MAS S.A. recently completed the upgrade of the generator and step-up transformer protection system of the Thomassen gas turbine at Soroni Power Station in Rhodes, enhancing protection reliability, operational visibility and lifecycle performance.
The project involved the replacement of the legacy protection system of the Thomassen gas turbine with modern protection equipment, supported by new automation and monitoring capabilities.
Due to the age of the existing installation, the project required detailed engineering assessment, precise execution and close coordination with plant personnel. The upgrade was implemented as a brownfield project, ensuring safe integration with the existing infrastructure and reliable operation of the generating asset.
The upgrade included the complete removal of the legacy protection system, full rewiring and installation of modern protection equipment, including:
- SEG MCDGV4 – Generator Protection Relay
- SEG MRDT4 – Step-Up Transformer Differential Protection
- SEG MRR1 – Generator Rotor Protection
- DEIF FAS115-DG – Synchronizer
MAS also integrated a Siemens S7-1200 PLC and Siemens KTP400 HMI to enable communication with the generator protection relay and support real-time temperature monitoring.
Comprehensive Site Acceptance Testing (SAT) was carried out with the unit in operation, verifying the correct functionality and performance of the upgraded protection system.
The project included full verification of critical protection functions, including:
- Generator Differential and Generator–Transformer Block Differential protection
- Overvoltage, overcurrent and negative sequence protection
- Loss of excitation and reverse power protection
- Breaker failure, rotor earth fault and synchronism check functions
- Successful black start of the unit
Through structured testing and validation, MAS ensured that the upgraded system met the operational and protection requirements of the installation.
The successful completion of the upgrade restored protection reliability, improved operational transparency and extended the lifecycle of a critical generating asset.
The project demonstrates MAS’ capability to deliver structured brownfield modernisation solutions for power generation assets, combining electrical protection expertise, automation integration and field-proven project execution.
Brownfield Protection Upgrade for Critical Power Assets
Aging protection systems can limit reliability, visibility and maintainability in power generation installations. MAS delivers structured protection upgrades that integrate modern relay technologies, automation systems and validated testing procedures, supporting safer and more reliable operation of critical generating assets.
