Study On Longitudinal Differential Protection Of Visual Transmission Line

Transmission lines are the largest number in the power system, Operation experience shows that the overwhelming majority of power system fault is transmission line fault. Therefore transmission line protection in power system relay protection occupies very important position. Longitudinal couplet differential protection is one of transmission line main protection preferred protection principle.Visualization technology is a technology using the computer graphics processing power, change the digital information into the image, and let us be clear at a glance get the change rule of the research objects. Visualization software platform for visual theory with reality, the application provides favorable support. Virtual Instrument software development tools towards to the direction of visual programming. In the power system to complete the phase angle measurement, equipment inspection and testing, the parameters measurement and analysis; also for condition monitoring of electrical equipment and part of experimental simulation and teaching.In this paper, both hardware and software are designed; Computer and Art USB2002 data acquisition card of Altai Company as the main hardware. Basically complete input amount of transformation, data acquisition and the filter function. LabVIEW is the software development platform, emphasize designed a multi-function virtual protection system, which can realize signal acquisition and processing. This system mainly designed from data acquisition, longitudinal league differential protection, and human-computer interface aspects and so on; which realize the TV break, TA saturation, TA break and differential relays operating criteria of the program, each programm modular designed, easy to understand, for connection and modification. Experimental results show that the system has the following functions: can realize signal acquisition, digital filter and signal analysis and processing function, as well as data storage and playback of historical data, can accurately determine fault protection and reliable operation. Study the visualization of longitudinal league differential protection, realizing the transparent protection process, to make up for the experiment by traditional instruments by time and space constraints, satisfying the schools lack the basic requirements of teaching and scientific research. In addition, this system in lower investment at the same time, have strong commonality, reusability high and function easily expanded.