HVDC protection criteria for transient stability of AC systems with embedded HVDC links

Juan Carlos Gonzalez‐Torres,Serge Poullain,Valentin Costan,Gilney Damm,Bruno Luscan,Alberto Bertinato,A Benchaib,Françoise Lamnabhi‐Lagarrigue

doi:10.1049/joe.2018.0264

Abstract

In recent years, different protection strategies for high-voltage direct current (HVDC) grids have been developed by the industry and academia for the reliable and safe operation of direct current grids. The proposed strategies have different impacts on the AC networks where HVDC grids are connected. In the case of embedded HVDC grids embedded in a synchronous AC network, a partial loss of the HVDC grid might cause the desynchronisation of the AC grid. Therefore, it is of utmost importance to assess the impact of those protection strategies into the stability of the whole network. The objective of this study is to propose a methodology for the transient stability assessment of a simple but representative AC grid in case of DC fault. After validation of the methodology, some HVDC link protection criteria are defined in terms of the Critical Time to Return to Operation. These criteria will be helpful for the design of HVDC protection systems or for the sizing of future HVDC links in order to respect the constraints of the existing protection strategies.

Highlights

Since the first High Voltage Direct Current (HVDC) transmission went into service in the 50’s, HVDC technologies have been quickly developed
Among the HVDC transmission lines all over the world, a few of them are embedded in AC networks (i.e. HVDC grids with at least two ends being physically connected within a synchronous AC network) [1]
Protection of HVDC grids had been a major hurdle to overcome in the creation of true HVDC grids using Voltage Source Converters (VSC), until the recent proposition of protection devices and schemes [2]

Summary

Introduction

Since the first High Voltage Direct Current (HVDC) transmission went into service in the 50’s, HVDC technologies have been quickly developed. Multi-converter power system composed of n generators and m HVDC stations interconnected via a transmission network. Considering that the HVDC converters have a constant power characteristic, their power injections are the same regardless the angles of the internal voltages of the machines.

Objectives

Results

Conclusion