UK: New Electrical Power Conversion System to Be Installed on HMS Vengeance

 A new alternative system to traditional motor generators for electrical power conversion is to be installed on HMS Vengeance during the current Long Overhaul Period and Refuel (LOP(R)) being undertaken by Babcock, in a first-of-class project that follows some four years of development and planning. The decision to undertake this first embodiment on Vengeance was taken by the MoD In-Service Submarines (ISM) team in late November 2012, and installation commenced this month (January).

The project is part of a programme to install Main Static Converters (MSCs) to replace the motor generators (MGs), an essential part of the onboard electrical power system, on all four Vanguard class submarines. The MGs have a high maintenance requirement (being subject to wear-related issues and performance degradation during operation) that can impact on submarine availability. The MSCs provide a fixed, solid state power electronics alternative that avoids the need for rotating machinery, with huge advantages over MGs, being significantly more reliable and with considerably reduced through-life maintenance requirements. Replacing the MGs with the MSCs will improve submarine availability to perform the at-sea deterrence role.

The MSC suites being installed, developed for the Vanguard class, are a derivative of the system originally designed for the new Astute Class submarines. Babcock and the MoD’s ISM team have been working together on this since January 2009, and the development programme has been taken forward by a joint project team involving the MoD, Babcock and Ultra Electronics PMES (the MSC Original Equipment Manufacturer and Equipment Design Authority), to enable integration of a new piece of equipment into an existing platform, while minimising time and cost consequences and optimising through life management. Among the challenges has been the need for the Vanguard class MSC solution to meet the higher power demands associated with ballistic nuclear submarines, while being smaller in size than the Astute class version in order to fit within the available compartment space.

As part of the development programme, electrical, constructive and mechanical integration requirements have been identified and addressed. Babcock undertook detailed assessments of the auxiliary machinery spaces on all Vanguard class submarines using a laser scanning technique which enabled a detailed 3D CAD model to be created for the mechanical and constructive designs. Size and available space have been key issues, both from the point of view of positioning and installation within the compartment and shipping routes into the submarine. Other considerations have included electrical integration, and integration into the current control systems, as well as determining the best method to shock mount the new suites, and minimising changes to the existing cooling water system. These were in addition to establishing the optimum installation routes and processes, as well as final equipment design and development of a prototype.

Manufacture of the MSCs for HMS Vengeance commenced in November 2011, and Factory Acceptance Testing was completed by Ultra in December 2012, successfully demonstrating that all functional requirements are achieved, with the results endorsed by the MoD ISM DA Power team. Significant planning has also been undertaken by the HMS Vengeance team and MSC JPT to demonstrate that the MSCs can be successfully integrated into the overall LOP(R) programme. Meanwhile, in preparation for installation, Babcock has purchased all supporting materials and undertaken trials and proving of all supporting equipment that will be required.

Installation on HMS Vengeance has now begun, with the cutting through of the main structure of the MG bedplates this month and the electrical package already underway. Installation of both MSC suites (six identical cubicles) will be complete by autumn 2013 and will then be followed by setting to work and commissioning over the following 12 months.

Babcock Submarines Managing Director Mike Homer said:

“Seeing this project starting to come to fruition with the first-of-class installation after a number of years’ development work is a significant milestone. The close working and collaboration between the MoD, Babcock and the OEM Ultra has been key to the successful development of the equipment and correct integration into the submarine, with knowledge sharing and an open and goal-focused relationship having considerably reduced the development timescales. Similarly, close working between the MSC joint project team, the Vengeance LOP(R) team and key build experiences on Astute Class from BAE Systems have also been vital to this first installation on Vengeance, helping to ensure successful integration of the MSC suites while minimising programme risk.”

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Naval Today Staff, January 29, 2013; Image: Royal Navy