CTM4000Distributed Optical Fiber Temperature Sensor System Applied In The Selection Of High-voltage Cable Design

With the rapid development of our national economy， citize construction andenterprise modernization improve， in order to satisfy the demand of the city electricpower supplying， so the proportion of cable is larger and larger. The electric designerconcern about the ampacity of cable， the theory with practical ampacities cabledifferences between ampacities theory，improving cable current-carrying capacity. Atpresent domestic electric institute of high-voltage cables， selection， is basically relyon theoretical calculated and cable ampacities to determine the cable is， but whencable laying back to his more， the depth is deep， groundwater level higher or theunderground environment is more complex， the theoretical calculation of electricparameter selection more difficult to determine， designers often more conservative，value design using the cable is may cause too large， the waste of resources. In viewof this situation this topic firstly introduces in detail electric cables， the structure andparameters are calculated， cable’s temperature conputation， cable fevercharacteristics and equivalent thermal power cable route computation and carryingcapacity calculation method， secondly analyzes the principle CTM4000distributedoptical fiber temperature sensor system， system composition， characteristics andresults， finally， using the xiamen electric power has been in operation ofCTM4000distributed optical fiber temperature measuring system of operational dataon actual engineering is the theoretical calculation， analyzes the cable laying invarious environmental download flow the size relations， further verified cableampacities in row pipe mode is the smallest， engineering design if installationenvironment is the exhaust pipe laying， should be to row pipe way the ampacities ofchoosing cable is the basis.At the same time the topic using temperature measuring fiber obtained frommonitoring of cable surface operating temperature， generation by IEC60287criteriaof the carrying capacity calculation formula of evolved simplified formula， throughto the simplified formula calculation result of standard method calculated ampacities calculation results were compared.According to cables depth， soil thermal resistancecoefficient， groundwater level and related parameters of various cable layingmethods under the influence of carrying capacity， through the analysis of the resultsshowed engineering design’s criteria of algorithm under certain conditions isexistence margins， especially in a row pipe， the result of difference is huge， it isrecommended that the design of cable model selection may be changed based onengineering actual conditions of soil moisture and groundwater considering theinfluence of cable ampacities， especially on the exhaust pipe depth is deep. It’s soilthermal resistance coefficient can decrease according to actual situation.It is help tochoose the more economical and reasonable cable section.