ZIV Automation delivers ESB's first VPP system.

The scheme includes a central Power Management Control system which is communicating with each of the wind farms and has the P-Q capacity information for each wind farm. Using the current readings, together with the P-Q information it can calculate the available Vars at each wind farm and present an aggregated Var import and export capacity to the TSO representing the capacity available across all wind farms. When the TSO has control enabled, it can request an aggregated VAR setpoint from the DSO Power Management System to provide voltage support for the Transmission Grid.

The ANM System calculates the necessary set-points for each of the associated wind farms to meet the requested VAR setpoint but ensures that the thermal and operational limits of the DSO system are not compromised. Intelligent Remote Controllers are installed at each Wind farm which will enter a fail-safe mode if communications are lost to the Central Control System. The wind farms support the following 3 control modes: − Voltage Control Mode − MVar (Q) Control Mode − Power Factor (PF) Control Mode When the DSO is in control, it can manually set the mode and setpoint on each wind farm but when the Power Management System is in auto mode and providing aggregated Vars to the TSO it only uses Voltage and MVar control modes. It always switches the wind farms to MVar mode for requesting the required Vars and once achieved it switches them to Voltage Control if this is the operating mode selected by the TSO. Two SCADA interfaces are provided, one to the DSO SCADA Centre and one to the TSO SCADA Centre. These provide full visibility on the system operation including readings for real and reactive power from each wind farm and the aggregated values at the 110kV substation. The Power Management System automatically determines if a tap change is possible at the GSP to rectify an Under-voltage or Over-voltage condition and if so, it will initiate the tap change. When evaluating the aggregated Var requirements, it will automatically determine if this will lead to a voltage violation and whether such a violation can be avoided by an available tap change. If not, the Var requirement may not be possible or may require a different allocation between the wind farms.