Southeast Asian countries including Vietnam, Indonesia, the Philippines and Malaysia accelerate the development of solar and wind power projects. New ground-mounted solar farms and commercial rooftop PV projects require supporting step-up transformers and box-type substations. Southeast Asia features hot and humid climate, putting higher requirements on moisture-proof, anti-condensation and anti-corrosion performance. Dry-type transformers are widely adopted in indoor factories and data centers, while oil-immersed transformers, European & American box substations are commonly used for outdoor PV plants.