Research, Design And Verification Of Shipboard Relay Protection

With the development of ship power grid,the demand of safty and reliability requires the implementation of relay protection device to protect the system. Relay protection devices utilize micro computer and digital signal process technology to detect ship power grid fault, trip breaker and send signal.In this paper, the design of hardware and software of protection devices are analysed, and the design methods and algorithm simulations are given. Due to large frequency variation of ship power system, in addition to software and hardware frequency synchronization method which is commonly used, windows and interpolation algorithm for frequency calculation is also analysed, which has better adaptability to harmonic and frequency variaton. In this paper, the sampling algorithms are simulated, and ship power system protection of each equipment are designed to achieve reliable protection. The procedure flow chart are given, and according to which, overcurrent and differential protection are realized. Then the program is transplanted to SYS/BIOS real-time operating system to make the program more flexible and convenient for maintenance. A background program is written in C# for device setting and debugging. According to the composition of short-circuit current, hardware in the loop simulation platform RT-Lab is used to establish a test platform, on which main protection functions are tested.