【正文】 ilures are connected to insulation problems or something else. The fault frequency in Stockholm’s XLPEcables was 3,34 in 2020 and 3,76 in 2020 faults per 100 km cable and year. The total fault frequency in Stockholm was 3,55, which is in the same size as the total fault frequency in G246。 Energi’s own statistics and the failure reports, which the statistics are based on. Extra information has also been available in some cases. The two largest fault categories reported to Darwin was fabrication or material faults and unknown. When the failure reports were examined, it showed that the seven faults reported under fabrication or material fault could be divided into five different categories. Of these seven faults only three were connected to insulation faults. The total fault frequency in Eker246。 grid was made. The statistics reported to Darwin, Eker246?！痵 total fault frequency is also lower than the total fault frequency reported to Darwin, which is 2,41. However, Eker246。 Energi’s failure reports could be divided into four different faults. These examples show that a lot of information is lost during the report procedure. To be able to get reliable information and to get an efficient use 8 of Darwin there has to be more categories inserted. Today it is impossible to separate for example treeing from a joint fault or a termination fault due to the fact that they are reported under the same category. Today the failures are reported on paper sheets and saved in paper form at Eker246。 Energi’s failure reports. It showed that these seven faults, which were reported under one category in Darwin, could be divided into five different fault categories. Even more fault information was available at internal notes at Eker246?！痵 XLPEcable grid connected to insulation failures was faults per 100 km cable and year, which is considered to be low. The fault frequency of total number of faults was 1,99, which is considered to be a low failure frequency pared to Stockholm and G246。’s XLPEcables is 0,4 faults per 100 km cable and year. Both statistics from the Stockholm and Eker246。teborg’s failure frequency on PILCcables. The statistics from Eker246。 Energi had only had three cable breakdowns related to cable insulation the last four years. At least one of the cables was placed in clay soil and had damage on the jacket. Further, there are very good condition to place cables in the soil at Eker246。ran Semart In today’s power consuming society it is important for the power panies to be a reliable distributor, especially in a nonregulated market as we have here in Sweden. Due to the last years large power cuts in Sweden, for example the storm Gudrun, the demand on the power panies to replace their overhead lines with underground cables has increased. As a result of a lot more underground cables it will probably in the future be more important to use cable diagnostic measurements. This is in order to discover and replace bad cables before a major failure occurs, and in this way minimize the failure frequency. Medium voltage XLPEcables suffer from water tree degradation. Water tree degradation means that water is perating insulation, not uniformly but in a structure that resembles a tree. The water tree degradation could be locally or evenly distributed along the cable depending on the cable construction. This phenomenon leads at the end to a cable breakdown. The breakdown often occurs when a transient over voltage enters the cable, for example when the cable is reconnected after it has been out of service. The main aim with this thesis was to perform cable diagnostic measurements on some of the Eker246。該協(xié)議或期刊應(yīng)給予有關(guān)類型的信息終端和制造商和任何的接口。這將是 在一段時(shí)間以后 更容易研究，則該故障報(bào)告被直接寫入失敗 的 一個(gè)數(shù)據(jù)庫。 現(xiàn)在 從 Eker246。 是Energi的報(bào)告中可能會(huì)分 成 四個(gè)不同的故障。這表明，這七個(gè)錯(cuò)誤， 在達(dá)爾文在一類報(bào)告 中 ，可劃分為五個(gè)不同的故障類別。 達(dá)爾文是一個(gè) 能源公司報(bào)告其故障統(tǒng)計(jì) 的 全國性的數(shù)據(jù)庫 。 總故障的頻率也比 跟 據(jù)報(bào)道達(dá)爾文頻率 總故障 低。 Eker246。電網(wǎng)的故障統(tǒng)計(jì)調(diào)查了更廣泛的。 從斯德哥爾摩電網(wǎng)的故障統(tǒng)計(jì)表明，斷層 數(shù) 主要 跟 地下電纜 有關(guān) 。 在文獻(xiàn)研究發(fā)現(xiàn)文書 中 故障定位 都基于相同的技術(shù) ，即 時(shí)域反射儀。 Tettex邁達(dá)斯 2820和 2877 能夠 在 低 頻率電源線 下 檢測 損耗因子 tanδ 。 那些在文獻(xiàn)研究發(fā)現(xiàn)絕緣診斷儀器都是離線 的 。漏電流的反應(yīng)最有可能的影響 是 二 個(gè) 電纜接頭。在這兩個(gè)電纜的兩端有電纜從 80 年代中期，在中間有一個(gè)從 70年代開始 使用 的電纜。該電容圖顯示無電壓依賴性。該電容圖顯示無電 壓依賴性，這表明該電纜 處于比較好 好 的 條件。 電容 特性 沒有顯示任何電壓依賴。小型水樹電纜可能惡化。 和 L1 L2和 L3相比具有較低的損失。蠕變電流 產(chǎn)生 的原因是最有可能 是 電纜沒有從隔離器斷開。第二組電纜 是 80年代 初的1號 電纜和 4號電纜 。從經(jīng)濟(jì)的角度來看，它是必不可少的電力公司，以盡量減少長期故障，避免償還電網(wǎng)費(fèi)。此外，交聯(lián)聚乙烯絕緣電纜的新 產(chǎn)品 雖然 遭受水樹惡化，但 水樹 的密度減少，而 水 樹的生長速度比第一代交聯(lián)聚乙烯絕緣電纜慢。 水樹的生長 有三個(gè) 不同的 情況 必須滿足。 據(jù)顯示， 第一代 由 石墨涂料和油漆 包裹 的 中壓交聯(lián)聚乙烯 電纜的