New Assembly Techniques for Repair and Redesign of Station Disconnecting Switches

摘要

Hydra-Quebec is currently upgrading its disconnecting switches, mainly by replacing the electrical contact terminals affected by degradation. Major technical improvements to the metallurgical nature of the materials, their interface and the assembly method have been already been made to this equipment and, in addition, the replacement parts have been redesigned. The ultimate objective was to achieve the best possible resistance to mechanical and electrical stress. Assembly techniques were developed to join thick silver plate to massive copper and aluminium substrates. Mechanical tests performed on Ag-Cu and Ag-Al indicated that joining interfaces behave very well. Their electrical conductivity was considerably improved as well as their wear resistance. Assemblies passed successfully wear resistance tests and electrical tests at equivalent nominal and short-circuit current. The prototype of the generating station disconnecting switches successfully passed all the certification tests. Subsequently, three phases of a disconnecting switch were built and installed at a generating station and subjected to tests designed in terms of the operator's requirements. At the substation level, three prototype models have also passed all the certification tests and the research team will now focus its efforts on the following aspects in situ repair of the three disconnecting switch models already studied, repairs to other models, and improvement of the rotating terminals. For the time being, work continues on exploring other assembly technologies which could also be used to refurbish the disconnecting switches at both substations and generating stations.