CEI's Project Development Manager dives into graphical analysis of solar PV plant data.

1. Graphical Analysis of PV Plant Data
Saurabh Samdani
Project Development Manager

2. Cupertino Electric (CEI) Overview
● Services: Engineering & construction
● Founded: 1954
● Employees: ≈ 1,400 (field + office)
● Revenue: $574 million (2011)
● Safety: AGC “Safety Awards of
Excellence” (2011)
● Customers: Fortune 100 companies
● Reach: National
● MW of Solar: 150 MW

3. Agenda
● Challenges/opportunities surrounding
PV plant data
● Why worry about how to display data?
● Charts for common questions
● Case study: irradiance sensors
● Q&A

5. Now that you have the data,
what do you do with it?

6. “People don’t want to buy a quarter‐inch drill.
People want a quarter‐inch hole.”
― Harvard Marke ng Professor, Theodore Levi
PLANT
STATUS
DATA

7. I II III IV
X Y X Y X Y X Y
10 8.04 10 9.14 10 7.46 8 6.58
8 6.95 8 8.14 8 6.77 8 5.76
13 7.58 13 8.74 13 12.74 8 7.71
9 8.81 9 8.77 9 7.11 8 8.84
11 8.33 11 9.26 11 7.81 8 8.47
14 9.96 14 8.1 14 8.84 8 7.04
6 7.24 6 6.13 6 6.08 8 5.25
4 4.26 4 3.1 4 5.39 19 12.5
12 10.84 12 9.13 12 8.15 8 5.56
7 4.82 7 7.26 7 6.42 8 7.91
5 5.68 5 4.74 5 5.73 8 6.89
9 11 9 11 9 11 9 11
Linear Regression . .

8. I II
10
5
0
III IV
10
5
0
5 10 15 5 10 15

10. The Big Question:
How is my plant doing?
Power Irradiance Capacity Index
18 MW 850 W/m2 93 %
Active Alarm
Needs Attention
Needs Acknowledge

11. Example Utility Plant Dashboard

12. DG System Dashboard

13. Kiosk View

14. Kiosk View

15. The Big Question:
How is my plant doing?
Power Irradiance Capacity Index
18 MW 850 W/m2 93 %
Active Alarm
Needs Attention
Needs Acknowledge

16. Metrics
Actual Simulated Historical

17. Cumulative Energy Production

18. Monthly Energy Production
MWh
Variance %

19. Back‐Up Data
Month of Date Actual MWh Simulated MWh Difference
Sep‐11 2,700 2,500 8.0%
Oct‐11 2,450 2,300 6.5%
Nov‐11 1,700 1,750 ‐2.9%
Dec‐11 1,833 2,028 ‐9.6%
Jan‐12 1,879 1,977 ‐5.0%
Feb‐12 2,250 2,263 ‐0.6%
Mar‐12 3,125 2,839 10.1%
Apr‐12 3,325 3,100 7.3%
May‐12 3,750 3,549 5.7%
Jun‐12 3,555 3,405 4.4%
Jul‐12 3,250 3,380 ‐3.8%
Aug‐12 2,800 3,083 ‐9.2%
Sep‐12 2,300 2,500 ‐8.0%
Total 34,917 34,674 1%

20. Longer Term: Progress Report
actual historical simulated

21. Problem?
Capacity index Capacity index
South System
92
78

22. Inverter AC kW Output

23. Inverter Issue?

24. Culprit: Coolant Leakage
Cabinet Temperature

25. Case Study: Irradiance Sensors

26. Add Second Sensor

27. Third Sensor

28. Zoomed‐in View

29. Scatterplot matrix

30. Marker Colors by
time of day
8 AM 5 PM

32. Final Thoughts
● Focus on ¼” hole, rather than the drill
● Data needs context
● Graphical formats are quick to understand
● Filter out the necessary from the extraneous
● Choose the appropriate chart

33. Q&A
● For comments or to follow the discussion, visit:
http://blog.cei.com