海底高压动力电缆在线监测技术与实验研究

海底动力电缆经常出现故障,为探索寻找电缆监测技术方法,分析了胜利油田埕岛海域海底动力电缆多次出现短路故障的可能原因和产生故障的机理,并由此提出了采用基于BOTDR技术的分布式光纤传感系统监测电缆所受外力变化和监测电缆内部温度变化的技术,以及应用局部放电检测技术监测电缆绝缘破损后放电现象。电缆截面温度场和电缆外表受力的数值模拟分布式光纤传感监测电缆内部不同温度和外部受力变形的实验,以及电缆绝缘破损后的局部放电监测证明,所研究的方法可较好地在线监测动力电缆的工作状态,能有效监测和预测海底高压动力电缆运行中的主要故障,该研究可对海洋动力电缆的健康运行与维护提供一种技术方法。

Experimental Study on Monitoring of High Voltage Power Cable in Seabed

The purpose of the paper is to find possible technology and approach of seabed cable fault detection.The possible reasons of short circuit fault of submarine power cable happened several times in the Chengdao oil field sea area of the Shengli Oil field are analyzed in the paper.The cause of submarine power cable fault is introduced as well.Fiber optical sensor,as a new technology,is used widely due to its advantages compared to conventional sensor.Distributed fiber sensor based on BOTDR is likely used to detect inner temperature or load and outside strain of submarine power cable.Partial discharge(PD) technology can monitor insulation ageing and monitor cable discharge.The frequency spectrum of partial discharge weak pulse signal is calculated and depicted to choose the sensor and amplifier of sampling and processing discharge signal.The surveillance principle of fiber optical sensor detection and PD detection methods are described in detail separately.Power cable inner temperature is related to electric power or current load,which indicate that on-line monitoring temperature can show power load.Temperature field of cable section and cable strain on distributed fiber optical sensors are mathematically simulated by the finite element model gridding method.The experimental results of distributed fiber optical sensor based on BOTDR that detects temperature and strain change of power cable are given and described.Different temperature testing fields and strain testing fields in submarine power cable specimen can be shown by BOTDR device.Partial discharge experiments with defect power cable sheath are obtained and described as well.It is proven that these techniques and methods in the paper are elementally effective and reliable.More experiments and studies are necessary for better submarine power cable surveillance.