Statistical correction scheme for the wind power allocation to transformer stations in the transmission grid

The expansion of photovoltaics and wind energy shifts the feed-in from the transmission grids down to the lower voltage levels of the distribution grids. It is a challenging task to determine at which transformer station of the extra-high voltage grid photovoltaic and wind energy is fed via the cascade of the different grid levels. In principle, this allocation problem of generation to transformer stations can be solved with a power flow calculation if the topology and parameters of all grids are known. In reality, however, this knowledge is spread over several grid operators and alternative solutions could be promising. We propose a method for inversely correcting an initially estimated allocation of wind power generators to transformer stations between the transmission and the distribution grid based on correlating the wind power feed-in with the vertical power flows measured at the considered transformer stations. Our experimental setup involves the allocation optimization of about 29 GW of installed wind power to 136 transformer stations within the two largest German control zones. By shifting a total amount of 12.6 GW of allocated wind power between these transformer stations, our scheme is able to detect and correct erroneous allocations and to improve the reliability of the estimated wind power feed-in per transformer station.