Large scale integration of wind power in a transmission grid

Abstract

In this report, only stationary analyses have been performed. The results and analyses performed are based on the model as described in the system description. Assumptions made and deviations from the real life grid may have impacts on the results, but the main observations in this report give indications on the problem areas which may need to be addressed. First, the loading values for branches in the 66 kV and 132 kV parts of the grid are investigated. By varying the production level at Ytre Vikna from 0 to 250 MW, key upgrades necessary has been identified. Secondly, the suggested upgrades have been modeled and investigated with regards to overloading. Bus voltages have also been monitored in order to search for indices of nearby voltage instability. Results from these analyses show that the branches between ABELVÆR JØA-T DALTRØA has to be upgraded in order to be able to have an acceptable loading situation in the NTE 66 kV grid. When producing 250 MW at Ytre Vikna, the transformer in Kolsvik has to be replaced in order to avoid overloading, when all the power from Ytre Vikna is fed towards Kolsvik. When investigating the n-1 criterion it was found that when one of the branches between RV130 and ARSANDY1, all the production from Ytre Vikna is fed into the NTE 66 kV grid. The maximum amount of power that can be fed into the 66 kV grid in RØRVIK was found to be 62.7 MW. When the branch from ARSANDY1 to KOLSVIK1 was set to be out of service, the wind generation at Ytre Vikna fed some power towards the load in ARSANDOY in addition to feeding into the NTE 66 kV grid. In this case, the maximum production at Ytre Vikna was 94 MW. In this case 62.7 MW was fed into the NTE 66 kV grid, while the rest was fed towards the load in ARSANDOY. In the case of 250 MW at Ytre Vikna and the transformer between RV130 and RØRVIK out of service, some kind of reactive power compensation is needed. Power flow analyses show that the buses ARSANDY1 and KOLSVIK1 have voltages below the specified minimum limit of 0.955 p.u.