Iwrch Hydro Scheme Refurbishment

Fault finding and re-commissioning of an existing hydro plant

The original developers of this scheme expected to produce 380kW. However, it was never fully commissioned and only ran for 7 hours before being shut down to prevent serious damage to the equipment. Dulas were contracted to investigate and implement the remedial actions required to ensure the scheme could run. During this process Dulas Hydro Generation Ltd acquired the scheme. Dulas now provides Operation and Maintenance services.

Iwrch Hydro Scheme
Hydro for utility company

Site Specific Issues

The existing plant suffered from various issues, rectified as follows:

The original intake was poorly designed, became blocked several times a day and could not be easily or safely cleaned. Dulas completely rebuilt the intake to allow installation of AquaShear Coanda screens. The new intake requires minimal cleaning and has significantly improved plant availability.

Deformed casing due to a mis-aligned turbine, generator and draft tube, and omission of a pipeline anchor block with resultant pipeline thrust forces acting on the turbine casing. Dulas stripped down the turbine, cut and rewelded the draft tube, re-aligned the turbine and generator, and restrained the inlet pipework.

Faulty wiring on the AVR and ventilation system was replaced.

Non-functioning PLC software was completely re-written and a SCADA System added to enable remote monitoring.


The scheme is now operating fully automatically, free of electro-mechanical and screen blockage problems, generating around 1000MWh/yr.

Technical Overview

  • Power output: 275kW
  • Intake screens: Type C – Coanda
  • Turbine: Ganz Francis
  • Generator: Newage synchronous
  • Control panel: Dulas

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