This article provides a deep technical comparison of PD and space charge in HVDC transformers, focusing on: • Physical mechanisms • Trigger conditions • Material sensitivity • Diagnostic methods • Design mitigation strategies • Implications for next-generation insulation systems 1. This investment is intended to enable future cost-effective grid upgrades required to integrate increasing renewable energy generation on to the grid, both onshore and offshore. HVDC transmission has significant advantages compared to conventional alternating current (AC) lines, including greater. High-voltage direct current (HVDC) transmission systems are playing an increasingly vital role in today's energy landscape, which is defined by rapid digitalization, accelerated decarbonization, and the unprecedented growth of distributed energy resources (DER), inverter-based resources (IBR), and. source: An Overview Introduction of VSC-HVDC: State-of-art and Potential Applications in Electric Power Systems; Feng Wang, Tuan Le, Anders Mannikoff, Anders Bergman; Cigrè International Symposium, Bologna, Italy, Sept. As a cost-effective, pro-market, and national security-enhancing approach to America's transmission needs, a high voltage direct current (HVDC) grid system, often called a macrogrid, fits the bill.