Resiliency to improve reliability

As COVID-19 began to spread throughout the United States, Minnkota’s power delivery crews took early action against the spread of the virus. Social distancing among personnel, enhanced sanitization efforts and the use of masks when working in close proximity have all been incorporated to protect the safety and health of the workforce.

Even with the additional requirements and obstacles presented by the pandemic, power delivery progress continues at a brisk pace throughout the summer construction season. Projects to help address aging infrastructure and system reliability have been the focus, as portions of the power delivery system are 60-70 years old.

Aging infrastructure is a focus for most utilities across the nation, and Minnkota is doing its part to make its grid smarter, stronger and more resilient. But with 2,138 miles of 69-kilovolt (kV) transmission line and 212 substations, it’s a big job that will take years to tackle. That’s why the cooperative is taking a data-driven approach to identifying and prioritizing projects. Advanced analytics are used to help determine if areas of the system should be modified, upgraded or completely rebuilt.

The efforts were prompted by an extensive study of Minnkota’s 69-kilovolt (kV) transmission system completed in 2015. Since that time, power delivery metrics – including sustained outages, blink outages and total outage time – are all steadily improving thanks to a wide array of programs to address aging infrastructure, in addition to routine maintenance plans. The following five programs have helped drive recent improvements in reliability.

Blink outage mitigation program

Blink outage mitigation includes adding technologies to existing transmission lines that reduce momentary outages often caused by lightning or wildlife impacts.

2020 focus: Crews have completed about 216 miles of blink outage mitigation.

Outlook: Minnkota is nearing the end of its accelerated plan to address blink outages. About 1,244 miles of 69-kV line have been blink mitigated, which is about 58% of the total system. This program has shown a blink outage reduction rate of 55-60% over non-mitigated circuits.

69-kV transmission line rebuild program

Transmission line rebuild includes disassembling the existing transmission line and building a new line in its place. The new line includes an enhanced design for greater reliability.

2020 focus: Crews will be rebuilding the Lincoln-Glasston-Hensel line sections in eastern North Dakota (22 miles).

Outlook: By 2022, Minnkota is scheduled to have rebuilt about 95 miles of transmission line, or about 4.4% of the total 69-kV system.

Distribution substation rebuild program

The distribution substation rebuild program includes disassembling the existing substation and building a new one in its place. The new substation includes an enhanced design for greater reliability.

2020 focus: Crews plan to rebuild the Oklee and Rindal substations in northwest Minnesota.

Outlook: Minnkota currently has plans to rebuild about two distribution substations per year.

Distribution automation program

The distribution automation program includes adding new communication technology at existing substation sites, which allows Minnkota personnel to collect, automate, analyze and optimize data. Better system visibility can assist in responding to outages and other issues.

2020 focus: Minnkota plans to complete 15-18 distribution automation projects by the end of the year.

Outlook: At the end of 2020, Minnkota anticipates having 46 substations with distribution automation capabilities. At a rate of approximately 15 substations per year, the cooperative should have all distribution substations equipped with the technology before the end of the decade.

Demand response equipment replacement program

To improve the long-term viability and reliability of Minnkota's demand response program, crews are replacing the ripple injectors at all 17 sites throughout the system.

2020 focus: Ripple injectors and associated equipment at the West Fargo and Wilton substations will be replaced this year.

Outlook: By the end of 2020, Minnkota will have completed work at nine of the 17 demand response sites. The current plan is to have all demand response sites completed by the end of 2024.

Main image: Crews string wire on a rebuilt section of 69-kV line near Cavalier, N.D. (Minnkota/Michael Hoeft)