If the line temperature falls by 20- 30 degree C due to some reason, the TT values start fluctuating drastically. Once power to the TT is recycled, its readings goes to normal. Please explain.
Check the body earth connection and earth leakage. Also, shield wire in the field side should be isolated( panel/jb side only connected). Also, check the damping time, the TT can be checked by RTD simulator.