Proactive and Strategic Readiness:
Are You Ready for TPL-001-5?

Q&A: Ask Multitel

Q1: Why Do Electric Utilities Have to Monitor Station DC Supply Systems for Open Circuit and Low Voltage?

Electric utilities operating in North America, as part of the bulk electric system (BES), must comply with NERC’s TPL-001-5 to ensure reliability and safeguard the performance requirements for their electrical transmission systems and the resilience of their infrastructure.

TPL-001-5 addresses multiple scenarios. This Q&A will focus on scenario P5, which states that a single station DC with only one battery string in an electric substation is considered a single point of failure and must be addressed. Specifically, utilities must ensure redundancy in their station DC supply systems, or, based on footnote 13cof the TPL-001-5 standard, they can deploy a 24/7 monitoring and reporting system connected to a SCADA or control center for low-voltage and open-circuit conditions of their single DC power systems.

To view the full TPL-001-5 standard, click here.

Q2: What Is the TPL-001-5 Implementation Timeline?

Below are some of the important dates to retain regarding the timeline of TPL-001-5:

  • Governmental authorities and the Federal Energy Regulatory Commission (FERC) approved the TPL-001-5 standard as well as its implementation plan on January 23rd, 2020.
  • TPL-001-5 became effective on July 1st, 2023.
  • Utilities have until July 1st, 2025 to develop a Corrective Action Plan (CAP) to address single points of failure in their protection systems under TPL-001-5 Category P5.

Considering this, it is crucial that North American electric utilities elaborate their CAPs promptly. The corrective action plans should include listing the different deficiencies to achieve the required system performances as well as actions to resolve those performance deficiencies. Therefore, utilities must now qualify devices and equipment in preparation to meet TPL-001-5 compliance.

Q3: What Are the Disadvantages of Deploying a Redundant DC Supply System?


As mentioned above, an option for TPL-001-5 compliance is to attain redundancy in backup DC power systems. However, this method can lead to the following problems:

  • The purchase of a second set of DC batteries for every substation is inevitably very expensive. Provisioning costs could indeed exceed $50,000 per substation, making it difficult to obtain funding.
  • Integrating new battery systems into substations can be challenging due to limited space. Therefore, the purchase of new batteries can potentially be impossible in substations where space management is critical.
  • The integration of new sets of batteries requires thorough planning as well as intrusive integration. Engineering resources are needed to redesign the substations to incorporate two sets of DC batteries.

Due to these reasons, redundancy in DC batteries in every substation can be difficult or even impossible to achieve. Thus, adding the monitoring of open-circuit and low-voltage conditions of a single DC supply would be a more feasible and cost-effective solution for electric utilities.

Q4: How to Comply with TPL-001-5?


With Multitel’s patented technology, we can empower substation teams with one of our TPL-001-5 solutions to help stay ahead and comply to this NERC regulation.  Depending on your specific substation or Corrective Action Plan requirements, there is a solution for each scenario as listed below:

  1. Comprehensive Detection Solution: The FCCP Box for Open-Circuit and Low-Voltage Detection

For substations lacking a redundant DC supply system and tools for low-voltage detection, the FCCP Box ensures full compliance. Beyond open-circuit and low-voltage detection, the FCCP Box incorporates additional features such as thermal runaway prevention and battery state of charge (SoC) elements, presenting an all-in-one solution for TPL-001-5 Scenario P5 compliance and optimized battery management.

More details on the FCCP Box are available on the Multitel webpage.


2. Open-Circuit Detection with Existing Low-Voltage Monitoring (FCCP)

If your substations are already equipped with a battery charger capable of monitoring low voltage, Multitel offers the FCCP (Float Charging Current Probe). The FCCP device excels in battery open-circuit and thermal-runaway detection. By adding the FCCP’s open-circuit detection to your battery charger’s low-voltage monitoring capability and by reporting to a control center, you can achieve full TPL-001-5 Scenario P5 compliance.

More technical details on the FCCP product are available in the FCCP Configuration Blog.

3. Already Compliant? An Alternative Deployment Option

If your site or substation is already TPL-001-5 compliant with DC power redundancy, the Multitel FCCP or FCCP Box can be deployed alternatively to align with industry best practices.

DC Power Optimization:

  • Monitor your battery strings’ float charging current for thermal runaway events.
  • Provide continuous monitoring and trending of the SoC for proactive battery optimization.
  • Monitor both battery strings for swift deployment of corrective actions if required.

Risk Mitigation:

  • Implement the FCCP technology to standardize your DC power monitoring and minimize the risks of failures and downtime.
  • Provide timely data for proactive and preventive measures.

Cost Efficiencies and Reliability:

  • Access real-time data through an RTU or SCADA system to optimize truck rolls to the substations or battery locations, minimizing operational costs.
  • Ensure consistency of service and uptime for delivery of enhanced customer satisfaction.

Q5: What Are the Advantages of Using the Float Charging Current Probe Products for TPL-001-5 Compliance?

In the ever-evolving arena of electric utilities, real-time monitoring solutions are indispensable tools, offering a pathway for efficient TPL-001-5 compliance and reinforcing the reliability of power systems in a cost-effective manner. Tailored to meet your specific requirements, the FCCP family of products stands out as a comprehensive solution.

Here’s what you need to consider when deploying a TPL-001-5 compliant solution:

  • Capital Expenditure:  Opt for a cost-effective TPL-001-05 solution that minimizes capital expenditures and that represents a fraction of the acquisition cost versus a redundant DC supply system;
  • Continuous Monitoring (24/7/365): Ensure round-the-clock monitoring for open-circuit and low-voltage detection to contribute to your reliability ratings;
  • Configurable Alarms: Tailor the solution to align with your internal best practices and integrate the FCCP products to a SCADA or RTU system;
  • Non-Intrusive Installation:  Prioritize solutions that are non-intrusive by eliminating the requirement for a power outage during deployment.  Also, target one that requires the least amount of space and minimal to no substation redesign; and
  • Additional regulations:  Aim to deploy a solution that does not require additional regulatory compliance such as NERC CIP (NERC Critical Infrastructure Protection) as it can involve a high level of investment and potential fines if found in non-compliance.

Summary and Review

With TPL-001-5 already in effect since July 2023, electric utilities on the bulk electric system (BES) must ensure that their Corrective Action Plans are developed before July 1st, 2025 to secure a planned pathway to TPL-001-5 compliance.

By preparing for this standard now, electric utilities will be better able to navigate the regulatory requirements more effectively.  Early planning and solution qualification can also minimize a substantial financial investment.  When coupled with a specialized, real-time monitoring solution, such as Multitel’s FCCP product line, the cost of such a solution versus the deployment of a redundant battery system can provide significant cost savings.

For additional reading: Multitel blogs related to TPL-001-5 or Float Current Monitoring:

Blog April 18, 2023

Blog April 25, 2022


If you would like to discuss about your specific needs and how the FCCP product line can help you comply with TPL-001-5, you can contact us here.

Share this post