Quantifying the Value of Underground Line Sensing
May 2nd, 2022
Implementing an Underground Line Sensing Pilot — A Recap
In our previous underground sensing blog, Enhance Visibility into Your Underground Power Lines With Intelligent Line Sensors, we outlined the best practice steps for implementing an underground line sensing pilot:
- Identification of pilot feeders
- Site surveys of potential locations
- Planning and installing software
- Training on sensors and software
- Deployment of pilot sensors
After the pilot is underway, there is an important next step that facilitates informed decision-making for wider implementation of an underground line sensing and faulted circuit indicator program — determining the net value of the program.
Calculating Overall Underground Line Sensing Value
How do you evaluate the effectiveness of your line sensing pilot?
To help estimate the net value of adding line sensors to your underground distribution system, we’ve created a new online tool — the Underground Line Sensing Value Calculator.
This easy-to-use tool considers costs for line sensor hardware, software, installation, and OT/IT integration cost, and the value associated with realized reliability improvements.s
Start With Line Sensor Costs
Hardware costs, installation time, the costs of integrating into OT/IT systems and using our Ample Analytics software for ongoing monitoring and management of energy grid sensors all should be included when calculating line sensor program costs.
Cost per line sensor location drives hardware costs while the cost of software and system integration can be spread across all line sensing locations. To estimate total hardware cost, an approach that specifies the density of sensing locations must be chosen.
Sentient Energy’s Underground Line Sensing Value Calculator provides the user a selection of three approaches:
- For a balanced underground line sensing approach, we suggest deploying line sensing at the 1/3 and 2/3 points along the feeder.
- For maximum reliability improvement, for example on feeders that service high value customers, installation at the quarter points of a feeder is recommended, yielding an even higher outage reduction payback.
- For a more conservative cost approach with a faster payback period, one line sensor can be installed at the midpoint of the feeder.
Line sensor installation times captured during the pilot (typically 30 minutes or less once a crew arrives at the designated install location) allow for easy and accurate estimation of the installation portion of sensor costs.
Next, Calculate Line Sensing Value
After quantifying costs, the next step is to use the calculator to estimate the value of the line sensing system. It’s most beneficial if outage data from actual faults is available from your pilot period, but underground outages are infrequent so estimates of CMI and O&M savings can also be made based on the deployment approach selected.
Typical first partial restoration time reductions of 20-50% are seen on feeders with line sensors as compared to restoration time for outages without the benefit of line sensors.
Improvements in restoration time are due to the following factors:
- Operations teams are alerted to and can analyze faults faster
- Appropriate crews can be sent to the locations
- A narrowed patrol area means reduced patrol times
An Example Line Sensing Value Calculation
The below example shows the value of line sensing based on a reduction in outage duration:
Line sensing value = outage duration reduction in minutes * CMI value/min * number of customers impacted
Example: 30 minutes * $1.50/minute * 500 customers = $22,500
The value of line sensing in this case is $22,500 per fault.
Frequency of underground faults is a required input to the calculator. We’ve set a default value of one fault per mile every 10 years based on information from: DOE ARPA (page 2).
The value estimate in the calculator is based only on the CMI value of outage time reductions.
In addition, you may consider factoring in O&M cost savings for crews and vehicles and savings associated with rate cases for capitalized equipment.
More Details to Keep in Mind
Results may vary as every utility and distribution circuit is unique. Generally, intelligent line sensing will help utilities most on feeders with low visibility that have a history of long outage duration times.
When terrain is difficult to patrol and/or there is limited automated switching on the feeder, the value of sensors further increases. Factors such as high metrics for customers per mile, CMI value, and fault rates also boost the value of line sensing.
Estimate Your Utility’s Underground Line Sensing Value and Let Us Know
Curious about the value an underground line sensor program could provide your utility? Try our calculator and let us know how we can assist you.
For more information on the benefits of intelligent line sensing on both overhead and underground distribution circuits, hear from leading utility experts on this webinar, Success with Line Sensing — Overhead and Underground [Energy Central PowerSession™]. On Demand – Success with Line Sensing – Overhead and Underground [an Energy Central PowerSession™] | Energy Central