Electric Starter and Generator Systems (ESGS) for Gas Turbines: Making Platform Integration Easier

Abstract

The US Navy has pursued gas turbine electric start systems since 2003. Such a system has been extensively tested at the Naval Surface Warfare Center, Carderock Division (NSWCCD) Land Based Engineering Site (LBES) in Philadelphia, PA. It was demonstrated on a General Electric (GE) LM2500 main propulsion engine as well as a Rolls Royce (RR) MT30 engine. Presently, the system is being refined and repackaged to undergo U.S. Navy qualification for production use. Given the performance success of electric start the next logical step is to extend its application to other engine lines such as the Ship Service Gas Turbine Generators (SSGTG). In order to facilitate platform integration, the electric start concept has been evolved into the Electric Start and Generation System (ESGS). As expected, this system has the ability to start a gas turbine by purely electrical means. Once the engine has reached idle speed or above, the ESGS becomes a generator capable of producing power. This power may be harnessed to address dark start capability on Surface Combatants. The ESGS configuration simplifies integration of bulk energy storage such as a flywheel device or battery pack. This will ensure availability to the engine under a loss of platform power scenario thus providing self-sustainability to all the gas turbine’s electrical functions. Another alternative is to continuously provide ESGS generated power back to the electrical grid in continuous support of the engine auxiliary systems. In this case, flywheels and batteries may be replaced by advanced transfer switches that redirect power where it is needed on demand. This paper describes a program undertaken by NSWCCD to carry out land based testing of an advanced design ESGS. An overview of system requirements is given from a perspective of platform integration. The system architecture is fully described. It is an evolution of ESGS technology that has been extensively tested on RR MT30 and GE LM2500 gas turbines at NSWCCD LBES. Compared with existing air and alternative hydraulic gas turbine starter systems, this system is more compact and provides the benefits of simplified platform integration. It incorporates energy storage to provide black start capability for the gas turbine. Battery and inertial energy storage technologies are discussed in detail for use with the ESGS.