Myuna Colliery is an underground coal mine located in Wangi Wangi, Lake Macquarie in the Newcastle NSW Coalfields. The mine is operated by Centennial Coal. PowerEarth has held a working relationship with Myuna Colliery for over 15 years. PowerEarth performs all High Voltage (HV) protection and substation earthing engineering for the site.
In 2017, energy provider Ausgrid advised Myuna of the need to perform 11kV circuit breaker maintenance in the Colliery’s supply substation. This included the replacement of protection CTs.
To reduce supply outages to the site, it was proposed that this maintenance should occur in two stages, with one half of the switchboard per stage.
To achieve this, some supplies would need to share a circuit breaker. Thus, cable loadings required confirmation and temporary protection settings.
For the connected site power system under the stage 1 and stage 2 maintenance arrangements, PowerEarth performed:
- Load monitoring studies on the proposed changed loads, evaluating equipment diversity and power usage
- Evaluating the current-carrying capacities of the affected HV feeder cables against overloading. For one specific loaded feeder, this included the consideration of different ambient temperatures and load cycles, advising of the limits required under extreme conditions
- Simulated over-current faults throughout the site power system network
- Provided and confirmed temporary protection settings for the affected 11kV and LV protection equipment
- Confirmed the final protection settings for the switchboard after maintenance.
PowerEarth collaborated with Myuna Colliery and Ausgrid to ensure the necessary settings were completed within the timeframes required for the various maintenance steps to occur.
Myuna Colliery was able to minimise downtime and maximise production. They were confident their system remained protected during and after the maintenance program.
Myuna and PowerEarth continue the working relationship up to today, and into the future. Enquire today to see how PowerEarth can perform HV protection or substation earthing for your worksite.