Optimerad styrning av kondensatorbatterier - Ny möjlighet att minska förluster med elektronisk brytteknik
Examensarbete för masterexamen
Transmission of reactive power is well known to cause active power losses. Thus, new components who can help minimizing these expensive reactive power flows are of great interest to the power distribution companies. ABB Corporate Research has developed the first electronic power breaker. One possible application for this breaker is transient-free switching of capacitor banks. This could prove a useful distribution voltage complement to the switch-sync technique, mainly applied to transmission voltage level. The Swedish grid is characterized by long distances between power plants and customers, hence long transmission lines carrying loads of varying sizes are frequent. This implies that reactive power compensation by capacitors will be necessary. Furthermore, a freedom of choice when to put specific capacitor banks into operation is desired to keep power losses at a minimum. However, capacitor bank switching at voltage levels below 130 kV is strictly regulated today due to the problems of transients. The scope of this report is to assess the economic potential of the electronic breaker concerning transient-free switching of capacitor banks. This has been achieved by comparing two cases of operating systems, controlling the shunt capacitors in a west-Swedish region network. The first case models todays operation scheme where shunts are divided into four categories, depending on how often they can be employed. The second case resembles a future situation where all capacitor banks can be put into/out of operation anytime, hence assuming transient-free switching. The two cases were implemented as IPLAN-programs in a PSS/E context. The shunt operations were controlled by an optimal power flow tool. A full year has been succesfully simulated on hour-basis. Load statistics were used in order to resemble how the active and reactive loads fluctuate over the year. The results show a significant decrease in active power losses for the future case. Consequently, the economic potential for applications of this kind could not be dismissed.
Elkraftteknik , Electric power engineering