Critical data reliability issues with Modbus protocol in smart grid application

One of the current challenges in industrial automation is efficient data acquisition and communication between the various field devices and the control station terminal. Modbus RTU protocol which is based on bus architecture has been the most popular and consistently proven industrial communication protocol since 1980´s. However recently, with the growth in economy and rise of industrial age, the size and number of the industries has become relatively large parallelely increasing the number of devices and complexities in reliable and efficient communication. Particularly, with the parallel advancements in the smart-grid technologies and the need for communicating the data to geographically distributed remote stations for the purpose of intelligent remote monitoring and control of the complete system, bus architecture based communication technologies are to be integrated with wireless communication protocols and technologies. Modbus when integrated with wireless technologies like Wi-Fi, Zigbee, GPRS etc. to enhance communication, poses critical problems with respect to data reliability. This paper presents these problems and their impact through simulation results and case studies and motivates the reader to develop protocols and algorithms to solve the problem.