Development Of Microcomputr Protection Experimental System Based On Virtual Instrument

The relay protection is an important component of the power system, and it plays an important role to the power system security. Therefore, the technology of relay protection has an important position not only in the power system actual operation, but also in the technology development of power system, professional teaching and staff training. With the rapid progress of electronic technology, computer technology and communication technology by leaps and bounds, microcomputer-based relay protection device is used widely for its unique advantage.The microcomputer-based relay protection has powerful function and complicated operation, the internal working principle can not be understood easily, and there are a lot of disadvantage in existing experimental divice. For these reasons, this paper develops a experimental system which has visible function and clear expression in the internal action, and it can help people to grasp the theory, process and operation of microcomputer-based relay protection, based on virtual instrument. The system could be used in practice teaching and staff training.There are two parts including hardware and software for the design of microcomputer-based relay protection experimental system. Hardware includes host computer and the measure control terminal which accomplish the transformation, low-pass filtering and data acquisition adopts standard chassis structure with 4U, the whole panel and pluggable components with locking function, and transmit the acquisition data to the host computer by USB. It makes use of graphical programming software LabVIEW to design distance protection, data acquisition and human-machine interface, and the software adopts blocking design for each part of programs so that it is easy to understand, debug, connect and modify. This paper makes use of virtual instrument technology to set up an experimental system of microcomputer-based relay protection with the function of data acquisition, digital filtering, signal analysis, human-machine interface settings and so on. The experimental system has the same appearance and function as the actual device. Besides reducing the cost, the system also has many advantages such as strong currency, simple data processing, convenient maintenance, easy function expansion and so on.