Solar Systems Parameters
Weather Variables
Wind Direction expressed in degrees from north. This is measured by an anemometer mounted on site (Windcap Ultrasonic Windsensor WS425) at 8 meters, with ± 2% accuracy. 10 second samples are averaged over 5 minutes.
Rainfall in mm recorded that day, reset at 12am. Rainfall is measured with an accuracy of ±2% for intensities from 24 to 300mm/hr, ±3% for intensities from 300 to 500mm/hr. (TB3A Rain Gauge) 10 second samples are averaged over 5 minutes.
Wind Speed in meters per second. This is measured by an anemometer (Windcap Ultrasonic Windsensor WS425) installed on site at 8m , with an accuracy of 0.135m/s (0.3mph, 0.26 knots) or 3% of the reading, whichever is greater. 10 second samples are averaged over 5 minutes.
Temperature measured in degrees Celsius on site at 2m with an accuracy of ± 0.2ºC. (Vaisala HMP45A.) 10 second samples are averaged over 5 minutes.
Diffuse Insolation is light that has been scattered by atmospheric particles out of the line of direct radiation from the sun. This is expressed in kW/m2, and measured on site. 95% of individual readings will be within an interval of ± 8% ± 10w.m2. (Delta T SPN 1 Sunshine Pyranometer) 10 second samples are averaged over 5 minutes.
Global Insolation Energy in sunlight on a horizontal plane at the surface of the earth, measured in kW/m2. 95% of individual readings will be within an interval of ± 8% ± 10w.m2. (Delta T SPN 1 Sunshine Pyranometer) 10 second samples are averaged over 5 minutes.
Humidity Relative humidity, expressed as a percentage. This is measured on site at 2m, with an accuracy of 2% at 0 - 90% humidity, 3% at 90 to 100%. (Vaisala HMP45A.) 10 second samples are averaged over 5 minutes.
Master Power
Power
kWh a del-rec, kWh b del-rec, kWh c del-rec, kWh tot del-rec
Total kWh delivered less received for each phase, and the system total. This is a cumulative record, since system install, with 1 second readings reported every 5 minutes. This is measured with a Class 0.2 meter with ± 0.2% accuracy. (Ion 7550, CT: 5/100)
5-Min-Avg kWa, 5-Min-Avg kWb, 5-Min-Avg kWc, 5-Min-Avg kWtot
Phase and total power in kW. One second readings are averaged over a 5 minute period. This is measured with a Class 0.2 meter with ± 0.2% accuracy. (Ion 7550, CT: 5/100)
Voltage/Current
5-Min-Avg V1THD, 5-Min-Avg V2THD, 5-Min-Avg V3THD
Total Harmonic Voltage Distortion for phases a,b and c (as 1, 2, 3): the ratio of the powers of voltage harmonic components to the power of the base frequency. Accuracy is ±1.0%. (Ion 7550, CT: 5/100)
5-Min-Avg Vln a, 5-Min-Avg Vln b, 5-Min-Avg Vln c.
Line to neutral AC voltage for each phase, measured with an accuracy of ± 0.1%. (Ion 7550, CT: 5/100)
5-Min-Avg Ia, 5-Min-Avg Ib, 5-Min-Avg Ic
Current on each phase in Amperes with an accuracy of ±0.1%. (Ion 7550, CT: 5/100)
5-Min-Avg Vllav
The average of the 3 line to line voltages, with one second values averaged over 5 minute periods. This is measured with a class 0.2 meter, with an accuracy of ± 0.1%. (Ion 7550, CT: 5/100)
Power Quality
5-Min-Avg PFa, 5-Min-Avg PFb, 5-Min-Avg PFc
Power Factor, for phases a, b and c, expressed as a percentage. This is measured with ± 0.2% accuracy. One second samples are averaged over 5 minutes. (Ion 7550, CT: 5/100)
5-Min-Avg Freq
AC frequency measured in Hz, with an accuracy of ± 0.005Hz. One second samples are averaged over 5 minutes. (Ion 7550, CT: 5/100)
5-Min-Avg I1THD, 5-Min-Avg I2THD, 5-Min-Avg I3THD
Total harmonic current distortion for the phases a,b and c (as 1, 2, 3.) This is the ratio of the powers of all current harmonic components to the power of the base current frequency. Accuracy is ± 1.0%. One second samples are averaged over 5 minutes. (Ion 7550, CT: 5/100)
Technology Power
kWh Del-Rec
Total kWh delivered less received. This is the accumulated value over the life of the system, with readings taken every second and reported every 5 minutes. This is measured with a Class 0.5 meter with ± 0.5% accuracy. (Ion 6200, CT: dependent on technology - see below.)
5-Min-Avg I
Current measured in Amperes, one second samples averaged over 5 minutes. For readings below 5% of the full scale, accuracy is 0.3%, for greater than 5% of the full scale accuracy is 0.3% + 0.05% of the full scale. (Ion 6200, CT: 50/5 except Solar Inception large scale trackers: 100/5.)
5-Min-Avg kW
Power in kW. One second readings are averaged over a 5 minute period. This is measured with a Class 0.5 meter with ± 0.5% accuracy. (Ion 6200, CT: 50/5 except Solar Inception large scale trackers: 100/5.)
Eff Ratio %
The efficiency with which the array is operating relative to the rated value of the PV Panels This compares power (accuracy 0.5%) with the total rated DC output of the panels installed on the array, ie kW (AC output measured at Ion 6200, CT: 50/5 except Solar Inception large scale trackers: 100/5.)/ Array kWp (DC SOC)
Technology Power Quality
5-Min-Avg ITHD
Total harmonic current distortion This is the ratio of the powers of all current harmonic components to the power of the base current frequency. Accuracy is ± 1.0%. One second samples are averaged over 5 minutes. (Ion 6200, CT: 50/5 except Solar Inception large scale trackers: 100/5.)