Impact of unplanned power flows in interconnected transmission systems - Case study of Central Eastern European region

The unplanned power flows at the interconnections of the Central Eastern Europe and Central Western Europe electricity markets are assessed. The assessment is accomplished using optimal power flow simulations of the linked transmission systems of Germany, Poland, the Czech Republic, Austria and Switzerland. The unplanned flows are modeled using a multivariate model that is a function of time series of wind- and solar-generated electricity, power demand and commercial power flows. It is shown that for the case of Poland there is a 25% higher loading on sections of transmission grid in Poland due to the unplanned flows. The unplanned power flows are largely a consequence of the wind-generated electricity in northern Germany that must be routed to southern Germany through the grid in Central Eastern Europe region due to an inadequate grid capacity along the north-south German corridor. It is shown without the planned 2020 developments of the grid, Poland's grid will be very susceptible to congestion and destabilization.