309 / 2018-09-25 23:49:03

Integrated Online Monitoring Technology of Oil Pressure and Temperature/Strain of AC 500 kV Oil-filled Submarine Cable

AC 500kV submarine cable,BOTDA,Oil pressure,Temperature,Strain

Hainan Networking System 500kV AC submarine cable is the first ultra-high voltage, large capacity and long-distance cross-sea networking power cable in China. At present, it is the only communication channel between Hainan Power Grid and China Southern Power Grid, which has very important political and economic significance. High-voltage cables are important equipment for power transmission in power systems and their safe operation is critical to power systems. When it fails, not only will there be huge direct and indirect economic losses, but also large-scale power outages will also have serious social impacts. The submarine cable part of the Hainan network system has a harsh operating environment, complex seabed topography, frequent earthquake occurrence areas, and frequent fishing vessels operating nearby, resulting in frequent failures and significant losses. At present, for the three-phase 31km submarine cable of the Hainan network system, the temperature and stress operation status and health level are still very limited. Therefore, using the principle of optical fiber sensing, how to realize the submarine cable by relying on the cable bundled by the submarine cable body. On-line monitoring of temperature and stress body operating conditions are critical. Real-time monitoring of the operation of submarine cables and ensuring the safe operation of submarine cables is not only to ensure the safety of submarine cables, but also to ensure the safe and stable operation of the entire power network. This paper mainly studies the online monitoring implementation of submarine cable body in Hainan networked system. Through on-line monitoring of submarine cable temperature, stress, oil flow and other parameters, the operating status of submarine cable is grasped in time, and the abnormality of submarine cable is predicted in advance. Effective precautionary measures to prevent further expansion of submarine cable faults are studied.
Firstly, the online monitoring technology of temperature and stress synchronization of submarine cable is studied in this paper. The fiber scattering model is established to study the influence of fiber stress, temperature and spectrum interaction and the relationship between stress, temperature and spectrum is separately calculated. The distributed temperature strain of BOTDA fiber is utilized. The sensing device measures online monitoring of the temperature and stress of the submarine cable at the same time. Secondly, the oil flow and oil pressure signal acquisition and online monitoring platform development of submarine cable oil pumping station were completed, the oil pressure signal acquisition and online monitoring scheme of submarine cable oil flow was studied, and the oil flow rate and oil pressure data of oil pump station were proposed and introduced into the online monitoring system. In the lab configuration, the system configuration customization is carried out, and a set of localized oil pump station monitoring background is developed, which can calculate the basic functions such as the retrieval of historical operation data and alarm information, and is transmitted to the submarine cable monitoring center. Finally, the development of the integrated online monitoring and control platform for submarine cables was completed. Through the online monitoring of the bundled cable temperature, combined with the electrical parameters of the submarine cable operation, the distributed monitoring of the temperature of the submarine cable body was reversed by the heat conduction model. The comprehensive online monitoring platform needs to integrate the submarine cable temperature, stress, oil flow, oil pressure, submarine cable coordinate water depth, buried depth, protection status and other parameter information, comprehensively grasp the current operating state of the submarine cable, and be able to integrate the submarine cable temperature and stress related data. Information is comprehensively judged and fault is predicted.
The developed system realizes real-time monitoring of the overall operation of the submarine cable, and can identify the abnormality of the submarine cable and analyze and predict the submarine cable fault. The accuracy of identification of abnormal types and the prediction rate of possible failures are both higher than 90%. In this way we can take effective measures in time, avoid further accident expansion, save the cost of troubleshooting, but also we can predict the accident point in advance, and check the hidden trouble points early.