Revitalising Power Generation: Transforming a 46-Year-Old Induction Generator into a Modern Powerhouse

Originally designed in 1977 as an 11 kV, 7 MW induction generator for Foster Wheeler, the generator operated in conjunction with a Power Recovery Train (PRT). This PRT system, consisting of a steam turbine, blower, and an expander, recovered some of the waste energy used to drive the generator. This PRT configuration continued until 1991 when a critical need arose to supply reactive power during grid outages.

To address the system’s insufficient reactive capacity and mitigate the impact of grid outages,  the solution required significant modification. The existing induction generator underwent a conversion process to enable synchronous operation. While the conversion was successful, and the generator continued to operate reliably for an impressive 33 years, it did suffer from operational drawbacks. For instance, high operating temperatures, vibrations, and bearing issues caused the generator’s output capacity to be reduced throughout its lifespan.

In 2023, recognising our expertise in high-voltage motor and generator capabilities, TDC Parsons Peebles was approached to provide a new generator. The goal was to replace the ageing generator with an interchangeable drop-in replacement. This new machine would address the inherited problems, offer increased performance (11 kV, 7.5 MW, 8333 kVA), and seamlessly integrate with the existing infrastructure. This included ensuring compatibility with the existing cabling, pipework, foundations and excitation system.

This project presented TDC Parsons Peebles with a unique opportunity to showcase our design and manufacturing capabilities. Leveraging our extensive experience in both new generator design and refurbishment, our engineering team completed a comprehensive design review. This review led to the redesign of the stator and rotor windings, an improved ventilation circuit, a redesigned shaft, base plate, and the incorporation of a new bearing design. These changes significantly improved the generator performance, reducing the operating temperature from over 158°C to 86°C, and full load vibration from 6.0mm/s to 1.3 mm/s (rms).

The new, like-for-like replacement generator provides increased output capacity and efficiency while minimising downtime and disruption during installation.

This is just one example of how TDC Parsons Peebles can provide tailored comprehensive solutions for critical industrial and power generation needs.