SMA Solar Technology AG September 2013

Technical benefits of String Inverter Technology

Mark Ryder

SMA Solar Technology AG

1 String inverter concept

Benefits of String inverters

Agenda

2

3 Low light conditions

2

4 Shading Management

5 Derating curves

6 Communication & Monitoring

7 Summary

SMA Solar Technology AG

String inverter concept and applications

3

Residential and small commercial sites:- Small string inverters (usually

single phase), the entire PV array can be just one string

Medium-size systems (50kW-250kW or more): commercial roofs, warehouses, farms... - Decentralised designs using

three or four strings connected to the inverter (mainly three-phase)With different oriented sub-arrays or shading

issues, the string inverter concept enables better power-related adaption to the irradiance conditions

SMA Solar Technology AG

1 String inverter concept

Benefits of String inverters

Agenda

2

3 Low light conditions

4

4 Shading Management

5 Derating curves

6 Communication & Monitoring

7 Summary

SMA Solar Technology AG

> Easy transport and installation

> Wide range of power classes available:

• Single phase

• Three phases

> Flexible designs (different orientation and

inclination): 2xMPPT's, OptiTrac...

> High Efficiency

> Easy maintenance

> Reliable

> Easy monitoring

Benefits of String inverters

5

SMA Solar Technology AG

1 String inverter concept

Benefits of String inverters

Agenda

2

3 Low light conditions

6

4 Shading Management

5 Derating curves

6 Communication & Monitoring

7 Summary

SMA Solar Technology AG

Low light conditions

7

> In countries with low levels of radiation, such as the UK, with less

than 1250kWh/m2 year, the efficiency curve for lower power

becomes more important.

SMA Solar Technology AG

1 String inverter concept

Benefits of String inverters

Agenda

2

3 Low light conditions

8

4 Shading Management

5 Derating curves

6 Communication & Monitoring

7 Summary

SMA Solar Technology AG

Shading Management

9

> It is not always possible to prevent shadows on PV plants.

> The loss must be minimized already in the planning phase.

> Influential factors:

> arrangement of the PV modules

> connection of PV modules

> the choice of the right inverter

Selecting the system connectionSevere shading: operate shaded and unshaded PV modules separately.

‒ No parallel connection of strings with different irradiation

2xMPP Tracker inverters

‒ The MPP tracking concept of the inverter is decisive to maximize the energy yield.

Improved MPP trackers can find the optimum operational point, the global MPP: SMA

OptiTrac Global Peak

SMA Solar Technology AG

1 String inverter concept

Benefits of String inverters

Agenda

2

3 Low light conditions

10

4 Shading Management

5 Derating curves

6 Communication & Monitoring

7 Summary

SMA Solar Technology AG

Derating curves

11

> The inverter reduces its power to protect components from

overheating.

> The correct design of a PV plant must not completely exclude

derating.

> High temperatures and overheating can occur when inverters are

mounted in commercial closed plant rooms with low ventilation

Best practices:> Install the inverters in cool locations

> Sufficient air exchange

> Not under direct sunlight

> Minimum clearance between inverters

> Select an inverter with good derating curves

SMA Solar Technology AG

1 String inverter concept

Benefits of String inverters

Agenda

2

3 Low light conditions

12

4 Shading Management

5 Derating curves

6 Communication & Monitoring

7 Summary

SMA Solar Technology AG

Communication & Monitoring

13

> Monitoring ensures that failures or faults are quickly detected

> For medium and large size systems a data logger is required

> New technologies allow faster communications

(Webconnect/Speedwire)

> With internet-base monitoring systems, a service provider takes over

the evaluation of the operating data.

SMA Solar Technology AG

1 String inverter concept

Benefits of String inverters

Agenda

2

3 Low light conditions

14

4 Shading Management

5 Derating curves

6 Communication & Monitoring

7 Summary – SMA Case study

SMA Solar Technology AG

Summary

15

> Wide range of string inverters depending on the application:

> For complicated commercial roofs:

> Shading issues, difficult configurations: standard Sunny Tripowers

(with 2xMPP Trackers and OptiTrac Global Peak)

> Easy and simple commercial roofs (cost-effective systems): Sunny

Tripowers-project version

> Useful for East-West configurations too: polystring concept

SMA Solar Technology AG

SMA solution for commercial roofs:Unique Project Performance Package

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>Sunny Tripower 20000 TLEE PROJECT – gains highest yields

>Cutting edge high speed communication– optimises the plant control and gives full visibility

INVERTER

COMMUNICATION

>Commissioning package – secures your investment

>Remote Service – reduces transaction cost

>99% Availability Guarantee – insures your ROI

SERVICE

>> This is unique in the market and only offered by SMA.

SMA Solar Technology AG

SMA Case study

17

Sunny Tripower inverters complete your projects with the all the

benefits of string inverters:

> High efficiency (over 98%) under low light conditions

> OptiTrac Global Peak and 2xMMP trackers for shading

management

> Good derating curves

> Easy and fast communication & monitoring with SMA devices

> Reliable and easy maintenance

SMA Solar Technology AG

THANKS FOR YOUR ATTENTION

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