CAREER:Toward a Self-Managing and Efficient Power Grid enabled by Corrective Power Flow Control and Distributed Grid Management

Carnegie Mellon University, Pittsburgh PA

Investigators

Abstract

The existing electric power grid was built for a situation in which power was injected at a few locations by dispatchable bulk power plants to supply inflexible loads. It was designed for reoccurring power flow patterns, has limited control capabilities and is operated such as to fulfill the requirement given by the deterministic formulation of N-1 security. The resulting constraints imposed on grid operations lead to an inefficient and conservative usage of the available transmission capacities and cause generation to be dispatched in an economically suboptimal way. To enable the transition to an efficient sustainable electric energy supply system, the transmission grid of the future needs to be able to adjust to the increasingly varying power flows caused by variable renewable generation and flexible demand. This also includes operating the grid according to a definition of security which reflects the probabilistic nature of system security to ensure a reasonable trade-off between the level of security and generation cost. A grid equipped with ubiquitous power flow control capable of rerouting power to where transmission capacity is available forms the basis to achieve these goals. However, the associated increase in the number of control variables also significantly increases the complexity of operating the power grid which is difficult or even impossible to handle with the traditional centralized grid management approach. Intellectual Merit: In this proposal, a fundamentally new approach for managing the transmission grid is proposed enabling a future in which ubiquitous power flow control has become a reality. A distributed grid management scheme based on decomposition theory is devised which takes into account the capability for corrective, i.e. post-contingency, actions provided by power flow control devices. Advantage is taken of the decoupling between normal state and contingency cases and of the spatially limited influence of outages to derive computationally efficient algorithms. The objective is to minimize a risk-based security index in which probabilities of contingencies and the severity of their consequences are used to define the level of system security. To preserve the existing centralized market structure for generation dispatch, Locational Security Impact Factors (LSIF) are newly introduced. These factors provide the operator with a measure of influence of a generation redispatch on security. Hence, the proposed research provides the methods to transform the power grid into a flexible asset and realizes the vision of a self-managing grid. The available transmission assets are used in a non-conservative yet secure way to accommodate an economically optimal generation dispatch achieving the desired trade-off between security and cost. Broader Impact: The proposed project offers a completely new view on power grid management. It is expected to yield significant computational improvements which are needed to make optimal usage of ubiquitous power flow control in the electric power system. Applying the proposed concepts promises substantial reductions in renewable generation curtailment and overall cost of generation expediting the development and adoption of power flow control and integration of renewable generation. Hence, the power grid is turned into an enabler rather than being an obstacle on the path towards a sustainable electric energy future. Furthermore, the developments in distributed system operation will be useful across other types of large-scale systems. The proposed research will be carried out by graduate and undergraduate students and the results will be integrated into undergraduate and graduate courses. As the chair of the IEEE Women in Engineering (WIE) Pittsburgh section and an instructor in the Summer Engineering Experience for Girls program at CMU, the PI will use this research as motivation for K12 students and women to choose power systems engineering as their field of study. This not only contributes to increasing the number of minorities in engineering but also to training students for a future in an industry for which one of the biggest challenges is the aging workforce.