International Standard IEC/ISO 81346 series "Industrial systems, installations and equipment and industrial products – structuring principles and reference designations" [1] defines the rules for reference designation systems (RDS).
(Standards developed in cooperation between IEC and ISO are assigned numbers in the 80000 series) The standard consists of two parts and two supplements: The supplementary sheets for application guidelines (IEC/TR 61346-3:2001) and considerations of terms and their relationships (IEC 61346-4:1998) for DIN EN 61346 were withdrawn in May 2010 without replacement.
[14] The latest version 81346-10:2022 is published as a full International Standard, and replaces the previous Technical Specification ISO/TS 81346-10:2015.
Upgrading form TS to IS implies greater maturity and more scrutiny in the development of the standard.
81346-101 "Modelling concepts and guidelines for power supply systems" is a proposed TS (Technical Specification) currently in committee stage of development.