Atmospheric and altitude corrections for air gaps and clean insulators

The tutorial introduces the work of CIGRE WG D1.50, focusing on atmospheric and altitude correction factors for air gaps and clean insulators used in high‑voltage testing and insulation coordination. It explains the motivation to harmonize IEC standards and outlines the complexity of environmental influences such as temperature, pressure, humidity, pollution, and voltage waveform. The presentation summarizes physical discharge mechanisms in air, differentiating between streamer and leader behavior in short and long gaps. It reviews the historical development of IEC correction methods, highlighting limitations of earlier standards and the challenges posed by high‑altitude applications. Extensive comparisons of existing correction approaches (IEC 60060‑1, IEC 60071‑2, and equipment…