This document focuses on recommended condition monitoring techniques for detecting and diagnosing developing machine faults associated with the most common potential failure modes for hydro unit components. It is intended to improve the reliability of implementing an effective condition monitoring approach for hydroelectric generating units (hydro units). It is also intended to help create a mutual understanding of the criteria for successful hydro unit condition monitoring and to foster cooperation between the various hydropower stakeholders.

This document is intended for end-users, contractors, consultants, service providers, machine manufacturers and instrument suppliers.

This document is machine-specific and is focused on the generator, shaft/bearing assembly, runner (and impeller for pumped storage applications), penstock (including the main inlet valve), spiral case and the upper draft tube of hydro units. It is primarily intended for medium to large sized hydro units with more than 50 MVA installed capacity, but it is equally valid for smaller units in many cases. It is applicable to various types of turbines such as Francis, Kaplan, Pelton, Bulb and other types. Generic auxiliary systems such as for lubrication and cooling are outside the scope, with the exception of some monitoring techniques that are related to condition monitoring of major systems covered by this document, such as oil analysis. Transmission systems, civil works and the foundation are outside the scope.

This document covers online (permanently installed) and portable instrument condition monitoring and diagnostic techniques for operational hydro units. Offline machine testing, i.e. that which is only done during shutdown, although very important, is not part of the scope of this document. Nor is one-time acceptance and performance testing within the scope. The condition monitoring techniques presented in this document cover a wide range of continuous and interval-based monitoring techniques under generalized conditions for a wide range of applications. Therefore, the actual monitoring approach required for a specific application can be different than that which is recommended in this generalized document.