The RTS GATE-2 inspection is a more thorough inspection of the generator and requires the generator to be disassembled and rotor removed. This test is frequently performed in conjunction with a turbine major to ensure completion during the outage window. Besides the GATE-2 testing, RTS can also perform the generator disassembly and reassembly. The following testing will be performed as base inspection scope during GATE-2 generator testing.
Inspections/Tests Performed
Borescope inspection of stator winding, rotor winding and blocking (as accessible), stator core step laminations and fingerplates
Insulation resistance of RTD’s, stator winding, and rotor winding
Stator Winding Test – Polarization Index (PI), Resistance, DC step voltage test. ELCID, Wedge map
Rotor Winding Test – Polarization Index, Resistance, AC Impedance, RSO
Exciter Inspection
Visual inspection
Insulation resistance tests
Final Report
Standardized format provided electronically (cd or electronic mail)
Photographs of critical areas in the stator winding, core, and rotor.
Dielectric absorption graph and analysis of insulation integrity
Summary of all insulation and winding resistance measurements taken.
Any anomalies reported immediately with the Final Report submitted within 10 days of inspection
Benefits
Reveals pending faults in winding of the rotor and stator
Reveals deterioration of coil insulation caused by corona or end winding
Reveals possible shorted core laminations
Reveals loose slot support system
Establishes a “base line” for evaluating future inspections and input for establishing planned major maintenance activities
Option – Electrical Isolation
RTS can also provide an estimate for the neutral and main leads disconnection prior to electrical testing and reconnect upon completion of testing.
