Santee Cooper Enhances Winyah Generating Station with GE’s Advanced Mark VIe Digital Control System

Located between Myrtle Beach and Charleston, South Carolina’s state‑owned utility, Santee Cooper, is upgrading the Winyah Generating Station’s turbine control system with GE Energy’s Mark VIe Triple‑Modular Redundant (TMR) digital platform.

As South Carolina’s largest power provider, Santee Cooper serves more than 165,000 residential and commercial customers in Berkeley, Georgetown and Horry counties, while also delivering wholesale power to all 46 counties in the state.

Winyah was the utility’s most ambitious project at the time of construction. Units 3 and 4 were the first in the Southeast to feature 'scrubbers,' devices that significantly reduce emissions.

This spring, the existing Westinghouse EHC control system on Unit 4’s steam‑turbine generator will be migrated to a GE Mark VIe TMR control system – the first time a Mark VIe replaces an existing Westinghouse system at Winyah. GE has already modernized other Santee Cooper assets, including the June 9, 2010 replacement of a Mark II with a Mark VI at Cross Station.

The Mark VIe TMR is a custom‑programmed, expandable digital control platform. It will be mounted and pre‑wired in new cabinetry before installation, and it offers modules that interface with virtually every sensor type on the market today.

Modernizing the control system extends Winyah’s operational life, improves equipment reliability, and cuts downtime and maintenance costs. The upgrade also gives Santee Cooper the ability to integrate modern instrumentation and achieve more precise, robust turbine control.

The scope of the Westinghouse conversion includes a Mark VIe TMR cabinet, two HMIs, four network switches, a primary emergency overspeed kit, a Watt/VAR transducer, factory acceptance testing, on‑site training, and technical direction.

Benefits of the Mark VIe TMR digital control:

• Reduced maintenance, costs, and downtime
• Increased mean time between failures (MTBF)
• Real‑time diagnostics with modern maintenance tools
• Remote monitoring capability to reduce manual oversight