Hitachi Energy Ltd

Hitachi Energy Switzerland Ag

Mats Andersson

Ying Jiang-Häfner

Lise Donzel

XiaoBo Yang

ChunMing Yuan

Dawei Yao

Gaurav-Kumar Kasal

Saurav Roy-Choudhury

Morteza Mohammadi

Neil-QiNan Li

The present disclosure relates to a high voltage bypass device, comprising a cavity, a trigger element arranged in the cavity, a reservoir filled with a conductive, flowable material, and a shutter separating the cavity and the reservoir. The trigger element is connected to a first terminal and a second terminal of the high voltage bypass device. The shutter is configured to open a passage between the cavity and the reservoir in case the trigger element is triggered by an overvoltage condition, such that the conductive, flowable material at least partially fills the cavity, thereby forming a conductive path from the first terminal to the second terminal. The present disclosure further relates to a voltage source converter (VSC), in particular a modular multi-cell converter, and an operating method for a high voltage bypass device.

High voltage bypass device, voltage source converter and operating method

A voltage source converter (VSC) system of a high-voltage direct current (HVDC) system is disclosed. The system includes a number of line-commutated converter (LCC) transformers. Each LCC transformer is operable to transform alternate current (AC) voltage. A number of VSC converter units are connected in series and coupled to the plurality of LCC transformers. Each VSC converter unit is operable to convert between the AC voltage and direct current (DC) voltage. A bypass breaker is connected in parallel with at least one of the VSC converter units and operable to be closed to bypass the at least one VSC converter unit.

UHVDC converter transformer re-usage for LCC to VSC upgrade

A first converter station is part of a high voltage direct current transmission system that includes a DC transmission link connected to the first converter station a second converter station. A DC current and a DC voltage of the DC transmission link are sensed by the first converter station. It is determined that the sensed DC current is equal to or larger than a threshold current value, that the sensed DC current is equal to or larger than the threshold current value, and that at least a partial recovery of the sensed DC voltage has occurred. On the basis that it is determined that the at least a partial recovery of the sensed DC voltage has occurred, it is determined that a phase-to-ground fault has occurred. In response to determining that a phase-to-ground fault has occurred, a power delivered by the first converter station can be reduced.

Communication less control technique for hybrid HVDC

Growing community of inventors

Beijing, China

Mats Andersson