-phase open position of both disconnectors) AND (maintenance pressure plate engaged) AND (steady state for 30 seconds). In this path, the switch position is not subject to mandatory constraints (open or closed is acceptable), and the engagement of the maintenance pressure plate confirms that the current maintenance operation is underway.

[0057] Path 1 and Path 2 are logically ORed – if the conditions of either path are met and the steady state is maintained for more than 30 seconds, it is determined to be a valid maintenance state.

[0058] In addition, a tiered image stabilization mechanism is established. This mechanism effectively filters out transient interference while accurately identifying changes in the actual state.

[0059] Innovation Point Two: A pioneering fully automatic error prevention mechanism featuring "forced exit via remote jump sending / receiving soft pressure plate + self-locking of operation permissions". Unlike traditional methods that rely on manual operation or temporary fiber optic cable insertion / removal, this innovation constructs a dual protection system: The first layer of protection is the forced deactivation of the remote tripping transmit / receive soft switch (core protection). After determining the maintenance status, the system automatically and remotely forces the remote tripping transmit and receive soft switches (corresponding to the GOOSE transmit and receive soft switches in IEC 61850-based smart substations) of the local line protection device to 0. This operation simultaneously blocks the transmit and receive paths of the remote tripping signal at the internal logic level of the protection device—after the transmit path is deactivated, the device no longer generates or forwards remote tripping messages; after the receive path is deactivated, the device no longer responds to any received remote tripping commands. The background system and the device's local status are updated synchronously, meeting the standardized requirements of maintenance logs, on-site visual inspections, and safety supervision.

[0060] The second layer is the self-locking of operating permissions (to prevent accidental restoration by human error). During the maintenance period, the human-machine interface of the background monitoring system automatically grays out the remote control button of the remote trip pressure plate (unoperable). Any operation of these two pressure plates by any operator workstation or engineer station will be rejected to prevent personnel from accidentally tripping the pressure plates during maintenance.

[0061] Innovation Point 3: Achieving self-adaptive and self-healing protection functions with zero human intervention throughout the entire process. This system possesses adaptive recovery capabilities, completely changing the traditional "manual deactivation and activation" operation mode. After line maintenance is switched to operation, primary equipment is restored to its closed position, and electrical quantities return to normal, the system automatically releases the access lock and automatically sets the remote tripping transceiver soft pressure plate to 1, fully restoring the line's cross-station remote tripping protection function. The entire process requires no manual verification or operation, avoiding the reverse safety hazards of missed protection activation or missing protection after maintenance, and achieving intelligent closed-loop management of "automatic maintenance interlocking and automatic operation recovery".

[0062] In summary, implementing the embodiments of the present invention has the following beneficial effects: This invention provides a method for preventing misoperation during single-sided maintenance of transmission lines. Addressing the industry-wide problem of erroneous remote tripping during single-sided line maintenance, it proposes a fully automated anti-misoperation system comprising "precise status identification—forced exit of soft pressure plate—rigid access control—automatic recovery." It constructs a multi-dimensional maintenance status determination method based on "three-dimensional fusion + dual-path parallelism + hierarchical anti-jitter." The innovative fully automated anti-misoperation mechanism of "forced exit of remote tripping transmission / reception soft pressure plate + self-locking of operation permissions" distinguishes it from traditional methods involving manual operation or temporary fiber optic cable insertion / removal. This achieves self-adaptive and self-healing protection functions with zero manual intervention throughout the entire process.

[0063] 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 preventing misoperation during single-sided maintenance of transmission lines, characterized in that, include: Collect operational data from the target substation; the target substation is either an intelligent substation with an intelligent control system or a conventional substation without an intelligent control system. Based on the operational data, determine whether the target substation meets the preset maintenance conditions. If it does, start the timing program and generate a valid line maintenance flag when the timing result meets the preset timing threshold. Once a valid line maintenance flag is generated, the maintenance phase begins and maintenance actions are performed. The maintenance status is then determined based on the execution results, including at least maintenance completion or an abnormality alert alarm.

2. The method as described in claim 1, characterized in that, The operational data of the target substation includes at least the following: switch position information, disconnector position information, voltage telemetry information, current telemetry information, and maintenance switch information.

3. The method as described in claim 1, characterized in that, The preset maintenance conditions include, Any one of the three phases of the switch is in the open position; Any one of the three phases of the disconnect switch is in the open position; If any one of the three phase voltages is less than the preset secondary voltage value; If any one of the three phase currents is less than the preset secondary current value.

4. The method as described in claim 1, characterized in that, The preset maintenance conditions include, Any one of the three phases of the line-side disconnector is in the open position; Any one of the three phases of the busbar-side disconnector is in the open position; The maintenance pressure plate is in the "in operation" state or the maintenance sign is in the "valid" state.

5. The method as described in claim 3 or 4, characterized in that, It also includes starting the corresponding timing when the preset maintenance conditions are met within the same program scan cycle; When the timing result reaches the preset timing threshold, a line maintenance validity flag is generated as a global read-only variable, and the line maintenance validity flag is sent to the line protection device through a preset protocol.

6. The method as described in claim 5, characterized in that, It also includes resetting the line maintenance validity flag to zero after the line resumes operation and the steady state is maintained for a preset steady state time; wherein, the line resumes operation when the switch is in the closed position, the disconnector is in the closed position, and there is voltage and current in the line.

7. The method as described in claim 5, characterized in that, The entry into the maintenance phase includes sending two preset remote control commands to the line protection device within the same logic scan cycle via a remote control protocol: The protection device verifies the validity of the two preset commands respectively; if the verification passes, it returns a correct confirmation message; if the verification fails, it returns a negative confirmation message to the master station to terminate the subsequent execution operation. The legality of the two preset commands includes at least whether the operation permission meets the preset conditions, whether the interlocking conditions meet the preset conditions, whether the object exists, and whether the object can be remotely controlled.

8. The method as described in claim 7, characterized in that, The maintenance actions include issuing a remote execution command after receiving confirmation of a correct return to school; After the protection device receives the execution command, it rewrites the parameter values ​​corresponding to the states of the two soft pressure plates to the corresponding values; when the execution is completed, it sends a status change message as the final confirmation result of the execution result. If any pressure plate fails to be remotely controlled, an alarm pop-up will immediately appear, prompting manual intervention; subsequent operations will be suspended and a complete error log will be recorded.

9. The method as described in claim 8, characterized in that, This also includes, after generating a valid line maintenance flag, simultaneously implementing access control for the operation entry point; wherein, implementing access control for the operation entry point includes at least the following: the remote control button for sending / receiving soft pressure plate on the human-machine interface is automatically grayed out and cannot be clicked; the operator's remote control interface for sending / receiving soft pressure plate rejects any operation requests; When an operator attempts to engage a locked remote jump soft pressure plate, the system displays a corresponding locking prompt. If it is necessary to forcibly engage the remote jump plate during maintenance, a user with the corresponding permissions needs to enter an advanced authorization code to temporarily unlock the self-lock. Setting the temporary unlock triggers a network-wide audible and visual alarm and records it to the security audit log. If the line maintenance validity flag still exists after the self-locking is released, the system will automatically lock again after the preset safe time threshold is reached.

10. The method as described in claim 6, characterized in that, It also includes unlocking the remote control button of the remote tripping pressure plate and restoring normal remote control operation permissions after the line maintenance valid indicator is cleared to zero; Send a remote preset command to the protection device, and after receiving the correct confirmation of the return calibration of the two pressure plates, send a remote execution command. After the device completes the execution, send a status change message. Compare the status of the pressure plate sent by the protection device with the instructions issued by the background. If they are all consistent, output a recovery reminder message and generate a confirmation record of successful maintenance. If the command fails to execute, an alarm will be triggered immediately.

Images