【作者】 王立；

【导师】 杜伯学；

【作者基本信息】 天津大学 ， 高电压与绝缘技术， 2013， 博士

【摘要】 交联聚乙烯绝缘电缆在国内己有40多年的运行历史，运行中的电缆绝缘劣化状况一直是电网运行单位关注的重点，但目前国内外对交联聚乙烯电缆绝缘劣化的研究多是未投入运行的新电缆，对运行交联聚乙烯电缆绝缘劣化性能的研究较少。另外，由于运行續动、环境不良、外力破坏等原因导致高压电缆金属护套接地系统失效，会引起电缆异常发热，降低电缆载流量，严重时甚至会引发电缆故障。因此，对运行中交联聚乙烯电缆绝缘状态及接地系统监测和评价非常重要。本文的研究内容和取得成果如下：1.建立了交联电缆绝缘老化状态与残留电荷之间的定量关系。通过对退运交联聚乙烯绝缘施加5.9kV/mm电场和热循环进行加速水树试验，经过4、6、12个月老化后，在绝缘样品施加直流电压，然后采用脉冲电压释放水树中的空间电荷，计算出和水树老化相关的残留电荷量。试验结果表明，残留电荷量与直流电压幅值和老化时间密切相关。脉冲频率从0.8kHz增加到1.6kHz时，空间电荷量先增加后减少，在1.2kHz达到峰值。2.根据热重、红外光谱、机械强度试验分析方法，以退运的llOkV及220kV交联聚乙烯电缆为试样，证明了交联聚乙烯绝缘的起始分解温度、簾基指数、断裂能在表征电缆绝缘劣化性能方面有很好的一致性。还分析了绝缘存在劣化的退运电缆历史运行数据，结果表明交联聚乙烯电缆绝缘劣化与穿越故障电流等因素产生的热效应密切相关。3.以220kV、110kV电缆的接地电流在线监测数据以及电缆负荷数据为依据，对高压电缆接地系统正常、异常以及缺陷情况进行分析，提出三类接地电流典型特征模型。在此基础上，通过建立数学模型并开发的计算软件分析其特征及影响因素，对高压电缆接地系统状态评价结果进行修正，并提出高压电缆接地系统状态评价的改进策略。4.针对运行高压电缆及敷设通道的实际情况，研究了涵盖电缆绝缘、接地系统、运行环境等多种参数的电缆网运行监控系统功能规范，系统架构，通信规约，状态信息展现等内容，并以此为支撑，建成了国内第一座电缆网运行监控中心。更多还原

【Abstract】 The XLPE cable has been more than40years’ operation history in China, Theoperating cable insulation degradation conditions is always the focus of attention ofthe grid operation corporation, but at present, most studies of XLPE cable insulationdegradation is new cable which is never put into operation in China and abroad, thestudy of performance of operating XLPE cable insulation degradation is less. Inaddition, Due to the operation peristalsis, poor circumstance, external force damageand other causes lead to the grounding system of XLPE cable metal sheath losteiffcacy, Also can caused cable abnormal heating, reduce current carrying capacity ofcable, and even caused the cable breakdown when being serious. In this paper, theresearch contents and achievements are as follows:1.It has established the quantitative relation between aging status of Cross-linkedcable insulation and residual charge.Via the return of XLPE insulation applied5.9kV/mm electric field and heat cycle experiment accelerated water-tree test, go through4,6,12months atfer aging, The samples of insulation applied direct voltage, then usepulse voltage release space charge of water-tree, and calculate the space chargeamount which is related to water-tree aging. The experimental results indicate that,space charge amount is closely related to the amplitude of direct voltage and ageingtime. The pulse frequency increased from0.8kHz to1.6kHz, the space chargeamount firstly increase then decrease, reached the peak at1.2kHz.2.According to the analysis method of thermo gravimetric, infrared spectrum,mechanical strength test, using the return of llOkV and220kV cross linkingpolyethylene cable as sample, it has proved that the start decomposition temperature、carbonyl index and fracture energy of cross linking polyethylene insulation in termsof characterization of the cable insulation degradation performance has very goodconsistency. Also analyzed the historical operation data of return cable of insulationexisting deterioration, the results indicate that XLPE cable insulation deterioration isclosely related to the heat effect produced by crossing the fault current and otherfactors.3.According to the grounding current online monitoring data of220kV,110kV cableand cable load data as the basis, analyzed normal、abnormal and defect these threekinds of situation of high voltage cable grounding system, then propose three kinds oftypical characteristics model of grounding current. On this basis, via establish mathematical model and calculation sotfware which is developed to analyze its factorsof characteristics and influence, and then correct the condition evaluation results ofhigh-voltage cable grounding system, and propose the improvement strategies ofcondition evaluation of high-voltage cable grounding system.4. For actual situation of operating high-voltage cable and laying channel,studied functional specification, system architecture, communication protocols, statusinformation display and etc. of cable network operation monitoring system of containthe cable insulation, grounding system, operating environment and various parameters,based on above indicated as theoretical support, and built the first domestic cablenetwork operation monitoring center.更多还原