High voltage direct current (HVDC) is more effective than traditional alternating current (AC) for bulk power transmission via overhead lines over long distances and under-ground/sub-sea cables over relatively shorter distances. This module will provide the knowledge of the two broad HVDC technologies and their system level impact. The focus will be on HVDC converter operation and control, operation of HVDC links and HVDC systems and interaction between HVDC and host AC systems. The role of HVDC in facilitating the decarbonisation of the electric power sector will be covered.

On successfully completing this module you should be able to: 1) appraise the pros and cons of using HVDC with respect to AC for overhead and cable transmission. 2) describe the operation and control of HVDC converters and HVDC systems. 3) recognise the benefits and limitations of two broad HVDC technologies and their suitability in a specific context. 4) design the control system for HVDC converters and systems. 5) analyse the interaction between HVDC and host AC systems. 6) appreciate the role of HVDC in renewable integration and decarbonisation of the electric power sector.

Introduction to HVDC: AC vs. HVDC Line Commutated Converter (LCC) based HVDC 1. Six-pulse converter operation and control 2. Control of point-to-point LCC HVDC links 3. Interaction with host AC systems 4. AC-DC power flow 5. Harmonics and filtering 6. System aspects Voltage Source Converter (VSC) based HVDC: 1. Characteristics of VSC vs LCC, basics of VSC for DC 2. Basics of VSC for AC 3. Modular Multi-level Converter (MMC) circuit topology and operation 4. Control of a MMC 5. VSC-HVDC grids: operation, protection and HVDC circuit breakers