“If they want to go fast, system operators could go alone, but if they want to go far, system operators have to go together”. The growing share of DRES connected at the distribution grid poses challenges to the stability of both the transmission and distribution grid.
We asked VITO / EnergyVille , Partner of the SmartNet Project, to analyse the interaction DSOs-TSOs and its challenges.
The balance at system level is more volatile due to the increase of RES. In addition, local congestions occur more frequently, having a substantial impact on DSO grid operation.
“Every problem contains within itself the seeds of its own solution ”
Several resources connected at distribution grid might not just put the system under stress, they could provide important advantages in case they are operated in a flexible way. This flexibility from resources connected at the distribution grid could be both beneficial for TSOs and DSOs. TSOs could e.g. use these resources to control and restore the frequency of the grid while DSOs could call these resources in case of local congestion. However, in case system operators want to make optimal use of these resources, collaboration is needed.
“5 ways of collaboration – 5 ways to improve system operation”
In general, five models for increased TSO-DSO interaction could be defined. The Centralized AS market model presents a centralised market, operated by the TSO, that respects constraints in the distribution grid. The Local AS market model starts from a local market organized by the DSO, that aggregates resources and transfers them to the TSO. In the Shared balancing responsibility model, the DSO takes over the responsibility of the balancing of the DSO-grid, according to a predefined schedule with the TSO. In the Common TSO-DSO AS market model, the TSO and DSO jointly organize a flexibility market that satisfies both needs from transmission and distribution grid and minimizes the cost of procuring these flexible resources. In the Integrated flexibility market model, TSOs , DSOs and commercial market players compete together in a common flexibility market.
“Collaboration divides the task and multiplies the success.”
Independent how the collaboration is organized, increaed interactions between network operators will allow a better use of flexibility from DRES. Not only will TSO and DSO support each other in an efficient operation of their grid, system operators will also avoid that actions, taken in one network, do not counteract actions taken in another network.
“System operators – strong alone – stronger together”
Nevertheless, a smooth collaboration between system operators will impact business processes, information exchanges and communication channels. Business processes will need to be adapted to recognize the new role of each system operator in the business model of the other system operator. This will require a paradigm shift in the way system operation is currently performed. This also implies new roles and responsibilities for system operators. Especially for the DSO, significant changes might occur. Today, DSOs are not contracting any flexibility for themselves. They are also barely involved in the procurement processes of AS by the TSO. In the future DSOs will not only use flexibility for their own local operation (as an alternative for grid expannsion), they will also support the TSO in an efficient procurement process of AS connected at the distribution grid.
In additon, as a result of these new roles and responsibilities, an appropriate ICT infrastructure needs to be installed to guarantee a smooth and efficient sharing of information. In case TSO and DSO will collaborate in real-time for the procurement and activation of flexibility, there is an increased need to quickly share large amounts of data in a secure way.
It is obvious that this change in roles, responsibilities, business processes, and ICT infrastructure will require a certain transition time. Nevertheless, it is clear that ‘if they want to go fast, system operators could go alone, but if they want to go far, system operators have to go together.
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