Study Of Temporary Over-voltage Occurred In Offshore Oil Platform Power System

According to China's oil development plans, during the days of the 11th five-year plan, the growth of offshore oil in China will usher in a period of rapid development, offshore oil project scale have been expanding, security and stability of offshore oil platform will show a great impact on the national economy and social construction.For all types of overvoltage occurred in onshore power systems, there has been many researches about them, and has put forward various restrictive solutions, which obtained good results in practical application. However, the overvoltage occurred in offshore oil platform is not well studied yet. The main reason may be that offshore oil platform power system is relatively special, generator capacity is small, and early sea oil platforms are small-scale, on which used the short length submarine cable, overvoltage shows no obvious impact on the power systems. As the scale of offshore oil platform construction gradually expanded, submarine cable's length has been growing, in the new offshore oil platform in the South China Sea, the length of the submarine cable used has reached over 100 km, and impact of overvoltage caused by no load submarine cable on the offshore oil platform will become more apparent. Therefore, the study of the overvoltage occurred in offshore oil platform power system has great significance.After the load rejection, there can be two types of overvoltage caused by no load submarine cable occurred in offshore oil platform: parametric resonance overvoltage and power frequency overvoltage. In this paper the reasons of occurrence the overvoltage, the process of its development and the characteristics of it are studied and analyzed. The simulations are done by using software named EDSA. This paper proposed using installation of arrester on submarine cable with generator installed AVR to curb the parametric resonance overvoltage. This paper also verified the inhibition of shunt reactor on the power frequency overvoltage caused by no load submarine cable; the impact of different installation location of reactor and compensation degree has been studied by theoretical analysis and digital simulation. Besides, this paper proposed using the difference value of voltage between the sampling value and the setting value as the diagnostic standard of shunt reactors'capacity to input, with the corporation of reactive power compensator installed on offshore oil platform power system, the real-time adjusting of the reactive compensation capacity of power frequency overvoltage can be achieved.