Page 22: of Offshore Engineer Magazine (Aug/Sep 2016)

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SUBSEA FACTORY

Small and smart

Photo from Nebb Engineering.

The 45kW subsea variable speed drive.

Nebb’s 45kW, 400V VSD was in part developed for a project with Kongsberg Oil & Gas and Fuglesangs, to develop an ac- tive subsea cooler, to cool production ? uid for export or com- pression, and which could be controlled to prevent hydrate formation. This project was due to complete full quali? cation this summer. The system comprises a heat exchanger, a pump, from Fuglesangs, which incorporates an oil-? lled motor isolated from the pump by a magnetic couple, and a control system, all for use up to 3000m water depth.

Nebb’s part of the project was developing the control system and communications including the 45kW subsea VSD, which is contained in a 1053mm high, 356mm-diameter canister.

This system could have been used on Shell’s Ormen Lange

Power requirements are not always project, until it was put on hold in 2014.

A 20-45kW VSD could also be used to power medium huge, nor are companies – and sized pumps. Meanwhile 300-1500kW VSDs, could be used sometimes smaller can be better. for electrical submersible pumps (ESPs), water injection or condensate pumps. This size VSD Nebb hopes to have ready in

Elaine Maslin reports on work to 2017. The 4kW VSD, due to be quali? ed this year, contained in qualify lower power subsea variable a 450mm-high, 210mm diameter canister, could be for use on small pumps (for grease, hydraulics etc.) and valve operation speed drives.

(from remotely operated vehicles). They could also be used in brown? eld applications by incorporating a battery pack, that

Nebb also has in development. orway’s Nebb has its eye on a market the larger “This is an enabler for all electric players are overlooking – subsea variable speed subsea control,” says Alexander Risøy,

N drives (VSD) for power users requiring smaller managing director at Nebb Engineering.

amounts of power than the likes of compressors. One of the main challenges is to get rid

To date, subsea VSDs, used to regulate the speed and ro- of the heat, he says. “On a 45kW VSD you tational force of an electric motor, have only been deployed need to get rid of 1.5kW heat and keep it once, in a pilot at Shell’s Nyhamna plant in Norway. These below 35°C to extend the life time.” This is were designed for the large Ormen Lange subsea compression Nebb’s secret and they’re not willing to say

Alexander Risøy system, which Shell put on hold in 2014. how they do it. “It is dif? cult, but possible

Yet now, Nebb Engineering, based in Asker, near Oslo, has to do,” says Wolfgang Trötscher, chief engineer. “It is even more quali? ed a 45kW subsea VSD, for operations down to 3000m, and dif? cult with 500kW unit, which produces 5kW heat.” is now working on VSDs for the 4kW and 350-1500kW ranges.

Nebb’s goal is a 1MW VSD, for which there would be a

While 45kW VSDs wouldn’t be quite big enough for the likes larger market than say a 500kW VSD. For this, the ? rm will be of a subsea compression project, they could be used to power ac- looking to work with oil majors. tuators or small pumps. Using electric power transmission, in-

The company was founded in 1996, and has about 40 staff, stead of hydraulic, for subsea power users, removes the need for with an of? ce in Macedonia. It also provides automation con- hydraulic power units and topside VSDs, in cases where electric trol and safety systems, SCADA and information management, power is supplied direct from the topside to sea? oor users.

as well as subsea control modules.

August 2016 | OE oedigital.com 24 024_OE0816_Feat1a_Nebb.indd 24 7/23/16 11:45 AM