Grid Reliability & Security

Reliability Results

We strive to minimize the frequency and duration of service interruptions. As part of a long-term reliability strategy, we perform critical analyses of our transmission and distribution systems to identify areas requiring proactive maintenance. We track our response to interruptions using four reliability performance indicators. Below are our 2017 and 2018 storm-normalized reliability results as recorded by our interruption monitoring system.

Reliability Results

The number of interruptions lasting more than five minutes that an average customer experienced during the year.

  2017 2018 2019
Goal  <1.3 <1.3  <1.3
Actual  1.4 1.31  


The average length of time a customer was without service during a sustained interruption.

  2017 2018 2019
Goal  <62 minutes <62 minutes <62 minutes
Actual  61.45 minutes 64.93 minutes  


The average minutes of sustained interruption per customer during a year.

  2017 2018 2019
Goal  <80 minutes <80 minutes  <80 minutes
Actual  86.5 minutes 85.29 minutes  


The number of interruptions lasting five minutes or less that an average customer experienced during the year.

  2017 2018 2019
Goal  <6.5 <6.5  <6.5
Actual 6.24  6.15  


Our plans for improving reliability include integrating geographic information system data, implementing a new interruption monitoring system, strengthening the electrical system, and developing continuous improvement workshops to improve efficiencies and processes.


Compromises to cybersecurity post a serious threat to the privacy of customer data and to the reliable operation of the electric system. To mitigate risk, we continue to secure systems and software and to educate and train employees on security and awareness. We’re regulated by the Federal Energy Regulatory Commission to comply with the Critical Infrastructure Protection Cybersecurity Standards. To comply with these standards, we leverage processes, controls, and technology to maintain physical, electronic, and protected information security for sites identified as impacted facilities.

The standards require us to categorize our cyber assets as high, medium, and low impact. We support our high- and medium-impact cyber assets to meet the required standards. These cyber assets must be programmable and located at certain control centers and generation and transmission facilities identified in the standards. We support our low-impact cyber assets for incident response/cybersecurity awareness to meet the required standards. We’re in position to meet the January 1, 2020, future standard requirement for physical security.

Preparedness Planning

Our company has approximately 20 situation-specific documents that provide a systematic approach to managing crises without causing major disruption to normal activities. These documents are general guidelines we supplement with employee education and training. Our company’s various preparedness plans incorporate recommendations and compliance from:

  • Federal Emergency Management Agency.
  • Midcontinent Independent System Operator, Inc.
  • North American Electric Reliability Corporation.
  • Federal Energy Regulatory Commission.