In addition to a number of successful
installations at power plants in
China, Sensonics, working with local
agent AKA Vietnam, has supplied
transducers and a Sentry G3 turbine
monitoring / protection system for
the 110MW Russian built turbine
operating at the PhaLai Power Plant
in Vietnam.

The retrofit project was fairly
complex and included a number of
measurement modes that the Sentry
G3 system was required to monitor.

For example, shaft position
measurement and protection, where
the relative position of the turbine
shaft is monitored within the bearings.

The system automatically shuts down
the turbine if the relative position
moves outside a pre-set window. For
the 110MW machine, this occurs if
the shaft moves towards the generator
side by more than 1.2mm or towards
the turbine side by more than
1.7mm.

Measurement was implemented
on the turbine using proximity
sensors mounted opposite a collar
machined as part of the shaft. A
similar technique was used for the
high pressure and LP low pressure
cylinder expansion channels.