Smart Renewable Energy Microgrid at Dayalbagh Educational Institute

Some weeks back we introduced you to the Renewable Energy efforts at Dayalbagh Educational Institute (DEI). We get a bit more technical this week and introduce you to the,

Smart Microgrid developed and implemented by the Institute.

The post is by Prof. Bhagwan Das, Professor of Renewable Energy in the Department of Electrical Engineering at DEI.

Prof. Bhagwan Das writes...

In order to carry out sustainable developmental activities in agreement with the concept of Eco-Village, DEI took bold initiatives in harnessing the renewable energy through Solar thermal and Solar Photovoltaic (SPV) power plants in 2010. Today, the institute has Solar Thermal Cooking systems in all the hostels. The whole university campus is powered by 11 Distributed Roof-Top Solar PV power Plants aggregating to a total of 668.2 kWp. 

To ensure efficient, reliable and economic operation of the distributed energy resources and achieve proper coordination among them, a need based R&D project to indigenously develop a Smart Micro Grid in the institute was started with support from DST’s Solar Energy Research Initiative (SERI) in 2014.

The Dayalbagh renewable energy smart microgrid is a modern, small scale electricity system comprising a group of distributed loads and distributed renewable energy resources acting as a single controllable entity in synergy with the grid. It is designed to achieve specific local goals, such as energy reliability, security, carbon emission reduction, diversification of energy sources, and cost reduction. Such smart microgrids are an ideal way to integrate renewable resources and form the building blocks of Smart Grids.

All the solar power plants at DEI are Hybrid PV Power Systems with battery storage to facilitate off-grid operation whenever required. The three phase DSP based, Grid Support Conditioners (GSC) are designed to operate as a multi-function power conditioning unit combining renewable energy sources on priority with the functionality of an industrial UPS system.

The effectiveness of renewable energy microgrid was evident during the major grid collapse on two consecutive days on 30th and 31st July 2012 in India when over 600 million people (nearly half of India's population), in 22 out of 28 states in India, were without power. The outage caused "chaos" for Monday morning rush hour, as passenger trains were shut down and traffic signals were non-operational Trains stalled for three to five hours. Several hospitals reported interruptions in health services, while others relied on back-up generators. Water treatment plants were shut down for several hours, and millions were unable to draw water from wells powered by electric pumps. Excessive use of diesel generators (a popular backup resource) caused local pollution and high cost for the consumers. However, Dayalbagh Educational Institute, having its own SPV microgrid, was not affected and the teaching – learning- co-curricular activities continued normally in a pollution free environment and economic fashion. Even on normal sun-shine days, the institute is self- sufficient in power and not affected by the frequent power outages. Under cloudy conditions, a careful battery management ensures uninterrupted power supply to the whole campus.  

INNOVATIVE FEATURES & BEST PRACTICES

The following features are being incorporated as part of the R&D project to develop the smart micro grid with remote monitoring, communication, control and fault diagnosis of DERs from a central control station, which would ultimately enable the development of a Decision Support System for Optimal efficiency, economics and reliability. 

• Display of Inverter parameters viz.  inverter voltage, current,  power, grid source for inverter parameters, solar current, voltage, power, solar irradiance, ambient temperature, heat sink temperatures, data logs etc. All of these parameters can be accessed from the central control station through our institute LAN. As per the requirement, the inverter behaviour can be controlled by remotely changing the software set points and selecting different modes of operations. All the inverters are on the institute LAN and accessible remotely through the front end program.

• Display of Load Parameters through integration of Smart Meters: Load currents, voltages, powers on all the outgoing circuits can be accessed at the central control station through smart meters over the institute LAN.

• Remotely controlled switchgear and change-over switches: Change-over switches for the selection of source (grid or solar) are installed for every outgoing circuit in various control rooms. A system has been designed and implemented to monitor the status of the switches and remotely control the selection through the software at the central control station.

• Battery charging: Battery charging is a very important feature of the system affecting the life of the battery and overall system efficiency. Battery charging is to be closely monitored and controlled so as to utilize the solar power fully and ensure float operation of the battery as far as possible. Grid charging schedules (in rainy, cloudy days) for all the 9 power plants are carefully scheduled to prevent overloading of the sub-station. 

• Water Pumping: A scheme is being designed for remote monitoring and control of water pumps in the institute for punctual and efficient operation of water pumps. This will be integrated to the central control system software. A prototype with remote control and monitoring using Short Messaging Service on GSM mobiles has been developed and implemented for field testing.

• String monitoring and fault diagnosis: With thousands of panels in the institute, it is difficult to identify a mal-functioning panel. The requirement has prompted development of a ZigBee based wireless monitoring system for string current measurement. All the measurements of a plant would be collected at a central computer for processing and analysis. An alarm would be raised if some string is found to be mal-functioning along with the geographical location of the string. A prototype of the same has been developed. 

The Dayalbagh Educational Institute initiative has demonstrated that Universities, building intellectual resources through teaching-learning and research, offer a perfect platform for establishing renewable energy microgrids. In addition to sustainable development through clean energy technologies and self-sufficiency in energy, a university microgrid is an ideal test bed for conducting indigenous research and development through UG & PG projects and Ph.D. thesis. This would ensure quality research with relevance as well as development of skilled man power and intellectual property in the area. Universities can design and implement model curriculum for vocational diploma and certificate courses in solar energy technologies, provide earn-while-you-learn schemes to the students and encourage entrepreneurial start-ups through incubation cells.