Graphical Analysis of PV Plant DataSaurabh SamdaniProject Development Manager

● 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 

Cupertino Electric (CEI) Overview

Agenda

● Challenges/opportunities surrounding PV plant data

●Why worry about how to display data? ● Charts for common questions● Case study: irradiance sensors● Q&A

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

PLANTSTATUS

DATA

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

LinearRegression . .

I II III IVX Y X Y X Y X Y10 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

10

5

0

10

5

05 10 15 5 10 15

I II

III IV

The Big Question: How is my plant doing?

Irradiance

850 W/m2

Power

18 MW

Active AlarmNeeds AttentionNeeds Acknowledge

Capacity Index

93 %

Example Utility Plant Dashboard

DG System Dashboard

Kiosk View

Kiosk View

The Big Question: How is my plant doing?

Irradiance

850 W/m2

Power

18 MW

Active AlarmNeeds AttentionNeeds Acknowledge

Capacity Index

93 %

Metrics

Actual Simulated Historical

Cumulative Energy Production

MWh

Variance %

Monthly Energy Production

Back‐Up DataMonth of Date Actual MWh Simulated MWh DifferenceSep‐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%

Longer Term: Progress Report

actual historical simulated

Problem?

Capacity indexSouth System

92

78

Capacity index

Inverter AC kW Output

Inverter Issue?

Culprit: Coolant Leakage

Cabinet Temperature

Case Study: Irradiance Sensors

Add Second Sensor

Third Sensor

Zoomed‐in View

Scatterplot matrix

8 AM 5 PM

Marker Colors by time of day

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

Q&A

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