Over the past 6 months, we have been working on a pro bono engagement with Tonga Power Ltd (TPL) to help them build an open source power system model for the Tongatapu network, the largest electricity system in Tonga supplying >85% of all electricity consumed in the country.
The case for open source power system modelling
For small nations like Tonga, the case for using open source software is a fairly straightforward economic one. While commercial software packages (such as PSS/E, ETAP and DIgSILENT PowerFactory) are polished and powerful tools, spending tens of thousands of dollars for a commercial software license is simply too cost-prohibitive.
In the past, donors have provided software licenses to TPL (e.g. the World Bank funded a license of PSS®SINCAL nearly a decade ago), but the costs of ongoing maintenance, support and version upgrades are typically not covered, so the software gradually goes out of date. Moreover, a single license (usually installed on one PC) practically limits the number of users that end up modelling and running simulations.
We’ve managed to build a base model of the grid
At this stage, we’ve done most of the painstaking model conversion work and have a functional, albeit preliminary, base model:
- Converted the Tongatapu base power system model to pandapower format
- Aligned the model data with known GPS coordinates of the network infrastructure
- Added metadata to the model (e.g. indicative load types)
- Applied consistent naming conventions for model elements
But there’s still a lot of work to be done
The model is by no means complete and there is a significant amount of development work that needs to be done to make the model usable by TPL for planning purposes, for example:
- Conversion to other open formats (such as Gridcal)
- Model validations with historical SCADA measurements
- User interfaces, visualisations and tools to make model usage easier, e.g. scenario configuration
- Align workflows with TPL processes, e.g. to keep model up to date
- Documentation and training material
- Models for the other major grid systems in Tonga – Vava’u, Ha’apai and ‘Eua
Please reach out if you’re interested in helping out
So far, this has been a part-time pro bono initiative that we work on when time permits. But in order to accelerate development, we will need help. We are offering 1 or 2 (unpaid) volunteer internship opportunities to assist with developing the model further. We have approval from TPL to bring interns onto this project (provided a confidentiality agreement is signed) and are looking for the following skills and experience:
- Power systems engineering knowledge
- Python coding skills
- Solid written communication skills
If you’re interested in contributing to a worthy cause while also working on a real power system, please reach out to us.