Predictive maintenance for power plant operations is vital. Power plants must shut down at least once a year to check for damage to boilers and conduct other maintenance inspections – a time consuming, dangerous, and sometimes imprecise process. Robotic systems enable faster generator inspections without removing rotors from machines. To automate this, GE developed remote, robotic inspection tools, first deployed in April 2016, to inspect Alinta Energy’s gas-fired power plants in Australia and New Zealand. The project was developed through GE’s Alstom power generation business, which it acquired in November 2015. GE’s legacy Alstom business has been developing robots for generator inspection since the 1980s.
DIRIS and TurboRotoscan inspection systems
Developed by the Alstom power generation business, which GE purchased last year, GE’s Diagnostic Inspection Rotor In-Situ (DIRIS) and TurboRotoscan inspection systems will alert Alinta Energy engineers to potential generator issues and give them time to evaluate their options. Under the terms of the inspection agreement, GE will inspect 19 generators manufactured by GE, Alstom, Mitsubishi, and Brush, at seven of Alinta Energy’s gas-fired power plants in Australia and New Zealand. The DIRIS robot will provide Alinta Energy with modern robotic instrumentation and tooling to allow fast and reliable remote inspection of the turbogenerators. The DIRIS robot performs critical tests of the generator stator iron core laminations and stator radial wedging system by conducting a visual (video) inspection of the inside surfaces of the rotor and stator. These tests would normally be part of an overhaul regime after removing the rotor using manual semi-automated tooling. A low-flux test permits the identification of short circuits between the stator iron core laminations which could otherwise develop into critical hot spots severely damaging the generator. A tightness test of the radial wedging system permits identifying loose wedges that could otherwise promote movement of the stator bars and damage to the stator winding insulation system.