Secondary network systems are both a critical part of the electric power infrastructure and a unique challenge for electric utilities. Designed to deliver highly reliable power to dense business districts, secondary networks are essential to the daily operations of many U.S. cities. Yet their proximity to the public presents serious risks.

The inherent reliability of secondary networks tends to mask safety issues, and many of the experienced engineers who were once responsible for these systems have been lost to the industry through mergers and attrition. Further compounding the problem is the challenge to properly assess the system then inform executive management of risks in clear terms and with confidence. Accordingly, utilities may struggle to identify secondary network issues, let alone implement plans to address them.

In this situation, a third-party “intervention,” or proactive assessment of the health of the secondary network, is often a way to lower risks and improve the safe operation of secondary network systems.

Secondary networks present several challenges for utility managers. Aging infrastructure requires frequent and costly maintenance. Construction in urban areas is expensive. And the presence of high-voltage power systems under city streets poses extreme safety hazards, including the potential for arc flash events.

Secondary networks typically provide high reliability. This is critical in city centers, but it may also cause utilities to overlook deficiencies that would be identified quickly in a less reliable system. When secondary networks do fail, the events tend to be catastrophic. A city’s entire business district may be affected, and the economic impact can be severe.

BMCD Aging Infrastructure
More secondary network projects are being considered to address aging infrastructure. (Burns & McDonnell)

Because secondary networks are complex systems, they require specialized experience to provide their safe and efficient operation, maintenance and improvement. However, over the last decade, many utilities have lost mission-critical knowledge due to attrition, retirement, and mergers and acquisitions.

According to a 2017 survey by the Center for Energy Workforce Development, forecasted retirement rates are now declining and younger workers are entering the industry in greater numbers. Still, the pool of qualified entry-level power engineers may not be keeping up with industry needs. This is yet another reason safety deficiency in secondary networks institutional knowledge may go undetected.

As utilities adopt more sophisticated grid modernization equipment and operating practices, the need for specialized knowledge will only become more pronounced.

Due to the shortage of operational institutional knowledge, it makes sense to commission an experienced third party to evaluate the health of secondary networks. To obtain comprehensive results, all key functional areas should be assessed, including planning, design, engineering, construction, operations, maintenance and safety. The assessment should follow a structured methodology that encompasses fact finding, asset condition evaluation, and benchmarking of practices and processes relative to network systems.

A successful intervention requires active involvement from the utility’s engineering and operations teams. This may take the form of on-site workshops, interviews and field inspections. Many utility teams are aware of the risks associated with secondary networks but simply don’t have the bandwidth or knowledge to address them. As such, they often welcome the opportunity to participate in the assessment process.

BMCD Network Protector 2017 web
A network protector is the heart of a secondary network system. (Burns & McDonnell)

Ultimately, the intervention should produce a tactical action plan and a strategic framework for optimizing the utility’s investment in grid modernization. While every utility is unique, many share similar challenges — and therefore receive similar recommendations — related to improving secondary network safety and operations.

Some recommendations may address the company’s organizational structure. This could include assigning engineering a leadership role in addressing secondary network issues or creating a dedicated network-only crew until issues are resolved.

Other recommendations may be designed to bring assets, infrastructure and processes up to speed. Examples include assessing network transformers, reviewing and validating the accuracy of network protector relay settings, and developing an accurate planning model to simulate the secondary network system.

Still other recommendations may be related to safety protocols. For instance, many utilities benefit from reviewing incident energy calculations, seeing that current protocols for work crews entering the network system are appropriate, and implementing a robust emergency response training program.

The precise action plan will vary depending on the utility, but all recommendations will align with the goals of addressing urgent safety and operational needs, and adhering to industry norms.

Both municipal utilities and investor-owned utilities are guided by a public service obligation to provide customers with safe, reliable and affordable electric power. Meeting this obligation can be challenging when it comes to secondary networks.

Having access to a data-driven assessment and detailed action plan allows utilities to move forward confidently with grid modernization initiatives that will support the safety and reliability of secondary network systems for many years.