Mismatch,Shade,tools recommended during energy audits- PV systems

1. Inspection
Why including measurements?
Visual inspections is not enough!
Andreas Iliou - shading and measurements analysis

2. 1 Module Circuit Design
2 Mismatch Effects
3 Hot-Spot Heating
4 Bypass diode, temperature

3. 01
Module Circuit Design
19 modules per string

4.  Module Circuit Design – Shading 4
Some strings are shaded , flowers / Pylones

5.  Module Circuit Design – Shading 5
Some strings are shaded , flowers / Pylones

6.  Module Circuit Design – Shading 6
Some strings are shaded , flowers / Pylones

7. Modules shaded via transmissionlines 7
PV Plant with similar shadings from a Transmission line

8.  Module Circuit Design -Shading 8
Modules performance less in substrings shaded
during the whole day
Could be regrouped easily as place is available
shade shading
Soft shade

9.  Module Circuit Design -Shading 9
shaded
Rows shaded
„Noise “measured on site during Shading e.g M9 O1 U3.2 G8 2,38 Ohm / 245 mA
AC leakage current !!!

10. Module Circuit Installation 10
1 module was dismantled from the wind, therefore shading
another 5 modules in different strings – future hotspot possible !!

11. Module Circuit Installation 11
Mountain/ Valley installation so different values as module strings
have different angles towards the sun

12. 02
Mismatch Effects

13.  Mismatch Effects 13
M9.O1 U3.2 C36 –G8
6,8 A 13,3 mA
7,4 A 14,7mA
6,5 A 15,9 mA
7,6 A 14,8mA
7,1 A 13,6mA
7,0 A 13,5 mA
AC leakage current
M9.O1 U3.2 –G8
2,38 Ohm / 245 mA
at earthing point
Different angles towards the sun
See more details sep. excel sheets

14.  Mismatch- what can be achieved with
14
measurements on site ?
A 1 / G 10
Shaded array
0,3mA 7,2 7,7 7,6 6,9 7,1 7,6 A1
2Ohm / 44, 44, 44, 45, 44, 51,
3,8mA 7 3 2 4 2 6 G10
Here 51,6 A instead normally 44,7 – 45 A
Due to contact problems increasing resistance
Shaded row , or burned busbars will show deviations

15.  Mismatch Effects 15
Instead of normal values 44- 45 A
this substring is over the limit
After investigation it shows
Burned current sensors
We need to do Visual and
Measurements on sites
One alone is not enough
See more details sep. excel sheets

16. 03
Hot-Spot Heating

17. Field Observation 17
Siemens Les Mees
This results have been caused by the shading permanently of some
substrings via transmission lines/ or –and Pylons
Hotspots are not accumulated right now- future ?! ( see page 7)

18. 04
Bypass Diodes

19.  Bypass Diodes 19
Normal picture with bypassdiodes getting cooled

20.  Bypass Diodes 20
Bypass diodes getting hotter, heating up -> shading