Reactive power market demonstration

The network operators in Finland are facing new challenges in reactive power control. This paper focuses on the reactive power flow at the TSO/DSO interface. The motivation is to add the control ability of reactive power by a market-based approach where so far untapped flexible inverter-based resources connected to the distribution system are used as controllable assets. This development benefits the Distribution System Operator and the work opens new business opportunities especially to asset owners and aggregators. A local reactive power market is demonstrated as a novel solution. As a part of the market concept, a forecast of reactive power at the TSO/DSO interface was developed and utilized by the Distribution System Operator. The reactive power demonstration was performed with two assets, a battery energy storage system and a photovoltaic power plant. The assets were controlled by an aggregator. The demonstration period was successfully performed. The work presented in this paper has been done as a part of the Finnish demonstration of the EU-SysFlex project. The presented approach also builds upon the current EU targets for the development of various market-based flexibility services. However, the development of these applications also challenges the aggregators and flexibility providers, since the control of manifold types of assets requires various technical solutions that may be case dependent. This may complicate the fluent scalability of the solutions.