Date of Award
8-2024
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Electrical and Computer Engineering
Committee Chair/Advisor
Dr. Sukumar Brahma
Committee Member
Dr. Ramtin Hadidi
Committee Member
Dr. Christopher Edrington
Committee Member
Dr. Hyesuk Lee
Abstract
Inverter based resources (IBRs) are crucial in integrating renewable energy sources into the power grid. However, their unique fault characteristics, significantly different from synchronous generators (SGs), present several challenges for existing line protection schemes at both transmission and distribution levels. These schemes, reliant on distance and directional relays designed in phasor domain, are not well-suited for IBRs. Most published literature addressing this problem concentrates on altering the control design of inverters. However, this approach faces practical limitations. Inverter controls, often proprietary, are not readily accessible to utilities, rendering the control-based solutions impractical for widespread implementation.
To address this challenge, this research proposes a novel time-domain line protection scheme with distance distance and directional protection features that operates independently of the source type. The foundation of this scheme is the development of source-agnostic time-domain distance and directional relays. The distance relay detects, classifies, and locates faults on any line it monitors, functioning seamlessly for systems with varying levels of IBR penetration. The directional relay eliminates the need for polarization and enhances adaptability to diverse system configurations. Both relays are immune to common issues faced by exisiting line protection schemes such as decaying dc offsets, load encroachment, and pre-fault currents.
The performance of these relays is documented using PSCAD simulations and shown superior to state-of-the-art commercial relays in hardware-in-the-loop (HIL) setup. Additionally, the distance relay algorithm is successfully implemented and tested on a Texas Instruments TI TMS320F28379D microcontroller in a real-time digital simulator (RTDS) environment, demonstrating its practical viability. A comprehensive time-domain distance protection scheme with coordinated main and backup protection functions is also proposed and validated using PSCAD simulations, demonstrating high selectivity, dependability, and security.
The final outcome of this research is a time-domain line protection scheme with comprehensive distance and directional protection features. The scheme is source-agnostic, system-independent, and exempt from the need for any polarization technique, while also being immune to common shortcomings of existing line protection schemes such as load encroachment, pre-fault currents, and decaying dc offsets in fault currents. The protection scheme is selective, dependable, and secure through coordinated main and backup functions. The proposed protection scheme, validated through extensive simulations and real-time testing, proves to be a viable solution for line protection in presence of renewables.
Recommended Citation
Adhikari, Prabin, "Time-Domain Line Protection in Presence of Renewables" (2024). All Dissertations. 3684.
https://open.clemson.edu/all_dissertations/3684
Author ORCID Identifier
https://orcid.org/0000-0003-3160-2226