The Design And Development Of Microcomputer Model Of Relay Protection Based On The DSP

As a kind of automated device to monitor operating state of electric power system and switch off accident to guarantee the normal operation of electric power system, relay protection system plays an important role in reliable operation of electric network. With the development of integrated circuit technique and microelectronic technique, it shows great more advantages if using special DSP chip instead of MCU in the field of microcomputer relay protection system.We have developed a model of microcomputer relay protection system using DSP with the function of Recorder which collects voltage, current, frequency and so on of the electric network, analyses protection algorithm, distinguishes the functional mode of the current power line or equipment. It also takes some action to protect electric power circuit, switch off malfunction and note the wrong data. This thesis mainly focuses on the development of protection model and design of software algorithm.After comparison of feasible schemes, we independently design software and hardware and fully consider the large need for data size and the high quality for reliability and real-time. Explicitly speaking, this system has following features:(1).In order to reduce the complexity of design of control circuit, we adopt technology of CPLD and HDL for the hardware design with the help of the EDA software. What we did has increased the flexibility of the system development.(2).We adopt flexible model of admixture program in the general design of software and blocking design in its function, which enhances the efficiency of development and is maintained easily.(3).In the software design of protection algorithm, we select differential algorithm to enable the criterion of waveform trouble rapidly; select DFT algorithm to enable the criterion of magnitude trouble; and design the simple count D-value to enable the criterion of frequency trouble.(4).In the model design of protection unit, we realize easy and reliable circuit of protection and checkout with the help of the CPLD technology, and realize the latching circuit with the NAND gate. All these are to avoid the wrong action during the real operation.After systematic design and debug, the microcomputer model of relay protection can realize each function normally, reached the due acquirement basically.