報告書番号

180018

タイトル（和文）

霧中耐電圧試験における最適蒸気霧とがいし表面の湿潤

タイトル（英文）

OPTIMUM STEAM FOG CONDITIONS FOR FOG WITHSTAND TEST AND WETTING OF CONTAMINATED INSULATORS

概要 （図表や脚注は「報告書全文」に掲載しております）

２種類の懸垂形がいしに対して蒸気霧による定印霧中試験を行ない，初期温度，蒸気吐出量が交流汚損耐電圧に及ぼす影響を検討した。結果の主要点は次の通りである。（１）霧中水分量が３．５～１０ｇ／立方ｍの範囲で霧中耐電圧はばらつきが少なく低い値を示した。得られた最低耐電圧は課電暴露試験による最低せん絡電圧とよく一致した。（２）ばらつきの少ない低い耐電圧を与え，しかも霧室の温度上昇を必要以上に大きくしないことを考慮して，霧中試験に用いる蒸気霧としては最大霧中水分量２．５～５ｇ／立方ｍ，供試がいしが動く霧の中にあることが最適な条件である。（３）がいし下面のもれ抵抗は上面のそれよりかなり高く，またもれ抵抗の時間変化は加湿量の増加とともに速くなった。このような実測抵抗値を基に計算した耐電圧特性は，実測耐電圧およびせん絡時間とかなりよい対応を示した。

概要 （英文）

THE AC WITHSTAND VOLTAGE TESTS ON ARTIFICIALLY CONTAMINATED 250MM SUSPENSION TYPE AND FOG TYPE INSULATORS WERE CARRIED OUT IN STEAM FOG. THE EFFECTS OF THE ROOM TEMPERATURE BEFORE TEST AND THE STEAM FLOW RATE ON THE WITHSTAND VOLTAGE WERE INVESTIGATED. THE MAIN POINTS OF THE TEST RESULTS ARE SUMMARIZED AS FOLLOWS; (1)THE STEAMFOG WITH THE WATER CONTENT BETWEEN 3.5 AND 10G/CUBIC M GAVE A LOWER WITHSTAND VOLTAGE WITH LITTLE SCATTERING. THE LOWEST WITHSTAND VOLTAGE OBTAINED BY THIS METHOD AGREED WELL WITH THE MINIMUM FLASHOVER VOLTAGE UNDER NATURAL CONDITIONS. (2)BY CONSIDERING THE FOG CONDITIONS IN WHICH ALOWER WITHSTAND VOLTAGE WITH LITTLE SCATTERING CAN BE OBTAINED AND THETEMPERATURE RISE OF A FOG ROOM IS DESIRABLE TO BE AS SMALL AS POSSIBLE, THE OPTIMUM STEAM FOG CONDITIONS FOR THE FOG WITHSTAND TESTS MIGHT BEDETERMINED AS FOLLOWS; THE MAXIMUM WATER CONTENT OF THE FOG IS 2.5 5G/CUBIC M. THE TESTED INSULATOR SHOULD BE LOCATED AT THE PLACE WHERE THE FOG IS MOVING, FOR EXAMPLE, WHERE THE FOG IS DRIFTING UPWARD NATURALLY.(3)THE LEAKAGE RESISTANCE OF THE BOTTOM SURFACE WAS MUCH HIGHER THAN THAT OF THE TOP SURFACE. AND THE INCREASE OF STEAM FLOW RATE MADE A CHANGE OF THE LEAKAGE RESISTANCE FASTER. THE CALCULATED WITHSTAND CHARACTESTICS BASED ON THE MEASURED LEAKAGE RESISTANCE VALUES OF THE TOP AND BOTTOM SURFACES CORRSPONDED WELL WITH THE MEASURED VALUES OF WITHSTAND VOLTAGE AND FLASHOVER TIME.

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