Experiences with Contingency Analysis in reliability and market operations at MISO

Abstract

Managing reliability and operating markets within the large reliability footprint of the Midwest Independent Transmission System Operator (MISO) is a challenging task. MISO built and continuously refines its extensive network model of its interconnected reliability region and surrounding systems, and utilizes State Estimator (SE) and Contingency Analysis (CA) to assess reliability within these regions. Visualization tools are implemented to maintain wide area visibility and operational awareness, and operating procedures and processes are established to coordinate, maintain and manage reliability across its footprint. The transmission congestion determined by the reliability assessment is modeled in the Unit Dispatch System (UDS) to calculate dispatch signals based on a Security Constrained Economic Dispatch (SCED) algorithm. Ten minute dispatch signals are generated every five minutes to continuously balance energy supply and demand at the least-possible cost while also recognizing transmission limitations based on current system conditions. Contingency Analysis plays a key role in this process of operating grid reliably and markets competitively. Providing most up to date constraint flow to the SCED algorithm is essential to manage volatile constraints. A Quick Contingency Analysis has been implemented to address the volatile constraints.