GE Plant GCP PLC obsolescence and reliability concern due to absence of crossover scheme for SFC’s
In times of production bubble, complex engineering is opted to have best cost for auxiliaries
The GE 6FA gas turbine, renowned for its exceptional efficiency, has been a popular choice for many customers. Units sold over a decade ago often featured Andritz Hydro-supplied GCP and AVR systems. These units were typically equipped with Converteam or Ansaldo SFC controllers.
The majority of GCPs were manufactured by Andritz Hydro and included Thyne 1 or Thyne 4 AVRs, DRS protection relays, and VATECH/Siemens 1703 mic PLCs. An HMI managed displays for digital inputs, outputs, analog inputs, outputs, and alarms. Communication between these components was facilitated through Modbus or Ethernet.
While AVR and protection relays remain in production, certain boards may require refurbishment by the OEM. However, the VA TECH/Siemens PLC is obsolete. Customers should consider upgrading their PLCs to the latest models, which are still in the early stages of their product life cycle.
Current GE 6FA Units uses
- Mark VI or MVIe turbine control panel
- Siemens PLC and HMI for Andritz Hydro GCP
- Andritz Hydro AVR- Thyne 1 or Thyne 4
- Ansaldo or Converteam SFC
Streamlining the engineering process
While it might seem unusual to have four or five OEMs involved in the electrical system of a gas turbine, this approach often results in optimized design and cost during the manufacturing stage. Continuing with the same design choices during upgrades or reliability improvements can lead to suboptimal results.
Crossover scheme missed
A significant challenge faced by some of these plants is the lack of a crossover scheme for SFCs. While they can start a gas turbine with a single SFC, there’s no redundancy in place. This means that a failure in one SFC can jeopardize the availability of the gas turbine. Even if a second SFC is operational, there may not be a facility to start multiple GTGs with a single SFC.
This lack of redundancy increases the risk of unavailability. Many customers may have avoided implementing a crossover scheme due to the high associated costs.
Solutions are not that difficult if customers are open for integrated solutions
A thorough review of design and engineering solutions can significantly reduce upgrade costs. By leveraging existing controls or planned upgrades, it’s often possible to implement an SFC crossover scheme without incurring substantial additional expenses. The primary cost would be for the transfer switch and interconnecting cables. Considering that control and engineering costs can account for nearly 50% of a project’s total expenditure, engaging consultants like Arjavin Power Techno Solution can lead to substantial savings. Our expertise extends to GE, Andritz, Siemens, and Ansaldo equipment, as well as PLCs from other manufacturers like GE Fanuc, Schneider Electric, and Allen Bradley. As an added benefit, implementing a crossover scheme can also enhance system reliability.