Adaptive Protection Strategy in a Microgrid Under Disparate Operating Modes

Abstract

Abstract—Microgrids usually operate in grid-connected or islanded mode. Due to substantial variation in fault current, same protection coordination scheme cannot be applied in both modes. Moreover, network topology keeps on changing due to momentary events. In this paper, an adaptive protection strategy is proposed to avoid any miscoordination between numerical directional overcurrent relays under a fault instance. Through this scheme, the relay settings can be updated online as per the operating mode and prevailing topology. The proposed tactic employs a central protection center with data storage and programming capability, smart electronic devices and communication channels to acquire and transfer real-time data. The relay coordination problem is formulated as a non-linear optimization function, with coordination time interval constraints. The optimal relay settings under both operating modes are obtained through non-linear programming and hybrid genetic algorithm non-linear programming method. To handle contingencies of communication channel failure, a novel inclusive mode settings are also introduced to protect the system in both modes even with line or DG outages. The proposed adaptive approach is tested on a nine bus radial distribution system with DGs. It has been found that the proposed scheme provides reliable system protection under different operating scenario.

Keywords:

• adaptive protection
• coordination
• communication
• genetic algorithm
• microgrid
• numerical directional overcurrent relay
• optimization
• plug setting

Additional information

Notes on contributors

Adhishree Srivastava

Adhishree Srivastava received the B.E. degree in Electrical and Electronics engineering from the Birla Institute of Technology (BIT) Mesra, Ranchi, India, in 2012, and the M.Tech. degree with a gold medal in Power System Engineering from the Motilal Nehru National Institute of Technology, Allahabad, India, in 2014. She worked as an Edison Engineer in General Electric (GE) Private Ltd. from 2014 to 2016. Currently, she is working as an Assistant Professor in BIT Mesra, Patna, Bihar, India. She is also working toward her Ph.D. degree in Electrical Engineering from Indian Institute of Technology, Patna, India. She has authored various papers in international journals and conferences. Ms. Srivastava is a member of the Institution of Engineers India. Her research interests include optimal relay coordination, distributed generation, and micro grid protection using machine learning and deep learning.

Sanjoy Kumar Parida

Sanjoy Kumar Parida is presently working as an Associate Professor in the Department of Electrical Engineering, IIT Patna. He was awarded the senior research fellowship (SRF) by Power Management Institute, NTPC Ltd. Noida in the year 2007. He has received Bhaskar Advanced Solar Energy (BASE-2015) Research Fellowship awards by Indo US Science and Technology Forum (IUSSTF), DST, Govt. of India in the year 2015. Also, he has received young faculty research fellowship (YFRF) award by Digital India Ltd., Ministry of Electronics and Information Technology (MeitY), Govt. of India in the year 2019. Above these, he has handled nine major projects as PI or Co-PI sponsored by DST, DietY etc. He is working as reviewer and technical advisor for many international journals and conferences. His research interests include electric power components and systems.