Largest Transmission MW for a converter Station HVDC-VSC a ±320 kVdc

[cuky2000]

We are in search of the largest bipolar HVDC system based in VSC technology to support a transmission capacity targeting around 1400 MW at ±320 kVdc using submarine and UG land cable including a neutral grounded metallic return.
[ul]
[li]Does anyone know what is the largest converter station available based on VSC technology?[/li]
[li]Does the converter station require a large grounding electrode near the converter station even if the metallic grounded return will be used with a permanent connection to the earthing grid?[/li]
[/ul]

 

[prc]

In India we just commissioined such a line(Pugalur_Trichur HV DC line) This is a 200 Km (out of which 32 KM cable) executed by Siemens_Sumitomo. Sumitomo supplied cable. This first in India, VSC enabled line at +-320 kV DC Transmits 2000 MW in two parallel converters to my native state.
Regarding grounding you may contact Siemens directly. ABB,Siemens and GE will be glad to furnish all details.

 

[cuky2000]

Thanks prc.

HVDC technology is developing faster than the information available. We are discussing with manufacturers, but unfortunately, they have difficulty to disclosure advances in the R&D group.

Although the US has in operation several HVDC, other countries have installed more advances in HVDC technology in recent years. I am wondering if outside the US there someone can offer better information for a single HVDC VSC converter station rated for >1,000 MW.

 

[FacEngrPE]

I suspect that the HVDC market is a small, but the projects are all high value.

https://en.wikipedia.org/wiki/List_of_HVDC_projects,

has a listing of worldwide projects. A small set of suppliers seem to be supplying all of the terminals. It looks like a case of choosing which supplier you prefer to work with.
The main suppliers trading in the US apear to be:
ABB might in partnership trading as - Hitachi ABB Power Grids
Alston Power was purchased by GE in 2015
Siemens is still Siemens.

VSC converters can not use thyrister valves, so they will have some sort of transistor valves. In the Wikipedia project list their are some recent projects using transistors (IGBT) in the 1000MW range, and some in construction in the 3000MW range.

The constraint on the grounding grid seem to derive from the usual approach of having a bipolar transmission line with both poles having approximately identical current flow. If one pole is off line the return is usually via an earth return. Earth resistance is likely lower then the metallic path, but enhanced anodic corrosion is likely within several miles of the grounding grid.

The terminal converter systems may need a tie to a ground reference to make the valve controls work correctly.

This looks like a fun project.

Fred

Fred

 

[fpalone]

Given the present limit of 3kA for IGBTs, the maximum theoretical rating for a single +/- 320 kV converter is 1920 MW.
3 kA power modules have been already certified by some manufacturers:

https://www.rxhk.co.uk/corporate/news/800kv-5gw-vsc-hvdc-valve/?ccm_paging_p_b236=4

however, they have been used for higher voltages, as it is more common to use an higher dc voltage for HVDC scheme exceeding 1 GW.

 

[prc]

[tt][/tt]The following documents will help in understanding HV DC transmission by VSC

1)IEC TR62543 ed1.2-2017 Performance of HV DC transmission by VSC
2)IEC 62747 ed1.0-2014 -Terminology for VSC for HV DC systems
3)CIGRE Brochure TB 492-2012 -VSC HV DC for Power Transmission
4)CIGRE TB 684-2017 Recommended voltages for HV DC Grids