In situ control panel upgrades at hydro scheme

Refurbishment and upgrade of control panels and associated equipment on four Biwater Francis turbines

Project overview

The client had been experiencing declining reliability of these schemes for some time. This was due to a number of factors including questionable original design choices, inadequate condition monitoring, minimal alarm reporting, and aging components. Dulas was initially requested to assist with the integration of new G59 relays under the Accelerated Loss of Mains Programme, however whilst undertaking this work it soon became apparent that there were many other issues with the control systems and that there was significant scope to improve the operation of the schemes.

It was agreed that Dulas would design and install a comprehensive program of upgrades to improve availability and generation. The scope of these works included:

Background

Dulas has provided O&M services to the client for a number of years across a fleet of turbines totaling more than 16MW of installed capacity, and is increasingly requested to propose upgrades and improvements to these schemes

The challenge

The first step was to reverse engineer the existing systems as little documentation was available, and to assess which components could reasonably be re-used, and which were end-of life and would need replacement. Historically, the schemes were not capable of shutting down gracefully when non-critical alarms occurred, nor were they inherently fail-safe in the event of a failure of the normal control systems. It was the client’s wish that we should not replace the existing PLCs, so although the code was to be upgraded, this needed to work within the existing hardware.

Our solution

Building on Dulas’ extensive experience of hydro turbine controls design, a package of works was undertaken for each scheme which included:

Impact

The Schemes’ turbines total 3.5MW of installed capacity. Therefore, when running, they produce a large amount of renewable energy, offsetting carbon and contributing a sizable revenue stream for the client as well as helping to meet the net zero targets of the organisation.