Independent Engineering Excellence for Complex Transformer Decisions
Reactance is a principal-led engineering consultancy specializing in the design, technical assessment, and lifecycle management of power transformers and shunt reactors.
In an industry where technical errors can lead to multi-million dollar losses and long-term grid instability, we provide Technical Sovereignty. We do not act as an equipment seller or manufacturer's representative. Our sole purpose is to provide an unbiased, independent technical judgment before costly decisions are made.
Lead Expert
Sergey Snagovskoy
Senior Lead Engineer of Power Transformers
LinkedIn Profile- Professional Background: Senior engineering roles at Siemens Transformers LLC, Pauwels Transformers NV, and Faramax Trafo SL — bringing inside knowledge of manufacturer processes to the client's side of the table. Active in major international projects since 2012.
- Technical Range: Power Transformers up to 300 MVA / 420 kV and Shunt Reactors up to 100 MVAR / 420 kV.
- Standards Expertise: IEC 60076, IEEE C57.12.00, IEEE C57.21, GOST R 52719, GOST 11677.
- Global Footprint: Project experience spanning Europe, the Middle East, South America, and the CIS countries.
Our Operational Model: The Principal-Led Advantage
We are not a high-volume consultancy. Reactance focuses on a limited number of assignments where senior-level transformer expertise is critical. Our work is structured to provide deep focus and specialized support:
- Principal-Led Execution: Every project is personally led by Sergey Snagovskoy, ensuring that your senior-level challenges are never delegated to junior staff.
- Senior Expert Network: For highly specialized or niche cases, we activate a curated network of senior experts and specialized consultants, providing project-specific support tailored to the unique technical requirements of the asset.
- Full Lifecycle Role: From new complex designs and design reviews to Factory Acceptance Tests (FAT), modernization, and Root Cause Analysis (RCA) of failures.
Integrity & Confidentiality
At Reactance, confidentiality is not just a policy — it is a cornerstone of our professional practice. Many of our clients operate in highly sensitive environments involving proprietary designs, competitive tenders, or failure investigations.
- We do not publish client names, OEM references, or sensitive project details
- The same high standard of non-disclosure applies to every client, from global utilities to private investors
- Selected references and detailed project credentials are available exclusively under NDA for qualified clients
Publications & Conference Contributions
CIRED 2023 – International Conference on Electricity Distribution
Members of the Reactance engineering team contributed to the technical paper:
11108 – Thermal Performance for Three-Winding Transformers with Axially Stacked Windings
The publication investigated advanced thermal modelling and experimental validation methods for large three-winding power transformers with axially stacked low-voltage windings.
The study analysed temperature rise distribution and thermal behaviour in a 160 MVA, 400/30/30 kV generator step-up transformer operating under ONAF cooling conditions. Particular attention was given to unequal oil temperature distribution along the winding height and its impact on insulation ageing, transformer loading capability, operational optimisation, and long-term asset reliability.
The work was supported by dedicated heat run testing and measured performance data.
Presented at the 27th International Conference on Electricity Distribution (CIRED 2023).
Research Article: Read Research Article →
Poster Session: View Poster Presentation →
