Congestion
Capacity you already own goes unused
Conservative ratings bind transfers well before conductors approach their temperature limit, raising congestion costs and delaying interconnections.
LineID™ · PMU-based dynamic line rating
See the real capacity of every transmission line.
LineID turns the synchrophasor data your utility already collects into live line parameters, conductor temperature, and a dynamic line rating set by the segment that actually limits the circuit.
Input
Existing PMUs at both line terminals
Recovered
R · L · C · Tc
Spatial
Temperature of every route segment
Rating
Limiting-segment DLR, updated continuously
Track record
Utility pilotsOklahoma Gas & Electric, 2026Grupo Energía Bogotá, 2022
345 kV field dataMathewson–Tatonga line, PMUs at both ends
California Energy CommissionCalSEED Concept Award, 28 selected of 212 applicants
Patented technologyU.S. Patent 11,063,472LineID patent pending
The problem
Static ratings assume the worst day of the year, every hour of the year.
Most lines are still operated to a fixed thermal limit. On a cool, windy afternoon that limit leaves transfer capacity unused. On a hot, still one it can be optimistic. Regulators now expect ratings that follow real conditions.
Regulation
Ratings must reflect conditions
FERC Order 881 requires ambient-adjusted ratings, and the Commission’s rulemaking on dynamic line ratings (RM24-6) looks further, to wind and solar conditions.
Instrumentation
Sensors on every span do not scale
Conductor-mounted devices measure one location each. Weather-only models never see the line itself. Utilities need both coverage and a measurement anchor.
How LineID works
From two PMUs to a rating for the whole route.
LineID is software. It runs on the phasor measurements already streaming from each end of the line and needs no new hardware on towers or conductors.
Measure
Voltage and current phasors are read from the PMUs at both terminals of the line.
Calibrate
Topolonet’s Automatic Calibration Algorithm compensates for mismatched instrument-transformer and PMU errors between the two ends.
Identify
LineID recovers series resistance, inductance, and shunt capacitance. Resistance gives the line’s average conductor temperature.
Localize and rate
Route geometry and local weather distribute that electrical reference along the line. Every segment is rated, and the lowest rating sets the circuit’s DLR.
R L C
Line parameters
Continuously recovered impedance and capacitance, with surge impedance loading.
Tc°C
Conductor temperature
An electrical measurement of the line’s average thermal state.
Tkper segment
Segment temperatures
A time-stamped temperature map along the entire route.
ImaxA
Limiting-segment DLR
Allowable current at the selected conductor limit, with the location that controls it.
One current, many temperatures
Why the limiting segment matters.
The same current flows through every segment of a line, but each segment sees different sun, air temperature, and wind. Wind crossing a conductor cools it far better than wind blowing along it, so a bend in the route can change the temperature.
- The PMU reference anchors the line’s thermal state in measurement.
- Route weather and orientation show where conditions differ.
- The segment with the lowest allowable current sets the rating.
Field study
Mathewson–Tatonga 345 kV, February 2017.
LineID processed a week of historical PMU data from both ends of the line and produced a temperature for each of 396 route segments, every five minutes.
- Voltage
- 345 kV
- Route length
- 59.53 mi
- Conductor
- 2 × ACSR Lapwing, 1590 kcmil
- Segments
- 396 × 0.15 mi
- Period
- Feb 5–11, 2017 (UTC)
- Data
- PMU phasors at both terminals; route weather
Still frame: 2017-02-07 22:55 UTC. Line current 1,307 A. Warmer sections at the southeastern end and on a short diagonal section run closer to the wind direction; the east–west sections see more crosswind and run cooler.
12–15°C
Temperature difference between selected segments with the same ambient temperature and total wind speed. The cause was crosswind exposure.
≈140MW
Loading above which resistance and temperature are reliably resolved on this line, about 0.31 of surge impedance loading. The threshold is known before deployment.
1of 396
At each timestamp, one segment controls the circuit rating. Its location moves as heating and cooling conditions change.
Applications
One data stream, several operating decisions.
The same parameter and temperature stream supports real-time rating, asset health, and field planning.
Dynamic line rating
A continuously updated limiting-segment rating for transmission operations and congestion management, with the controlling location identified.
Demonstrated on field dataAsset health monitoring
Resistance trends at comparable loading and temperature point to deteriorating splices and hot joints before they fail.
Available from the parameter streamSensor placement and field review
Recurring warm segments show where a small number of conductor sensors or clearance checks give the most information.
Available from the segment mapForecast ratings
Weather forecasts and the anticipated load profile, started from the latest PMU-anchored state, extend the rating over an operating horizon.
In developmentCompany
Built by power-systems engineers in San Diego.
Topolonet is an early-stage company focused on grid congestion. Our team brings industry and academic experience in power-system modeling, power electronics, signal processing, and renewable energy.
Mission
Give grid operators the measurements they need to use the full capacity of the equipment they already own.
Vision
A modern power grid equipped with Predictive Grid Intelligence™, delivering safe, resilient, reliable, and sustainable power to end users.
Milestones
- Upcoming
Presentation at the NASPI Work Group Meeting
“Real-Time Conductor Temperature and Dynamic Line Rating from Synchrophasor Measurements,” Advanced Applications session, 4:30–4:50 pm ET, EPRI, Charlotte, North Carolina. View the agenda
Pilot project with OG&E concluded
LineID was applied to PMU data from Oklahoma Gas & Electric 345 kV transmission lines, producing line parameters, segment temperatures, and limiting-segment ratings.
LineID patent application filed
“Real-Time Estimation of Transmission Line Rating Parameters, Temperatures, and Transmission Line Health,” U.S. patent application, pending.
Pilot project with Grupo Energía Bogotá
A collaborative pilot to study BusID for dynamic line rating and vegetation management.
U.S. patent granted
“Topology Identification and State Estimation of Power Grids,” U.S. Patent 11,063,472. View the patent
CalSEED Concept Award
California Energy Commission award, one of 28 companies selected from 212 applicants.
Work with us
Run LineID on one of your lines.
A pilot needs historical or streaming PMU data from both ends of a line, the conductor type, and the route. We return line parameters, segment temperatures, and a limiting-segment rating for your engineers to review.
- info@topolonet.com
- Phone
- (858) 605-9302
- Office
- 11440 West Bernardo Court, Suite 300
San Diego, CA 92127 - Topolonet Corporation