| Popis: |
In Croatia, all power plants included in load-frequency control (LFC) are hydro power plants (HPPs). There are four of them and all are owned by the largest Croatian electrical power production company, HEP Generation. Until recently, hydropower plants engaged in LFC in Croatia could have only been controlled from Automatic Generation Control (AGC) application located in Transmission System Operator’s (TSO) National Control Centre (NCC). However, in 2019, a river basin control centre Generation Centre (GC) West was inserted as a midpoint in Croatian AGC hierarchy. It stands between NCC and two hydro power plants engaged in LFC. In master AGC application in NCC those two power plants are modelled as one common virtual plant and setpoint of their total power is sent to GC West. In slave AGC application in GC West the required power is optimally distributed between the plants, based on local criteria, which might not be the same as TSO’s criteria. This scenario should bring improvements to both parties included. In TSO’s AGC the control algorithm is simplified by replacing two physical LFC power plants with one virtual LFC plant. Besides, HEP Generation has a possibility to calculate LFC setpoints for its power plants using its own criteria and integrate AGC application with other applications in GC West. An application for hydro scheduling and optimization calculates optimal production of all other non-LFC units controlled by GC West, while ensuring that required secondary reserve of LFC units is maintained, as well as the overall multi-criteria optimization function is minimized. An application for river flow simulation simulates system’s hydrodynamic response for three cases: the most likely case where LFC unit’s output power is estimated, and two extreme cases: the maximum and minimum possible LFC power. The results of those simulations give a guidance to operating personnel in NCC on how and when to engage tertiary reserve or make a replan of generation of other units. |
