What Is Misoperations:

Protection systems help support overall system reliability by protecting sensitive equipment. A protection system element (e.g., a relay device) misoperates when it either does not operate as designed or operates unintentionally or outside of its zone of protection. Misoperations contribute to outages of generation and transmission facilities and place the system in a less reliable state.

Information about misoperations is collected through the NERC Misoperations Information and Data Analysis System (MIDAS). NERC measures the rate of misoperations by the ratio of misoperations to correct operations—the misoperations rate. Efforts are underway to achieve a nationwide misoperations rate of 8% by 2020. To contribute to these efforts, WECC is working with stakeholders to develop misoperations reduction strategies and share recommended practices.

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In this section of the report, the information is not shown by region or BA. This section shows how the Western Interconnection is doing overall, so the map and regional functions are not present. However, in this section, the use of statistical significance is introduced.

The chart on the right shows the historical data that is selected by the filters and a trend line over the last five years. The summary box shows the change per year, a p-value (a statistical measure showing the significance of the trend), and a flag that shows whether something is significant.