Operation & maintenance |


Excitation upgrades boost reliability and extend life


Recent EES (Excitation & Engineering Services Ltd) upgrade projects, one at a combined cycle power plant, the other at a 90 year old hydro power unit, demonstrate the benefits of replacing legacy excitation technology


EES engineers test newly installed combined cycle power plant excitation equipment.


Among recent contracts secured by Excitation & Engineering Services Ltd (EES) is that to replace static excitation systems at a combined cycle power station in Hull, UK. The scope includes power system stabilisation (PSS) and grid compliance upgrades. The project is scheduled to run until 2028/29 and will see upgrade of excitation infrastructure on two 400 MW gas turbine units. EES will design, manufacture, install and commission new static excitation systems rated at 2800 A with 5756 A forcing. The project entails detailed grid compliance modelling to meet stringent NESO PSS requirements. The upgrade must integrate with existing cabling and busbar arrangements, while complex installation logistics require large cubicles to be split for transport and assembly.


The project was triggered by the site’s legacy excitation system becoming obsolete and the withdrawal of OEM support. The decision to replace followed reliability issues with the legacy excitation assets, increasing failure rates, limited


Carsfad hydro plant, consisting of two 7.5 MVA (6 MW with 0.8pf) vertical shaft synchronous generating units. Originally equipped with a shaft-mounted DC exciter


18 | July/August 2026 | www.modernpowersystems.com


All photos and diagrams: EES


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