In May 2019, Live Power added Smith Mountain, a key pumped storage hydro facility in PJM, to our real-time monitoring network.
Smith Mountain like it’s sister to the north, Bath County, acts like a giant battery capable of delivering 588 MW to be called in times of peak demand and high prices. Normal operations are daily cycles of pumping off-peak and generation during peak. Additionally, because of its location in PJM South it has an impact on tie lines moving imports from the Southeast. As the figure shows, it is very price responsive.
How Live Power Monitors Facilities
By using aerial imagery and reference datasets from PJM, FERC and transmission owners we plan out where we need sensors. At Smith Mountain, we selected five(5) 138kV lines for monitoring. Once the planning was completed, we dispatched 2 technicians to knock on doors and deploy sensors. It took us 4 different trips to the area to complete this facility.
After placement of the sensors, our technician conducts a detailed field site survey measuring the position of transmission conductors with respect to the position of our sensor. This provides the input for a precise modeling of the magnetic field geometry.
After we have sensors in place the field surveys completed, we begin the process of fine tuning our estimate of total generation or load for pumping. A team of analysts will critique each plant before releasing it to customers. This process includes these steps:
The geometric model of the sensor position to the conductors is used as input to calculate current (power) from the magnetic field measurements. This is independent of any external control or reference data.
We identify periods that appear to be zero output and zero load. This provides a training period to model for no activity.
Then we scale the maximum generation and maximum pumping to the plant capacity during a period that makes economic sense, i.e., a high price period for maximum generation output.
The result over a period of a week or two is examined for total efficiency of energy for pumping versus generation.
The final review is to discern clear on and off of each generating unit.
Over time we will continue to monitor these and adjust as necessary.
Because Live Power measures every 1 min, the operations at the Leesville Dam of the 2 x 20 MW turbines in the lower reservoir below Smith Mountain are very clear as roughly 20 generation peaks each hour which appear in the time series chart each hour.
Releases for flood control June 8-10th
Smith Mountain showed some unusual generation over the last weekend with no pumping cycles. We believe the reservoir was drawn down as a precaution to manage flood waters from upstream precipitation. This was confirmed by a NWS flood warning alert. We are excited to be able to spot this type of event and look to improve the timeliness and context this sort of hydro event in the future.