Barcelona May 13 2003 ASSET MANAGEMENT Development of
Barcelona, May 13, 2003 ASSET MANAGEMENT Development of new approaches Gerd Balzer Darmstadt University of Technology TU Darmstadt Institute of Electrical Power Systems
Overview - Introduction - Age profile of equipment - Consequence of the ageing process - Maintenance strategies - Reliability-Centered Maintenance (RCM) - Example: - Renovation strategy with Fuzzy-Logic - Proposal for a Risk-Assessment - Conclusion TU Darmstadt Assessment of substations Institute of Electrical Power Systems
Technical information (on assets) 1: Maintenance and diagnostic evaluation scenario search and evaluation of effectiveness & usability Component level Economical information (on assets) Technical information (on grid) 2: Economical evaluation of scenarios, creation of maintenance strategies, calculation of non-availability of energy System level Economical information (on business) Sociological information 3: Risk management, selection of optimal scenario, and optimal strategy Decision Corporate level Asset Management decision process (Cigre WG 23/39) TU Darmstadt Institute of Electrical Power Systems
Population Year of installation Age distribution for m. v. equipment (VDEW-statistic, Germany) TU Darmstadt Institute of Electrical Power Systems
Age distribution for substations (AIS) (Cigre Brochure no. 176) TU Darmstadt Institute of Electrical Power Systems
Installations and replacement distribution (substation equipment, Cigre Brochure no. 176) TU Darmstadt Institute of Electrical Power Systems
Consequence of ageing Falling reliability of the system is a major consequence of the ageing process: - decision to delay asset replacement an attempt to recover by increasing asset replacement at a later stage Lower availability and further fault outages TU Darmstadt Institute of Electrical Power Systems
The spiral of decline TU Darmstadt Institute of Electrical Power Systems
In general the Reliability Centered Maintenance (RCM) strategy for substation can be used in two different ways: - substation approach: Which equipment/components influence the function of the complete substation (Failure Mode Effect Analysis, FMEA) - system approach: Which substations influence the availability and the performance of the system (reliability calculation and assessment of the non-delivered energy, risk management) The report deals with the system approach TU Darmstadt Institute of Electrical Power Systems
The system approach solves the main task of an utility, due to the financial constraints and to receive a ranking of substations concerning the yearly budget: which substation has to be maintained first, second, and so on. TU Darmstadt Institute of Electrical Power Systems
Reliability-centered Condition-based Time-based Corrective Different types of maintenance strategies TU Darmstadt Institute of Electrical Power Systems
Corrective or Reactive Maintenance - repair or replacement after a fault - no influence on the time of failure - availability of the substation depends on the reliability of the single equipment - lowest maintenance costs without consideration of further expense TU Darmstadt Institute of Electrical Power Systems
Time-Based or Scheduled Maintenance - predefined inspections (time period) - replacement after a fixed life time - high availability - no use of the equipment up to the end of the life time - most expensive maintenance strategy TU Darmstadt Institute of Electrical Power Systems
Condition-Based or Predictive Maintenance - inspection or replacement due to the condition - all identical equipment are treated in the same manner TU Darmstadt Institute of Electrical Power Systems
Reliability-Centered Maintenance - inspection or replacement due to the technical condition - importance of the equipment for the network - optimal maintenance strategy TU Darmstadt Institute of Electrical Power Systems
Maintenance activities for specific types of equipment no no CM Corrective Maintenance ? yes diagnostic CBM Condition. Based Maintenance importance no TBM Time. Based Maintenance ? yes RCM Reliability. Centered Maintenance Strategies TU Darmstadt Institute of Electrical Power Systems
Index o Index c overall index of equipment condition of equipment Index i importance of equipment Maintenance strategy Procedure for maintenance planning (equipment) TU Darmstadt Institute of Electrical Power Systems
Bay Disconnector Circuitbreaker Building Protection & Control Index c condition of substation Index i importance of substation Index o overall index of substation Procedure for maintenance planning (substation) TU Darmstadt Institute of Electrical Power Systems
Interpretation of the assessment result c i TU Darmstadt condition of the equipment importance of the equipment Institute of Electrical Power Systems
Replacement maintenance work inspections Condition based maintenance c i TU Darmstadt condition of the equipment importance of the equipment Institute of Electrical Power Systems
inspections maintenance work replacement Corrective, time-based or reliability centered maintenance c condition of the equipment TU Darmstadt i importance of the equipment Institute of Electrical Power Systems
Combination of different strategies c i TU Darmstadt condition of the equipment importance of the equipment Institute of Electrical Power Systems
Assessment of 40 secondary substations 21 6/10 k. V 19 30 k. V (four tower stations) TU Darmstadt Institute of Electrical Power Systems
Equipment of the substations TU Darmstadt - bay/type of construction - disconnector - load disconnector - transformer - building/tower Institute of Electrical Power Systems
condition criteria for the assessment of bays TU Darmstadt - age; type - experiences; spare parts - safety aspects - partial discharge - pollution; humidity Institute of Electrical Power Systems
Condition/% Impact of equipment evaluationg the condition assessment in percentage TU Darmstadt Institute of Electrical Power Systems
Importance criteria for the assessment of secondary substations - kind of substation - maximum active power - customer - redundancy of the substation - hazard rate TU Darmstadt Institute of Electrical Power Systems
100 condition c 80 B C POHL-301 A 60 d. C 40 replacement d. A service SHAF-299 EHSN-307 d. B 20 HOHA-601 0 0 10 d 20 30 40 50 60 70 80 90 i 100 importance Final result of the assessment TU Darmstadt Institute of Electrical Power Systems
Rules Output values Input values Fuzzification Knowledge processing Defuzzification Basic principle of a decision-taking process using fuzzy logic TU Darmstadt Institute of Electrical Power Systems
Implementation of a maintenance strategy for substations TU Darmstadt Institute of Electrical Power Systems
result Conditon 1 Conditon 3 Secondary substation condition 3: load/disconnector TU Darmstadt condition 1: bay Institute of Electrical Power Systems
Risk Assessment Time after commissioning resp. service Equipment model Propability of outage of equipment Interruption costs - repair - interuption of supply - penalty and so on “sociological effects” TU Darmstadt Outage costs Result of reliability calculation Non delivered energy Szenario: - no action - service - renovation Maintenance costs - service - renovation Risk-Management Institute of Electrical Power Systems
hazard rate 4 1 III II I 2 T 1 T 2 T 3 T 4 time after commissioning/last servive Equipment model TU Darmstadt Institute of Electrical Power Systems
probability of outages 1. 0 0. 8 0. 6 0. 4 0. 2 0. 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 T T + t time after commissioning/last service Probability of outages of the considered equipment TU Darmstadt Institute of Electrical Power Systems
Probability of outages 0. 40 0. 35 0. 30 0. 25 0. 20 0. 15 Qb 0. 10 Q 0. 05 0. 00 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 time after commissioning/last service Probability of outages of the considered equipment TU Darmstadt Institute of Electrical Power Systems
Result of the assessment (substation): - comparison of different substations - determination, which equipment influences mainly the condition of the substation - what is the optimal order of substation to be maintained or replaced Decision: TU Darmstadt replacement of the equipment or new investment of the complete substation Institute of Electrical Power Systems
Advantage of a computer aided assessment: - fixing of compulsory criteria - determination of the ranking due to replacementor ranking - documentation of the decision TU Darmstadt Institute of Electrical Power Systems
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