Journal of the Korean Society of Safety, Vol. 31, No. 5, pp. 7-15, October 2016 Copyright@2016 by The Korean Society of Safety (pissn 1738-3803, eissn 2383-9953) All right reserved. http://dx.doi.org/10.14346/jkosos.2016.31.5.7 박영호 김두현 * 동양대학교 * 충북대학교안전공학과 (2016. 5. 4. 접수 / 2016. 8. 3. 수정 / 2016. 8. 21. 채택 ) Failure Modes and Effects Analysis for Electric Power Installations of D University Young Ho Park Doo-Hyun Kim * Dongyang University * Department of Safety Engineering, Chungbuk National University (Received May 4, 2016 / Revised August 3, 2016 / Accepted August 21, 2016) Abstract : The purpose of this paper is to carry out Failure Modes and Effects Analysis (FMEA) and use criticality in order to determine risk priority number of the components of electric power installations in Engineering college building of D university. In risk priority number, GROUP A had 7 failure modes; more specifically, Transfomer had 4 modes, Filter(C)(1 mode), LA(1 mode), and CB(MCCB)(1 mode), and thus 4 components had failure modes. In terms of criticality, high-grade group a total of 16 failure modes, and 7 components-la(1 mode), CB(MCCB)(1 mode), MOF(2 modes), PT(1 mode), Transformer(7 modes), Cable(3 modes), and Filter(C)(1 mode)-had failure modes. Comparison of risk priority number and criticality was made. The components which had high risk priority number and high criticality were Transformer, Filter(C), LA, and CB(MCCB). The components which had high criticality were MOF and cable. In particular, Transformer(RPN: 4 modes, Criticality: 7 modes) was chosen as an intensive management component. Key Words : risk priority number, criticality, electric power installations, FMEA 1. 서론 한국전기안전공사통계자료에의하면, 연간발생하는전기설비사고건수는고압의경우조사대상 2 만 4 천 5 백여호중약 1 천 5 백건이발생하고있어서백호당연간 6 호정도가사고발생이있는것으로나타났다 1). 고압수전설비의이상이나고장의발생은정전을초래하여사업활동에현저한지장을일으키게된다. 전기설비의이상이나고장을미연에방지하기위해서는일상의보수관리가중요하다. 특히대학의경우는공학적실험및연구를위하여전기설비들이장시간가동되고있고전기의의존도또한높다. 그러나실험중에발생되는정전사고는대학연구실에치명적인데이터손실과직결된다. 국내에서는현장에서중대사고또는설비의이상징후가발생했을때, 이를경험한선임자또는실질적전문가에게문답을통해해답을얻는경우 가많아시간적, 경제적손실을초래하고있으며, 또한복구를서두르는나머지판단처치를잘못하여사고를확대시켜 2 차재해를일으킨다 2). 이렇게고압수전설비에대한사고는관리부재에서발생하는것이현실이다. 철저한관리를위해서는해당설비에대한관리우선순위가필요한데여기에대한데이터가없다 2). 관리우선순위라함은고장우선순위를말하며해당순위가결정되면중요부품에대한내구성을강화하는것도전제로하고있다. 이런위험우선순위를결정하기위해서는다양한위험성평가기법들이있는데그중에서 FMEA(Failure modes and effects analysis) 를많이사용한다. FMEA 기법과중요도를활용하면위험우선순위도출이가능하다. 따라서본연구에서는 D 대학공과대학과연계된수배전설비에대하여구성부품별위험성에대한고장모드영향분석 (FMEA) 과중요도를활용하여위험우선순 Corresponding Author : Young Ho Park, Tel : +82-54-630-1304, E-mail : pyh@dyu.ac.kr Dongyang University, 145 Dongyangdaero, Pungi, Yeongju, Gyeongbuk, 36040, Korea 7
박영호 김두현 위를도출하고자한다. 본연구는생활안전위기의산업재해인감전방지와전력, 에너지의안정적운용과수배전설비의내구년한을높일수있는데이터로활용가능하다. 2.1 FMEA 기법 2. 이론적고찰 정성적평가방법중에서도 FMEA 는부품고장간의인과관계를체계적으로규명하고, 시스템에치명적일수있는고장모드, 특히전파될수있는단일결함의최초징후를제공한다는큰장점이있으며이전에알려져있지않은가능한결과들을탐색할수있다. 또한정상적인기능으로부터의이탈뿐만아니라, 파생되는결과들을규명할수있다는점에서여러시스템의안전성분석기법으로널리사용되고있다. Table 1 은 FMEA 의분석절차를나타내는일반적인과정이다. 이러한 FMEA 와중요도등을활용하면위험우선순위를결정할수있다. 위험우선순위를결정하기위해서는각각의심각도 (Severity) 와발생도 (Occurrence) 에의한중요도 (Criticality) 를평가하고, 중요도에검출도 (Detection) 를포함하면위험우선순위를계산할수있다 4-5). 이러한위험우선순위는상대적으로고장이높게발생하는부품을선정하여집중관리및유지하는데보조자료로활용가능하다. Table 2 4 는심각도, 발생도및검출도에대한각각의기준을나타냈다. 각각의기준은 1-5 단계로제시하였다. Table 2. Severity Ranking Criteria 4-5) Class Severity Level Criteria Ⅰ Negligible 1 No effect Ⅱ Minor 2 Ⅲ Major 3 Ⅳ Serious 4 Ⅴ Hazardous 5 Table 3. Occurrence ranking criteria 4-5) Failure inducing unplanned maintenance but has no severe effect on system Inducing failure such as functional incapability on corresponding subsystem Failure inducing consequence such as operable incapability of system Failure has possibility of very severe consequence Class Occurrence Level Criteria Ⅰ Almost never 1 Failure unlikely Ⅱ Remote 2 Rare number of failures likely Ⅲ Medium 3 Moderate number of failures likely Ⅳ Moderately high 4 Frequent high number of failures likely Ⅴ Very high 5 Very high number of failures likely Table 4. Detection ranking criteria 4-5) Class Detection Level Criteria Ⅰ Very high 1 Has very high effectiveness Ⅱ Moderately high 2 Has moderately high effectiveness Ⅲ Low 3 Has low effectiveness Ⅳ Remote 4 Ⅴ Very remote 5 Is unproven, or unreliable, or effectiveness is unknown Is very unproven, or unreliable, or effectiveness is unknown Table 1. FMEA procedure of IEC 812 for FMECA 3) Numbers 01 02 03 04 05 Contents The definition of the system and its minimum functional operation demand Development of functional reliability block diagram, other diagram, or mathematical model and description Basic principles of performing analysis and setting the corresponding document format Failure mode, its cause and effect, relative importance, and investigating its links Failure detection, isolation investigation, and method investigation 06 Investigation on planning and operation regulation of especially undesirable incidents 07 Determining event criticality 08 Assessment of failure possibility 09 If necessary, investigating the multi-failure of certain combination that needs to be considered 10 Recommendation 2.2 중요도등급기준중요도는일명리스크행렬 (Risk Matrix) 이라고불리는것으로, 고장이발생하는경우그로인하여부품이나시스템또는운영자가받는영향의정도를평가하며, 심각도를주안점으로하여분석하는것이다. 특히, 발생빈도가높으며, 높은심각도등급을갖는고장모드에주의를기울이기위하여사용되는수단이다. 중요도는고장모드의심각도와발생빈도에의해평가하여등급화함으로서설비의중요도를매기는것으로다음식 (1) 로구할수있다. 이것은리스크의개념과같다. 즉, 바람직하지않은사건의발생확률 ( 발생빈도, Occurrence) 과그로인해야기될수있는피해결과 ( 심각도, Severity) 로부터추정된다 4). 중요도 (Criticality) = Severity Occurrence (1) 여기에서발생확률이낮고, 피해강도도낮은사건에 8 J. Korean Soc. Saf., Vol. 31, No. 5, 2016
Table 5. Criticality grade matrix 대해서는크게주의를기울일필요가없다. 왜냐하면제한된시간과제한된자금으로완벽한재해예방을한다는것은사실상불가능하기때문이다. 발생확률은높지만발생시재해강도가낮은형태의사건에는, 흔히우리주변에서볼수있는시스템의사소한고장에해당된다. 반면발생확률은낮더라도일단발생하면피해규모가큰사건, 더욱이발생확률까지크다면문제는심각하지않을수없다. 시스템의안전성은바로이러한유형의재해를구별해내고이런재해에안전의노력을극대화하자는것이다 6-8). 10 이상은그영향및발생빈도를고려하여철저한관리가필요한높은 H(High) 등급으로, 5 9 는중간정도의중요도평가등급인 M(Medium) 등급으로, 그리고 5 미만은낮은등급인 L(Low) 등급으로하여관리지침을설정하는데이용하였다. Table 5 는중요도등급을나타내었다. 용전압으로변환하려는목적으로전력회사의배전선로를통하여전기를공급받아구내배전설비로전기를공급하는시스템으로구성되어있다. 수변전설비는여러가지의단위전력설비와그전력설비가모여진형태의계층별로구성되어있다. Fig. 1 의수변전설비의주요구성기기류는변성기류인변압기, 계기용변압기 (PT ;Potential Transformer), 계기용변류기 (CT; Current Transformer), 계기용변성기 (MOF; Metering Out Fit) 등이있고케이블, 피뢰기, 차단기, 개폐기류, 콘덴서등으로구성되어있다. 인입선은 2.3 위험우선지수 FMEA 와중요도를평가하고추가적으로검출도를적용한위험우선순위 (RPN; Risk Priority Number) 를결정할수있다. RPN 은식 (2) 와같은심각도, 발생도, 검출도를모두동일한중요성을두고평가한다. 따라서 RPN 값은 1 과 125 사이로정했으며숫자가크면관리를우선적으로실행해야한다는의미를포함하고있다. RPN = Severity Occurrence Detection (2) 3. 작동흐름도및구성부품분류중요도등급기준 공과대학의수배전설비는전기의심장과같다. 또한모든연구실이다양한소비전력을가지고있으며계측기는물론이고다양한전기설비들이실험에관여한다. 또한계측장비를통하여실험데이터와직결되기때문에정전이나오작동으로인한사고는연구기간이나또는업무에많은지장을초래한다. 수배전설비에있어서가장먼저알아야할부분은수배전설비의작동흐름도이다. 수변전설비는수용가로공급된특고압을사 Fig. 1. The simplified power installation diagram of D university. 한국안전학회지, 제 31 권제 5 호, 2016 년 9
박영호 김두현 강심알루미늄절연전선 (ACSR-OC; Aluminum Conductor Steel Reinforced Outdoor Crosslinked Polyethylene insulated Wires) 를사용하고있다. 인입부는기중부하개폐기 (IS; Interrupter Switch), 피뢰기 (LA; Lighting Arrester), 케이블로구성되어있으며 IS 는통상의부하전류를개폐하며 LA 는뇌로인한과전압을제한하여전기설비의절연을보호하고속류를차단하는목적으로사용되고있다. 부하개폐기반은부하개폐기 (LBS; Load Break Switch) 와전력퓨즈 (PF; Power Fuse) 로구성되어있으며부하개폐기는변전설비의인입구개폐기로많이사용되고있으며전력퓨즈용단시결상을방지하는목적으로사용하고있다. 계기용변성기반은전력퓨즈 (PF; Power Fuse) 와계기용변성기 (MOF; Metering Out Fit) 로구성되어있으며 PF 는전로의단락보호용이고, MOF 는전력량측정을위해 PT 와 CT 를한탱크에수납한기기 Table 6. Component, sub-components and failure rates of the power installation 9) Components Sub-components Incoming LBS Panel MOF Panel PF/PT/CT CB TR Low Voltage IS(25.8 kv 200 A) 4.13 LA(18 kv 2.5 ka) 18.88 Cable(FR-CNCOO-W) 8.63 LBS(24 kv 60 0A) 5.39 LA(18 kv 2.5 ka) 18.88 PF(25.8 kv 65 A) 5.39 MOF(13.2 kv/110 V 50/5 A) 8.6 PF(25.8 kv 200 AT) 5.39 PT(13.2 kv/110 V) 1.85 CT(50/5 A) 2.40 OCR 11.27 UVR 11.27 VCB(24 kv 630 A) 9.48 SA(18 KV 5 ka) 18.88 PF(25.8 kv 65 A) 5.39 Transfomer(Oil, 1000 kva, 3상4선식 ) 2.59 Cable(CV) 8.63 PT(380/110 V) 1.85 CT(2000/5 A) 2.40 이다. PF/PT/CT 반은전력퓨즈, 계기용변압기, 계기용변류기로구성되어있으며 PT 용 PF 는 PT 의고장이선로에파급되는것을방지하기위한기기이며 PT 는고전압을저압으로변성하여전압계로전압을측정하는기기이고, CT 는대전류를이에비례하는전류값으로변성하여전류계에공급하는역할을한다. 차단기반은진공차단기 (VCB; Vacuum Circuit Breaker) 와서지흡수기 (SA; Surge Absorbe) 로구성되어있으며 VCB 는진공도가높은상태에서절연내력이높아지고아크가분산되는원리를이용하여소호하는차단기이며통상의상태에서부하전류를개폐하고이상시고장전류를차단한다. 변압기반은컷아웃스위치 (COS; Cut Out Swtich) 와트랜스포머 (TR; Transformer) 로구성되어있으며 COS 는변압기 1 차측의각상마다설치하여변압기의보호와개폐를위한것이며 TR 은전자기유도현상을이용하여교류전압을변화시키는장치이다. 저압반은기중차단기 (ACB; Air Circuit Breaker) 와 PT, CT 로구성되어있으며 ACB 는저압에서통상의상태에서부하전류를개폐하고이상시고장전류를차단한다. Table 6 는 D 대학수배전설비에대한구성부품과하부구성품에대한고장률을제시하였다. 본고장률은 D 대학수배전설비의신뢰성을분석하는데중요한자료로활용되고있다. 4. 위험우선순위지수및중요도분석 공과대학수배전설비의부품별잠재적고장모드분석을기초로잠재적원인및효과를분석하였으며, 하위구성요소에대한 RPN 과중요도분석결과를 Table 7 에나타냈다. 고장의잠재적원인은전문가들의의견과미국의 NPRD 보고서에서제시된데이터및수배전설비에서분석한자료를바탕으로하였다. 잠재적효과는첫째전력공급 ( 출력에너지 ), 둘째기계적손상, 셋째는안전을바탕으로하였다. 본연구에서는각부품에대한 RPN 값으로위험의우선순위를결정하였다. 고장모드별위험수준이허용불가수준의경우 RPN 값이최대 125 까지책정될수있으며본연구에서최고 60 까지도출되어 60 이포함된등급까지만본논문에서언급하였으며, 그이상의등급인중대한위험과허용불가위험에대해서는무시하였다. 위험우선순위의값이크다는것은해당고장모드로인해시스템이나기기가큰영향을받을수있고, 혹은그와같은고장이자주발생할수있으며, 고장이발생하더라도감지가어렵다는것을의미한다. 그리고우 10 J. Korean Soc. Saf., Vol. 31, No. 5, 2016
Table 7. RPN and criticality at FMEA sheet Item No. Potential failure mode Potential causes Potential effects 100 SWITCH 110 ASS/DS/IS 10) S E V O CC D ET R PN C RI 111 Insulator crack Faulty switch, damages to structural parts Power cut, Degradation 4 2 3 24 8 112 Fuse link faulty Discoloration, scratches Degradation 2 2 3 12 4 113 Incoming fauilure Erosion, fault current Power cut 4 1 1 4 4 120 COS 10) 121 Fused fusible disconnecting Breaking current lack of capacity Degradation, erosion Power cut to loads 4 2 4 32 8 122 Flashover distance error Power cut 3 2 2 12 6 123 Malfunction Attach bad connection, salt and other obstruction Power cut and degradation 2 3 2 12 6 200 LA 10) 201 Stop function Surges, isolating poor performance, flaskover Transformers and other equipment damage 5 3 3 45 15 202 Malfunction Lack of aging, the compression gasket Fasteners Temperatures and relaxation terminal Deterioration 4 2 2 16 8 203 Crack Separation of grounding, crack Power cut 5 2 3 30 2 300 OVERCURRENT DETECTORS 310 PF 10) 311 Fusing Corrosion and degradation by overcurrent Overcurrent blocking impossibility, power cut 4 2 4 32 8 Close interval, joint and partial release of tightenings 312 Flashover Deterioration 3 2 3 18 6 rogue 313 Insulator crack Attach bad connection, salt and other obstruction Power cut 4 1 1 4 4 320 CB(MCCB) 9) 321 Open without stimuli 322 Does not open Bad system configuration, construction defect, mechanical defects, improper maintenance No energy output 3 3 3 27 9 Faulty switch, damages to structural parts, flashover/arc, No disconnection, safety, fire, arcs 5 3 3 45 15 improper maintenance, aging 400 INSTRUMENTTRANSFO RMERS 410 MOF 9) 411 Contamination Bad system configuration, salt and other obstruction Degradation 4 5 2 40 20 412 Shorted Cracks/ruptures, insulation failure Power cut and degradation 4 3 1 12 12 413 Inductor danage Cracks/ruptures, insulation failure Power cut and degradation 4 1 3 12 4 420 CT 10) 421 OCR operation Deterioration Power cut 4 2 4 32 8 422 Malfunction Deterioration Power cut 4 2 4 32 2 423 Loss by combustion or destroyed Abnormal voltage, Lighting Power cut 4 1 2 8 4 424 Flashover Flashover at connetcor, Leakage currnet Power cut and degradation 3 2 2 12 6 430 PT 10) 431 Creak Aging, environmental degradation, lightning, bad manufacturing, the roof leaks as crack, the shot Power cut, fire 4 2 5 40 8 432 Exprosion Degradation Power cut 5 1 5 25 5 433 Murmur PT primary circuit short circuit, Natural degradation Power cut 3 2 4 24 6 434 Indicator fauilure PT secondary circuit short circuit, mitering faulure Power cut 2 2 4 16 4 435 ZCT damage Short Power cut 3 2 3 18 6 436 Breakage Natural degradation Power cut 5 2 4 40 10 한국안전학회지, 제 31 권제 5 호, 2016 년 11
박영호 김두현 Item No. Potential failure mode Potential causes Potential effects 500 TRANSFORMER 10) S E V O CC D ET R PN C RI 501 Abnormal metering Instrument failure, overload Malfunction, degradation 2 2 1 4 4 502 Abnormal temperature Instrument failure, voltage droup, overload winding interior error Life loss, damage 4 3 5 60 12 Overvoltage Unstable, resonant installation Partial 503 Murmur damage 4 4 3 48 16 discharge occurred, unstable ground Bolts loosening 504 Strange smell Local heating Malfunction, degradation 3 2 3 18 6 505 Insulating oil leak 506 Terminal error 507 508 Insulator damage, Damage of parts of elimination Trace discharges from discharge Bad gasket degradation, packing, corrosion, Instrument failure, the cracks, oil leakage Overheating, damage, power cut 5 3 4 60 15 Overload or Abnormal current, looseness, bad contact Discoloration caused by overheating 1 3 2 6 3 surface External short circuit, Leakage, Abnormal intermal Power cut 4 2 1 8 8 Abnormal voltage Inductor damage, accelerated deterioration 3 3 1 9 9 509 Rust outbreak Degradation of paint film 1 2 2 4 2 510 Abnormal operetion Sign a small animal Power cut 5 1 1 5 5 511 Oil leakage Bad packing rusting Overheating 5 2 2 20 10 512 Creak Shunt coil by a loss, flashover of the bushing by the Power cut lighting 5 1 1 5 5 513 Explosion Rapid overload, not open breaker Power cut 5 5 1 25 25 514 Incoming power error Overload transformer internal failure, and feeder circuit Power cut 2 2 2 8 2 515 Trip breaker Both internal and feeder ground leakage at transformer Power cut 2 2 2 8 2 516 Temperature rise Overload, transformer internal failure, Cooling fan failure, Thermometer failure, Air filter contamination Power cut, degradation 2 2 1 4 2 blockage 517 Deterioration Local heating, the passing of degradation Discoloration of insulation, cracking 4 3 5 60 12 518 519 Abnormal insulation resistance Abnormal core terminal and tabs 600 CABLE 610 GROUNDING 9) 611 Open Hygroscopic, pollution Accelerated deterioration 3 2 4 24 6 Bad current relaxation, fasteners, contact area, overload, Faulty cabling, material aging, animals, vandalism, extreme weather conditions, earthquake Discolor by heating dust, parts, component damaged 3 4 2 24 12 No energy output, safety 5 1 2 10 5 612 Short, arc Cracks/ruptures on cables, insulation failure, aging, No energy output, safety, fire animals 5 1 2 10 5 613 Excessive wear Improper system design Reduced energy output, thermal damages 3 1 4 12 3 620 CV 9) 621 Open Faulty cabling, material aging, animals, vandalism, extreme weather conditions, earthquake No energy output, safety 5 2 2 20 10 622 Short, arc Cracks/ruptures on cables, insulation failure, aging, No energy output, safety, fire animals 5 2 1 10 10 623 Excessive wear Improper system design Reduced energy output, thermal damages 3 2 4 24 12 630 CONNECTOR 9) 631 Open Damage, disconnection, animals, vandalism, strong wind, pulled cables 632 Poor contact/intermittent Corrosion, improper installation, lightning damage 633 Short 700 FILTER(C) 9) Damages, improper installation, disconnections, animals, vandalism No energy output 5 1 2 10 5 Reduced energy output, no energy output, thermal damage No energy output, safety, thermal damages, fire 5 1 4 20 5 4 1 5 20 4 701 Shorted Damages, improper installation, disconnections, Reduced energy output, safety, thermal damages, fire 5 5 2 50 25 702 Opened Damage, disconnection Reduced energy output, safety 3 3 1 9 9 703 Drift Thermal damages, fire 3 2 3 18 6 12 J. Korean Soc. Saf., Vol. 31, No. 5, 2016
선적으로시정조치를시행하여영향도나발생도, 검출도중의한, 두개또는전부를감소시킴으로써그값을감소시켜야하는고장모드라는것을의미한다. RPN 값을가지고총 3 개의그룹으로나누어평가를하였다. RPN 값이 45 60 사이의상당한위험으로평가된고장모드를 Group A, RPN 값이 16 44 사이의경미한위험으로평가된고장모드의경우를 Group B, 그리고 1 15 사이의무시할수있는위험으로평가된고장모드를 Group C 로분류하였다. Group A(7 개모 드 ) 에해당되는고장모드는 502, 505, 517 에서가장높은 RPN 이 60 으로나타났고, 다음순으로 701, 503, 201 과 322 이었다. 구성부품으로분석하면 Transformer 에서 4 개모드, Filter(C) 1 개모드, LA 1 개모드, CB(MCCB) 1 개모드로 4 개의구성부품에서차지하였다. 그리고, 심각도와발생도만을가지고평가한중요도또한 3 개의등급으로분류를하였다. 먼저 10 25 사이의철저한관리가필요한등급은 H 로분류하였으며, 5 9 사이의중간정도의경우를 M 등급으로, 5 미만 Fig. 2. Risk classification rating through RPN. Fig. 3. Risk classification rating through criticality. 한국안전학회지, 제 31 권제 5 호, 2016 년 13
박영호 김두현 Fig. 4. RPN and criticality analysis. 의낮은등급은 L 등급으로분류하였다. 중요도의 H 등급은총 16 개의고장모드로가장높은순으로하면 513 과 701, 411, 503, 201, 322, 505, 412, 502, 517, 519, 623, 436, 511, 621, 622 로나타났다. 구성부품은총 7 개로 LA(1 개모드 ), CB(MCCB)(1 개모드 ), MOF(2 개모드 ), PT(1 개모드 ), Transformer(7 개모드 ), Cable(3 개모드 ), Filter(C)(1 개모드 ) 에서나타났다. Fig. 2 는위험우선순위를 Fig. 3 은중요도를나타내었다. Fig. 4 는위험우선순위와중요도를상호비교해보았는데둘다높게나타난것은 Transformer, Filter (C), LA 와 CB(MCCB), 중요도에서만높게나타난부품은 MOF 와 Cable 이었다. 이중에서도 Transformer(RPN: 4 개모드, 중요도 : 7 개모드 ) 가집중관리부품으로선정되었다. 5. 결론 본연구에서는 D 대학공과대학수배전설비의구성부품별위험성에대하여고장모드영향분석 (FMEA) 과중요도등을활용하여위험우선순위를결정하고자하였으며, 다음과같은결론을도출하였다. 1) 위험우선순위는변압기에서 4 개모드, Filter(C) 1 개모드, LA 1 개모드, CB(MCCB) 1 개모드로 4 개의 구성부품에서차지하였고, 중요도에서는총 7 개의구성부품으로 LA, CB(MCCB), MOF, PT, 변압기, Cable, Filter(C) 에서나타났다. 또한위험우선순위와중요도를상호비교해보았는데둘다높게나타난것은변압기, Filter(C), LA 와 CB(MCCB), 중요도에서만높게나타난부품은 MOF 와 Cable 이었다. 2) Group A 에 57% 를차지한변압기의경우내부이상, 고조파등에의한 이상온도상승 고장모드와가스킷열화, 패킹불량, 부식, 균열등에의한 절연유누유 고장모드, 열에의한 절연물열화 고장모드그리고과전압, 부분방전, 공진등에의한 이상음발생 의고장모드가변압기의주요고장모드가되어철저한관리및정기점검에주의를기울여야한다. 3) 과전류의안전보호장치인 MCCB 의경우주위온도저하및성능문제에따른 MCCB 의 과전류부동작 이수배전설비의 MCCB 를고장시킬수있는것으로평가되었으며, MCCB 의 Open without stimuli 은중요도지수가 Medium 이지만이에따른조작이상으로산업재해인감전사고를유발시킬수있는가능성이높아철저한관리를필요로하며, 또한전체시스템에직접적인영향을주지는않지만과전류에의한시스템을보호해주는역할을하기때문에점검시주의해야한다. 4) 본데이터는 D 대학뿐만아니라유사한수변전 14 J. Korean Soc. Saf., Vol. 31, No. 5, 2016
설비를가진대학에서정전및감전등의유지및관리자료로활용가능하다. References 1) http://www.aptn.co.kr/, Check of Power installations to prevent safety accidents, 2005. 2) Y. -S. Kim and K. -M. Shong, Investigation of Facility Accident and Suggestion of Guide Line for Accident Process on 22.9 kv Class Electrical Installation. The Korean Institute of Electrical Engineers (KIEE), pp.137-138, 2009. 3) IEC-60812(2001) : Analysis Techniques for System Reliability-procedure for Failure Mode and Effects Analysis(FMEA), IEC. 4) B. J. Bowles, The New SAE FMECA Standard, Proc. Ann, Reliability & Maintainability Symp., pp.48-58, 1998. 5) D. -H. Kim and J. -H. Lee, Qualitative Assessment for Hazard on the Electric Power Installations of a Construction Field Using FMEA, J. Korean Soc. Saf.,Vol.19, No.4. pp.36-41, 2004. 6) H. -K. Lim, System Safety Engineering, Hansol Academy, pp. 93, 2012. 7) SAE-ARP5580, Failure Modes, Effects, and Criticality Analysis Procedures, SAE, 2001. 8) MIL-1629a, Procedures for Performing a Failure Mode and, Efects and Criticality Analysis, DOD, 1980. 9) Reliability Analysis Center,2011, Non-electronic Parts Reliability Data & Electronic Parts Reliability Data, 2011. 10) D. -h. Kim, A Study on Development of Evaluation Model for Reliability and Safety of Temporary Electric Power Installations, Chungbuk National University, pp.35-40, 2004. 한국안전학회지, 제 31 권제 5 호, 2016 년 15