System for determining target misalignment in turbine shaft and related method

A method comprising:

• determining a first primary displacement between a first horizontal probe and at least one first target on a shaft, the at least one first target located proximate a first end of the shaft;
• determining a second primary displacement between a first axial probe and the at least one first target;
• calculating a first gradient of the at least one first target based on the first primary displacement and the second primary displacement;
• monitoring axial movement of the shaft via an end probe;
• and
• determining an amount of false twisting of the shaft at load condition based on:
• a difference between the first gradient and a calculated second gradient;
• and
• the axial movement of the shaft.

A turbine comprising:

• a stator;
• a working fluid passage substantially surrounded by the stator;
• and
• a shaft configured radially inboard of the stator and in the working fluid passage;
• and
• a target monitoring system communicatively connected to the shaft and configured to monitor displacement of the shaft during operation of the turbine, the target monitoring system including:
• a first horizontal probe located radially outboard of the shaft and communicatively connected to at least one first horizontal target connected to the shaft, the at least one first horizontal target disposed proximate a first end of the shaft;
• a first axial probe located axially adjacent to the first horizontal probe and communicatively connected to the at least one first horizontal target;
• a second horizontal probe located radially outboard of the shaft communicatively connected to at least one second horizontal target connected to the shaft, the at least one second horizontal target disposed proximate a second end of the shaft;
• a second axial probe located axially adjacent to the second horizontal probe and communicatively connected to the at least one second horizontal target;
• an end probe disposed proximate the first end of the shaft, the end probe configured to monitor axial movement of the shaft;
• and
• a computing device communicatively connected to the end probe and each of the first horizontal probe, the first axial probe, the second horizontal probe and the second axial probe,
• wherein the computing device is configured to:
• determine a first gradient for the at least one first horizontal target based on a displacement between the first horizontal probe and the at least one first horizontal target and the first axial probe and the at least one first horizontal target;
• and
• determine a second gradient for the at least one second horizontal target based on a displacement between the second horizontal probe and the at least one second horizontal target and the second axial probe and the at least one second horizontal target.