# New multi-injection commutation topology for circuit breakers of HVDC transmission lines

## TL;DR

This paper introduces a new, cost-effective HVDC circuit breaker design that significantly reduces arcing time for better performance in high-voltage power systems.

## Contribution

A novel multi-injection commutation topology for HVDC circuit breakers that improves speed and cost-efficiency without adding external components.

## Key findings

- The MICS-HVDC-CB reduced arcing time to 38.5% of passive DC-CBs and 20% of active DC-CBs.
- The design maintains a simple and economic structure while improving performance.
- The impact of cooling power, arcing time constant, and fault resistance was validated through simulations.

## Abstract

Power-sharing between countries has an essential effect on increasing the power system’s reliability and allowing a resilient energy market. High voltage direct current (HVDC) transmission systems are preferable for long-distance transmission to decrease power losses. However, HVDC transmission lines have many protection challenges including the differentiability between various types of HVDC circuit breakers (HVDC-CB). Although mechanical HVDC-CBs suffered from long response time, they superseded their solid-state counterparts in terms of price and power losses. In this paper, a multi-injection commutation system MICS-HVDC-CB is developed to provide economic and fast response HVDC-CB. The proposed breaker doesn’t add external elements to avoid any price increase but instead modifies the existing topology. The MICS consists of multiple L–C commutation circuits inserted sequentially following the receiving of the tripping signal. The proposed MICS-HVDC-CB was tested upon a real transmission line using ATP simulation software. The results emphasize that the developed MICS-HVDC-CB decreased the arcing time to 38.5% and 20% compared to passive and active DC-CBs. The impact of cooling power, arcing time constant, and fault resistance was also investigated. The results showed the effectiveness of the proposed MICS topology in reducing the arcing time while keeping a simple and economic breaker structure.