Reliability allocation method for traction substation based on importance and reliability cross iteration

Abstract

The application discloses a traction substation reliability allocation method based on importance and reliability cross iteration, and specifically comprises the following steps: a mapping relationship between device function states and system function states is established according to device connection relationships; a system reliability target value is determined according to operation requirements, and initial reliabilities of devices are set as the system reliability target value; complexity of each device is set based on device structure characteristics and maintenance difficulty; influence of each device under completely reliable and completely unreliable conditions on system reliability is analyzed, and importance of each device is determined according to the influence; reliabilities of each device are iteratively solved based on a reliability allocation function; and the reliabilities and the importance are continuously cross iteratively updated to solve final reliability allocation results of the traction substation. The application realizes effective fusion and correction of subjective and objective factors, has self-adaptive adjustment capability, realizes dynamic adjustment of the reliability allocation scheme, and improves adaptability of the method to different system conditions.

Description

Technical Field

[0001] This invention belongs to the field of reliability of rail transit power supply systems, and specifically relates to a reliability allocation method for traction substations based on cross-iteration of importance and reliability. Background Technology

[0002] Traction substations are key facilities in the traction power supply system of electrified railways, and their operational reliability directly affects the safety and continuity of railway transportation. During the design phase, it is necessary to rationally allocate the reliability of various electrical equipment based on the overall system reliability requirements to guide the design and selection of key equipment and improve the safety and stability of system operation.

[0003] However, existing reliability allocation methods largely rely on empirical weights or static parameter settings, making them highly susceptible to subjective influences. This makes it difficult to objectively reflect the differences in functional importance of different devices within the system topology, thus limiting the rationality of the reliability allocation results. Furthermore, existing methods typically employ a one-time or fixed-weight allocation strategy during the reliability allocation process, lacking a mechanism for feedback correction of the allocation results. When the reliability allocation scheme changes, leading to alterations in device importance, it is difficult to adjust the allocation strategy in a timely manner, thus failing to achieve dynamic updates to the reliability allocation scheme. Summary of the Invention

[0004] To address the problem that existing reliability allocation methods rely too heavily on empirical weights and lack a dynamic update mechanism, this invention provides a reliability allocation method for traction substations based on cross-iteration of reliability and importance.

[0005] The present invention provides a reliability allocation method for traction substations based on cross-iteration of importance and reliability, comprising the following steps:

[0006] Step 1: Establish device functional status based on device connection relationships With system functional status Mapping relationship between x and y take values ​​of 1 or 0 (normal or faulty), and N is the total number of devices.

[0007] Step 2: Determine the target system reliability value based on operational needs. The initial reliability of each device Set as the system reliability target value The complexity level is set for each piece of equipment based on its structural characteristics and maintenance difficulty. .

[0008] Step 3: Analyze the impact of each device on the system reliability under completely reliable and completely unreliable conditions, and determine the importance of each device based on the impact.

[0009] Step 3.1: Set the i-th device to be in a completely reliable state with a reliability value of 1, and keep the reliability of the other devices unchanged to form the first type of device reliability condition.

[0010] Step 3.2: Under given equipment reliability conditions, perform probability sampling on the operating states of all equipment in the system to generate an equipment state matrix. :

[0011]

[0012] Where M represents the total number of samplings; the system state sequence is determined based on the device state matrix and the mapping relationship G between device states and system states. :

[0013]

[0014] Among them, the system state sequence The j-th item in the matrix is ​​derived from the device state matrix. The j-th column determines the system state sequence; Calculate the system reliability under the corresponding equipment reliability conditions. :

[0015]

[0016] Step 3.3: Under the reliability conditions of the first type of equipment, execute step 3.2 to obtain the system reliability of the i-th equipment under the condition of complete reliability. .

[0017] Step 3.4: Assume the i-th device is in a completely unreliable state, with a reliability value of 0. The reliability parameters of the remaining devices remain unchanged, forming the second type of device reliability condition. Following step 3.2, obtain the system reliability under the condition that the i-th device is completely unreliable. .

[0018] Step 3.5: Perform steps 3.1 to 3.4 sequentially on all devices in the system to obtain the system reliability of each device under completely reliable and completely unreliable conditions. and The importance of each device is calculated according to the following formula. :

[0019]

[0020] Step 4: Iteratively solve the reliability of each device based on the reliability allocation function.

[0021] Step 4.1: Set the initial upper bound of the allocation coefficients. and the lower realm .

[0022] Step 4.2: Determine the current allocation coefficient C according to the following formula:

[0023]

[0024] Step 4.3: Based on the current allocation coefficients, equipment importance, and equipment complexity, assess the reliability of each device in the system. Solve the following:

[0025]

[0026] Step 4.4: Based on the updated device reliability value, solve for the system reliability according to Step 3.2. ; to assess the current system reliability Greater than the system reliability target value If the current allocation coefficient C is correct, then the current allocation coefficient C will be used as the new lower bound B; otherwise, the current allocation coefficient C will be used as the new upper bound U.

[0027] Step 4.5: Repeat steps 4.2 to 4.4, continuously update the allocation coefficient C, and solve for the equipment reliability until the preset number of solutions is reached; use the equipment reliability obtained from the last solution as the system reliability allocation result under the current importance setting conditions.

[0028] Step 5: Repeat steps 3 and 4 to continuously iterate and update the importance and reliability of the equipment until the average reliability error of each equipment in two adjacent iterations is less than the preset threshold; take the reliability solution of each equipment obtained when the convergence condition is met as the final reliability allocation result of the traction substation.

[0029] Furthermore, the path for establishing the mapping relationship between equipment status and system functional status in step 1 can be a fault tree, state tree, or a graph-based system functional status assessment method.

[0030] Furthermore, in step 2, the range of equipment complexity values ​​is as follows: 0.1~0.3 for simple equipment; 0.4~0.6 for moderately complex equipment; 0.7~1 for particularly complex equipment; and the same type of equipment has the same complexity value.

[0031] Furthermore, in step 3.2, the number of probability samplings is not less than 100,000.

[0032] Furthermore, in step 4.5, the preset number of solutions is 15 to 25.

[0033] Furthermore, the preset threshold for step 5 is 0.0001.

[0034] The beneficial technical effects of this invention are as follows:

[0035] 1. Effective integration and correction of subjective and objective factors: Based on the introduction of empirical parameters such as equipment complexity, this invention quantifies the impact of equipment state changes on system reliability, obtains equipment importance based on probability analysis, and dynamically corrects the reliability allocation weights accordingly, avoiding static weights dominating the allocation results.

[0036] 2. Possesses adaptive adjustment capability: This invention establishes a closed-loop feedback mechanism in the reliability allocation process. When the reliability allocation scheme changes, causing a change in the importance of the equipment, the allocation weight coefficient can be updated synchronously to realize the dynamic adjustment of the reliability allocation scheme and improve the adaptability of the method to different system conditions. Attached Figure Description

[0037] Figure 1 This is a flowchart of the reliability allocation method for traction substations based on the cross-iteration of reliability and importance according to the present invention. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0039] The flowchart of the reliability allocation method for traction substations based on cross-iteration of importance and reliability according to the present invention is as follows: Figure 1 As shown, the specific steps include:

[0040] Step 1: Model incoming and feeder lines as nodes, and equipment as edges. Based on the equipment connection relationships, establish a "node-edge" system functional evaluation model; define normal system operation as the existence of a connected path between a feeder node and at least one incoming node, and establish the equipment functional status. With system functional status Mapping relationship between x and y take values ​​of 1 or 0 (normal or faulty), and N is the total number of devices.

[0041] Step 2: Determine the target system reliability value based on operational needs. The initial reliability of each device Set as the system reliability target value The complexity level is set for each piece of equipment based on its structural characteristics and maintenance difficulty. The equipment complexity ranges as follows: simple equipment 0.1~0.3; moderately complex equipment 0.4~0.6; and extremely complex equipment 0.7~1. Table 1 lists the equipment complexity set in this embodiment.

[0042] Table 1 Equipment Complexity

[0043]

[0044] Step 3: Analyze the impact of each device on the system reliability under completely reliable and completely unreliable conditions, and determine the importance of each device based on the impact.

[0045] Step 3.1: Set the i-th device to be in a completely reliable state with a reliability value of 1, and keep the reliability of the other devices unchanged to form the first type of device reliability condition.

[0046] Step 3.2: Under given equipment reliability conditions, perform 100,000 probability samplings of the operating status of all equipment in the system to generate an equipment state matrix. :

[0047]

[0048] Where M represents the total number of samplings; the system state sequence is determined based on the device state matrix and the mapping relationship G between device states and system states. :

[0049]

[0050] Among them, the system state sequence The j-th item in the matrix is ​​derived from the device state matrix. The j-th column determines the system state sequence; Calculate the system reliability under the corresponding equipment reliability conditions. :

[0051]

[0052] Step 3.3: Under the reliability conditions of the first type of equipment, execute step 3.2 to obtain the system reliability of the i-th equipment under the condition of complete reliability. .

[0053] Step 3.4: Assume the i-th device is in a completely unreliable state, with a reliability value of 0. The reliability parameters of the remaining devices remain unchanged, forming the second type of device reliability condition. Following step 3.2, obtain the system reliability under the condition that the i-th device is completely unreliable. .

[0054] Step 3.5: Perform steps 3.1 to 3.4 sequentially on all devices in the system to obtain the system reliability of each device under completely reliable and completely unreliable conditions. and The importance of each device is calculated according to the following formula. :

[0055]

[0056] Step 4: Iteratively solve the reliability of each device based on the reliability allocation function.

[0057] Step 4.1: Set the initial upper bound of the allocation coefficients. and the lower realm .

[0058] Step 4.2: Determine the current allocation coefficient C according to the following formula:

[0059]

[0060] Step 4.3: Based on the current allocation coefficients, equipment importance, and equipment complexity, assess the reliability of each device in the system. Solve the following:

[0061]

[0062] Step 4.4: Based on the updated device reliability value, solve for the system reliability according to Step 3.2. ; to assess the current system reliability Greater than the system reliability target value If the current allocation coefficient C is correct, then the current allocation coefficient C will be used as the new lower bound B; otherwise, the current allocation coefficient C will be used as the new upper bound U.

[0063] Step 4.5: Repeat steps 4.2 to 4.4, continuously update the allocation coefficient C, and solve for the equipment reliability until the preset number of solutions is reached (20 solutions in this embodiment); use the equipment reliability obtained from the last solution as the system reliability allocation result under the current importance setting conditions.

[0064] Step 5: Repeat steps 3 and 4 to continuously iterate and update the importance and reliability of the equipment until the average reliability error of each equipment in two adjacent iterations is less than a preset threshold (the preset threshold is 0.0001 in this embodiment); the reliability solution results of each equipment obtained when the convergence condition is met are taken as the final reliability allocation result of the traction substation.

Claims

1. A reliability allocation method for traction substations based on cross-iteration of importance and reliability, characterized in that, Includes the following steps: Step 1: Establish device functional status based on device connection relationships With system functional status Mapping relationship between x and y take values ​​of 1 or 0, and N is the total number of devices; Step 2: Determine the target system reliability value based on operational needs. The initial reliability of each device Set as the system reliability target value The complexity level is set for each piece of equipment based on its structural characteristics and maintenance difficulty. ; Step 3: Analyze the impact of each device under completely reliable and completely unreliable conditions on the system reliability, and determine the importance of each device based on the impact. Step 3.1: Set the i-th device to be in a completely reliable state with a reliability value of 1, and keep the reliability of the other devices unchanged to form the first type of device reliability condition; Step 3.2: Under given equipment reliability conditions, perform probability sampling on the operating states of all equipment in the system to generate an equipment state matrix. : ； Where M represents the total number of samplings; the system state sequence is determined based on the device state matrix and the mapping relationship G between device states and system states. : ； Among them, the system state sequence The j-th item in the matrix is ​​derived from the device state matrix. The j-th column determines the system state sequence; Calculate the system reliability under the corresponding equipment reliability conditions. : ； Step 3.3: Under the reliability conditions of the first type of equipment, execute step 3.2 to obtain the system reliability of the i-th equipment under the condition of complete reliability. ; Step 3.4: Assume the i-th device is in a completely unreliable state, with a reliability value of 0. The reliability parameters of the remaining devices remain unchanged, forming the second type of device reliability condition. Following step 3.2, obtain the system reliability under the condition that the i-th device is completely unreliable. ; Step 3.5: Perform steps 3.1 to 3.4 sequentially on all devices in the system to obtain the system reliability of each device under completely reliable and completely unreliable conditions. and The importance of each device is calculated according to the following formula. : ； Step 4: Iteratively solve for the reliability of each device based on the reliability allocation function; Step 4.1: Set the initial upper bound of the allocation coefficients. and the lower realm ; Step 4.2: Determine the current allocation coefficient C according to the following formula: ； Step 4.3: Based on the current allocation coefficients, equipment importance, and equipment complexity, assess the reliability of each device in the system. Solve the following: ； Step 4.4: Based on the updated device reliability value, solve for the system reliability according to Step 3.

2. ; to assess the current system reliability Greater than the system reliability target value If the current allocation coefficient C is true, then the current allocation coefficient C is taken as the new lower bound B; otherwise, the current allocation coefficient C is taken as the new upper bound U. Step 4.5: Repeat steps 4.2 to 4.4, continuously updating the allocation coefficient C and solving for the equipment reliability until the preset number of solutions is reached; use the equipment reliability obtained from the last solution as the system reliability allocation result under the current importance setting conditions; Step 5: Repeat steps 3 and 4 to continuously iterate and update the importance and reliability of the equipment until the average reliability error of each equipment in two adjacent iterations is less than the preset threshold; take the reliability solution of each equipment obtained when the convergence condition is met as the final reliability allocation result of the traction substation.

2. The reliability allocation method for traction substations based on cross-iteration of importance and reliability as described in claim 1, characterized in that, The path for establishing the mapping relationship between equipment status and system functional status in step 1 is a fault tree, state tree, or graph theory-based system functional status assessment method.

3. The reliability allocation method for traction substations based on cross-iteration of importance and reliability as described in claim 1, characterized in that, In step 2, the equipment complexity range is 0.1 to 0.3 for simple equipment. For general complex equipment, the value is 0.4 to 0.6; for particularly complex equipment, the value is 0.7 to 1; equipment of the same type has the same complexity value.

4. The reliability allocation method for traction substations based on cross-iteration of importance and reliability as described in claim 1, characterized in that, In step 3.2, the number of probability samplings shall not be less than 100,000.

5. The reliability allocation method for traction substations based on cross-iteration of importance and reliability as described in claim 1, characterized in that, In step 4.5, the preset number of solutions is 15 to 25.

6. The reliability allocation method for traction substations based on cross-iteration of importance and reliability as described in claim 1, characterized in that, The preset threshold for step 5 is 0.0001.

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