A Design Of Transform Protection Relay Test Control Set Based On DSP Technology

This paper begins with introducing the electric power system relay protection and analyzes the basic requirement of the electric power system protection relay set. Then the paper introduces the transformer protection relay system. Power transformers are essential and important elements of electric power system, and the reliability of power transformers directly determines whether the electric power system works safely or not. At present, the main protection of internal faults of the power transformer is the differential protection. When the unloaded power transformer is connected to the power system or the power transformer is reconnected to the power system after fault cleared, it will usually produce magnetizing inrush current, which often cause the differential protection relay acting wrongly. And we introduce other transform protection algorithms also. On the basis of introducing the principle and configuration of the transformer protection relay, this paper puts forward the hardware design of a transformer protection relay system which bases on double CPU, that is the DSP and MCU. On the design of the hardware system, we use the high performance DSP as the core of the algorithmic manipulate and DSP also manages some switch input and output. MSP430F149 ,an ultra-low power dissipation ,high performance MCU, which is produced by TI, is used as the communication MCU. The keyboard input system and the liquid crystal display (LCD) system are controlled by MSP430F149 also. On the aspect of the memory, according to the actual requirement, we choose Ramtron company's low voltage,nonvolatile memory—FRAM ,which can preserve the data for ten years and can write and read forever, the main data memory. In order to adapt to various situation, we select the RS-232,RS-485 and CAN as the communication modes. The set chooses the Chinese LCD--OCMJ5X10 which embedded the standard Chinese Characters Library as the displayer. In this system, in order to insure the system can work properly, CPUs are equipped with watchdogs, and each system can reset by itself. The whole system's logic control is realized by a CPLD chip which is produced by Xilinx Corporation. Anti-jamming is necessary for the electric protection system, because an unexpected action would cause severe damage. In the last chapter, the paper discusses some anti-jamming methods in the hardware and software design.