John Butters Power Station upgrade

Client: Hydro Tasmania
Location: Tasmania, Australia
Date: May 2008 – September 2009

Upgrading controls and protection at a hydropower station to ensure ongoing reliable, safe and effective electricity generation.

Background

John Butters Power Station, commissioned in 1992, houses a single Francis turbine coupled to a 160 MVA generator. The station output is fed to the transmission grid via a 13.8 kV/220 kV generator transformer and 220 kV outdoor switchgear.

The objective of this project was to upgrade the controls, protection, synchronising and SCADA systems at John Butters Power Station, to ensure its ongoing reliability and availability.

Solution

The scope of the project included replacing the synchroniser, electrical protection and SCADA, upgrading the main inlet valve controls, replacing the cooling water flow meters, upgrading the dam dewatering outlet controls and implementing a pressure pulsation protection system including high-speed data logger.

Entura designed the new machine protection, controls and SCADA systems, and undertook factory acceptance testing of all equipment prior to installation on site.

The upgrade embodied an electrical control system and a new hydraulic panel to improve control and monitoring of the turbine inlet valve. The turbine inlet valve controls had previously included a mechanical interlock system that had become unreliable and difficult to maintain.

The upgrades included a protection system which detects and performs control actions to mitigate any penstock pressure pulsation (penstock auto oscillation). This also included development of a high-speed data logger to detect and record any pressure pulsation events including pre and post event data.

In the construction stage Entura undertook site acceptance testing, pre-commissioning and commissioning of all new equipment.

Outcome

Entura designed, procured and commissioned the new controls, protection, synchronising and SCADA systems at John Butters Power Station. The original systems had become unreliable and difficult to maintain and these upgrades ensure the ongoing reliability and availability of the power station to provide reliable, safe and cost-effective power. The upgrade also included a protection system to reduce the risk to the power station from uncontrolled penstock pressure pulsations.

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