Summary
High-energy arcing faults in liquid-immersed transformers and reactors can cause rapid pressure rises, leading to tank rupture and severe consequences. Traditional design guidance relies on a primary design equation that estimates a peak pressure based on fault energy, tank flexibility, gas generation from oil decomposition, and a dynamic amplification factor. This equation assumes isothermal gas expansion, constant tank flexibility, and incompressible oil.
Read more Read lessThis study introduces an updated design equation that retains the general form of the primary design equation, but incorporates more realistic assumptions: adiabatic gas expansion, variable tank flexibility, oil compressibility, and energy balance considerations. It also adds hydrostatic pressure effects. The updated equation requires the use of nonlinear finite-element analysis to account for the variation of tank flexibility in the elastic-plastic range of deformation.
Explicit dynamic simulations on 15 transformer models were used to develop and validate the updated equation. Results show that the updated equation predicts peak pressures more accurately and conservatively than the primary equation, reducing overestimation from 40% to 25% on average. However, significant variability remains due to factors like tank construction, meaning that the updated equation should be used as a conservative estimate rather than an exact predictor.
Additional informations
| Publication type | Session Materials |
|---|---|
| Reference | A2_11716_2026 |
| Publication year | |
| Publisher | CIGRE |
| Country | Canada |
| Study committees | |
| File size | 913 KB |
| Price for non member | 30 € |
| Price for member | 30 € |
Authors
DASTOUS Jean-Bernard - Hydro-Québec; BÉLANGER Sylvain - Hydro-Québec
Keywords
Arc resistant design, design pressure equation, explicit dynamics simulation, finite-element analysis, high-energy arcing fault, liquid-immersed power transformer, pressure, tank rupture, transformer tank design
