Smart Sensor and Internet of Things Enabled Condition Monitoring for Electrical Substations

Abstract

The objective of this thesis report is to present some of the possible uses of Sensors and Internet of Things in the Smart Grid environment while keeping a focus on Electrical Substations. A Micro-Electro-Mechanical Syatems (MEMS) sensor based moisture measurement system for SF6 gas in Gas Insulated Switchgears has been designed along with COMSOL simulations. A possible scheme to connect the sensor to the internet has also been discussed. The MEMS sensor proposed is a rectangular microcantilever which can be used detect the added mass i.e. moisture deposited on it by measuring a change in its resonance frequency. A new scheme to detect the resonant frequency change by measuring a change in Q-factor has been proposed. Elementary experimental work has been performed using a polyimide strip cantilever to test the moisture detection principle. Further, an Internet of Things (IoT) based system for sensing in Substation Automation has been proposed. The proposed system is a wirelessly connected system which will enable the sensors to send their data continuously to the internet, store it in a database as well as enable the users of the system to selectively receive data from the sensors they subscribe to. MQTT protocol has been proposed as the communication protocol for the system. It is an open source protocol that is lightweight and easy to implement. Open source hardware such as Arduino and Raspberry Pi have been proposed in the system for a cost effective solution. The possible alternatives for communication networking and security have been proposed.