Electronic overspeed protection systems to replace old analogue electronic or mechanical devices. Systems can be SIL 3 according to IEC 61508.
Mechanical and older analogue overspeed trip systems are prone to:
- Drift of the setpoint resulting in inconsistent operation.
- The turbine has to run in order to test them.
- Hard to maintain and scarcity of spares.
Microprocessor based overspeed systems offer the following advantages:
- Can be tested whilst the turbine is shutdown.
- Operating setpoint is constant.
- Improved diagnostics.
The scope of supply may include:
- Panel mounted monitor with test signal injector.
- Magnetic or eddy current type speed probes.
- Signal cabling.
- Installation design.
- Setup and testing of the complete system.