Implicitly Modeling Frequency Control within Power Flow

In this paper, we extend a circuit-based, current-voltage power flow formulation to include frequency deviations and implicitly model generator primary and secondary control actions as a function of their temporal dependence. This includes extending the slack bus generator model(s) to better represents its true behavior with frequency controls. These implicit models obviate the need for outer iteration loops and improve the robustness of the simulation convergence when frequency deviations are considered. The simulation framework is highly scalable and is demonstrated on 85k+ bus systems.Comment: To be presented at IEEE ISGT 2019 Europe, Buchares

Robust Sequential Steady-State Analysis of Cascading Outages

Simulating potential cascading failures can be useful for avoiding or mitigating such events. Currently, existing steady-state analysis tools are ill-suited for simulating cascading outages as they do not model frequency dependencies, they require good initial conditions to converge, and they are unable to distinguish between a collapsed grid state from a hard-to-solve test case. In this paper, we extend a circuit-theoretic approach for simulating the steady-state of a power grid to incorporate frequency deviations and implicit models for underfrequency and undervoltage load shedding. Using these models, we introduce a framework capable of robustly solving cascading outages of large-scale systems that can also locate infeasible regions. We demonstrate the efficacy of our approach by simulating entire cascading outages on more than 8000 nodes sample testcase.Comment: Presented in IEEE PES Innovative Smart Grid Technologies Europe Conference, Bucharest, Romania, 201

SUGAR-R: Robust Online Restoration Platform for SCADA-Absent Grid

Secure and fast grid restoration from a collapsed state is increasingly critical as blackouts are becoming more prevalent around the globe. Generally, the restoration of grid during a blackout is achieved with the help of Supervisory Control and Data Acquisition System (SCADA) based central control; however, with the threat of cyber-blackouts, this presumption of an available and secure SCADA system is not valid. This is also true for grids in developing countries as well as for many distribution and micro grids that lack SCADA. In this paper, we introduce an online framework for localized grid restoration that validates and updates a pre-defined crank path in real-time based on the vital grid states of voltages, currents and frequency. The proposed framework maintains an online network topology of the localized grid that can continuously sample local measurements and update the grid model, thereby circumventing SCADA based central control. In the results section we demonstrate the efficacy of this framework for blackstart by ensuring a feasible crank path with voltage and frequency states within bounds, while further assisting in synchronization of two disconnected sub-grids during the re-energization process using a distributed framework.Comment: 8 Pages. Manuscript submitted to PES Transactions on Power Delivery (Special Issue) for revie