Melbourne Water’s Eastern Treatment Plant high-voltage 22kV and 6.6kV switchgear is more than 30 years old. Although the equipment had been well maintained and remained serviceable, the electromechanical protection relays protecting the plant's electrical system needed to be replaced with modern numerical protection relays to extend the life of the existing switchgear.
Beca was commissioned as sub-consultant to Parsons Brinckerhoff to:
- select and specify new numerical protection relays;
- detail protection and control design to integrate the new relays into the existing 22kV and 6.6kV switchboards;
- develop protection schemes and protection settings for plant intake 22kV pilot wire protection scheme; unit protection schemes for 22kV and 6.6kV transformers, feeders; motors (Fixed and variable speed) and the bus zone and breaker fail protection schemes;
- design of SCADA/communications infrastructure to interconnect the numerical relays to the plant SCADA system.
The scope included construction and commissioning support, procurement of protection relays and components, upgrade of the switchgear battery systems and facilitation of the project HAZOP and Risk Assessment process.
A major challenge was implementing the new protection components within existing space-constrained protection cubicles with minimal physical impact on the existing switchgear.
Melbourne Water’s Eastern Treatment Plant now has a modern and reliable power system protection and control scheme, providing enhanced remote plant operation with recording and analysis of plant energy consumption and power system faults.