20111010 gcs training wuxi common mistakes in planning and installation - v02

WUXI GCS Workshop

Common mistakes in planning and installing PV systems in Germany

October 2011Andreas Iliou Technical Customer Service Engineers Germany

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Content

1. Common mistakes in planning a PV system

2. Common mistakes in installing a PV system

3. Consequences for Claim Management

2

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1. Common mistakes in planning a PV system

3

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a) Shadowing (can cause Bypass diode damages)

b) Temperature zones (performance issues)

c) Layout of the panels (vertical, horizontal) (performance issues with dirt)

d) Snow loads (glass breakage or frame damage)

e) EMC and surge protection (can cause surges and Bypass diode damages)

Planning mistakes 4

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Plan your solar plant w/o shadow (12PM on the shortest day of the year (Dec/21))!

a) Shadowing (1) 5

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Plan your solar plant w/o shadow (12PM on the shortest day of the year (Dec/21))!

a) Shadowing (2) 6

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Plan your solar plant w/o shadow (12PM on the shortest day of the year (Dec/21))!

a) Shadowing (3) 7

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Connect all panels together which are in one horizontal temperature zone!

b) Temperature Zones 8

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Optimize the string layout aiming for:

• matching string lengths for various strings (same string length for all strings)

• horizontal or vertical layout for a good mounting solution

• inclination should be >10°to effectively remove dirt (self cleaning effect)

• leave sufficient space between the panels for thermal expansion

c) Layout of the panels 9

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Check for a suitable mounting solution according to the snow load zone:

• for a higher snow load zone (Bavarian forest), a higher mechanical load must be chosen

• Installation Manual p. 9

• Modules should not be installed to narrow to roof-top limits

• mounting surface; >15m space between mounting structures

d) Snow Load and Wind load 10

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Always do not separate the plus pole and the minus pole on distance as it creates Electrical fields!

e) EMC and surge protection 11

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2. Common mistakes in installing a PV system

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a) Mounting systems (glass breakage)

b) Loose cables and connectors (connectors burnt)

c) Grounding and Earthing (equipotential)

d) Dirty panels

e) Inverter dimensioning (performance issues)

Installation mistakes 13

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a) Mounting systems 14

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b) Loose cables and connectors 15

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c) Grounding and Earthing 16

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d) Dirty panels 17

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e) Inverter dimensioning 18

• For Germany, a typical dimensioning is DC/AC: 110...115% depending on orientation, installation type, inverter, heat dissipation

• Always double-check with the inverter manufacturer sizing tool if the string length and the dimensioning is done properly!

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3. Consequences for Claim Management

19

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Planning & Installation mistakes 20

• Influences on Performance:

– dirty panels cause up to 10% losses

– wrong string connections (too short, too long) cause around 1...5% losses

– shadowing can cause up to 50% losses

– a wrong panel layout (with temperature zones) can cause around 1...10% losses

– loose connectors can cause up to 5% losses

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Planning & Installation mistakes 21

• Influences on Bypass diode:

– missing surge protection can cause Bypass diode damages

– permanent shading can cause Bypass diode damages

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Planning & Installation mistakes 22

• Further Influences:

– Glass breakage: too tight mounting solutions can cause glass breakage

– Hot Spots: permanent dirt on the panel has not been cleaned and can cause hot spots

– Isolation issues: inconsistent grounding in the field can cause isolation issues with the inverter and the panels

THANK YOU!

October 2011Andreas Iliou Technical Customer Service Engineers Germany