Team Members

Mohamed Rashwan, Ph.D, P.Eng President

Dr. Mohamed Rashwan is a professional engineer with over 40 years of experience in HVDC and FACTS. His expertise is in the areas of equipment specifications and design, economic assessment of projects, project execution, O&M, witnessing of factory tests, commissioning & system tests, and integration of HVDC and FACTS into the power system.

After working for Manitoba Hydro for 25 years in the HVDC Engineering Department, Mohamed co-founded TGS in 2002.

Dr. Rashwan is current chair of Cigre study committee B4 “HVDC and power electronics”.

In 2010, he was the recipient of the prestigious IEEE PES Uno Lamm HVDC award. This award recognizes outstanding contributions to HVDC technology. The technology has developed into an effective power system tool for long-distance energy transport, ac network interconnections, and system stability enhancement. These developments have come from the work of dedicated engineers and scientists in many countries throughout the world. (Source:

Mojtaba Mohaddes, Ph.D, P. Eng Chief Operating Officer

Mojtaba Mohaddes is a professional electrical engineer with over 25 years of experience in a wide range of activities including academic and international consultancy with a focus on HVDC and FACTS devices.

After seven years of university teaching and five years with Brandt Consultants, Mojtaba co-founded TGS in 2002.

Dr. Mohaddes has been involved with numerous HVDC and FACTS projects, ranging from feasibility studies, technical specification preparation and tender review. Dr. Mohaddes’ main area of expertise is in the development of controls for HVDC and FACTS and power system simulation, in particular in the area of time-domain electromagnetic transient modeling.  He is actively involved in Cigre and is the convenor of working group B4.71 “Application guide for the insulation coordination of VSC HVDC stations”.

Rebecca Ostash, P.Eng Vice President - Business Development

Rebecca Ostash is a professional electrical engineer specializing in power system studies, with a particular focus on HVDC, FACTS, renewable generation and AC system planning studies.

Mrs. Ostash also specializes in developing custom stability models for HVDC and FACTS devices, with emphasis on power system stability software packages PSS/E and PSLF. She is the author of several papers on this subject.

Rebecca joined TGS in 2004, after working for Manitoba Hydro in the System Planning department and at the Dorsey Converter station.

Chandana Karawita, Ph.D, P. Eng Vice President - Studies

Dr. Chandana Karawita is a professional engineer with both industrial and academic experience in power systems. Dr. Karawita joined TGS in 2007 while doing his doctoral research at the University of Manitoba.

He is well experienced in system planning studies related to HVAC, HVDC and FACTS devices. He is also involved in state-of-the-art custom model development for HVDC and FACTS in both transient stability (PSSE, PSLF) and electromagnetic transient simulation (PSCAD) platforms.

Dr. Karawita was instrumental in developing the dynamic phasor based small signal stability analysis package (TGSSR) for analyzing sub-synchronous frequency oscillations in power systems and many other in-house software tools. He actively contributes to various CIGRE working groups related to HVDC and FACTS, and is involved in academic research activities as an adjunct professor at the University of Manitoba.

Narinder Dhaliwal, M.Sc., P. Eng Chief HVDC Engineer

Narinder Dhaliwal is a professional electrical engineer specializing in HVDC, FACTS and synchronous condensers.

He has over 35 years of experience in commissioning, operating and maintenance of HVDC systems. He specializes in specification preparation, bid evaluation, design review, factory testing, on-line commissioning and fault analysis of HVDC systems and synchronous condensers. His other specialty is providing HVDC training.

After working for Manitoba Hydro for 41 years in the HVDC Engineering Department, Narinder joined TGS in 2015.