This standard specifies the terms and definitions, symbols and abbreviations, product structure and classification, product model, usage conditions, technical requirements, deviations, test items and methods, nameplates, markings, packaging, transportation, and storage of transformers for flexible direct current transmission (also referred to as flexible direct current transformers). This standard applies to the following oil immersed products connected to modular multi-level voltage source inverters: symmetrical single pole flexible direct transformers Bipolar flexible direct transformer. The following normative references are essential for the application of this document. For dated references, only the dated version applies to this document. For undated references, the latest version (including all modification orders) applies to this document. GB/T 1094.1 Power Transformers Part 1: General GB/T 1094.2 Power Transformers Part 2: Temperature Rise of Liquid Immersed Transformers GB/T 1094.3-2017 Power Transformers Part 3; Insulation levels, insulation tests, and external insulation air gaps GB/T 1094.5 Power Transformers Part 5: Ability to withstand short circuits GB/T 1094.7 Power Transformers Part 7: Load Guidelines for Oil Immersed Power Transformers GB/T1094.10 Power Transformers Part 10: Determination of Sound Levels GB/T 2900.33 Electrical Terminology Power Electronics Technology GB/T 2900.95 Electrical Terminology Transformers Voltage Regulators and Reactors GB/T 3859,1 General Requirements for Semiconductor Converters and Grid Commutated Converters - Part 1-1: Basic Requirements Specification - GB/T 4109 Insulating Bushings for AC Voltages Above 1000 V - GB/T 10230.1 Tapping Switches - Part 1: Performance Requirements and Test Methods - GB/T 10230.2 Tapping Switches - Part 2: Application Guidelines - GB/T 17623- Determination of Dissolved Gas Components in Insulating Oil - Gas Chromatography Method - GB/T 18494.2- Converter Transformers - Part 2: High Voltage Direct Current Converter Transformers for Transmission GB/T 20838 Technical Parameters and Requirements for Oil Immersed Converter Transformers for High Voltage Direct Current Transmission
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