IEC 62325-451-3:2014+A1:2017 specifies a package for the transmission capacity allocation business process through explicit or implicit auctions and the associated document contextual models, assembly models and XML schema for use within European style markets. This International standard is based on the European style market contextual model (IEC 62325-351). The relevant aggregate core components (ACCs) defined in IEC 62325-351 have been contextualised into aggregated business information entities (ABIEs) to satisfy the requirements of these business processes. The contextualised ABIEs have been assembled into the relevant document contextual models. This consolidated version consists of the first edition (2014) and its amendment 1 (2017). Therefore, no need to order amendment in addition to this publication.