Replacement of Generator and Gearbox

Description

Nordværk I/S - an environmental waste handling facility - is in need of a replacement of a generator and gearbox of the unit 4 at the WTE plant at Nordværk, Aalborg, Denmark. The generator of 23,5 MVA is driven by a steam turbine. The delivery will include a turn-key delivery of a new generator and gear box and auxiliary equipment. The steam turbine is not to be replaced. Lot 1: Nordværk I/S is an environmental waste handling facility. One of the methods of getting rid of waste, is a waste incinerator. For this purpose, Nordværk I/S has two lines. Furnace line 3 (unit 3) and furnace line 4 (unit 4). Furnace line 4 comprises a steam turbine connected through a planetary gear to a generator. The generator is a LDW from 2005 and has been in operation since then. In 2016, while the rotor was dismantled and sent to workshop for rewinding, a reversal of the star point was performed on the generator. In this operation, the terminals and the star point were moved to the other end of the generator. The reasoning behind the reversal was that the stator was starting to suffer from severe partial discharge. This operation had positive effects on the partial discharge level. The generator's partial discharge level has been monitored since April 2017. The level of partial discharge has now reached a level of intensity, where prolonged usage of the generator may cause economic consequences. I conjunction with the partial discharge, the generator's main terminal box is showing signs of heavy ozone contamination. This is visible on wires where some of the insulation is deteriorated and the metal in the main terminal box has layers of discoloration. To avoid a critical, undue breakdown a replacement of the generator is required. Further, the unit have a history of leakage current damages to the gear teeth, which have necessitated frequent and costly maintenance works to be carried out, and the rotating parts are getting closer to their end of life. On top of this, the future operating profile of the unit will differ from the original design basis. Thus, as part of the project of replacing the generator, the gear box must be replaced by a parallel shaft gear box. The delivery will include a turn-key delivery of a new generator and gear box and auxiliary equipment. It includes removal of the old equipment, design, engineering and installation of the new equipment including necessary changes to and reallocations of foundations and sup-porting structures and piping systems. It includes testing and commissioning, and the interoperability of the complete unit must be guaranteed. The delivery will include optional work as well. The optional work covers strategic spare parts and some back-up equipment and system set up.