Understanding the space charge dynamics and its impact on insulation degradation in power transformers: A critical review

• Published in: Electric power systems research Vol. 245; p. 111644
• Main Authors: Rafiq, Muhammad, Zink, Markus H.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2025
• Subjects: Breakdown; HVDC; Insulation degradation; Space charge; Transformer oil; Space charge; Breakdown; Insulation degradation; Transformer oil; HVDC
• ISSN: 0378-7796
• DOI: 10.1016/j.epsr.2025.111644

•Space charge accumulation in oil-paper insulation systems poses an increasing threat to the HVDC transformer lifespan.•In power transformers, space charge dynamics involve accumulating and distributing electric charges within the insulation.•Space charges can affect insulation dielectric properties, leading to electric field distortion, voltage breakdown, and insulation degradation.•Understanding and controlling space charge dynamics ensures reliable transformer operation and longevity.•Space charge dynamics significantly impact insulation aging and dielectric performance, affecting overall transformer function and reliability. The lifespan of HVDC transformers encounters a rising hazard from space charge accumulation in oil-paper insulation systems. Space charge involves the accumulation of electric charges inside a definite locality of a material or medium. Space charge dynamics relates to the migration and interaction of electric charges within this material or medium. In the context of power transformers, space charge dynamics imply the buildup and distribution of electric charges inside the medium/material. Space charges may impact the dielectric characteristics of the insulation, resulting in an event, e.g. electric field distortion, voltage breakdown (BD), and ultimately, insulation deterioration. Realizing and regulating space charge dynamics is critical for warranting power transformers' reliable function and life. Space charge dynamics may have a vital effect on the ageing and dielectric performance of insulation materials, eventually affecting the general functioning and reliability of transformers. A critical review of this subject would likely evaluate state-of-the-art research, methodologies, and prospective consequences for the industry. By gaining insight into how space charge dynamics prompt insulation deterioration, academics and engineers can develop more efficient techniques to improve the lifespan and performance of power transformers.