Improved transient performance of GE’s Jenbacher type 6 gas engines

The increasing requirements on transient operation for power generation engines both in grid parallel and isolated operation mode pose a challenge for the development of large gas engines. The stability and reliability of small, isolated grids are determined by the non-stationary capabilities of the power suppliers, which are required to increase or reduce the load within a short period of time.Several limiting factors need to be addressed for improving the transient capabilities of a large premixed gas engine with a pre-chamber combustion concept. Genset inertia, combustion stability limits, turbocharger inertia and surge limit, mixture preparation concept, control strategy and engine safe operation limits are some of the aspects to be considered when improving and extending the engine dynamic response.Based on combining detailed system analysis, simulations and engine tests several hardware and software measures were derived and implemented for GE’s Jenbacher Type 6 engines. A fast detection and a feed-forward control strategy (actuators, ignition time, gas dosage, etc.), together with hardware modifications on the mixture preparation and pre-chamber systems enable the engine to reject up to 100% load (both in grid parallel mode and isolated operation) immediately with a frequency deviation lower than 12% and a recovery time of less than 10 seconds.The new features provide grid stability and high flexibility, which results in a reliable and responsive power supply system for the customer; preparing the GE’s Jenbacher Type 6 engine for future requirements both in grid parallel and isolated operation modes.