signal for mutation

WANG Bin，HUANG Xu，FANG Yin，YU Yi-jin，WANG Liang

（Hangzhou Steam Turbine Co.，Ltd.，Hangzhou 310022，China）

Abstract：Aiming at the Petrochemical Industries Co GB201 compressor unit，the shaft displacement and shaft vibration signal of the turbine side appeared mutation phenomenon，the grounding brush for steam turbine，the BENTLY 3500 grounding system and the static electricity causes were researched. The unit could not be stopped，only to analyse related factors which could lead to malfunction.Exclude factors could be excluded，the steam turbine grounding brush was inspected and replaced on-line，the BENTLY 3500 grounding system was inspected and the influence of rotor electric or magnetic was analysised. Finally，it was determined that the static electricity from the

lube oil by high speed rotor and bearing extrusion friction，and the bearing house was too larger to the joint of the TSI probe in the bearing house，the joint was soaked in the lube oil which temperature is 50° for a long time，the insulation may become worse，the electrostatic was accumulated to the joint，resulted electric charge accumulation and mutation phenomenon.After the unit was overhaul， the bearing house was opend and inspected，the prode joints were isolated afresh，when the unit was running again it was back to normal.

The results indicate that the signal mutation is because of the static electricity from the lube oil by high speed rotor and bearing extrusion friction and the insulation of the TSI probe's joint is failure.

Key words：TSI；eddy current sensor；signal mutation；single point grounding；grounding brush