The electrical energy generated from renewable energy resources connected to transmission and distribution systems and the displacement of synchronous generators continues to grow. This presages a paradigm-shift away from the traditional provision of ancillary services, essential to ensure a robust system, from transmission-connected synchronous generators towards provision from synchronous and non-synchronous generation (including distribution-connected resources). Given that the available resources at the disposal of system operators are continuously increasing, the flexibility for operating the network can be enlarged. In this context, this paper introduces a dedicated voltage ancillary services strategy for provision of reactive power. A main feature of the proposed strategy is that it is technology-neutral, unlike existing ones that are focused on synchronous generators. The system need for voltage stability is placed at the core of this strategy, which is translated into a requirement for reactive power provision. The proposed strategy achieves, through the combined utilization of distributed generation and traditional resources, to defer the investments in reactive compensating equipment. Dynamic and transient studies are conducted to demonstrate the technical benefits of the strategy, while its practical feasibility is also validated through hardware-in-the-loop testing.
- ancillary services
- voltage stability
- reactive power provision
Oulis-Rousis, A., Tzelepis, D., Pipelzadeh, Y., Strbac, G., Booth, C. D., & Green, T. (2020). Provision of voltage ancillary services through enhanced TSO-DSO interaction and aggregated distributed energy resources. IEEE Transactions on Sustainable Energy. https://doi.org/10.1109/TSTE.2020.3024278