Basic Structure and Agent Roles

A more detailed description of the agent roles is as follows:

• Local device agent: Representative of a DER device. A control agent which tries to operate the process associated with the device in an economical optimal way. This agent coordinates its actions with all other agents in the cluster by buying or selling the electricity consumed or produced by the device on an electronic market. In order to do so, the agent communicates its latest bid to the auctioneer and receives price updates from the auctioneer. Its own latest bid, together with the current price, determines the amount of power the agent is obliged to produce or consume. 

• Auctioneer agent: Agent that performs the price-forming process. The auctioneer concentrates the bids of all agents directly connected to it into one single bid, searches for the equilibrium price and communicates a price update back whenever there is a significant price change. 

• Concentrator agent: Representative of a sub-cluster of local device agents. It concentrates the market bids of the agents it represents into one bid and communicates this to the auctioneer. In the opposite direction, it passes price updates to the agents in its sub-cluster. This agent uses ‘role playing’. On the auctioneer’s side it mimics a device agent: sending bid updates to the auctioneer whenever necessary and receiving price updates from the auctioneer. Towards the subcluster agents directly connected to it, it mimics the auctioneer: receiving bid updates and providing price updates.
• Objective agent: The objective agent gives a cluster its purpose. When the objective agent is absent, the goal of the cluster is to balance itself, i.e., it strives for an equal supply and demand within the cluster itself. Depending on the specific application, the goal of the cluster might be different. If the cluster has to operate as a virtual power plant, for example, it needs to follow a certain externally provided setpoint schedule. Such an externally imposed objective can be realized by implementing an objective agent. The objective agent interfaces to the business logic behind the specific application.