Rapidly and continuously changing technological processes in the turbines require reliable high-speed control systems with an emergency shutdown (ESD) function.

The Protection and Control System for Steam and Gas Turbines solution for steam turbines was developed as a system with redundant configuration, extended to cover maximum availability. The system can automatically control a steam turbine in standard and emergency modes (of generation unit and of the power system), while monitoring load, live-steam pressure, positions of the control valves, signals from control devices at power unit/station/system.

Range of turbines to be used with Protection and Control System for Steam and Gas Turbines varies from the small turbines for industrial applications to the large 800 MW and more powerful turbines. The solution can be used with the steam turbines for the power unit participation in primary and secondary frequency control.

The redundancy is implemented at the levels of PLC, control, measurement equipment. And the solution provides timely diagnostics of the individual systems and control circuits of the actuators.

Implementation of the solution with the use of REGUL R600 (R500) PLCs allows a flexible configuration, connection to a remote SCADA (with support of the most common vendors on the market). Hot-standby operation of the CPU units and hot-swappable modules allow for a stable and continuous operation of the system.

Major functions

  • Steam pressure control, with alignment to the power system frequency
  • Pressure control throttle (adjustment of live-steam pressure before the turbine)
  • Turbine protection against an inappropriate reduction in steam pressure
  • Sliding pressure operation (control mode with variable live-steam pressure)
  • Activation of the turbine’s control valves when the electrical load is dropped
  • Activation of the control and shutoff valves in case of increased frequency and acceleration
  • Turbine shutdown (via relay channel) without disconnecting the generator from the grid
  • Control of turbine rotation speed
  • Short- and long-term emergency load release of the power unit, with restoring load by the signals from emergency automation. By the conditions for dynamic and static stability
  • Deep system diagnostics

At the core of the Protection and Control System for Steam and Gas Turbines solution is DA 03 011 custom-designed counter/digital module with integrated software algorithms and frequency generator. Depending on the selected internal subprogram, it can:

  1. Measure frequency over three channels in two ranges (up to 10 and up to 500 kHz)
  2. Provide turbine overspeed protection, together with TMR electronic overspeed trip; verify protection state on a stopped turbine or during idling from a built-in generator
  3. Receive signals from an incremental encoder (control of the actuator position)
  4. Receive signals from flow meters and control calibration setting for flow meter calibration

System specifications

  • 100 % redundancy (including RTU modules)
  • Generation of control actions in 10 ms
  • Protection against issuing false control signals
  • Archiving in 10‑ms, 100‑ms, and 1‑s intervals
  • Implementation of hot-standby redundancy of control channels for 20 ms
  • Hot-swapping of the PLC modules
  • Heavy-duty operating conditions
  • Mean time between failures of at least 100,000 hours

Structural scheme of Protection and Control System