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Available Technology

Sustainable Energy

Source-Agnostic Time-Domain Directional Relay

Inventors: Dr. Sukumar Brahma and Prabin Adhikari

Market Overview

The power grid market has witnessed a surge in the integration of renewable energy resources (RERs) driven by growing environmental concerns and the pressing demand for sustainable energy solutions. Consequently, to meet this demand, there is an increased need for inverter-based resources (IBRs) as they are instrumental in facilitating integration of RERs into the power grid.  However, IBRs exhibit unique fault characteristics significantly different from synchronous generators (SGs), posing challenges for traditional directional overcurrent relays. These challenges include limited fault currents, absence of negative sequence currents, and rapid changes in output voltage, making traditional phasor-domain relays unreliable.


Renewable energy grids, Hybrid systems, Microgrids, and Smart grids

Technical Summary:

The proposed solution is a directional protective relay formulated in the time domain, eliminating the need for polarization techniques. This relay is designed to detect faults reliably regardless of the type of power source, whether IBRs or SGs. It is immune to decaying DC offsets and prefault currents, making it suitable for grids with up to 100% IBR penetration. The relay operates effectively at a sampling rate of 24 samples per cycle, facilitating its implementation in existing commercial numerical relays. Performance validation through PSCAD simulations demonstrates its superiority over current commercial relays.


  • Universal Compatibility: Functions reliably with both IBRs and synchronous generators.
  • Enhanced Reliability: Immune to decaying DC offsets and prefault currents.
  • High Compatibility: Easily integrates with existing commercial numerical relays.
  • Improved Fault Detection: Superior performance in both transmission and distribution systems.
  • Regulatory Compliance: Aligns with IEEE standards, ensuring future-proof protection solutions.

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Technology Overview

State of Development

TRL 2/3

Patent Type

Provisional Patent Application


Sustainable Energy

Serial Number


CURF Reference No.



Dr. Sukumar Brahma and Prabin Adhikari

For More Info, Contact:

Please put technology ID “2024-026” in the subject line of the email.


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