Cross-grid level interface using P-v-capability for flexibility determination and operation point adjustment of subordinated distribution systems

摘要

In Germany the installed capacity of conventional thermal power plants is reduced due to several reasons. However, with their decreasing number classic re-dispatch as well as voltage control potential will be reduced. New potentials may be found in the distribution grids taking e. g. renewable resources into account if necessary. Therefore a new approach for the system operation coordination of Distribution System Operator (DSO) and Transmission System Operator (TSO) is required. Concerning the future challenges, more information have to be exchanged describing flexibility options, which could be potentially provided by the subordinated system operator. This paper proposes such a possible coordination approach concerning the available active power adjustment potential and achievable voltage bands at the point of common coupling (PCC) between TSO and DSO as well as DSO and DSO, the so called P-v-capability. Furthermore the required methodologies for the calculation of the P-v-capability and the adjustment of the operation point are described. Thereby the proposed methodologies not only take into account the operational degrees of freedom of each grid_like decentralized power plants, renewable energy sources, storage devices (if applicable) or e. g. demand side management and the potential of the subordinated distribution grids. Furthermore, grid restrictions like maximum line loadings and voltage limits as well as regulatory constraints are considered. The approach is validated by means of numerical case studies using a reference case taking the different voltage levels of a power system into account.