This book covers the development, modelling and simulation for high-voltage DC (HVDC) transmission systems. The development of HVDC technologies is introduced briefly before the role of modelling and simulation in the research and development of HVDC systems is discussed. The title covers the electromagnetic transient model, electromechanical transient model and the dynamic average model, with the electromagnetic transient model being emphasised. This book is a great resource for engineers, researchers and advanced students majoring in electric engineering.