This Technical Report provides general guidance on basic principles and general proposals for the safe and economic operation and maintenance of an LCC converter station. These guidelines are based on the operation and maintenance practices that have been used successfully during the last decades at HVDC converter stations all over the world@ and can be referred to by new HVDC users to optimize operation and maintenance policy and assist in performing the operation and maintenance work. This document focuses only on the operation and maintenance of the equipment inside an LCC converter station@ including back-to-back HVDC systems. The operation and maintenance of HVDC overhead transmission lines@ HVDC cables and voltage sourced converter (VSC) are not covered by this document. NOTE Usually the agreement between the purchaser and the suppliers of the HVDC converter station includes specific requirements regarding contractual requirements of particular systems. Such specific requirements will supersede the general/typical description mentioned in this document and all functions mentioned in this document are not necessarily applicable for all systems.