This guide describes the general requirements, functional and technical performance requirements, test requirements, labeling requirements, packaging, transportation and storage requirements, supply integrity requirements and quality assurance requirements for hybrid high-voltage direct current (HVDC) Transmission control and protection equipment. This guide applies to in control and protection equipment of double-ended or multi-ended HVDC Transmission systems including line commutated converter (LCC) valves and modular multilevel converter (MMC) valves, and can be used as the basis for equipment design, manufacturing, testing and acceptance.