Solar generation estimation

A method for estimating solar generation capacity in a distribution grid feeder, the method comprising:

• measuring voltage and current at a source to the feeder, at sample times spaced at a regular interval, for a time duration of ten or more days;
• computing, using a processor having a memory, a maximum solar irradiance curve applicable for a geographic location of the feeder and for a current time of year, where the maximum solar irradiance curve defines a maximum solar irradiance power per unit area as a function of time of day, from sunrise to sunset;
• calculating a change in load (ΔLoad) data point at each sample time, using the processor, from the measured voltage and current, where the ΔLoad data points calculated as an absolute value of a difference between load at a current sample time and load at an immediately previous sample time;
• arranging all of the ΔLoad data points in a data array by time of day of the sample time;
• modifying the ΔLoad data points in the data array to eliminate changes in load caused by actual consumer power usage changes, where the actual consumer power usage changes are indicated by a change in active power provided to the feeder accompanied by a coincident and proportional change in reactive power provided to the feeder;
• scaling the maximum solar irradiance curve to fit the modified ΔLoad data points in the data array;
• estimating the solar generation capacity in the feeder as a maximum value of the maximum solar irradiance curve after scaling;
• and
• using the estimated solar generation capacity in the feeder for grid operational control.

A system for estimating solar generation capacity, the system comprising:

• a distribution grid feeder with a source providing power to the feeder, where the source includes sensors measuring voltage and current provided to the feeder;
• and
• a computer having a processor and memory, the computer being in communication with the source and receiving voltage and current data from the sensors,
• where the processor is configured with an algorithm performing steps of;
• computing a maximum solar irradiance curve applicable for a location of the feeder and a current time of year, calculating a change in load between a current sample time and a previous sample time, where the sample times are spaced at a regular interval and span a time duration of ten or more days, arranging each calculated change in load and its time of day as a data point in a data array, scaling the maximum solar irradiance curve to fit all of the data points, and estimating the solar generation capacity of the feeder based on the scaled maximum solar irradiance curve.