Power grid main characteristics

The transmission grid in the MISO footprint reaches from the Great Lakes to the Gulf of Mexico covering 15 states and the Province of Manitoba making MISO the largest ISO/RTO in the world. Our footprint covers the entire Midwest and great majority of the Southern part of the United States. The MISO-administered grid interconnects with the Independent Electricity System Operator of Ontario, the Mid-Continent Area Power Pool, PJM, Southwest Power Pool and the Tennessee Valley Authority. MISO has seams agreements or memorandums of understanding with each of these organizations to facilitate operations.

MISO’s greatest source of fuel is coal followed by gas and oil. However as implementation of the EPA’s regulations approaches we will likely see a shift in our fuel mix from coal to natural gas. Renewable energy is growing but remains low in comparison at just 14% while nuclear hovers around 6%.

Major incidents & preventive measures

Blackout of 2003

The blackout’s primary cause was a software bug in the alarm system at a control room of the First Energy Corporation in Ohio. Operators were unaware of the need to re-distribute power after overloaded transmission lines hit un-pruned foliage. Improvements were made in the following areas in response to the blackout.

  • Visibility. We now have a real-time view of our entire 900,000-square-mile footprint, allowing us to monitor for disturbances from New York to the Gulf of Mexico. Additionally, we can now observe the systems of our neighbors including, PJM, SPP, TVA and IESO in Ontario – making it much easier to prepare and respond to critical issues.

  • Data. MISO’s State Estimator features a sophisticated mathematical formula that rapidly digests raw data from 300,000 points along the power grid, providing system operators with invaluable information on grid conditions not only in MISO, but in neighbouring systems as well.

  • Balancing Area. In 2003, MISO and many other Reliability Coordinators monitored key facilities identified by transmission owners. Today, MISO operates as a single area, streamlining certain tasks and responsibilities and improving reliability.

  • Forward Thinking. Every five minutes, MISO’s real-time Contingency Analysis tool gives system operators the worst-case “what-if” scenarios allowing our operators the opportunity to plan and mitigate those scenarios before they can be realized. This invaluable information is paramount in heading off potential problems before they occur.

  • Energy Markets. By managing all generation in a coordinated manner and dispatching the lowest-cost energy through our wholesale energy and reserves markets, MISO streamlines the use of the system, increasing reliability.

  • Warning Systems. Other tools add to the system operators’ knowledge of real-time grid conditions, including a range of audible alarms that check for voltage conditions, system limitations, line status and topology changes.

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