Ethernet Communication for Control and Monitoring of Pole top Remote Terminal Unit (RTU)

Abstract

Remote terminal unit (RTU) is a microcontroller based device that communicates to a Distributed Control System (DCS) or supervisory control and data acquisition (SCADA) system by transmitting data to a master controller in a power distribution system. An RTU monitors the field‟s digital and analog parameters and transmits these to the central monitoring station. It contains setup software to connect data input streams to data output streams, defines communication protocols, and troubleshoots the problems. In this dissertation, the design and study of various sections of RTU has been explained. In RTU, exchange of information is very much essential to acquire complete information for further transmission to substations. Therefore, the main emphasis is put on Ethernet communication and the TCP/IP (Transmission Control Protocol/Internet Protocol) stack in embedded systems. The exchange of information takes place with the help of some communication media and protocols. A communication protocol is a set of rules that computers must follow to communicate with each other. The TCP/IP protocol suite refers to several separate protocols that computers make use to transfer the data across the networks. Two most important protocols in its suite: Transmission Control Protocol (TCP) and Internet Protocol (IP) are widely used because of their ability to switch packets from all shapes and sizes and varieties of networks. However, other protocols like ARP, HTTP and ICMP of this suite have also been discussed in the dissertation. A comparison between fiber optic and Ethernet has been made to provide the understanding of the best type of device and its optimal use. Moreover, the hardware and software implementation of this communication section has also been studied. The main objective of the dissertation has been to implement TCP/IP stack to make interaction between Remote Terminal Unit and the web server. In this work, an Ethernet module using PIC microcontroller and micrel‟s Ethernet switch has been designed where TCP/IP stack has been used to make interactions. The analysis of network protocols and their interaction with each other has been carried out through simulations using Wireshark network protocol analyzer. The simulation has shown that transmission and reception of the packets are recognized by the sequence and the acknowledgement number. Also, analog section of the RTU is tested for its accuracy for all types of inputs. The future scope of the work includes the implementation of the fiber optic communication, used in the present RTU, successfully.