KR101341248B1 - Risk based maintenance system for power generation facilities - Google Patents

Abstract

The present invention composes the questionnaire for the probability of failure (POF) and the size of the failure damage (COF) to safely derive the risk in power plants with different operation and maintenance conditions, and at the same time the quantitative residual life assessment. And on-site inspection results can be a relatively important factor in risk assessment, and also through remaining life assessment, POF (probability of failure), and COF (failure damage size) question Regarding the risk-based maintenance system of the power plant to predict the next inspection time and to interpret the risk class,
By using the real-time operation information system to provide operation history information, the power generation facility management system to provide maintenance history information, and the operation history information input from the real-time operation information system and the maintenance history information input from the power generation facility management system. Risk management system that determines risk-failing equipment as equipment to be managed by risk, and risk assessment master management that prepares risk assessment master by inputting information on equipment to be managed by risk management. And a non-destructive test result input unit for providing a non-destructive test result, basic information on equipment inspection from the risk assessment master management unit, operation history information and maintenance history information from the real-time operation information system, and the non-destructive test result. To test result input section The failure probability calculation unit calculates the probability of failure (POF) using the values obtained from all seven questionnaires (PF1 to PF7) by inputting the data from the non-destructive inspection, and information on maintenance history from the power generation facility management system. Provides a trouble damage size calculation unit that calculates the failure damage size (COF) using the values obtained from all five paperweights (CF1 to CF5), and creates a risk matrix to display the area according to the risk level. Risk assessment unit that evaluates the risk according to which area specified on the risk matrix according to the probability of failure (POF) and the size of failure damage (COF), and according to the defined risk definition It includes a maintenance planner, which establishes a maintenance plan by mapping the risk change of the most dangerous part of the equipment components.

Description

Risk based maintenance system for power generation facilities

The present invention relates to a risk-based maintenance system of a power plant. More specifically, a questionnaire about a probability of failure (POF) and a damage damage size (COF) for safely deriving a risk in power plants with different operating and maintenance conditions is described. At the same time, the questionnaire value is constructed so that the quantitative residual life assessment and on-site inspection results can be a relatively important factor in the risk assessment. It relates to the risk-based maintenance system of power generation facilities for predicting the next inspection time and interpreting the risk class through the probability (POF) and failure damage size (COF) questionnaire.

Since the 1980s, the plant industry such as nuclear power, oil refining, and petrochemical has made great efforts to develop preventive technologies for serious accidents that have a huge negative impact on not only the company's existence but also the surrounding society such as radioactive leaks, large fires and explosions, and toxic material spills. Has been tilted. These industries, which are at risk of large-scale disasters, have gradually suppressed the accident rate through thorough preventive maintenance, but the effect of lowering the accident rate has not been satisfactory compared to the cost invested in preventive maintenance. In particular, long-distance piping and large pressure vessels, despite the enormous cost of inspection, failed to capture the proper inspection time, resulting in accidents involving large-scale damage to property and casualties.

The American Petro-Chemical Industry (API) has established a new facility diagnostic technology system using risk to prevent catastrophic accidents. The US Petrochemical Industry (API) has developed and distributed official guidelines for the risk diagnosis technology system, which has significantly reduced the failure rate. As a result, the nuclear and refinery industries have been accepting this, and have been developing and applying risk assessment procedures and diagnostic techniques that are appropriate for their industry.

The risk of the facility is an indicator that can simultaneously evaluate the probability of failure that can occur during the operation of the facility and the scale of damage that occurs when a failure occurs.Probability of Failure (POF) is as follows: As the product of the Consequence Of Failure (COF).

RISK = POF × COF

As can be seen from the above formula, the equipment is considered to be a high risk when the equipment is frequently out of order or the damage caused by the failure is very high.In contrast, when the equipment has little or no damage, Classified as low equipment. However, even if the frequency of failure is high, the damage is minor or negligible, and it is classified as a low-risk facility, and even if the damage is very large, it is classified as a low-risk facility even if there is little possibility of failure. In general, risk levels are divided into five levels in the US and Europe, and four levels in Japan to establish maintenance standards for each level to perform maintenance and inspection work.

Conventionally, there is a high risk that large accidents may occur by manually managing the risk of power generation facilities.

In addition, conventionally, all the equipments to be evaluated are specific to the petrochemical plant, so each questionnaire for evaluating the probability of failure (POF) and the damage size (COF) consists of the contents representing the operation and maintenance conditions of the chemical plant. As a result, there was a difficulty in accurately and safely deriving the risk of power generation facilities.

An object of the present invention is to solve the conventional problems as described above, a questionnaire about the probability of failure (POF) and the size of the failure damage (COF) to safely derive the risk in power plants with different operation and maintenance conditions At the same time, it is to provide a risk-based maintenance system for power generation facilities to configure the value of the questionnaire so that quantitative residual life assessment and on-site inspection results can be a relatively important factor in risk assessment.

Another object of the present invention is to predict the next inspection time through the remaining life evaluation and POF (probability of occurrence of failure), COF (failure damage size) by the inspection results of each part of the power plant, and to analyze the risk level, To provide a risk-based maintenance system for power plants.

As a means for achieving the above object, the configuration of the present invention includes a real-time operation information system for providing operation history information, a power generation facility management system for providing maintenance history information, and operation history information input from the real-time operation information system. And a risk management target facility determination unit for determining a facility that is deteriorated with age using the maintenance history information inputted from the power generation facility management system as a facility to be managed by risk, and from the risk management facility determination unit to a facility to be managed for risk management. A risk assessment master management unit for receiving a risk information master to create a risk assessment master, a non-destructive inspection result input unit for providing a non-destructive inspection result, and basic information on equipment inspection from the risk assessment master management unit; Operation history information and information from the system Non-destructive test result input unit receives the non-destructive test result from the non-destructive test result input unit and calculates the probability of failure occurrence probability (POF) using the values obtained in all seven paperweights (PF1 ~ PF7), and The failure damage size calculation unit that calculates the failure damage size (COF) using the values obtained from all five paperweights (CF1 to CF5) by receiving information on maintenance history from the power generation facility management system, and a risk matrix Area is displayed according to the risk level, and the risk is assessed according to which area is specified on the risk matrix by the probability of failure (POF) and size of failure damage (COF). According to the risk assessment unit and the defined risk definition, the maintenance plan is drawn up by drawing the risk change of the highest risk component among the components of the facility. It is desirable to include the maintenance planning department.

The configuration of the present invention is preferably such that the risk assessment master includes a facility number, a facility name, a part code, a part name, a damage mechanism code, and a damage mechanism name.

In the configuration of the present invention, the probability of failure occurrence (POF) is preferably calculated by the following equation.

POF = PF2 × (PF1 + PF3 + PF4 + PF5 + PF6 + PF7)

PFn = Wn × Vn

PFn = Wn × Vn

Here, PFn represents seven paperweights PF1 to PF7, Wn represents a weight, and Vn represents a value of the answer to the paperweight.

In the configuration of the present invention, the paperweight PF1 is a paperweight on the deterioration state of the current equipment. When the defect has not occurred and the currently evaluated residual life exceeds the design standard remaining life, the answer of PF1-1 is selected. However, if no remaining defects occur but the estimated remaining life is less than 80% of the design basis remaining life or if a defect has occurred but the estimated remaining life is greater than 80% of the design basis remaining life, the answer of PF1-2 is chosen. If a defect has occurred while the current evaluation remaining life is less than 80% of the design criterion remaining life, the answer of PF1-3 is selected, and the weight (Wn) of the paperweight is '5' and The value Vn is preferably set as follows.

PF1-1: 1, PF1-2: 5, PF1-3: 9

The configuration of the present invention, the paperweight (PF2) is a questionnaire for the probability of failure by the damage mechanism of the equipment or parts, and the next inspection or evaluation period (AP, Assessment Period) and the evaluation remaining life (EL, Evaluated Life) and Is determined by the comparison of PF2-1 when AP <EL / 2, and when PF2-2 is selected when EL / 2 <AP <EL, The answer of PF2-3 is selected, and the weight Wn of the paperweight is 1, and the value Vn of the answer of each paperweight is preferably set as follows.

PF2-1: 1, PF2-2: 2, PF2-3: 10

In the configuration of the present invention, the questionnaire PF3 is a questionnaire for evaluating the defect detection reliability of the inspection technology applied to the corresponding equipment or component, and when the utility value calculated is '10' or more, the answer of PF3-1 is selected and the utility value is selected. The answer of PF3-2 is selected when the value is less than '7' and the 'PF' is less than '7'. When the efficiency is less than '5' or more, the answer of PF3-3 is selected. When the answer of PF3-4 is selected and the utility is less than '3', the answer of PF3-5 is selected, and the weight of the paperweight is 6 and the value Vn of each paperweight is set as follows.

PF3-1: 1, PF3-2: 3, PF3-3: 5, PF3-4: 7, PF3-5: 9

In the configuration of the present invention, the paperweight PF4 is a paperweight for evaluating the influence according to the start-stop operation mode of a facility equipped with the corresponding equipment or parts, and in the case where there is little output fluctuation or start-stop like a nuclear power plant -1 answer is selected, if there are intermittent output fluctuations or start stops, such as large-scale coal-fired power plants, the answer of PF4-2 is selected, and daily start-up or weekly start-stops such as complex, gas turbine, and pumping are performed. In this case, an answer of PF4-3 is selected, and the weight Wn of the paperweight is 1.5 and the value Vn of the answer of each paperweight is preferably set as follows.

PF4-1: 1, PF4-2: 3.5, PF4-3: 6

The configuration of the present invention, the paperweight (PF5) is a paperweight for evaluating the influence of the operating variables (temperature, pressure, vibration, flow rate, etc.) during the normal operation of the equipment or equipment equipped with the equipment, The answer of PF5-1 is selected when the operating variables appearing during normal operation remain unchanged, and the answer of PF5-2 is selected when there is a sudden increase or decrease of the values of the operating variables. If the frequent increase and decrease of the operating variables is repeated, the answer of PF5-3 is selected, and the weight (Wn) of this paperweight is 3, and the value (Vn) of each paperweight is set as follows. desirable.

PF4-1: 1, PF4-2: 3.5, PF4-3: 6

In the configuration of the present invention, the paperweight PF6 is a paperweight for evaluating how the equipment or the equipment in which the component is installed is operated in comparison with the design standard or the manufacturer's recommendation standard. PF6-1 is selected when operating within 60% of the design limit, and PF6-2 is selected when the reference operating variable is operating in the range of 60% to 90% of the design limit. If the reference operating variable is operated in the range of 90% ~ 100% of the design limit, the answer of PF6-3 is selected. If the reference operating variable exceeds the design limit, the answer of PF6-4 is selected, and the weight of the paper (Wn) is 3 and the value Vn of the answer of each questionnaire is preferably set as follows.

PF6-1: 1, PF6-2: 2.67, PF6-3: 4.33, PF6-4: 6

In the configuration of the present invention, the paperweight PF7 is a paperweight for evaluating whether the damage caused to the corresponding equipment or parts has occurred in the past, and if the same damage or failure has not occurred, PF7-1 is selected, and the same damage If PF7-2 is selected, the weight Wn of the paperweight is 1 and the value Vn of the answer of each paperweight is set as follows.

PF7-1: 1.5, PF7-2: 7.5

In the configuration of the present invention, the above-described failure damage size COF is preferably calculated by the following equation.

COF = CF1 + CF2 + CF3 + CF4 + CF5

CFn = Wn × Vn

PFn = Wn × Vn

Here, CFn represents five paperweights CF1 to CF5, Wn represents a weight, and Vn represents a value of the answer to the paperweight.

According to the configuration of the present invention, the paperweight CF1 is a paperweight for evaluating the loss of maintenance repair cost when a failure occurs. If the maintenance repair cost loss is low, CF1-1 is selected, and if the maintenance repair cost loss is medium, CF1 CF-2 is selected if -2 is selected, and the loss of maintenance repair cost is high, and the weight (Wn) of the paperweight is 8 and the value Vn of the answer of each paperweight is set as follows.

CF1-1: 1, CF1-2: 2, CF1-3: 3

In the configuration of the present invention, the paperweight CF2 is a paperweight for evaluating the severity of the failure due to the failure mode expected when the failure occurs, and the expected failure mode of the equipment or component to be evaluated is leakage due to pinholes or cracks. In case the CF2-1 answer is selected, in case of secondary damage such as deformation or material deterioration instead of simple leakage, the answer in CF2-2 is selected. It is preferable that the weight Wn of the paperweight is 5.5 and the value Vn of the answer of each paperweight is set as follows.

CF2-1: 1, CF2-2: 2, CF2-3: 3

The configuration of the present invention, the paperweight (CF3) is a paperweight for evaluating the severity caused by secondary damage or ripple failure when a failure occurs, if the failure is locally limited and does not affect the surroundings of CF3-1 Is selected, the response of CF3-2 is selected if there is an influence on the surroundings but no significant equipment or parts is selected, and the response of CF3-3 is selected if it affects the surrounding important equipment or parts. The weight Wn of the paperweight is 7 and the value Vn of the answer of each paperweight is preferably set as follows.

CF3-1: 1, CF3-2: 2, CF3-3: 3

The configuration of the present invention, the paperweight (CF4) is a paperweight for evaluating the severity of the failure damage through the effect on the availability of the entire facility or plant when a failure occurs, if the number of days of failure due to failure is less than one day CF4-1 is selected, CF4-2 is selected for 3 days or less, CF4-3 is selected for 1 week or less, CF4-4 is selected for 1 month or less, and CF4-5 is selected for 1 month or less. The weight Wn of the paperweight is 7.3 and the value Vn of the answer of each paperweight is preferably set as follows.

CF4-1: 1, CF4-2: 2, CF4-3: 3, CF4-4: 4, CF4-5: 5

The configuration of the present invention, the paperweight (CF5) is a paperweight for evaluating the severity of the failure damage through the impact on the human injury or the surrounding environment when the failure occurs, the damage to the life or environment due to the expected failure If none, the CF5-1 answer is selected, if only one of the damages to life and the environment occurs, the CF5-2 answer is selected, and if both the life and the environment are harmed, the CF5-3 answer is selected. The weight Wn of the paperweight is 4 and the value Vn of the answer of each paperweight is preferably set as follows.

CF5-1: 1, CF5-2: 2, CF5-3: 3

This invention has the following effects.

Severe failure and accident control

Mid- and long-term measures to systematically define major accidents such as human injury, surrounding environmental pollution, fire, and explosion and major failures requiring long-term shutdown of the plant, and to monitor and manage failure risks through risks Can be presented.

Optimization of maintenance resources

The basic principle of equipment failure analysis is that 80% of major failures are caused by 20% of the total equipment. Therefore, to minimize failures, focus 80% of maintenance resources (cost, time, manpower, etc.) on 20% facilities causing major failures, and invest the remaining maintenance resources on 80% facilities with low risk of failure. Risk assessment is an evaluation technique and analytical procedure for selecting 20% equipment that causes a serious failure.

Establish a specialized preventive maintenance system

In order to prevent the failure, various failure information can be obtained such as the cause of the failure of the equipment, the progress of the failure, the detection method of the failure sign, and the countermeasures against the failure. In addition, it is possible to establish appropriate preventive measures at the early stage of failure by predicting the time of failure from the type of failure. Risk assessment can predict the proper inspection and maintenance time of equipment through evaluation of the probability of failure occurrence, and suggest effective inspection and maintenance methods by analyzing failure mechanisms.

1 is a block diagram of a risk-based maintenance system of a power plant according to an embodiment of the present invention.
2 is a configuration diagram of a risk assessment master of a risk-based maintenance system of a power plant according to an embodiment of the present invention.
3 is a configuration diagram of the paperweights PF1 to PF7 for calculating the probability of failure occurrence (POF) of the risk-based maintenance system of the power generation equipment according to an embodiment of the present invention.
Figure 4 is a block diagram of the paperweight (CF1 ~ CF5) for calculating the failure damage size (COF) of the risk-based maintenance system of the power plant according to an embodiment of the present invention.
5 is a configuration diagram of a risk matrix of a risk-based maintenance system of a power plant according to an embodiment of the present invention.
FIG. 6 is a view to help understand the concept of a failure rate of change probability (LCR) of a risk-based maintenance system of a power generation system according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily carry out the present invention. Other objects, features, and operational advantages, including the purpose, operation, and effect of the present invention will become more apparent from the description of the preferred embodiments.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory only and are not to be construed as limiting the scope of the invention as disclosed in the accompanying claims. It is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and similarities, many of which are within the scope of the present invention. In addition, the terms or words used in the specification and claims herein should not be construed as being limited to the ordinary or dictionary meanings, and the inventors should properly explain the concept of terms in order to best explain their invention in the best way. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.

1 is a block diagram of a risk-based maintenance system of a power plant according to an embodiment of the present invention.

As shown in Figure 1, the configuration of the risk-based maintenance system of the power generation equipment according to an embodiment of the present invention, the real-time operation information system 1 for providing operation history information, and the power generation for providing maintenance history information The facility management system (2), the operation history information input from the real-time operation information system (1) and the maintenance history information input from the power generation equipment management system (2) using the equipment that is aged deterioration risk management target A risk assessment master manager (4) which receives a risk management target facility determination unit (3) determined by the facility and a risk assessment master by receiving information on the risk management target facility from the risk management target facility decision unit (3); In order to provide a non-destructive test result, the non-destructive test result input unit 5 and the risk assessment master management unit 4 provide basic information on equipment inspection. Values obtained in seven questionnaires (PF1 to PF7) by receiving the non-destructive inspection result from the non-destructive inspection result input unit 5 and receiving the operation history information and the maintenance history information from the real-time operation information system (1). The probability of failure occurrence calculation (6) for calculating the probability of failure occurrence (POF) using the information and the maintenance history from the power generation facility management system (2) were obtained in five paperweights (CF1 to CF5) Calculate the damage damage size (COF) by using the value, and create a risk matrix (Risk Matrix) to display the area according to the risk level, the probability of failure (POF) and the damage damage size A risk assessment section 8 for evaluating the risks by which area the location specified on the risk matrix is defined by the size of the COF, and the corresponding equipment configuration according to the defined risk definitions; Comprises a pumjung establish maintenance plan for the maintenance plan to establish a risk that illustrates a high-risk changes in the element portion (9).

The operation of the risk-based maintenance system and control method of the power plant according to an embodiment of the present invention by the above configuration is as follows.

Equipment for risk management target determination unit 3 receives operation history information such as temperature and pressure from real-time operation information system 1 and receives maintenance history information from power generation facility management system 2 to generate deterioration over time. That is, as a facility that is determined to have a lifespan, it is operated in the high-temperature and high-pressure section, the equipment that has a large economic loss in the event of a failure is determined as a risk management target equipment and output to the risk assessment master management unit (4).

The risk assessment master management unit 4 receives the information on the risk management target facility from the risk management target facility determination unit 3, and as shown in FIG. 2, the equipment number, equipment name, part code, part name, damage You will create a risk assessment master that includes the instrument code and damage instrument name. Here, the risk assessment master for each part includes a life assessment method, an early damage form, a progressive damage form, and a final damage form, and then prepares inspection methods for each inspection site in detail.

The probability of failure occurrence calculation unit 6 is provided with basic information on equipment inspection from the risk assessment master management unit 4, and operation history information (for example, temperature and pressure) and maintenance history information from the real-time operation information system 1. The non-destructive test result input unit 5 receives the non-destructive test result, and as shown in FIG. 3, using the values obtained in all seven paperweights PF1 to PF7, the probability of failure occurrence (POF) is expressed as follows. Calculate

POF = PF2 × (PF1 + PF3 + PF4 + PF5 + PF6 + PF7)

In the above equations, each of the paperweights PFn has a weight to indicate the relative importance between the paperweights. These weights were defined through extensive surveys of specialists and maintenance engineers. An important point in weight selection is that the influence of any particular questionnaire should not be dominant. If the entire level is determined by one paperweight, the meaning of existence of other paperweights disappears.

The value of each paperweight PFn is configured as follows.

PFn = Wn × Vn

Here, Wn represents a weight and Vn represents a value of the answer to the paperweight.

The content and evaluation criteria of each paperweight are as follows.

○ PF1: Operation and management status of equipment (Current Condition)

As a questionnaire about the deterioration status of the current equipment, one of the answers below is selected by receiving a non-destructive test result.

PF1-1: New or Deteriorated (Better)

PF1-2: Deterioration detection or micro damage (As Expected)

PF1-3: degradation progress and damage growth (Worse)

If no defects have occurred and the currently assessed remaining life exceeds the design criterion remaining life, the answer to PF1-1 is selected, and no defect has occurred but the estimated remaining life is less than 80% of the design life remaining. If a defect has occurred but the estimated remaining life is greater than 80% of the design criterion remaining life, then the answer of PF1-2 is selected, and the defect has occurred when the current remaining life is less than 80% of the design life remaining. In that case, the answer of PF1-3 is selected.

The weight (Wn) of the paperweight is '5' and the value (Vn) of each paperweight's answer is set as follows.

PF1-1: 1, PF1-2: 5, PF1-3: 9

○ PF2: Failure Likelihood

As the questionnaire about the probability of failure caused by the damage mechanism of the corresponding equipment or parts, one of the following answers is selected by receiving operation history information of the real-time operation information system 1.

PF2-1: There is little chance of damage or failure occurring within the standard evaluation period. (Not Credible)

PF2-2: Damage or failure may occur within the standard evaluation period. (Unlikely)

PF2-3: Almost no damage or failure occurs within the standard evaluation period. (Likely)

The selection criteria for each response is determined by comparing the next assessment or assessment period (AP) with the assessed life (EL). That is, if AP <EL / 2, the answer of PF2-1 is selected; if EL / 2 <AP <EL, the answer of PF2-2 is selected; if AP> EL, the answer of PF2-3 is greater. Is selected.

The weight Wn of this paperweight is 1, and the value Vn of the answer of each paperweight is set as follows.

PF2-1: 1, PF2-2: 2, PF2-3: 10

○ PF3: Inspection Effectiveness of Damage Mechanism Program

As a questionnaire for evaluating the defect detection reliability of the inspection technique applied to the equipment or component, one of the following answers is selected based on the inspection technique utility comparison table.

PF3-1: The defect detection reliability of the current inspection program is very high. (Very Good)

PF3-2: The reliability of defect detection in the current inspection program is high. (Good)

PF3-3: The defect detection reliability of the current inspection program is average (medium). (Average)

PF3-4: The defect detection reliability of the current inspection program is low. (Poor)

PF3-5: Current inspection programs are difficult to detect defects. (Inefficient)

For each answer, the answer of the questionnaire is selected in consideration of the expected defect type and the defect detection characteristics of the inspection technique applied. If multiple inspection techniques are used, add the utility of each technique and calculate the value considering the inspection scope of the entire target range. If the calculated utility value is '10' or more, the answer of PF3-1 is selected, and if the utility value is '10' or less, '7' or more, the answer of PF3-2 is selected, and the utility is less than '7' and '5' or more If the answer of PF3-3 is selected, and the utility is less than '5', the answer of PF3-4 is selected. If the utility is less than '3', the answer of PF3-5 is selected.

The weight Wn of this paperweight is 6 and the value Vn of the answer of each paperweight is set as follows.

PF3-1: 1, PF3-2: 3, PF3-3: 5, PF3-4: 7, PF3-5: 9

○ PF4: Frequency of stopping of equipment (Impact of Cycling)

As a questionnaire for evaluating the influence according to the start stop operation mode of a facility equipped with a corresponding facility or part, one of the following answers is selected by receiving operation history information from the real-time operation information system 1.

PF4-1: The frequency of start stop is very low with almost constant output. (No Effect)

PF4-2: Output change or start stop intermittently. (Moderate Effect)

PF4-3: Frequency of output change or start stop is high. (Severe)

Each answer is selected to reflect the type of shutdown operation of the installation. The answer of PF4-1 is selected when there is almost no output fluctuation or starting stop, such as in nuclear power plants. The answer of PF4-2 is selected when there are intermittent output fluctuations or starting stops, such as large-scale coal-fired power plants. In case of daily stop or weekly stop such as gas turbine, pumping, etc., the answer of PF4-3 is selected.

The weight Wn of this paperweight is 1.5 and the value Vn of the answer of each paperweight is set as follows.

PF4-1: 1, PF4-2: 3.5, PF4-3: 6

○ PF5: Operational Stability

As a questionnaire for evaluating the influence of the operating variables (temperature, pressure, vibration, flow rate, etc.) during the normal operation of the equipment or parts equipped equipment, the operation history information is received from the real-time operation information system (1). One of the answers below is selected.

PF5-1: The state of operating variables is very stable during normal operation. (Very Stable)

PF5-2: The state of operating variables is intermittently unstable during normal operation. (Infrequent Operational Upset)

PF5-3: Operational variables show frequent instability during normal operation. (Regular Operational Upset)

For each answer, the answer of PF5-1 is selected when the operating variables that appear during normal operation of the equipment remain unchanged, and when the value of the operating variables increases or decreases intermittently, PF5-2 is observed. The answer of PF5-3 is selected when the sudden increase and decrease of the operating variables is repeated frequently.

The weight Wn of this paperweight is 3, and the value Vn of the answer of each paperweight is set as follows.

PF4-1: 1, PF4-2: 3.5, PF4-3: 6

○ PF6: Operation in Relation to Design

As a questionnaire for evaluating how the equipment or parts equipped equipment is operated in comparison with the design standard or the manufacturer's recommended standard, the operation history information is input from the real-time operation information system (1) and compared with the design value. One of is selected.

PF6-1: Operate in a safer and more conservative manner than the design recommended operation criteria. (Significantly Below Normal Operating Range)

PF6-2: Follow the design recommended operation criteria. (Within Normal Operating Range)

PF6-3: Operate close to the design limit. (Close to Design Limit)

PF6-4: Run over the design limit. (Above Design Limit)

Each answer is selected by comparing the design's normal operating conditions with the design limits. If the reference variables (temperature, pressure, vibration, flow rate, etc.) of the operating state are operated at less than 60% of the design limit, the answer of PF6-1 is selected and the reference operating variable is within the range of 60% to 90% of the design limit. In case of operation, the answer of PF6-2 is selected.If the reference operation variable is operated in the range of 90% ~ 100% of the design limit, the answer of PF6-3 is selected, and if the reference operation variable exceeds the design limit, PF6-4 Your answer is selected.

The weight Wn of the paperweight is 3 and the value Vn of the answer of each paperweight is set as follows.

PF6-1: 1, PF6-2: 2.67, PF6-3: 4.33, PF6-4: 6

○ PF7: Failure Recurrence

As a questionnaire for evaluating whether the damage caused to the equipment or parts has occurred in the past, one of the following answers is selected by receiving maintenance history information from the power generation equipment management system 2.

PF7-1: No identical damage or failure occurred. (No)

PF7-2: Same damage or failure occurred. (Yes)

The weight Wn of this paperweight is 1 and the value Vn of the answer of each paperweight is set as follows.

PF7-1: 1.5, PF7-2: 7.5,

The failure damage size calculation unit 7 is provided with information on maintenance history from the power generation facility management system 2, and as shown in Fig. 4, using values obtained from all five paperweights CF1 to CF5. Calculate the failure damage size (COF) by the following equation.

COF = CF1 + CF2 + CF3 + CF4 + CF5

In the above equations, each of the paperweights CFn has a weight to indicate the relative importance between the paperweights, and the value of the paperweight CFn is configured as follows.

CFn = Wn × Vn

Here, Wn represents a weight and Vn represents a value of the answer to the paperweight.

The contents and evaluation criteria of each paperweight are as follows.

○ CF1: Repair cost in case of failure

As a questionnaire for evaluating the loss of maintenance repair cost in the event of a failure, one of the following answers is selected by receiving maintenance history information from the power generation facility management system (2).

CF1-1: low (Low Repair Cost)

CF1-2: Medium (Medium Repair Cost)

CF1-3: high. (High Repair Cost)

In coal-fired power plants, the high energy loss in the process is mainly high temperature and high pressure equipment. The main steam final superheater has the highest energy, while energy losses due to failure are the lowest at low temperatures, such as in seawater cooling water systems.

The weight Wn of the paperweight is 8 and the value Vn of the answer of each paperweight is set as follows.

CF1-1: 1, CF1-2: 2, CF1-3: 3

○ CF2: Expected Failure Mode

As a questionnaire for evaluating the severity of the failure due to the expected failure mode when a failure occurs, one of the following answers is selected by receiving maintenance history information from the power generation facility management system 2.

CF2-1: Leak

CF2-2: Mixed Damage

CF2-3: Damage

Major accidents such as plant fires, explosions, pollution and toxic releases are mainly caused by failure modes such as leakage of process materials or equipment damage. If the expected failure mode of the equipment or component to be evaluated is leakage due to pinholes or cracks, the CF2-1 answer is selected. If the damage is accompanied by secondary damage such as deformation or material degradation, rather than simple leakage, the CF2-2 answer is selected. Is selected, and the answer of CF2-3 is selected if the plant or part is destroyed.

The weight Wn of the paperweight is 5.5 and the value Vn of the answer of each paperweight is set as follows.

CF2-1: 1, CF2-2: 2, CF2-3: 3

CF3: Consequential Damage Potential

As a questionnaire for evaluating the severity caused by secondary damage or ripple failure when a failure occurs, one of the following answers is selected by receiving maintenance history information from the power generation facility management system (2).

CF3-1: None

CF3-2: but no secondary failure damage to critical equipment / parts (No Other Major Component)

CF3-3: Several Other Major Component

The answer is selected by judging whether the expected failure is affecting the surrounding equipment or parts in addition to the corresponding equipment or parts. If the fault is localized and there is no impact on the surroundings, the CF3-1 answer is selected. If there is an impact on the surroundings but no significant equipment or parts are affected, the CF3-2 answer is selected. In the case of influencing components, the CF3-3 answer is chosen.

The weight of this paperweight (Wn is 7 and the value Vn of each paperweight answer is set as follows).

CF3-1: 1, CF3-2: 2, CF3-3: 3

○ CF4: Effect on Avaliablity

As a questionnaire for evaluating the severity of failure damage through the effect on the availability of the corresponding equipment or the entire plant in case of failure, one of the following answers is selected by receiving maintenance history information from the power generation facility management system (2). .

CF4-1: Less than 1 day

CF4-2: Less than 3 days

CF4-3: Less than 1 week

CF4-4: Less than 1 month

CF4-5: Greater than 1 month

Anticipated failures assess the availability degradation due to failure damage through the number of downtimes of the plant or plant. The answers are selected among the answers from CF4-1 to CF4-5 by the number of stops due to the failure.

The weight Wn of this paperweight is 7.3 and the value Vn of the answer of each paperweight is set as follows.

CF4-1: 1, CF4-2: 2, CF4-3: 3, CF4-4: 4, CF4-5: 5

○ CF5: Impact on Life and Environment (Threat Personnel / Environment)

In the event of a failure, one of the following answers is selected as a questionnaire for evaluating the severity of the failure through the effects on human injury or the surrounding environment.

CF5-1: None (Threat to None)

CF5-2: damage to person or environment

CF5-3: Threat to Personnel and Environment

The CF5-1 answer is selected if there is no damage to life or the environment due to the expected failure, the CF5-2 answer is selected if only one of the damage to life and the environment occurs, and the damage to life and the environment is avoided. If all occur, the CF5-3 answer is selected.

The weight Wn of the paperweight is 4 and the value Vn of the answer of each paperweight is set as follows.

CF5-1: 1, CF5-2: 2, CF5-3: 3

Since the probability of failure (POF) calculated by the probability of occurrence of failure (6) and the magnitude of failure (COF) calculated by the size of failure damage calculation (7) are relative indices for comparing sizes, they have no physical meaning. By the basic definition of risk, multiplying two values does not yield a meaningful value.

Therefore, the risk assessment unit 8 prepares a risk matrix and displays the area according to the risk level in the risk matrix and displays the risk according to the probability of failure occurrence (POF) and the size of failure damage (COF). The risk is assessed by which area the location specified on the Risk Matrix belongs to.

The risk assessment unit 5 evaluates the questionnaire answer combinations in all cases of the probability of failure (POF) and the size of the failure damage (COF) to obtain a value that distinguishes each stage, and divides the score ranges in which they are distributed into five stages. use. The risk evaluation unit 5 may evaluate the risk using a combination of two values, a probability of failure (POF) and a failure damage size (COF). As shown in FIG. 5 by the magnitude of the assessed risk, the risk matrix is created by dividing the facilities into five groups of very high risk, high risk, medium risk, low risk and very low risk.

Very high risk

Very high risk installations are indicated in the red areas (5D, 5E, 4E, 3E) of the Risk Matrix, which are very serious and have a moderate frequency. The failure can occur in a short time and the damage caused by the failure is so great that it is necessary to install the real-time monitoring facilities or to immediately inspect and improve the equipment.

○ high risk

High-risk equipment is indicated in the orange area of the Risk Matrix (5A, 5B, 5C, 4C, 4D, 3D, 2E, 1E) and has a low probability of failure and a very high probability of failure or failure. This is the case when the damage is high and the probability of failure is less than medium. In this case, systematic monitoring and diagnosis of the equipment is required. Therefore, short-term, low-cost preventive maintenance measures should be established for facilities with low severity of failure damage and high probability of failure, and for facilities with low severity of failure damage. In this regard, it is necessary to establish and operate a preventive maintenance plan with high long-term inspection accuracy.

○ Medium risk

Medium risk installations are indicated in the yellow areas of the risk matrix (4A, 4B, 3C, 2C, 2D, 1C, 1D) and have a low probability of failure and a rather high probability of failure or This is the case with medium severity and low probability of failure. In this case, preventive maintenance is not essential and, if a preventive maintenance plan is in place, it is reasonable to allocate maintenance resources at the normal level of visual inspection at the normal or long period of normal overhaul.

○ low risk

Low-risk equipment is indicated in the lime green areas (3A, 3B, 2B) of the Risk Matrix, and the failure probability is low and the probability of failure is less than medium. In general, preventive maintenance is not required and attention is only paid to changes in risk.

Very low risk

Very low-risk equipment is indicated in the green areas (2A, 1A, 1B) of the Risk Matrix, where both the severity and the probability of failure are low. Preventive maintenance and inspection are not necessary and it is decided whether to exclude from the equipment to be assessed according to the risk change.

When the risk matrix is created through the risk assessment unit 5, the maintenance plan establishment unit 9 plots the risk change from 1AP to 3AP of the highest risk component among the components of the corresponding equipment according to the defined risk definition. A maintenance plan can be established, or a maintenance plan can be developed by plotting the risk change from 1AP to 3AP of the parts with the highest probability of failure of each facility (ie, the shortest safety inspection time). Although these criteria alone can greatly contribute to the maintenance planning, the maintenance planning section 6 provides an algorithm for predicting the unique next maintenance and inspection timing, called the Remaining Life Indicator (RLI).

Considering thinning, the remaining service life (LR) of the pipe, the simplest damage mechanism, is calculated as follows.

LR = (ta-tc) / Rc * Fs

Where ta is the design minimum allowable thickness, tc is the current thickness, Rc is the thickness reduction rate due to corrosion, and Fs is the safety factor.

The remaining life indicator (RLI) is similar to the remaining life (LR) of the pipes calculated above, so the maximum probability of failure (POFmax) instead of the design minimum allowable thickness (ta) in the above equation is given instead of the current thickness (tc). This can be obtained by replacing the probability of failure (POFc) and the rate of change of failure probability (PCR) over time instead of the thickness reduction rate (Rc) due to corrosion. Therefore, the remaining life indicator (RLI) is as follows.

IR = (POFmax-POFc) / PCR * Fs

In the above equation, IR is the calculated value of the remaining life indicator (RLI), POFmax is the maximum value of the probability of failure (POF), and it is the reference value that is expected to cause the failure as the design minimum allowable thickness (ta), and POFc is the current thickness ( As shown in tc), the current probability of failure (POF) is the value, and the PCR (Possibility Change Rate) is the rate of change of the probability of failure (POF) over time, such as the thickness reduction rate (Rc) due to corrosion. The maximum probability of failure probability (POFmax) can be obtained from the answers of the aforementioned PF questionnaires, and the probability of change of failure probability (PCR) is defined as a function of expected evaluation time (AP) and evaluation life (EL).

PCR = f (AP, EL)

If the predictive evaluation timing (AP) is relatively short in a facility having the same lifetime as shown in the left graph in FIG. 6, even if the time passes for 3AP, the change in the probability of failure occurrence (POF) during the evaluation period is small and vice versa. As shown in the graph on the right, if the predictive evaluation time period (AP) is relatively long, the change rate of the probability of failure (POF) increases during the evaluation period, and the probability of change of the probability of failure (PCR) is also large. Therefore, the size of predictive evaluation time (AP) for the life expectancy of the failure rate (PCR) is very important.

The maintenance plan establishment unit 6 establishes the next maintenance plan by reflecting the risk assessment result. As shown in FIG. 7, the predictive evaluation time point (AP) is three times as the unit elapsed time. The probability of failure occurrence probability (PCR) is calculated by evaluating the probability of failure occurrence (POF) at each AP. This can be expressed as follows.

PCR = [POF (T = 3AP)-POF (T = 1AP)] / (3AP-1AP)

1: Real time operation information system 2: Power plant management system
3: risk management target equipment determination unit 4: risk assessment master management unit
5: Non-breakthrough test result input unit 6: Failure probability calculation unit
7: Damage damage calculation unit 5: Risk assessment unit
9: Maintenance Planning Department

Claims (16)

Real-time driving information system that provides driving history information,
Power plant management system that provides maintenance history information,
A risk management target facility determination unit that determines a facility that is subject to risk management by using operation history information received from the real-time operation information system and maintenance history information received from the power generation facility management system, as a facility to be managed by risk;
A risk assessment master management unit which receives information on the risk management target equipment from the risk management target equipment determination unit and prepares a risk assessment master;
A non-destructive test result input unit for providing a non-destructive test result,
Received basic information on equipment inspection from the risk assessment master management unit, operation history information and maintenance history information from the real-time operation information system, and non-destructive inspection result input from the non-destructive inspection result input unit. A failure probability calculation unit for calculating a probability of failure occurrence (POF) by using the value obtained at ~ PF7),
The failure damage size calculation unit receives the information on the maintenance history from the power generation facility management system and calculates the failure damage size (COF) using the values obtained from all five paperweights (CF1 to CF5);
A risk matrix is created to indicate areas according to risk levels, and the location specified on the risk matrix by the magnitude of the probability of failure (POF) and the size of the failure damage (COF) belongs to which area. A risk assessment unit for evaluating risks by
According to the defined risk definition, it includes a maintenance plan establishment unit which sets up a maintenance plan by mapping the risk change of the highest risk component among the corresponding components of the facility.
The probability of failure (POF) is calculated by the following formula,
POF = PF2 × (PF1 + PF3 + PF4 + PF5 + PF6 + PF7)
PFn = Wn × Vn
(Here, PFn represents seven paperweights (PF1 to PF7), Wn represents weight, and Vn represents a value of the answer to the paperweight)
The paperweight PF1 is a paperweight on the deterioration state of the current equipment. If no defect has occurred and the currently evaluated residual life exceeds the design criterion remaining life, the answer of PF1-1 is selected, and no defect has occurred. If the estimated remaining life is less than 80% of the design basis remaining life or if a defect has occurred but the estimated remaining life is greater than 80% of the design basis remaining life, the answer of PF1-2 is selected and the current life remaining If a defect has occurred while it is less than 80% of the remaining life of this design criterion, the answer of PF1-3 is selected, and the weight (Wn) of this paperweight is '5' and the value (Vn) of each paperweight is Risk-based maintenance system, characterized in that set as.
PF1-1: 1, PF1-2: 5, PF1-3: 9 The method of claim 1,
The risk assessment master is a risk-based maintenance system, characterized in that consisting of equipment number, equipment name, part code, part name, damage mechanism code, damage mechanism name. delete delete The method of claim 1,
The questionnaire PF2 is a questionnaire for a probability of failure caused by a damage mechanism of a corresponding equipment or component, and is determined by comparing the next inspection or evaluation period (AP) with the evaluation remaining life (EL). , If AP <EL / 2, the answer of PF2-1 is selected, if EL / 2 <AP <EL, the answer of PF2-2 is selected, if AP> EL, the answer of PF2-3 is And the weight (Wn) of the paperweight is 1 and the value (Vn) of the answer of each paperweight is set as follows.
PF2-1: 1, PF2-2: 2, PF2-3: 10 The method of claim 1,
The questionnaire PF3 is a questionnaire for evaluating defect detection reliability of an inspection technology applied to a corresponding equipment or part, and when the calculated utility value is '10' or more, the answer of PF3-1 is selected and the utility value is less than '10'. If it is 7 'or higher, the answer of PF3-2 is selected. If the utility is less than' 7 ', the answer of PF3-3 is selected. If the utility is less than' 5 ', the answer of PF3-4 is answered. If selected, and the utility is less than '3', the answer of PF3-5 is selected, the weight of the questionnaire is 6 and the value (Vn) of the answer of each questionnaire is set as follows.
PF3-1: 1, PF3-2: 3, PF3-3: 5, PF3-4: 7, PF3-5: 9 The method of claim 1,
The paperweight (PF4) is a paperweight for evaluating the influence of the start-up operation mode of the facility or equipment in which the corresponding equipment or parts are installed. If there is no output change or start-stop like a nuclear power plant, the answer of PF4-1 is selected. In the case of intermittent output fluctuations or start-up stops, such as large-scale coal-fired power plants, the PF4-2 answer is selected.In the case of a daily start-stop or weekly start-up, such as a complex, gas turbine, or pumping, the PF4-3 answer Wherein the weight (Wn) of the paperweight is 1.5 and the value (Vn) of the answer of each paperweight is set as follows.
PF4-1: 1, PF4-2: 3.5, PF4-3: 6 The method of claim 1,
The paperweight PF5 is a paperweight for evaluating the influence of the operating variables (temperature, pressure, vibration, flow rate, etc.) during the normal operation of the equipment or equipment in which the equipment is installed. The response of PF5-1 is selected when the values remain constant without change, and the response of PF5-2 is selected when an intermittent increase or decrease of the values of the operating variables is observed intermittently. If the sudden increase and decrease is repeated, the answer of PF5-3 is selected, the weight of the questionnaire (Wn) is 3, and the value (Vn) of the answer of each questionnaire is set as follows. Maintenance system.
PF4-1: 1, PF4-2: 3.5, PF4-3: 6 The method of claim 1,
The paperweight PF6 is a paperweight for evaluating how the equipment or parts equipped equipment is operated in comparison with the design criteria or the manufacturer's recommendation criteria. When operating at less than 60% of design limit, the answer of PF6-1 is selected, and when the reference operating variable is operated at 60% to 90% of the design limit, the answer of PF6-2 is selected, and the reference operating variable is When operating in the range of 90% ~ 100% of the design limit, the answer of PF6-3 is selected. When the reference operating variable exceeds the design limit, the answer of PF6-4 is selected, and the weight of the paper (Wn) is 3 The value (Vn) of the answer of each questionnaire is set as follows.
PF6-1: 1, PF6-2: 2.67, PF6-3: 4.33, PF6-4: 6 The method of claim 1,
The paperweight PF7 is a paperweight that evaluates whether damage to the equipment or components has occurred in the past. If the same damage or failure has not occurred, PF7-1 is selected, and if the same damage or failure occurs, PF7 -2 is selected, and the weight (Wn) of the paperweight is 1 and the value (Vn) of the answer of each paperweight is set as follows.
PF7-1: 1.5, PF7-2: 7.5 The method of claim 1,
The failure damage size (COF) is a risk-based maintenance system, characterized in that calculated by the following formula.
COF = CF1 + CF2 + CF3 + CF4 + CF5
CFn = Wn × Vn
Here, CFn represents five paperweights CF1 to CF5, Wn represents a weight, and Vn represents a value of the answer to the paperweight. 12. The method of claim 11,
The paperweight CF1 is a paperweight for evaluating a loss of maintenance repair cost when a failure occurs. If the loss of maintenance repair cost is low, CF1-1 is selected, and if the maintenance repair cost is medium, CF1-2 is selected. CF1-3 is selected when the cost of maintenance repair loss is high, the weight of the questionnaire (Wn) is 8 and the value (Vn) of the answer of each questionnaire is set as follows.
CF1-1: 1, CF1-2: 2, CF1-3: 3 12. The method of claim 11,
The paperweight CF2 is a paperweight for evaluating the severity of the failure due to the failure mode expected when the failure occurs. When the expected failure mode of the equipment or component to be evaluated is leakage due to pinholes or cracks, the CF2-1 answer Is selected, if it is accompanied by secondary damage such as deformation or material deterioration instead of simple leakage, the answer of CF2-2 is selected, and the answer of CF2-3 is selected when equipment or parts are destroyed. Weight (Wn) is 5.5 and the value (Vn) of the answer of each questionnaire is risk-based maintenance system, characterized in that set as follows.
CF2-1: 1, CF2-2: 2, CF2-3: 3 12. The method of claim 11,
The paperweight CF3 is a paperweight for evaluating the severity caused by secondary damage or ripple failure when a failure occurs, and when the failure is locally limited and does not affect the surroundings, the answer of CF3-1 is selected and If there is an impact but no significant equipment or parts are affected, the answer of CF3-2 is selected. If it affects the surrounding important equipment or parts, the answer of CF3-3 is selected. Is 7 and the value (Vn) of each questionnaire is set as follows.
CF3-1: 1, CF3-2: 2, CF3-3: 3 12. The method of claim 11,
The paperweight (CF4) is a paperweight for evaluating the severity of the damage caused by the impact on the availability of the entire facility or plant when a failure occurs, CF4-1 is selected if the number of days due to the failure is less than one day CF4-2 is selected for 3 days or less, CF4-3 is selected for 1 week or less, CF4-4 is selected for 1 month or less, CF4-5 is selected for 1 month or less, and the weight of the paperweight ( Wn) is 7.3 and the value (Vn) of the answer of each questionnaire is set as follows.
CF4-1: 1, CF4-2: 2, CF4-3: 3, CF4-4: 4, CF4-5: 5 12. The method of claim 11,
The paperweight (CF5) is a paperweight for evaluating the severity of the damage caused by the human injury or the surrounding environment when the failure occurs, CF5-1 answer when there is no damage to life or the environment due to the expected failure Is selected, the answer of CF5-2 is selected if only one of the damages to life and the environment occurs, and the answer of CF5-3 is selected if both the damage to the life and the environment occurs, the weight of this paper (Wn ) Is 4 and the value (Vn) of each questionnaire is set as follows.
CF5-1: 1, CF5-2: 2, CF5-3: 3

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