General Overview & Capabilities
How does the Claw system work?
Claw calculates ratings for each span individually based on hyper-local weather conditions. The rating for the line is determined by the minimum rating found amongst all the spans. We provide these rating forecasts to your SCADA or EMS, which can then be forwarded to or used by the system operator.
What is the specific output provided to SCADA/EMS?
Claw outputs the ratings of each line in amperes, or in MVA based on the nominal voltage. Operators use these values in real-time monitoring and operational planning.
What is the forecast horizon and update frequency?
Ratings are provided for each line with hourly resolution and up to 10 days ahead. Forecasts are updated hourly.
0–5 Days (Dynamic): Gridraven's wind forecasts have sufficient certainty to provide dynamic capacity increases.
5–10 Days (Ambient): Wind forecast uncertainty becomes too high, so ratings revert to Ambient Ratings.
10+ Days (Seasonal): Beyond ten days, the ratings revert to standard Seasonal Ratings.
How volatile are the line ratings?
Dynamic ratings depend on large-scale wind patterns. The ratings will naturally rise and fall over the course of a few hours. This movement is clearly visible on DLR graphs.
In contrast, each forecast is stable. The predicted value for any specific hour does not "jump around" as real-time approaches. You can rely on the forecasted value to remain consistent.
Does the system require physical sensors?
No, the solution is entirely software-based. It does not require any sensors to be installed on towers or wires, meaning that the system is immediately scalable to your full network and there is no hardware to calibrate or maintain in harsh conditions.
How do you validate accuracy without sensors?
We continually validate our weather forecasts against over 100,000 ground based weather stations. Further, we have done validations comparing our weather forecasts against measurements taken on high voltage lines in critical spans.
Methodology & Calculations
What weather models do you use for ratings?
Claw is powered by a proprietary weather model built by Gridraven. The uniqueness of Gridraven’s weather model is twofold: first, it’s the highest resolution weather prediction out there, using meter-scale landscape data for forecasting weather parameters in each individual span. Second, the model outputs probability distributions for each variable, allowing the operator to set a desired safety level for the ratings, such as 98%.
How do you handle weather uncertainty?
Our key breakthrough is providing confidence ranges for weather parameters. For example, we can calculate the minimum wind speed with 99% certainty to ensure safety and reliability. Further, our models utilize satellite data, radar, and 1-meter resolution elevation models to understand the terrain, including ground objects like buildings and trees, ensuring reliability also in sheltered spans.
What methodology do you use for line ratings?
We primarily use CIGRE TB 601 or IEEE 738 methodology for both line rating and static rating calculations. The system can also switch to CIGRE TB 207 or custom methodologies if required.
Why do Dynamic Line Ratings (DLR) sometimes fall below the Static Rating (SR)?
This is a common occurrence because DLR calculations use more conservative assumptions regarding wind than the standard Static Rating to ensure safety. First, SR often assumes an optimal cooling angle of 90 degrees, while DLR uses a conservative minimum of 30 degrees (or 45 degrees fixed for Ambient Adjusted Ratings). Second, DLR applies a lower bound wind speed of 0.5 m/s, whereas SR often uses a fixed 0.61 m/s.
What are the default parameters for Static Rating (SR)?
Unless customized, the default settings are an ambient temperature of 35 degrees Celsius, a wind speed of 0.61 m/s, a wind attack angle of 90 degrees, and solar irradiance of 1033 W/m2.
How is conductor sag accounted for?
We account for sag by using the maximum allowed temperature for each span individually. We assume each span has a valid maximum temperature that avoids ground clearance violations. If LiDAR survey data is available, you can set individual temperature limits for specific spans to maximize capacity safely.
Implementation & Data Requirements
What data is needed to set up the system?
To configure the system, you are required to input: conductor type, conductor parameters and tower coordinates. Our system also makes use of high-resolution landscape data, which Gridraven obtains in the background. In most of Europe and the US, we rely on public LiDAR data with 1-meter resolution. If that is not available, we rely on satellite data.
Can you support secure, on-premise installations?
Yes, we support on-premise installation. Setup usually requires VPN access.
Can this be used for distribution lines?
Yes. We have customers with lines ranging from 30 kV to 400 kV. The thermal balance calculations apply across this whole range. Our weather models are validated for accuracy at 5 meters from the ground to account for the lower ground clearance of distribution lines compared to transmission lines.
How is the system integrated?
Claw can be hosted either on premises or in the Cloud. The integration is then customized to your SCADA / EMS. Options include for example IEC 104 for SCADA connection as a virtual RTU, or a REST API or Kafka for integrating to your EMS.
Business & Safety
Why choose software over sensors?
Sensors only measure real-time conditions and cannot forecast, which is essential for day-ahead markets and operational planning. Furthermore, sensors only measure the specific span they are installed on, whereas our software covers 100% of spans to ensure the limiting span is always identified. Further, software scales up to cover all lines and ensures that congestion is reduced and not just pushed down to the next weakest line.
Is the system safe given that ratings change hour to hour?
Safety is our priority. We address the risk of sag and flashover by using conservative lower bound inputs, such as 99% confidence on wind speed and conservative wind attack angles, rather than average values. This ensures that even when ratings change, the operation remains within safe thermal limits.
Is it possible to view an evaluation package or trial?
Yes, we offer a trial version where you can add a line and see the forecast. The free trial has a 30-day duration. We also offer a 12-month trial for one line for 8900 USD.