報告書番号

181039

タイトル（和文）

６６ｋＶ級ＸＬＰＥケーブルの長期絶縁性能

タイトル（英文）

LONG-TERM INSULATION PERFORMANCE OF 66KV XLPE CABLES MANUFACTURED BY DRY CURING PROCESS

概要 （図表や脚注は「報告書全文」に掲載しております）

高電圧（６６ｋＶ以上）ＸＬＰＥケーブルの長期絶縁性能を交流破壊特性の視点から検証するため，６種の乾式架橋法で製造した６６ｋＶＸＬＰＥケーブルについて実使用２３年相当の周波数加速劣化試験（３７ｋＶ，２ｋＨｚ，８０℃外導内浸水有及び無）を行い，劣化試験前と後の交流長時間破壊電圧（ＢＤＶ）を測定した。この結果，１）劣化後のＢＤＶは劣化前のＢＤＶに比べやや低下を示しているもののいずれも初期耐電圧値（１９５ｋＶ）の１．５倍以上の値であり，さらに３０年相当の劣化後におけるＢＤＶは２７０～６３０ｋＶ（平均破壊強度：２５～５７ｋＶ／ｍｍ）になると予想される。２）劣化後の絶縁体には浸水の有無に関係なくボウタイ状水トリーが発生し，その最大長さとＢＤＶの間にある程度の相関性が認められる，等が明らかになり，交流破壊特性からは現在の絶縁厚１１ｍｍを９ｍｍ程度に低減できる可能性があることがわかった。

概要 （英文）

AT PRESENT,XLPE CABLES MANUFACTURED BY DRY-CURING PROCESS,ARE USED IN XLPE CABLES FOR HV ABOVE 66KV TRANSMISSION LINES,THEREFORE,IT IS VERY IMPORTANT TO MAKE CLEAR LONG TERM INSULATION PERFORMANCE OF DRY-CURED XLPE CABLES FOR APPLYING THEM TO EHV AND UHV LINES OR FOR DECREASING THE INSULATION THICKNESS.THIS PAPER DESCRIBES THERESULTS OF AN ACCELERATED ENDURANCE TEST CARRIED OUT IN ORDER TO MAKE CLEAR LONG-TERM INSULATION PERFORMANCES OF 66KV XLPE CABLES MANUFACTURED WITH THE SIX VARIETIES OF DRY-CURING PROCESS.THE ACCELERATED ENDURANCE TESTS WERE CARRIED OUT FOR ABOUT SEVEN MONTHS(EQUIVALENT SERVICE TIMES:23YEARS)WITH THE FOLLOWING TEST CONDITION:APPLIED VOLTAGE 38KV,FREQUENCY 2KHZ,CONDUCTOR TEMPRATURE 80 DEGREE,WATER IMMERSION AND NOT.IT WAS CONFIRMED THAT THESE CABLES HAVE EXCELLENT LONG-TERM AS WELL AS INITIALINSULATION PERFORMANCE.THE RESULTS ARE SUMMARIZED AS FOLLOWS:(1)AFTER ENDURANCE TEST,SAMPLE CABLES WERE SUBJECTED TO AC BREAKDOWN TEST.THE BREAKDOWN VOLTAGE OF THE ALMOST ALL DETERIORATED CABLES,EXCLUSIVE OF ONE OR TWO SAMPLES DETERIORATED WITH WATER IMMERSION,SHOWED FROM 480KV TO 630KV.(2)BOW-TIE WATER TREES ORIGINATED FROM VERY SMALL SIZE OF CONTAMINANTS OR VOIDS IN THE INSULATION OF THE ALL DETERIORATED CABLES.MAXIMUM TREE LENGTH REACHED 0.3 TO 1.3MM.(3)MOISTURE CONTENT IN THE DETERIORATED CABLES WAS FROM 0.01TO 0.20%.GENERATION AND GROWTH OF BOW-TIE WATER TREES DEPEND ON MOISTURE CONTENT.(4)THE POWER FACTOR OF SAMPLE CABLES MEASURED BEFORE AND AFTER THE ENDURANCE TESTS,WAS IN THE RANGE OF 0.01 TO0.03%.

報告者

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