PNNL

Abstract

The Dynamic Contingency Analysis Tool (DCAT) is an open-platform and publicly available methodology to help develop applications that aim to improve the capabilities of power system planning engineers to assess the impact and likelihood of extreme contingencies and potential cascading events across their systems and interconnections. Outputs from the DCAT will help find mitigation solutions to reduce the risk of cascading outages in technically sound and effective ways. Overall, the ultimate goal of the DCAT is to bridge multiple gaps in cascading-outage analysis in a single, unique prototype tool capable of automatically simulating and analyzing cascading sequences in real systems using multiprocessor computers. This study has been conducted in close collaboration with grid operators, Siemens Power Technologies International (PTI), and the Electric Power Research Institute (EPRI). The principal objective and innovation of this project is to equip the power industry with the ability to simulate, understand, predict, and prevent consequences of major disturbances on the grid including cascading, blackouts, and widespread power supply interruptions. Despite some recent progress achieved in this area, the main objective has not been addressed to any practically significant extent. The simulation component includes the modeling accuracy, speed of computations, and comprehensiveness considerations (which are important because of the multitude of possible causes of cascades and multiple variants of cascade development). Understanding blackouts is essential for mitigating and preventing them. This knowledge is very limited at present. Prediction of blackouts is a very challenging task. It can be addressed by revealing the most frequent (or most probable) potential cascade development scenarios. Prevention of blackouts is currently a very limited practice in the industry. There are no systematic, well-orchestrated, industry-wide activities in this area. One of the additional goals of this study is to overcome the difficulties facing the power industry in implementing the North American Electric Reliability Corporation (NERC) Standard TPL-001-4, “Transmission System Planning Performance Requirements,” that has been partially enforced since the beginning of 2015. The standard states that “studies shall be performed to assess the impact of the extreme events.” In this study, this requirement is addressed by developing the DCAT. The DCAT is an open-platform and publicly available methodology to help develop applications that aim to improve the capabilities of power system planning engineers to assess the impact and likelihood of extreme contingencies and potential cascading events across their systems and interconnections. Outputs from the DCAT will help find mitigation solutions to reduce the risk of cascading outages in technically sound and effective ways. The current prototype DCAT implementation has been developed as a Python code that accesses the simulation functions of the Siemens PSS®E planning tool (PSS/E). It has the following features: It uses a hybrid dynamic and steady-state approach to simulating the cascading outage sequences that includes fast dynamic and slower steady-state events. It integrates dynamic models with protection scheme models for generation, transmission, and load. It models special protection systems (SPSs)/remedial action schemes (RASs) and automatic and manual corrective actions.