Method for improving closed-loop operation reliability of ship power station

Abstract

The invention relates to a ship power station closed-loop operation reliability improving method, which not only considers the selectivity of upper and lower level equipment protection of the same bus, but also considers the selectivity of protection between different buses. For protection refusal possibly caused by faults of a sensor, a circuit breaker and a protection device, a backup protection function which is completely independent of main protection is configured, and global consideration is performed on a protection setting value, so that a short circuit or a grounding fault of a power supply system can still be limited in a section of bus under the condition that at most one circuit breaker or protection device has a fault; aiming at protection misoperation possibly caused by disconnection and short circuit of the sensor, configured protection does not generate misoperation under the condition of disconnection and short circuit of the sensor through redundancy configuration and algorithm optimization of hardware; the real-time performance of the system is ensured by adopting a multi-task scheduling architecture and redundancy design, and technologies such as dynamic control, fault ride-through and predictive maintenance are combined, so that the misoperation rate is greatly reduced, and a foundation is laid for improving the protection capability and reliability during closed-loop operation of a ship power supply system.

Description

Technical Field

[0001] The present invention relates to the field of electric power technology, and in particular to a method for improving the closed-loop operation reliability of a ship power station. Background Art

[0002] The closed-loop power system of a ship's power station is a core component of the ship's propulsion system. Its reliability directly affects the safe operation of the ship and the power supply stability of key equipment. Due to the complex operating environment of ships (such as vibration, salt spray, temperature and humidity fluctuations, etc.), the power system is prone to hidden faults (sensor malfunction, sensor refusal to operate, communication interruption), etc., which can lead to misjudgment or failure of the protection system. The existing technology for the reliability of traditional closed-loop operation of ship power stations has the following problems:

[0003] 1. Traditional protection mechanisms are inadequate for detecting hidden faults, which can easily lead to false operation or failure to operate;

[0004] 2. Task scheduling has poor flexibility, making it difficult to balance real-time performance with multi-priority requirements;

[0005] 3. Redundant design lacks systematicity, and the risk of single-point failure of key components is high;

[0006] 4. Lack of comprehensive health diagnosis and rapid recovery capabilities.

[0007] The current protection methods for ship power systems do not adequately consider hidden faults such as sensor disconnection or failure, misoperation or refusal of protection devices, and circuit breaker failures. When hidden faults occur, they are unable to maintain continuous power supply to important loads. Summary of the Invention

[0008] To address these issues, a method for improving the closed-loop reliability of marine power plants was proposed. This method integrates multi-task scheduling, intelligent fault-tolerant protection, systemic redundancy, and predictive maintenance into a closed-loop solution. This comprehensive approach improves the reliability of marine power plant closed-loop operations and addresses the hidden risks of closed-loop operations in complex operating conditions.

[0009] The technical solution of the present invention is: a method for improving the reliability of the closed-loop operation of a ship power station, by establishing a graphical closed-loop operation control system for the ship power station, configuring the control scheme as needed, completing monitoring, protection design and predictive maintenance of the closed-loop operation of the ship power station, and establishing the graphical closed-loop operation control system for the ship power station includes the following steps:

[0010] 1) Build a three-layer control system architecture for closed-loop operation of the power plant. The three-layer control system includes a hardware driver layer, a runtime system layer, and a function block library for configuring selective protection devices, providing an environment and support for multi-tasking execution.

[0011] 2) The control system is designed to support a mixed scheduling mechanism of at least 5 levels of cyclic tasks and 3 levels of interrupt tasks in real time, ensuring a balance between real-time performance and task priority. Users can set the execution period of each cyclic task and select the interrupt source for each interrupt task according to actual application requirements. This system serves as a universal system to meet the task design requirements of different applications.

[0012] 3) During operation, the system layer is configured with a three-level protection system including main protection, backup protection and failure protection, circuit breaker failure protection and trip circuit monitoring to detect and handle circuit breaker and trip circuit faults to prevent false operation or protection failure;

[0013] 4) A hardware platform based on N+1 redundancy design is deployed in the hardware driver layer to ensure the normal operation of the system under single point failure of key components;

[0014] 5) Applying model predictive control algorithms in the runtime system layer to achieve dynamic optimization control, which is used to suppress transient voltage fluctuations and predict life based on equipment status data to reduce unplanned downtime;

[0015] 6) Establish a graphical development environment to quickly program the constructed control system and complete its application.

[0016] Furthermore, the interrupt task priority in step 2) is as follows: external communication interruption > timed sampling interruption > circuit breaker status hard-wired interruption task, realizing hierarchical actions of tripping commands for cross-device protection interlocking, analog tripping commands collected by sensors, and tripping commands caused by circuit breaker failure or position change; the time delay for switching between interrupt tasks is in microseconds; if there is no interrupt task, the cyclic task is executed, and the priority of the five cyclic tasks is set as fast protection algorithm > directional protection + selective logic > sensor detection data > dynamic topology analysis and related calculations > routine system maintenance analysis and calculations.

[0017] Furthermore, in step 3), the three-level protection system: the main protection is based on the instantaneous action of electrical quantities to quickly isolate the proximal fault; if the main protection fails, the backup protection is started in a short-delay step-by-step manner, relying on directional locking and global setting values ​​to avoid over-tripping; when the circuit breaker in the backup protection refuses to operate, the failure protection triggers the protection device to operate through the "current continuity + position judgment" logic; through high-speed communication interlocking, the coordinated operation between the various levels of protection is ensured, thereby improving the reliability of the closed-loop operation of the ship power station.

[0018] Furthermore, in step 3), the three-level protection system: for short-circuit faults, the generator is configured with current differential protection as the main protection, which instantly and selectively cuts off the short-circuit faults in the generator area; the backup protection for short-circuit faults adopts busbar directional overcurrent protection, which can quickly cut off all circuit breakers in the fault row to ensure that the fault is limited to the minimum range; for ground faults, the generator is configured with directional ground fault protection as the main protection; the backup protection adopts busbar directional ground fault protection; and at the same time, the generator is configured with time-limited non-directional ground fault protection.

[0019] Furthermore, in step 3), the three-level protection system is as follows: for short-circuit faults, busbar differential protection is configured as the main protection for the main busbar. If a busbar short circuit occurs, the protection device can instantly trip all circuit breakers in this section of the busbar; the backup protection adopts busbar directional overcurrent protection, which can also quickly cut off all circuit breakers in the faulty busbar; for ground faults, busbar directional grounding protection is configured as the main protection, which can cut off all circuit breakers in the faulty busbar; busbar non-directional grounding protection is used as the backup protection, and its action causes all bus tie circuit breakers to trip.

[0020] Furthermore, the three-level protection system in step 3) is as follows: for short-circuit faults, cable differential protection is used as the main protection for the busbar cable. After the fault occurs, the busbar circuit breakers at both ends of the fault point are instantaneously tripped to achieve instantaneous and selective removal of the short-circuit fault in the busbar cable area; cable directional overcurrent protection is used as backup protection, and the busbar circuit breakers at both ends of the fault point are disconnected after a delay; for ground faults, cable differential grounding protection is used as the main protection, and cable directional grounding protection is used as the backup protection, and the action range is the busbar circuit breakers at both ends of the fault point.

[0021] Furthermore, in step 3), the three-level protection system: for short-circuit faults, short-delay short-circuit protection is configured for the load feeder as the main protection, wherein the selection of the action time setting value needs to take into account the selective coordination with the lower-level circuit breaker to achieve instantaneous or short-time disconnection of the fault point; the backup protection adopts busbar directional overcurrent protection to quickly disconnect all circuit breakers in the fault row; for ground faults, the main protection adopts time-limited non-directional ground fault protection to selectively disconnect the fault feeder circuit breaker; the backup protection adopts busbar directional ground fault protection.

[0022] Furthermore, in the hardware driver layer of step 4), an N+1 redundant configuration is implemented for sensors, controllers, tripping circuits, and communication networks, and single-point malfunction is eliminated through physical isolation, functional isolation, and fault-safe design; redundant switching is triggered by an FPGA monitor: sensor and network failures can be switched, the controller has a hot standby takeover function, the tripping channel has a backup enable function, and power outages can be switched to UPS power supply, ensuring that the fault does not spread and the system operates continuously with zero disturbance.

[0023] Furthermore, the model predictive control algorithm described in step 5) adopts hierarchical fuzzy adaptive model predictive control, and constructs a coupled state space model of the power generation end and the power consumption end during the closed-loop operation of the ship power station based on the dynamic matrix control algorithm. The sensor sampling data is input into the hierarchical fuzzy adaptive model through the FPGA, and a confidence weighted fusion mechanism is adopted to ensure the accuracy and real-time performance of the predictive maintenance algorithm. The prediction time domain and weight matrix are dynamically adjusted through the fuzzy reasoning layer to adapt to 0% to 150% load fluctuations in real time, and the quadratic programming output excitation and speed regulation correction are dynamically solved.

[0024] The beneficial effects of the present invention are as follows: the method for improving the reliability of closed-loop operation of a ship power station of the present invention, with respect to the closed-loop protection method, not only considers the selectivity of protection of upper and lower level equipment on the same bus, but also considers the selectivity of protection between different busbars; for protection refusal that may be caused by failure of sensors, circuit breakers, and protection devices, a backup protection function that is completely independent of the main protection is configured, and a global consideration is given to the protection setting value, so that when at most one circuit breaker or protection device fails, the short circuit or grounding fault of the power supply system can still be limited to a section of the busbar; for protection malfunction that may be caused by sensor disconnection or short circuit, through hardware redundancy configuration and algorithm optimization, the configured protection will not malfunction in the case of sensor disconnection or short circuit; a multi-task scheduling architecture and redundant design are used to ensure the real-time performance of the system, and combined with dynamic control, fault crossing and predictive maintenance technologies, the malfunction rate is greatly reduced, laying the foundation for improving the protection capability and reliability of the ship power supply system during closed-loop operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the protection configuration system of the ship closed-loop power system of the present invention;

[0026] Figure 2 This is a hardware schematic diagram of the protection device of the present invention;

[0027] Figure 3 This is a block diagram of the software and hardware platform of the present invention;

[0028] Figure 4 This is a schematic diagram of the test system-level supporting equipment of the present invention. DETAILED DESCRIPTION

[0029] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0030] A method for improving the reliability of closed-loop operation of a ship power station is provided. By establishing a graphical closed-loop operation control system for a ship power station, a control scheme is configured as needed, and monitoring, protection design, and predictive maintenance are performed on the closed-loop operation of the ship power station. Establishing the graphical closed-loop operation control system for a ship power station includes the following steps:

[0031] 1. Build a three-layer control system architecture for closed-loop operation of the power plant. The three-layer control system includes a hardware driver layer, a runtime system layer, and a function block library for configuring selective protection devices, providing an environment and support for multi-task execution.

[0032] 2. The control system design supports a mixed scheduling mechanism of at least 5-level cyclic tasks and 3-level interrupt tasks in real time, ensuring a balance between real-time performance and task priority. Users can set the execution period of each cyclic task and select the interrupt source of each interrupt task according to actual application requirements. As a universal system, it can meet the task design requirements of different applications.

[0033] Interrupt task priority: external communication interrupt > timed sampling interrupt > circuit breaker status hardwired interrupt task. This design avoids the traditional PLC practice of treating all interrupt priorities equally. It implements hierarchical action for trip commands for cross-device protection interlocks, analog trip commands collected by sensors, and trip commands caused by circuit breaker failures or position changes. The switching delay between interrupt tasks is microseconds. If there is no interrupt task, the cyclic task is executed. The priority of the five cyclic tasks is set as follows: fast protection algorithm > directional protection + selective logic > sensor detection data > dynamic topology analysis and related calculations > routine system maintenance analysis and calculations.

[0034] 3. During operation, the system layer is configured with a three-level protection system consisting of main protection, backup protection, and failure protection. The circuit breaker failure protection (50BF) and trip circuit monitoring (74TC) are used to detect and handle circuit breaker and trip circuit faults to prevent false operation or protection failure.

[0035] The reliability of the ship's power station's closed-loop operation is centered on the multi-level protection system's "layered disconnection and redundant fault tolerance." Primary protection operates instantaneously based on electrical quantities, rapidly isolating local faults. If the primary protection fails, backup protection activates in a short, step-by-step manner, relying on directional blocking and global settings to prevent over-tripping. If the backup protection circuit breaker fails to operate, the failure protection triggers the protection device using "current continuity + position criteria" logic. High-speed communication interlocking ensures coordinated operation among each level of protection, enhancing the reliability of the ship's power station's closed-loop operation.

[0036] 4. A hardware platform based on N+1 redundancy design is deployed in the hardware driver layer to ensure the normal operation of the system under single point failure of key components;

[0037] The hardware driver layer implements an N+1 redundant configuration for sensors (CT / VT three-winding magnetic circuits are independent), controllers, trip circuits, and communication networks. Physical and functional isolation, along with a fail-safe design (forced lockout in the event of a fault), prevents single-point malfunction. Redundant switching is triggered by an FPGA monitor: sensor and network failures enable failover, controllers feature hot standby takeover, trip channels enable backup activation, and power outages enable switchover to a UPS, ensuring fault propagation and continuous, zero-disruption system operation.

[0038] 5. Apply model predictive control algorithms in the runtime system layer to achieve dynamic optimization control, which is used to suppress transient voltage fluctuations and predict life based on equipment status data, thereby reducing unplanned downtime;

[0039] The closed-loop protection of the ship's power station utilizes a hierarchical fuzzy adaptive model predictive control. Based on a dynamic matrix control algorithm, a state-space model of the coupled power generation and consumption ends of the ship's power station's closed-loop operation is constructed. The fuzzy inference layer dynamically adjusts the prediction time domain and weight matrix to adapt to load fluctuations of 0% to 150% in real time, dynamically solving quadratic programming output excitation and speed regulation corrections. Sensor sampling data is input into the hierarchical fuzzy adaptive model via an FPGA, and a confidence-weighted fusion mechanism is employed to ensure the accuracy and real-time performance of the predictive maintenance algorithm.

[0040] 6. Establish a graphical development environment to quickly program the constructed control system and complete its application.

[0041] The reliability of a ship's power station's closed-loop operation is primarily reflected in its ability to maintain stable, reliable, and safe operation before and after hidden faults occur. Common hidden faults include sensor failures, protection device failures, protection and control device failures, communication line failures, and interface failures.

[0042] Aiming at the selective protection mechanism of the ship's closed-loop power system, it realizes functions such as multi-task multi-priority scheduling, asynchronous interrupt processing, system fault diagnosis, multi-task data consistency protection, and communication between the target system and the graphical programming platform, forming an operating environment for multi-task execution.

[0043] The ship power station closed-loop protection system ensures multi-task data consistency through a hierarchical locking mechanism. Sampled data uses a self-locking mechanism, and configuration parameters utilize read-write locks with inherited priority. Tasks are written only to the buffer, with pointer switching performed by the FPGA. Control instruction updates are hardware-based and locked in conjunction with write operations. This hierarchical locking mechanism ensures that data conflict rates meet safety requirements even in scenarios with sudden load changes and multiple concurrent faults.

[0044] The system supports up to five levels of cyclic tasks and three levels of interrupt tasks. The execution period of each cyclic task can be set according to actual application requirements, and the interrupt source of each interrupt task can be flexibly selected. As a universal system, it can meet the task design requirements of different applications.

[0045] The control system consists of a driver layer, a runtime system layer, a function block library, and a visual programming tool. It offers two task modes: three interrupts and five periodic tasks, with a minimum task interval of 100µs. Over 500 mature algorithm modules can be run in both task modes. It utilizes the CFC programming language based on IEEE 61131-3.

[0046] The control system layer consists of two major components: a graphical development tool and a control and protection application function block library. The graphical development tool offers five PLC languages ​​compliant with the IEC61131-3 standard, as well as an enhanced CFC graphical programming language suitable for complex application development. It integrates a range of functions, including project establishment, control and protection system hardware configuration, communication configuration, function block library management, graphical application software development, and online debugging. This provides efficient and convenient engineering application development and powerful operational maintenance capabilities to enhance the reliability of ship closed-loop power systems.

[0047] The selective protection device for the closed-loop power system of ships provides a function block library, which is divided into general function blocks and special function blocks. It includes six basic categories: control protection, arithmetic and logical operations, I / O functions, network communications, service diagnosis, and special applications, with a total of more than 500 function blocks. The function blocks have undergone rigorous professional testing and repeated verification, with high integrity and correct operation, ensuring the correctness and reliability of the application and operation of the selective protection system.

[0048] Primary protection in a system ensures system stability and equipment safety, selectively and quickly disconnecting protected equipment and line faults. Backup protection in a system is a protective device or system that activates when the protective device closest to the fault point fails or lacks capacity, or when other protective devices fail, preventing the system fault from being cleared promptly. Auxiliary protection in a system supplements the performance of primary and backup protection, or is a simple protection added when primary or backup protection is out of service. Auxiliary protection does not replace primary or backup protection.

[0049] The trip circuit monitoring (74TC) is used to identify trip circuit disconnections. The status of the protection device's trip command contacts and the position of the switch auxiliary contacts determine the trip circuit status and issue an alarm signal.

[0050] The circuit breaker failure protection (50BF) monitors the tripping behavior of the associated switch and issues a backup trip command in the event of a switch failure. It detects the current flowing through the circuit breaker and activates if the current remains above the set value for a period of time after the circuit breaker trip command is issued.

[0051] Fault ride-through capability is applied to relevant equipment (excluding equipment isolated due to a fault). After the fault is automatically cleared, the system can resume operation to the same level as before the fault occurred, without restarting or manual intervention. If a redundant group loses power due to overload, short circuit, or misoperation, the system, including the main generator set, switchboard, and thruster system, can be restored to a usable state within a specified time according to pre-set logic.

[0052] The ship's power station's closed-loop system achieves fault ride-through through active voltage support (converter reactive power compensation), frequency inertia control (flywheel energy storage transient response), and multi-unit power redistribution. After the fault is cleared, automatic reclosing is achieved based on phase synchronization detection (±2°) and residual voltage blocking logic, eliminating the need for manual intervention. Faults that can be ride-through include instantaneous short circuits, single-phase grounding, and sudden 150% load changes. During the ride-through period, the critical load voltage is maintained at 85% to 110% of the rated value, with a frequency deviation of ≤±0.5Hz, ensuring continuous operation of the propulsion system.

[0053] The buses of different redundancy groups supply power to one bus at the same time. The control circuits, UPS, and auxiliary systems of different redundancy groups should not cross each other as much as possible.

[0054] When the ship's power station is in closed-loop operation, the control system and other systems required to achieve overall ship control must have interfaces that meet certain electrical / physical isolation requirements, and hardware equipment and communication lines must meet certain redundancy requirements.

[0055] Use additional physical isolation whenever possible. Improve the insulation level of high-reliability equipment, transformers, and control components. Use busbar cables with as few cores as possible. Use additional protection logic to assist with judgments. Monitor the trip coils of circuit breakers connected to the main busbar.

[0056] More / additional auxiliary communications, monitoring and alarms, indications, monitoring of equipment / system status, measurement signals, action execution and results, reverse blocking and other auxiliary measures, auxiliary system protection and management logic judgment.

[0057] Key components (such as sensors, controllers, and power supplies) utilize an N+1 configuration to ensure that single-point failures do not impact system operation. An independent multi-channel control architecture is also implemented to prevent malfunctions. Input signals for primary and backup protection do not originate from the same transformer, and calibration signals for protection and management functions do not originate from the same transformer. This minimizes the impact of a single failure on the closed-loop operation of the ship's power station.

[0058] The backup system should also be equipped with status monitoring or alarm indication functions to enhance the reliability of the closed-loop operation of the ship's power station.

[0059] A hierarchical fuzzy adaptive model predictive control system dynamically adjusts parameters to address load fluctuations or disturbances, and high-precision sensors provide rapid feedback, shortening response time. A health diagnostic system is installed within the ship's power station closed loop to provide timely alarms when inconsistencies in control commands, status signals, and communication connections occur, preventing malfunctions.

[0060] The ship's power plant health diagnostic system monitors consistency through real-time comparison of control commands with IGBT execution feedback (deviations greater than 5% are considered abnormal) using FPGA hardware, as well as GOOSE message timing verification (out-of-sequence / frame loss detection). If an anomaly is detected, the system immediately switches to a backup controller, and if communication is interrupted, it falls back to a local hardwired strategy. The core hardware, the FPGA, performs consistency verification.

[0061] The generator main circuit breaker and feeder circuit breaker connected to the main busbar adopt monitoring circuits and set up circuit breaker fault protection and other measures to avoid hidden faults in the system.

[0062] Quantify and assess system failure probability to target weaknesses and improve them. Use simulation to verify system stability under extreme operating conditions. Combine the power grid, diesel generators, and supercapacitors to improve power supply continuity, and use dynamic voltage regulation to mitigate the impact of transient voltage fluctuations on sensitive equipment. Finally, lifespan predictions based on vibration and temperature data reduce unplanned downtime and enable predictive maintenance of the closed-loop operation of the ship's power station, thereby improving system reliability.

[0063] During closed-loop operation of the ship's power station, the control system dynamically adjusts the medium-voltage busbar voltage. This dynamic voltage regulation mechanism coordinates with the power system's selective protection mechanism to enhance system reliability. The voltage regulation response time, range, and accuracy are implemented in accordance with classification society specifications, and the protection devices set their protection action values ​​based on the voltage regulation range.

[0064] like Figure 1 Figure 1 shows a schematic diagram of the closed-loop protection configuration system for a marine power station, encompassing four protection zones: the main generator, busbar, bus-tie cable, and load feeder. To prevent a single protection failure from causing a complete grid blackout, the present invention proposes a method for improving the reliability of marine power station closed-loop operation. By installing protection devices in different zones of the system, these devices implement various protection functions, including system short circuit, ground fault, overload, undervoltage, overvoltage, underfrequency, overfrequency, differential, and busbar differential, instantly and selectively clearing faults.

[0065] like Figure 2 As shown, the protection processing and communication plug-in is responsible for the external communication and software and hardware architecture configuration and management of the entire protection device. It is connected to the analog acquisition plug-in, the binary input and output plug-in, and the external human-machine interface plug-in via the high-speed backplane bus plug-in. The device has an electrical interface to collect current and voltage signals.

[0066] The ship's power station protection and communication plug-ins utilize the IEC 61850 protocol. Each integrated protection device features four network communication interfaces: two electrical interfaces with RJ45 connections and two optical interfaces with SFP plug-in connections. Modbus-TCP or GOOSE communication protocols are optional. Zero-delay redundant switching is provided in the event of communication interruptions or anomalies.

[0067] like Figure 3 As shown, the system software platform implements multi-task multi-priority scheduling, asynchronous interrupt handling, system fault diagnosis, multi-task data consistency protection, and communication between the target system and the graphical programming platform, forming a multi-tasking execution environment. The system supports up to five levels of cyclic tasks and eight levels of interrupt tasks. Users can set the execution period of each cyclic task according to actual application requirements and flexibly select the interrupt source for each interrupt task. As a universal system, it can meet the task design requirements of different applications.

[0068] The reliability of closed-loop operation in ship power plants is primarily enhanced through coordinated protection across various zones. For short-circuit faults, generators are equipped with current differential protection as primary protection, enabling instantaneous and selective clearing of short-circuit faults within the generator zone. Busbar directional overcurrent protection is used as backup protection for short-circuit faults, rapidly disconnecting all circuit breakers in the faulty row to minimize the fault. For ground faults, generators are equipped with directional ground fault protection as primary protection, with busbar directional ground fault protection as backup protection. Furthermore, definite-time non-directional ground fault protection is also provided for the generators.

[0069] For short-circuit faults, busbar differential protection is configured as primary protection for the main busbar. If a busbar short circuit occurs, the protection device will instantly trip all circuit breakers on that busbar section. Busbar directional overcurrent protection is used as backup protection, which also quickly disconnects all circuit breakers on the faulty busbar. For ground faults, busbar directional ground fault protection is configured as primary protection, disconnecting all circuit breakers on the faulty busbar. Non-directional busbar ground fault protection is used as backup protection, tripping all bus tie circuit breakers.

[0070] For short-circuit faults, cable differential protection is used as the primary protection for the bus tie cables. Upon a fault, the bus tie circuit breakers at both ends of the fault point are instantly tripped, enabling instantaneous and selective clearing of short-circuit faults within the bus tie cable area. Cable directional overcurrent protection is used as backup protection, with a time delay to disconnect the bus tie circuit breakers at both ends of the fault point. For ground faults, cable differential ground fault protection is used as the primary protection, and cable directional ground fault protection is used as the backup protection. Both protections operate within the bus tie circuit breakers at both ends of the fault point.

[0071] For short-circuit faults, short-delay short-circuit protection is configured as primary protection for the load feeder. The operating time setting must be carefully considered in conjunction with the selectivity of the downstream circuit breakers to ensure instantaneous or short-term fault clearing. Busbar directional overcurrent protection is used as backup protection, rapidly disconnecting all circuit breakers in the faulty busbar. For ground faults, definite-time non-directional ground fault protection is used as primary protection, selectively disconnecting the faulty feeder circuit breaker; busbar directional ground fault protection is used as backup protection.

[0072] Figure 4 In order to implement the experimental system-level supporting equipment schematic diagram of the system protection scheme, the RT-LAB simulation platform is used to complete the research and design of the simulation platform interface and the closed-loop power grid system protection debugging. On this basis, a closed-loop power grid hidden fault simulation method is formed through hardware-in-the-loop simulation test, and the hardware-in-the-loop experiment of the closed-loop power system protection scheme is completed to verify the effectiveness of the present invention.

[0073] The above-described embodiments merely represent specific implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for improving the closed-loop operation reliability of a ship power station, characterized in that: By establishing a graphical closed-loop operation control system for a ship power station, configuring the control scheme as needed, and completing monitoring, protection design, and predictive maintenance for the closed-loop operation of the ship power station, establishing a graphical closed-loop operation control system for a ship power station includes the following steps: 1) Build a three-layer control system architecture for closed-loop operation of the power plant. The three-layer control system includes a hardware driver layer, a runtime system layer, and a function block library for configuring selective protection devices, providing an environment and support for multi-tasking execution. 2) The control system is designed to support a mixed scheduling mechanism of at least 5 levels of cyclic tasks and 3 levels of interrupt tasks in real time, ensuring a balance between real-time performance and task priority. Users can set the execution period of each cyclic task and select the interrupt source for each interrupt task according to actual application requirements. This system serves as a universal system to meet the task design requirements of different applications. 3) During operation, the system layer is configured with a three-level protection system including main protection, backup protection and failure protection, circuit breaker failure protection and trip circuit monitoring to detect and handle circuit breaker and trip circuit faults to prevent false operation or protection failure; 4) A hardware platform based on N+1 redundancy design is deployed in the hardware driver layer to ensure the normal operation of the system under single point failure of key components; 5) Applying model predictive control algorithms in the runtime system layer to achieve dynamic optimization control, which is used to suppress transient voltage fluctuations and predict life based on equipment status data to reduce unplanned downtime; 6) Establish a graphical development environment to quickly program the constructed control system and complete its application.

2. The method for improving the closed-loop operation reliability of a ship power station according to claim 1, characterized in that: The interrupt task priority in step 2) is as follows: external communication interruption > timed sampling interruption > circuit breaker status hard-wired interruption task, to implement hierarchical actions of tripping commands for cross-device protection interlocking, analog tripping commands collected by sensors, and tripping commands caused by circuit breaker failures or position changes; the time delay for switching between interrupt tasks is in microseconds; if there is no interrupt task, the cyclic task is executed, and the priority of the five cyclic tasks is set as fast protection algorithm > directional protection + selective logic > sensor detection data > dynamic topology analysis and related calculations > routine system maintenance analysis and calculations.

3. The method for improving the closed-loop operation reliability of a ship power station according to claim 2, characterized in that: The three-level protection system in step 3): the primary protection is based on instantaneous action of electrical quantities to quickly isolate the proximal fault; If the primary protection fails, the backup protection is activated in a short-delay, step-by-step manner, relying on directional blocking and global setting values ​​to avoid over-tripping. If the circuit breaker in the backup protection fails to operate, the failure protection triggers the protection device through the "current continuity + position judgment" logic. High-speed communication interlocking ensures coordinated operation between various protection levels, improving the reliability of the closed-loop operation of the ship power station.

4. The method for improving the closed-loop operation reliability of a ship power station according to claim 3, characterized in that: The three-level protection system in step 3) is as follows: for short-circuit faults, the generator is configured with current differential protection as the main protection, which instantly and selectively cuts off the short-circuit faults in the generator area; the backup protection for short-circuit faults adopts busbar directional overcurrent protection, which can quickly cut off all circuit breakers in the fault row to ensure that the fault is limited to the minimum range; for ground faults, the generator is configured with directional ground fault protection as the main protection; the backup protection adopts busbar directional ground fault protection; and the generator is also configured with time-limited non-directional ground fault protection.

5. The method for improving the closed-loop operation reliability of a ship power station according to claim 3, characterized in that: The three-level protection system in step 3): for short-circuit faults, busbar differential protection is configured as the main protection for the main busbar. If a busbar short circuit occurs, the protection device can instantly trip all circuit breakers in this section of the busbar; The backup protection uses busbar directional overcurrent protection, which can also quickly cut off all circuit breakers in the fault row; For ground faults, busbar directional ground fault protection is configured as the main protection, which can cut off all circuit breakers in the faulty busbar; busbar non-directional ground fault protection is used as the backup protection, and its action causes all bus tie circuit breakers to trip.

6. The method for improving the closed-loop operation reliability of a ship power station according to claim 3, characterized in that: The three-level protection system in step 3) adopts cable differential protection as the main protection for the bus tie cable for short circuit faults. After a fault occurs, the bus tie circuit breakers at both ends of the fault point are instantly tripped to achieve instant and selective removal of the short circuit fault in the bus tie cable area. The cable direction overcurrent protection is used as backup protection, and the busbar circuit breakers at both ends of the fault point are disconnected after a delay; For ground faults, cable differential grounding protection is used as the main protection, and cable directional grounding protection is used as the backup protection. The action range is the busbar circuit breakers at both ends of the fault point.

7. The method for improving the closed-loop operation reliability of a ship power station according to claim 3, characterized in that: In step 3), the three-level protection system: for short-circuit faults, short-delay short-circuit protection is configured for the load feeder as the main protection, wherein the selection of the action time setting value needs to take into account the selective coordination with the lower-level circuit breaker to achieve instantaneous or short-term fault removal; the backup protection adopts busbar directional overcurrent protection to quickly disconnect all circuit breakers in the faulty busbar; For ground faults, the main protection adopts time-limited non-directional ground fault protection to selectively cut off the faulty feeder circuit breaker; The backup protection adopts busbar directional grounding protection.

8. The method for improving the closed-loop operation reliability of a ship power station according to claim 1, characterized in that: In the step 4), the hardware driver layer implements an N+1 redundant configuration for sensors, controllers, tripping circuits, and communication networks, and eliminates single-point malfunction through physical isolation, functional isolation, and fault-safe design. Redundant switching is triggered by the FPGA monitor: sensor and network failures can be switched, the controller has a hot standby takeover function, the tripping channel has a backup enable function, and power outages can be switched to UPS power supply, ensuring that the fault does not spread and the system operates continuously with zero disturbance.

9. The method for improving the closed-loop operation reliability of a ship power station according to claim 1, characterized in that: The model predictive control algorithm in step 5) adopts a hierarchical fuzzy adaptive model predictive control, and constructs a coupled state space model of the power generation end and the power consumption end during the closed-loop operation of the ship power station based on the dynamic matrix control algorithm. The sensor sampling data is input into the hierarchical fuzzy adaptive model through the FPGA, and a confidence weighted fusion mechanism is adopted to ensure the accuracy and real-time performance of the predictive maintenance algorithm. The prediction time domain and weight matrix are dynamically adjusted through the fuzzy reasoning layer to adapt to load fluctuations of 0% to 150% in real time, and the quadratic programming output excitation and speed regulation correction are dynamically solved.

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