APA Group
Power Station Control System Upgrade and Engineering Services
- Mount Isa, Queensland
- Process Control Improvement
- Control System - Siemens T3000
Mipac has provided control systems and electrical engineering services to the Diamantina Power Station since 2014. During this period many varied projects have been taken from concept/scoping through design to commissioning, integration and support to develop the power station asset capability.
Site overview
Within the Gulf Country region of Queensland’s northwest lies the city of Mount Isa, and near it, APA’s Diamantina Power Station (DPS) – a modern, high-efficiency power station that services the power needs of Mount Isa and surrounds. As this region is not connected to the National Electricity Market (NEM) and relies on the Northwest Power System to power both industry and residences, this power station is an extremely important asset to the region.
Background
Mipac was first engaged by APA DPS in 2014 as an owner’s representative for the installation and commissioning of the power plant. We were involved in the preparation of an AVEVA PI Historian and assisting APA DPS to bridge the gap between the existing control system, delivered by Siemens, and what was required for the operation. Our engagement covered project management, engineering and procuring.
For close to a decade Mipac has continued to provide control systems and electrical engineering services to the DPS across several varied projects. These included concept/scoping, design, commissioning, integration and support services to develop the power station asset capability.
Lead Control System Engineering Services
For close to a decade, Mipac engineers have been acting as the lead control systems engineers for APA DPS. During this time, Mipac has worked collaboratively with APA and played a critical role in stabilising the plant and enhancing its capacity.
Over multiple small-scale projects, Mipac has been helping bring the plant to specification and adding value to the client. This has included:
- Upgrading the control system architecture to remove bottlenecks from the T3000 system by splitting one control system into three because one was overloaded
- Integrating a third-party PLC SCADA into T3000 DCS
- Writing graphic and configuration standards
- Optimising and modernising the control system
- Addressing the unique challenges of being on an isolated grid by working on frequency control, voltage control and load stabilisation
- Value-adding by properly reporting on production, costing and consumption, as well as fault-finding
- Designing and commissioning the control system and instrumentation for plant modifications
- Preparing and integrating data from various systems at the DPS into the APA AVEVA PI Historian and producing dashboards using AVEVA PI data
- Transitioning the DPS Excel-based reporting into the APA AVEVA PI system
Challenges
The Mipac team has overcome numerous challenges over the course of its work with the DPS, including:
- That the DPS is connected to an isolated power grid which supports both residential and industrial customers. The industrial loads are large and variable, which poses unique challenges of peaks and troughs of power consumption.
- Due to the collapse of the EPCM during the commissioning of the power plant, there was little to no handover from critical suppliers. This caused a significant issue with a lack of documentation.
- The T3000 DCS is inflexible, specialised and protected. As a result, every element of control system engineering needed to be carefully planned and structured.
- Since the DPS is the main power generator in the Northwest Power grid, every modification needed to be properly planned, analysed and worked on, as any additional downtime would have serious commercial impacts for APA and the whole Northwest region.
- The work had an ad hoc nature, meaning the Mipac team had to constantly adapt and change direction.
- It is time-consuming, complex and logistically challenging to make changes on the site.
Outcomes
Over the course of this work, Mipac has:
- Helped to bring the DPS plant to the design specification
- Customised the Master Load Shed System to suit the commercial agreements of the Northwest Power System Grid network
- Assisted APA to develop its organisation wide, standard DCS/SCADA specifications
- Assisted the DPS in the integration of the APA power group
- Helped APA to integrate and transition their existing PI standards to include power generation
- Helped the DPS to integrate their data sources into the APA corporate PI system
- Provided ongoing support upon completion
- Over 25 control and electrical projects engaged and delivered on-site
Results
Increased stability of the plant
- Load sharing on the generators ensured that these could better cope with variable loads.
- Mipac’s work resulted in a consistent operation, minimising operator input and providing additional operational flexibility and stability.
Decreased maintenance requirements
- Mipac’s work introduced more documentation and better diagnostics for the control system. It also provided a back-up system for the data collected. As a result of this, maintenance time and required effort decreased, with operators having more time to get on with their work.
