Design Of High Voltage DC Breaker And Validation Of Principles

Vigorously develop renewable energy will be the inevitable choice to solve the unbalanced distribution of energy resources, ease electricity supply and demand tension, and achieve sustainable economic development in China. Integrated conventional HVDC transmission technology and flexible HVDC transmission technology and establishing high voltage DC grid would be effective means to solve the problems of large-scale grid-connected of renewable energy.This paper reviews the development course of HVDC breaker devices, illustrates the challenge of in current conditions. Based on this, a variety of different technical routes of HVDC breaker is compared. The paper details the classification, topology and the different working principles of mechanical, solid-state and hybrid HVDC breaker, analyzes their respective advantages and disadvantages. Relying on Zhoushan flexible HVDC transmission project, a five-terminal VSC-MTDC simulation model is built in PSCAD/EMTDC software. The paper analyzes the characteristics of the fault current on DC bus when the most severe short circuit occurs. Moreover, the basic interrupting parameters of HVDC breaker are presented resulting from the simulation results.This paper proposes a novel topology of hybrid HVDC breaker based on the thyristor, which makes full use of the commutation principle, through the way of superposition of reverse current to break DC current, realizing two-direction fast resection of DC fault currents with no arc created. The paper introduces its principle, analyzes and calculates the equivalent circuit diagrams of the different stages of the current transfer period. Furthermore, its simulation model is established and tested in the five-terminal simulation model, which prove its feasibility and limitations.This paper presents a new full control type of hybrid HVDC breaker topological structure, detailed the analysis of its working principle, a simulation model is built based on PSCAD/EMTDC software, simulated and tested in the simulation scenario of Zhoushan the five- terminal DC transmission system, selected the equipment and analyzes the power loss. Based on this topology, a low power prototype is established in the laboratory and tested in different voltage level, which verifies the related theoretical analysis and simulation results, demonstrates feasibility of the design.