KR20110117276A - The condition assessment method of electrical panel using expert system - Google Patents

Abstract

The present invention relates to an electrical panel condition evaluation method through an expert system. The present invention is to calculate the weight using the expert system, to perform technical analysis and economic analysis, to analyze the evaluation results of the electrical panel and to judge the replacement or maintenance, and to terminate the maintenance and replacement If so, characterized in that it comprises the steps of analyzing and evaluating the criticality, determining the priority and terminating the state assessment method.
The present invention calculates the weight for each evaluation using the expert system, and the comprehensive status evaluation directly or indirectly evaluates the device performance, the device environment and the device state, and predicts the deterioration acceleration rate of the device, It is possible to accurately predict the timing of electrical panel replacement by calculating the economic life using the investment cost and operating cost over the life cycle.

Description

Condition condition method of electrical panel using expert system

The present invention relates to a method for evaluating electric panel status through an expert system, which directly or indirectly evaluates device performance, device environment, and device status, predicts deterioration acceleration rate of the device, and calculates economic life using investment and operating costs. That's the way it is.

With the expansion of the information society, the importance of power supply is emphasized more and more, stable electric machine operation is increasingly required. At present, a large number of electric devices have been installed and operated since the development period in the 70s and 80s, and future electric devices are expected to require various evaluation methods for replacement and maintenance due to the rapid increase of old equipment.

 In the meantime, the replacement and maintenance method for electric equipment has been a uniform method that follows the time-based maintenance technology implemented after a certain period of time according to the accounting useful life. Excessive maintenance costs are causing economic losses for companies.

Recently, in order to solve such problems, various methods such as economic evaluation method using investment cost and operating cost, reliability evaluation method using statistical data such as failure history, etc. are being actively researched. However, although there are many evaluation methods, the method of integrating and utilizing various evaluation results is still inadequate.

The present invention relates to a method for evaluating the condition of an electric panel that has undergone aging. The weight of each evaluation is calculated using an expert system, and the comprehensive state evaluation directly or indirectly evaluates device performance, device environment, and device state. Predicting the deterioration acceleration rate of equipment, and economic overlife evaluation calculates economic life using investment cost and operating cost over the whole life cycle, and accurately estimates the electrical panel status to reasonably predict the timing of electrical panel replacement accurately. There is that purpose. It is also intended to enable rational facility investment by selecting priorities using critical analysis.

Therefore, in the electrical panel state evaluation method through the expert system of the present invention,

Steps to calculate weights using expert system, perform technical analysis and economic analysis, analyze electric panel evaluation results, judge replacement or maintenance, terminate when maintenance and replace Analyzing and evaluating the criticality and determining and prioritizing; It characterized in that it comprises (S 700).

In addition, the formula for calculating the weight using the expert system is

인 것을 특징으로 하는 것이다.

It is characterized by that.

In addition, the technical analysis includes the steps of evaluating the overall status, electric panel status check, fault history investigation and component parts investigation, analyzing the technical properties of the subsystem, and the condition evaluation, environmental evaluation, and performance evaluation of the device. And determining the comprehensive status evaluation index for the subsystem; (S 50) is characterized in that it comprises a.

Economic analysis includes the steps of evaluating economic excess life, investigating electrical panel investment and operating costs, analyzing economics for subsystems, calculating economic lifespan, and economic excess life for subsystems. It characterized in that it comprises the step of determining the index (S 95).

And, the formula for analyzing the criticality is C _i = lambda _j x alpha _i x beta _i x t _j .

In the present invention, the weight of each evaluation was calculated by using an expert system, and the comprehensive status evaluation directly or indirectly evaluates the device performance, the device environment, and the condition of the device to predict the degree of deterioration acceleration of the device. It is possible to accurately predict the timing of electrical panel replacement by calculating the economic life using the investment cost and operating cost over the life cycle.

1 is a flow chart of the electrical panel condition evaluation method through the expert system according to the present invention.

Evaluation method of the electrical panel state through the expert system of the present invention

Calculating a weight using an expert system; (S 100)

Performing technical analysis and economic analysis; (S 200)

 Analyzing the evaluation results of the electrical panel; (S 300)

Determining a replacement or maintenance; (S 400)

If maintenance is to end and if the replacement of the criticality analysis step; (S 500)

 Determining the priority; (S 600)

Terminating; It characterized in that it comprises (S 700).

이다. In addition, the formula for calculating the weight using the expert system is

to be.

And, in (S 200) the technical analysis is

Evaluating the comprehensive state; (S 10)

Electrical panel status check and fault history investigation and component parts investigation; (S 20)

Analyzing the technicality of the subsystem; (S 30)

Performing a condition evaluation, an environmental evaluation, and a performance evaluation of the device; (S 40)

Determining a comprehensive status evaluation index for the subsystem; (S 50) characterized in that it comprises a.

And, the economic analysis in the (S 200)

Assessing economic excess life; (S 60)

Investigating the electrical panel investment costs and operating costs; (S 70)

Analyzing economics for the subsystem; (S 80)

Calculating the economic life; (S 90)

Determining the economic excess life index for the subsystem (S 95).

And, the formula for analyzing the criticality is C _i = lambda _j x alpha _i x beta _i x t _j .

(C _i : Criticality value of failure mode i, λ _j : Failure rate of failure mode i,

α _i : Incidence rate of failure mode i during failure, β _i : Failure impact degree of failure mode i

t _j : Operation period (operation start date, registration date or modification date) during the evaluation period

Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

In order to evaluate the state of the electric panel of the present invention, very many evaluation elements are required, which will be described in detail.

① Expert System: The survey was conducted to experts in and out of the company in consideration of career, education, and rank, and the weight of each evaluation was calculated by using Expert System.

② Comprehensive condition evaluation: Comprehensive condition evaluation is a quantitative evaluation of aging, performance, and use environment of the electrical panel. The evaluation detail items are classified into device condition evaluation, environmental factor evaluation, and performance condition evaluation.

 ③ Equipment condition evaluation: If the equipment is deteriorated or used for a long time, a failure occurs. As a result, an increase in the number of failures shortens the use time of the device, resulting in a decrease in the efficiency of the device operation. Therefore, by quantifying the state of these devices and comparing them with each other, if the score is disadvantageous compared to other devices, it is possible to increase the efficiency by performing fault prevention measures. In this respect, the equipment condition was evaluated by availability, equipment aging, part condition and frequency of failure.

         ④ Device environmental evaluation: As a factor of deteriorating the performance of electric equipment in distribution, there are various environmental factors besides the natural deterioration caused by long time use. Electrical equipment that operates in poor operating conditions and can quickly deteriorate or cause significant damage in case of failure should be strictly controlled compared to general equipment. The same applies to socially important facilities. In this respect, the environmental assessment of the equipment was evaluated by the installation environment, the effects of harmonics, the characteristics of the consumer of tap water supply, the impact of equipment failure, and the maintenance of repaired products.

         ⑤ Device performance evaluation: Performance status evaluation is the evaluation of device performance as a result of regular or irregular inspection or performance test such as diagnosis or visual inspection of each electric equipment. Since the type of diagnosis and the visual inspection method are different because of the difference in operation method, structure, and function of each electric device, a device performance evaluation table is constructed for each electric device.

  ⑥ Economic excess life evaluation: The economic excess life was calculated by considering the investment cost and operating cost over the entire life cycle of the electrical panel, and was used for the electrical panel condition evaluation along with the technical evaluation.

  ⑦ Criticality Analysis: The failure history, the importance of the facility, the impact level were grasped and used to apply the priority of the replacement of equipment.

 ⑧ Classification of electric panel parts: The electric panel is a form in which various electric devices are collected and consists of various forms. For an efficient and systematic evaluation of each electrical device, each facility should be classified and organized according to its configuration and hierarchy. The first column of Table 1 is the system hierarchy divided according to the functions of water works such as water purification plant, water intake plant and pressurized plant. Substation layer representing switchboards such as panels and MCC panels, and the third column is a unit layer representing the smallest unit set of electrical devices constituting the electric panel, and the fourth column is a component layer representing each electric device constituting the unit. to be.

Electrical panel parts classification      System   Sub system      Unit   Component     Water purification plant  Special high voltage board    ALTS class    MOF     Intake  High voltage switchboard    High voltage cable    CT     Pressurized field  Low Voltage Switchgear    Low voltage cable    PT       Etc  Mobile Team (All)  Ambient Pressure Base (Mold Type)    ZCT  Capacitor Board (All) Intraocular Transformer
(Molded type)    GPT   MCC Class (All)   Commutation base    ALTS   MOF class    ASS   LBS class    LS (INT S / W)   DS (single-based)     COS   ATS class     LBS  Emergency Development Foundation     DS (disconnector)   Distribution board     GCB   Insulator     VCB  LA (Lightning Arrester)     OCB  Power fuse     ACB  Blocking base     VC   CT class     VCS   PT class     VSS   VCS Class     ASS

Electrical panel parts classification   High voltage switchboard     ATS   Low Voltage Switchgear     OCR   Mobile Team (Individual)     OCGR   Capacitor board (individual)     OVR   MCC class (individual)     OVGR     SGR     UVR     DGR     POR     RDR     2E     3E     4E  Composite digital relay     SA    Condenser   Series reactor (SR)   Starting reactor  Emergency power supply facility   Uninterruptible Power Supply

Electrical panel parts classification    charger    Battery

            ① Calculation of weight for each evaluation using expert system (FIG. 1 a2)

 The evaluation items are largely divided into comprehensive status evaluation and economic over-life evaluation, and comprehensive status evaluation is classified into device status evaluation, device environmental evaluation and device performance evaluation. In the present invention, the weight between the evaluation items was determined by using the expert system based on the results of the survey results of the internal expert staff and external experts.

                     1) Selection of Survey Subjects

A total of 19 people were surveyed, and each questionnaire was given a score according to the position and experience as shown in Table 4 below.

 Survey weighting      Classification    Class (person)    Score (di) Korea Water Resources Corporation    Deputy General Manager (4)     3       "    Manager (4)     2       "    Agent (2)     One       "    Over 15 years     3       "    10 years or more and 15 years or less     2       "    Less than 10 years     One External expert (use and production body)    Average position     2 External expert (use and professional company)    Average working years     2   1 university expert    More than 5 years     3

         2) Calculation of weight using Expert System

   As for the weight, the weight of the survey subjects and the weight of each evaluation item should be calculated. First, the formula for calculating the weight of the survey subjects is as follows.

        3) Survey Table

Weighted questionnaire of comprehensive evaluation   No.    Evaluation item           Explanation    weight
One
Technical evaluation Evaluation of device condition diagnosis (equipment utilization rate, facility aging, etc.) and device performance diagnosis (opening and closing performance, insulation performance, current carrying performance, etc.)
2
Economic evaluation  Calculate economic life based on airway particle cost and maintenance cost and evaluate economic feasibility based on economic life excess rate                        Sum        100

Weighting Survey Table for Sub-Items  No.    Evaluation item             Explanation    weight

One

Instrument status diagnosis The detailed evaluation content is an evaluation item that is determined by combining the facility utilization rate that indicates the ratio of facility use time to the total service life and the facility aging that represents the use period to the number of years of use.
2
Instrument performance diagnosis Evaluation item that checks performance by analyzing diagnostic test result (eg insulation diagnosis operation test, etc.)


3

Driving environment diagnosis Evaluation items that comprehensively determine the installation environment (indoor, outdoor, etc.), supply load characteristics (special area, general water supply, etc.), breakdown impact (fire occurrence, etc.), and maintenance of the repaired product (time to secure, availability)                       Sum       100

Materiality Questionnaire by Electric Device
Representative Unit
Electrical equipment
                          Materiality test item Breakdown
effect Preventive Check
Way Failure
frequency  Convenience of material supply Conservative
Ease Troubleshooting
time   ALTS   LBS   PF   DS   MOF   PT   breaker  Protective relay   CT  Mold Transformer  charger  Capacitor  rectifier  lightning arrester  Insulator  cable  Condenser   ATS

  VCS   inverter   Reactor soft
start    SC    SR   Switches   ELB   MCCB  Emergency generator

     ② Comprehensive Status Evaluation (Figure 1 a3)

Comprehensive condition evaluation is to quantify and evaluate the aging, performance, and use environment of power equipment. Comprehensive condition evaluation is evaluated using the proposed technical evaluation table, and the detailed items are classified into device condition evaluation (A), environmental factor evaluation (B), and performance status evaluation (C), and the relationship between the evaluation results of the evaluation items and the evaluation points Is shown in Table 9, and the comprehensive state evaluation score is as follows.

P _A · A + W _B W _A = B · _C · W + C

P _A : Overall condition evaluation score

W _A : weight of A (0.31), A: device health evaluation score

W _B : weight of B (0.24), B: device environmental score

W _C : weight of C (0.45), C: instrument performance score

Relationship between Evaluation Contents and Evaluation Points            Diagnosis     Score (point) Fatal: Fatal for the purpose and equipment performance of the facility.        One  Important: Losses the purpose and equipment performance.        2  Minor: Loss of purpose and equipment performance.        3  Fine: Some loss of purpose and equipment performance.        4  Safety: There is no problem with the purpose of the facility or with the equipment performance.        5

    ③ Instrument condition evaluation (Fig. 1 a6)

If the power equipment is used for a long time or if there is a problem with the product, a failure occurs and the frequency of failure increases accordingly, which reduces the efficiency in operation and generates a single complaint due to the inability to supply water. Therefore, if the state of the equipment is quantified to obtain an unfavorable score compared to other power equipments, the efficiency of the equipment operation can be improved, such as failure prevention measures. In this sense, the equipment condition evaluation is based on how long the power equipment has a history of failures over time, such as age, failure time during use, and the frequency of failure of accessories and main functions. Item. In this study, the equipment condition evaluation items were available, equipment aging, parts status of accessories, and the frequency of failures. The definition of each item and the method of calculating the scores are as follows.

            (1) Availability (A1)

  Definition: Means the percentage of failure time in use time. Less than 94% of the results are treated as 0 points.

Calculation: Availability = [1-Breakdown time / time of use] × 100

            (2) Facility old road (A2)

 Definition: It means the usage time for the useful life and is calculated based on 100 points when using twice the useful life. Less than 10% of the results will be scored as 0.

 Calculation: Equipment age = [1-(service hours / useful life) × 0.5] × 100

              (3) Parts status (A3)

  Definition: Calculate the annual number of failures of the representative components and related accessories composing the unit. Related accessories include indicators (voltmeters, ammeters, power factor meters, power meters, thermometers, etc.), control switches, cooling fans, timers, heaters, control transformers, power supplies, etc. If accurate data are not obtained, it can be calculated as the subjective judgment score of judges who have experience in operating the equipment.

  Calculation: 5 points for cases where there is no problem at all and 1 point for each number of failure

              (4) Frequency of failure (A4)

  Definition: Means the annual frequency of failures related to the representative components composing the unit. If accurate data are not obtained, it can be calculated as the subjective judgment score of judges who have experience in operating the equipment.

  Calculation: 5 points for cases that never occurred and 1 point deduction for each occurrence

             (5) Arrangement of device condition evaluation (A1 + A2 + A3 + A4)

  Definition: The highest point of the sum total of each subassembly is adjusted by 100 points. If no equipment is available for evaluation or evaluation is not possible, it is not included in the evaluation. In the event of a fatal flaw in the equipment, the scoring is evaluated as zero.

  Calculation: Equipment condition evaluation (A), A = (Scoring meter / 20) x 100 (point)

                      (6) Equipment condition evaluation table

   Equipment condition evaluation table is shown in Table 10.

Device condition evaluation table     Evaluation item               Evaluation Condition  Score  Remarks

A1. Availability 95% or less
95% or more but less than 96%
96% or more but less than 97%
97% or more but less than 98%
More than 99% One
2
3
4
5

A2. Facility deterioration 10% or more but less than 20%
20% or more but less than 30%
30% or more but less than 40%
40% or more but less than 50%
50% or more One
2
3
4
5
A3. Parts Status (Accessories of Major Equipment, etc.) Three or more component failures of the accessory.
There are two or more failures of the accessories.
At least one component failure of the accessory.
Component failures of accessories are negligible.
No problem at all One
2
3
4
5

A4. Fault frequency The frequency of failure of major equipment is more than three times a year.
The frequency of failure of major equipment is more than twice a year.
The frequency of failure of major equipment is more than once a year.
The failure frequency of major equipment can be ignored.
Never happened. One
2
3
4
5

               ④ Device environmental evaluation

 As a factor that degrades the performance of the power equipment constituting the switchgear, there are various environmental factors besides the natural deterioration due to long-term use, and depending on the environmental factors, The impact of the failure can be greater. At this time, the power equipment that operates in a bad operating environment or the impact of failure is so large that the performance may be degraded quickly or cause great damage in case of failure should be strictly controlled than the general equipment. In view of this, this study set up environmental factor evaluation items as the evaluation items of switchgear panel, and evaluated the installation environment, the influence of harmonics, the characteristics of customers subject to tap water supply, the impact of equipment failure, and the securing of repaired items. The study was designed to allow the addition and deletion of evaluation items. The definition of each item and the method of calculating the score are as follows and expressed as B.

                    (1) Installation environment (B1)

  Definition: The environment where the subsystem is installed.

  Considerations: The deterioration of power equipment is affected by the installation environment (corrosive gas, ambient temperature, humidity, etc.). The evaluation conditions were set according to the installation location (indoor or outdoor), corrosive gas, and the degree of influence on ambient temperature and humidity. Significantly affected by the evaluation conditions is determined by the presence of failure experience, and some exposure may be determined by the presence of the symptom but no experience of failure.

 Calculation: Apply the calculation method to reduce the point by 5 points if it does not matter at all according to the installation environment.

                    (2) Influence of harmonics (B2)

 Definition: It means the influence of harmonics received by subsystem.

 Considerations: The evaluation conditions are set as harmonic disturbance factors that can occur generally as the degree of influence of harmonics generated from power supply and control equipment on power equipment.

Calculation: Applied to the calculation method of reducing the point by one point according to the harmonic effect to five points that have no effect at all

                 (3) Characteristics of consumers subject to tap water supply (B3)

 Definition: The importance of the consumer of a tap water supply system operated by a subsystem.

 Considerations: The type of administrative area in the supply area was evaluated according to the importance of the consumer.

Calculation: Applied the calculation method which reduces by one point according to the characteristics of the customer to 5 points where there is no problem at all

                 (4) Impact of equipment failure (B4)

 Definition: When component breaks down, it means the degree of breakdown of surrounding facilities and equipment.

 Considerations: If a power equipment breaks down, it may cause a fire, etc. depending on the type of equipment, and all or part of the functioning of the power equipment may be lost. Considering these points, evaluation conditions were set.

Calculation: Applied the calculation method to reduce the case where there is no problem to 5 points by 1 point according to the effect of failure

                 (5) Securing of repaired goods (B5)

 Definition: Means the method and possibility of securing a repaired product in case of component failure.

 Considerations: If the repair time is long or difficult, such as discontinued equipment, it is desirable to plan for replacement and replacement more quickly than other facilities.

Calculation: Applied to the calculation method of reducing the score to 5 points if there is no problem at all by securing the repaired items.

                (6) Environmental Factor Evaluation (B1 + B2 + B3 + B4 + B5)

  Definition: The highest point of the sum total of each subassembly is adjusted by 100 points. If no equipment is available for evaluation or evaluation is not possible, it is not included in the evaluation. In the event of a fatal flaw in the equipment, the scoring is evaluated as zero.

 Score calculation: The environmental factor evaluation (B) becomes B = (scoring system / 25) x 100 (point).

               (7) Environmental Factor Evaluation Table

   The table of environmental factors is shown in Table 11.

Device environmental evaluation table     Evaluation item             Evaluation Condition   Score   Remarks  B1. Installation environment Installed outdoors, it is significantly affected by corrosive gases, ambient temperature and humidity.
Installed indoors, it is significantly affected by corrosive gases, ambient temperature and humidity.
It is installed outdoors and is exposed to corrosive gas, ambient temperature and humidity.
It is installed indoors and is exposed to corrosive gas, ambient temperature and humidity.
The effects on corrosive gases, ambient temperature and humidity are not a problem at all. One

2

3

4

5



B2. Harmonic Influence More than two breakage accidents were caused by harmonics.
The harmonics caused damage to the installation.
The effect of harmonics is the amount of flickering fluorescent lights.
The effects of harmonics are negligible.
There are high frequency measures, and there is no effect on other equipment. One

2
3

4
5
B3. Characteristics of Consumers Subject to Tap Water Supply Special Area
Metropolitan City
General poetry
Other Area
No problem. One
2
3
4
5

B4. Equipment failure
Ripple effect Occurrence of safety accidents (explosion, fire) in case of accident or breakdown
In case of an accident or failure, all the facilities' unique functions are stopped.
In case of an accident or breakdown, there is a risk that the facility's unique function may be halved.
In the event of an accident or breakdown, the facility will be shut down, but the facility's own function will not be affected.
There is no problem in case of accident or breakdown. One
2
3

4

5

B5. Securing Repairs Producers can't order, and it's impossible to order.
You can't order the maker, but you can order it.
Manufacturer orders are available, but take time.
Manufacturer order is available and no spare parts are available.
No problem at all One

2

3
4
5

⑤ Device performance evaluation

 Performance status evaluation is the evaluation of equipment performance as a result of regular or irregular inspections or performance tests, such as the diagnosis or visual inspection of each electrical equipment. Although the type of diagnosis and visual inspection are different because of the difference in operation, structure, and function of electrical equipment, the typical test methods are as follows. The detailed items on the device performance evaluation were configured to allow the addition and deletion of evaluation items through continuous research. The definition of each item and the method of calculating the score are as follows and expressed in C.

                            (1) temperature

 Definition: Most insulated or energized metal conductors have a maximum usable temperature. Therefore, this test determines the evaluation conditions depending on whether the measured temperature exceeds the specified temperature.

 Method: Measure the temperature of the target using an infrared thermometer or a thermal video camera.

                          (2) insulation resistance

 Definition: All power installations are required to have adequate insulation resistance according to the voltage used to ensure insulation. Therefore, this test determines the evaluation condition according to the measured insulation resistance exceeding specified insulation resistance.

 Method: Measure the insulation resistance using an insulation ohmmeter appropriate for the voltage of the EUT. Through the insulation resistance test, DC leakage current, polarity ratio and weakness ratio can be found.

                           (3) vacuum degree

 Definition: Devices that operate contacts in vacuum, such as VCB or VC, must maintain adequate vacuum to maintain insulation and breaking performance. Therefore, this test determines the evaluation conditions depending on the presence or absence of the specified vacuum degree of vacuum.

 Method: Measure the vacuum level using a vacuum gauge (leakage current or vacuum level) appropriate for the voltage of the EUT.

                         (4) Contact consumption

 Definition: The breaking performance and energizing performance of breakers such as VCB and ACB are greatly affected by the contact consumption. This test determines the evaluation condition according to the measured number of disconnection times directly according to the measured direct current consumption or breaking current.

 Method: Since it is impossible to measure the consumption directly, indirectly calculate the contact consumption as the number of cutoffs to the reference current by recording the current magnitude and the number of cutoffs.

                       (5) gas pressure and gas water content

 Definition: The insulation performance of breakers and switches using gas pressures such as GCB and ALTS is affected by gas pressure and moisture. This test determines the evaluation conditions in accordance with the provisions of the measured gas pressure or gas moisture content.

 Method: Record the indication of the pressure gauge installed on the instrument, and if gas extraction is possible, extract the gas and measure the amount of gas with a moisture meter.

                     (6) operating status

 Definition: The switchgear or breaker must have a specified switching time or protection coordination to ensure proper shutoff in case of failure. This test determines the evaluation conditions from a comparison of the measured opening and closing times or the results of protection coordination.

 Method: Measure the opening and closing time or contact operation using a suitable measuring instrument.

                     (7) Average load rate

 Definition: Power cables or fuses increase the rate of thermal degradation when used at high temperatures. Since temperature is proportional to the load factor, this test determines the evaluation conditions as the average load factor.

 Method: Calculate the average load factor of the cable.

                   (8) Cable installation method

 Definition: Depending on the cable installation method, deterioration is accelerated by moisture infiltration. This test determines the evaluation conditions according to the cable installation method.

 Method: Investigate cable installation.

                       (9) dielectric loss

 Definition: When an AC voltage is applied to an insulation of a power device, heat is generated by leakage current, which appears as a dielectric loss, resulting in thermal degradation. This test determines the evaluation conditions from the comparison of the measured dielectric loss with the specified values. For liquid insulators, ambient temperature affects the dielectric loss, so the dielectric loss regulation is applied according to the ambient temperature.

 Method: Apply a regulated AC voltage to the instrument and measure the dielectric loss using a loss angle meter or a shearing bridge.

                      (10) transformer ratio, current ratio

 Definition: Transformers or transformers must maintain the turn ratio between the primary and secondary specified for modification. This test determines the evaluation conditions from the measured transformer ratio and the comparison with the specified values of the transformer ratio.

 Method: Measure turn ratio between 1st and 2nd stage using turn ratio meter.

                     (11) Insulating oil acid value

 Definition: Insulating oils, when exposed to oxygen or air, oxidize and degrade their physical properties. This test determines the evaluation conditions from a comparison with the specified values of the measured acid values.

 Method: Measure the acid value using an insulating oil acid value meter.

                    (12) Operation characteristic test

 Definition: If the operating characteristics of the protective relay do not match, failure to disconnect the faulted device or interrupt the fault current may result in a fault such as insulation breakdown or short circuit. This test determines the evaluation conditions from the comparison of the measured operational test results of the protective relay with the specified values.

 Method: Measure the operation time, protection coordination, etc. using the protective relay motion meter.

                   (13) Characteristic test of storage battery

 Definition: Lead or alkali accumulators must be kept above a certain voltage during use. To this end, the permissible minimum voltage, floating charge voltage, and electrolyte weight per cell must be maintained above the specified value. This test determines the evaluation conditions from the comparison of the battery characteristics test results with the specified values of each test.

 Method: The permissible minimum voltage per cell is determined by measuring the voltage of the unit cell using a voltmeter to determine if the permissible minimum voltage is above. Measure specific gravity.

                 (14) Partial discharge test

 Definition: Mainly performed for mold power equipment and measuring partial discharge amount and partial discharge start voltage. This test determines the evaluation conditions from the comparison of the measured partial discharge measurement results of the mold insulation with the specified values.

 Method: Measure using partial discharge meter, but if development test is not possible due to noise on site, it shall be received at factory and tested.

                  (15) Permissible expansion standard

 Definition: If an abnormality occurs inside the power capacitor, the temperature rises and the enclosure expands. Excessive enclosure expansion can lead to explosion of the condenser, so expansion should be limited to an appropriate extent. This test determines the evaluation conditions from the comparison of the measured expansion results of the capacitor with the specified values.

 Method: Measure the maximum inflation length.

                  (16) capacitance

 Definition: The capacitance changes when the insulation of the power capacitor is electrically or physically abnormal. This test determines the evaluation conditions from the comparison of the measured capacitance of the capacitor with the specified value.

 Method: Measure the capacitance of the capacitor using a capacitance meter or Schering bridge and compare with the initial value.

                 (17) Arrester leakage current

 Definition: The leakage current increases when the arrester element deteriorates. Therefore, measuring the leakage current can determine the performance of the arrester. This test determines the evaluation conditions from the comparison between the measured leakage current of the arrester and the specified value.

 Method: Measure the leakage current from the ground wire with a leakage current meter under rated voltage.

              (18) Emergency generator voltage change rate, frequency change rate

 Definition: In order to receive good quality power from the generator, the rate of voltage fluctuation and frequency fluctuation must be limited to a certain range. This test determines the evaluation conditions from the comparison of the measured voltage fluctuations of the emergency generator with the specified values of frequency fluctuations.

 Method: Measure voltage and frequency by measuring voltage and frequency from generator output voltage.

              (19) rectifier noise

 Definition: An error in the rectifier increases the noise. This test determines the value of the evaluation condition from the comparison of the measured noise level of the rectifier with the specified value.

 Method: Start the rectifier and measure the noise with a noise meter at a certain distance.

              (20) I / O voltage current measurement

 Definition: If the rectifier element fails, the output voltage current against the input voltage will be abnormal. This test determines the value of the evaluation condition from the comparison of the measured input and output voltage currents of the rectifier with the specified values.

 Method: Measure the voltage current from the input and output terminals of the rectifier and compare it with the initial value.

               (21) inverter characteristic test

 Definition: In order for the inverter to control properly, the output voltage accuracy, frequency accuracy, output waveform distortion rate and efficiency must be within specified values. This test determines the value of the evaluation condition from the comparison of the measured characteristic values of the inverter with the specified values.

 Method: Measure the output voltage, frequency fluctuation, output voltage waveform and input / output capacity to get each characteristic value.

                (22) Characteristic test of charger

 Definition: For the performance review of chargers, automatic charge recovery test and equal charge test are performed. This test determines the value of the condition of the evaluation as the operating condition of the charger.

 Method: Perform the automatic charging recovery test and the uniform charging test according to the test procedure.

               (23) Tracking trace of epoxy insulator

 Definition: Epoxy insulators cause tracking of discharge paths due to dust, moisture, etc. during use. This test determines the value of the evaluation condition from the presence of tracking traces by visual inspection of the insulator.

 Method: Visually observe live parts.

               (24) Operation time test of earth leakage breaker

 Definition: An earth leakage breaker shall be operated within the prescribed time depending on the type of the earth leakage breaker if an earth leakage is observed. This test determines the value of the evaluation condition from the comparison between the measured operating time of the earth leakage breaker and the specified value.

 Method: Measure the operation time while passing the test current through the earth leakage breaker.

               (25) General inspection

 Definition: The power equipment is not a fatal failure during use, but a failure such as rusting and loosening of the terminals. As the number of failures increases, it can be considered that the equipment has been used for a long time, which is related to the performance of the equipment. This test is limited to the items that can be visually inspected at each installation and the value of the evaluation conditions is determined from the number of abnormalities resulting from visual inspection.

 Method: Visually check the appropriate power equipment to determine the abnormality.

              (26) Device performance evaluation

 Definition: The highest point of the sum total of each subassembly is adjusted by 100 points. If no equipment is available for evaluation or evaluation is not possible, it is not included in the evaluation. In the event of a fatal flaw in the equipment, the scoring is evaluated as zero. The device performance evaluation score calculation for unit evaluation or subsystem evaluation differs only in the type of component and the number of components.

 Score calculation: Equipment performance evaluation (C) is C = (scoring system / evaluation item score meter) x 100 (point).

Device performance evaluation table (ex: VCB)  Evaluation item             Evaluation Condition  Score




C. Device performance evaluation

C1.Valve
Vacuum degree Over current set value exceeded
Below overcurrent setpoint 0
5
C2. valve
Vacuum degree 3 X 10 ^-2 or higher: bad
5 X 10 ^-4 << 3 X 10 ^-2 : Caution
5 X 10 ^-4 or less; Good 0

3
5 C3.Opening and closing performance Bad
normal 0
5
C4. Insulation performance 500 ㏁ or less
2 ㏁ or less
normal 0
0
5
C5.Conductivity Performance Bad
Watch out
Good 0
3
5 C6.Contact
Consumption > 100%
> 70%
≤ 50% 0
3
5 C7.General Inspection Status Corrosion, metal fittings, loosening deformation, joints, poor grounding
clear 5, 0.5 / or more
5 C8.Exothermic temperature of connection Exceeded allowable temperature of electrical equipment connection
Below the allowable temperature of the connection of electrical equipment 0
5
C9.Replacement History
Replacement history Total score
5 points / one
Addition

            ⑥ Economic excess life assessment (Fig. 1 a8)

The Equivalent Uniform Annual Cost Method (EUAC) used in economic analysis is a method that compares all cash flows generated during the analysis period of an investment alternative at an annual equivalent rate, reflecting the interest rate, and compares the investment life of the investment alternative. In other cases, the best alternative can be selected by simply comparing the annual equivalence, so it is an appropriate analysis method for economic evaluation for economic decision making.

Economic Lifetime Assessment Index        Cost Category       Details min (CR (i) + OC (i))
==> Economic Life Calculation


  Investment Cost CR (i)  1. Initial Purchase Cost (I) Operating Cost OC (i)
(Operating Cost)  2. Inspection maintenance fee (M)  3. Maintenance cost for replacement  4. Interest rate (i)

CR (i) × (i (1 + i) ⁿ ) / ((1 + i) ⁿ -1) + OC (i) = annual equivalent cost

1) Select Economic Index

   The economic life expectancy index is calculated using the economic life and years of use calculated from Table 13.

Economic Overlife Index = Years Used / Calculated Economic Lifespan

             ⑦ Criticality Analysis (FIG. 1 a15)

In general, lethality is a method for relative quantitative evaluation in FMEA and is used to extract important failure modes. Because the evaluation results can be obtained quantitatively, the importance ranking of failure modes can be relatively determined and the policy ranking can be determined from the results.

Criticality evaluates the frequency of failure modes and the impact of safety and economics on higher systems. According to IEC 60812 Analysis techniques for system reliability procedure for failure mode and effects analysis (FMEA), the criticality value is defined as follows. Ci is the criticality of failure mode i and is expressed as follows.

C _i = λ _j × α _i × β _i × t _j

C _i : Criticality value of failure mode i

λ _j : failure rate of failure mode i

α _i : Rate of failure mode i during failure

β _i : Failure influence chart of failure mode i

t _j : Operation period during the evaluation period (operation start date, registration date or modification date)

                    ⑧ Calculation of electrical panel condition

   1) The comprehensive state evaluation of the electrical panel can be calculated with three evaluation scores as in a3 of FIG.

   Equipment condition evaluation (A) is A = (scoring meter / 20) x 100 (point)

   Environmental factor evaluation (B) becomes C = (scoring meter / 25) * 100 (point)

   Instrument performance evaluation (C). B = (Scoring System / Evaluation Point Scorer) × 100 (Point)

P _A · A + W _B W _A = B · _C · W + C

P _A : Overall status score

W _A : Weight of A (0.31), A: device condition evaluation score

W _B : Weight of B (0.24), B: device condition score

W _C : Weight of C (0.45), C: device health score

   2) The economic lifespan evaluation of the electrical panel can be calculated as shown in FIG.

   Economic Excess Lifetime Index = Years Used / Calculated Economic Lifespan

P _B : Economic Excess Lifetime Index

  3) Result of condition evaluation of electric panel

P _T = P _A Α + P _B Β

P _T : Overall Condition Score

P _A : Overall Condition Score

P _B Economic Overlife Index

   α: weight of the comprehensive state assessment (0.64)

   β: weight of economic excess life (0.36)

Therefore, by using the expert system to calculate the weight for each evaluation by the method according to the present invention, the evaluation of the comprehensive state directly or indirectly evaluates the device performance, device environment and device status, and predict the degree of deterioration acceleration of the device The economic overtime assessment can accurately predict the timing of electrical panel replacement by calculating the economic life span using the investment cost and operating cost over the life cycle.

Claims (5)

In the electric panel condition evaluation method through expert system,
Calculating a weight using an expert system; (S 100)
Performing technical analysis and economic analysis; (S 200)
Analyzing the evaluation results of the electrical panel; (S 300)
Determining a replacement or maintenance; (S 400)
If maintenance is to end and if the replacement of the criticality analysis step; (S 500)
Determining the priority; (S 600)
Terminating; Electrical panel status evaluation method through the expert system, characterized in that it comprises (S 700).
According to claim 1, wherein the equation for calculating the weight using the expert system is

Electrical panel status evaluation method through an expert system, characterized in that the.
According to claim 1, wherein the technical analysis in (S 200)
Evaluating the comprehensive state; (S 10)
Electrical panel status check and fault history investigation and component parts investigation; (S 20)
Analyzing the technicality of the subsystem; (S 30)
Performing a condition evaluation, an environmental evaluation, and a performance evaluation of the device; (S 40)
Determining a comprehensive condition evaluation index for the subsystem; (S 50) electrical panel status evaluation method through an expert system comprising a.
According to claim 1, wherein the economic analysis in the (S 200)
Assessing economic excess life; (S 60)
Investigating the electrical panel investment costs and operating costs; (S 70)
Analyzing economics for the subsystem; (S 80)
Calculating the economic life; (S 90)
A method for evaluating electrical panel status through an expert system, comprising the step (S 95) of determining the economic excess life index for the subsystem.
The method of claim 1, wherein the formula for analyzing the criticality is C _i = λ _j × α _i × β _i × t _{j The} electrical panel state evaluation method through the expert system, characterized in that.
(C _i : Criticality value of failure mode i, λ _j : Failure rate of failure mode i,
α _i : Incidence rate of failure mode i during failure, β _i : Failure impact degree of failure mode i
t _j : Operation period (operation start date, registration date or modification date) during the evaluation period

Images