Protection of large partitioned MTDC Networks Using DC-DC converters and circuit breakers

Md Habibur Rahman,Lie Xu,Liangzhong Yao

doi:10.1186/s41601-016-0030-0

Abstract

This paper proposes a DC fault protection strategy for large multi-terminal HVDC (MTDC) network where MMC based DC-DC converter is configured at strategic locations to allow the large MTDC network to be operated interconnected but partitioned into islanded DC network zones following faults. Each DC network zone is protected using either AC circuit breakers coordinated with DC switches or slow mechanical type DC circuit breakers to minimize the capital cost. In case of a DC fault event, DC-DC converters which have inherent DC fault isolation capability provide ‘firewall’ between the faulty and healthy zones such that the faulty DC network zone can be quickly isolated from the remaining of the MTDC network to allow the healthy DC network zones to remain operational. The validity of the proposed protection arrangement is confirmed using MATLAB/SIMULINK simulations.

Highlights

HVDC is an economic solution of transmitting large amount of power over a long distance compare to the traditional HVAC transmission system due to less transmission losses and smaller cable size for given power level
Radial network configuration is similar to the traditional AC distribution system
The main purpose of this work is to keep the healthy zone in the large multi-terminal HVDC (MTDC) system operational all times following a DC fault by means of using DC-DC converter at strategic location

Summary

Introduction

HVDC is an economic solution of transmitting large amount of power over a long distance compare to the traditional HVAC transmission system due to less transmission losses and smaller cable size for given power level. Voltage source converter (VSC) technology is becoming the main focusing area of recent HVDC research due to its inherent flexible ability of independent active and reactive power control, AC voltage support, and black–start capabilities [1, 2]. There are different network topologies to develop a large MTDC network. At present radial and meshed type network configurations are the most common ones. Radial network configuration is similar to the traditional AC distribution system. Meshed network configuration is more reliable than radial due to redundant supply channels but incur higher cable cost. Any topology can be configured, once technical and economic benefits of the network operators have been dealt with [3]

Objectives

Conclusion