School of Engineering and Energy ENG460€¦ · School of Engineering and Energy ENG460 Engineering Thesis 2011 Performance Evaluation, Simulation and Design Assessment of the 56

School of Engineering and Energy

ENG460

Engineering Thesis

2011

Performance Evaluation, Simulation and Design

Assessment of the 56 kWp Murdoch University

Library Photovoltaic System

Digital Appendices for software and data handling purposes

Stephen Rose

30658774

“A report submitted to the School of Engineering and Energy, Murdoch University in partial

fulfilment of the requirements for the degree of Bachelor of Engineering”

Unit Coordinator: Professor Parisa Bahri

Supervisor: Dr. Martina Calais

Associate Supervisor: Dr. Trevor Pryor

i

Contents

1 Appendix B ..........................................................................................................................4

1.1 Establishment of Data Logging System ......................................................................4

1.2 Data Downloading Steps .............................................................................................4

18 Appendix F....................................................................................................................12

18.1 PVsyst Component Electrical Parameters .................................................................12

18.1.1 SMA SMC 6000A.............................................................................................. 12

18.1.2 Kyocera KD135GH-2P ...................................................................................... 14

18.1.3 Sungrid SG-175M5 – Default Model ................................................................ 16

18.1.4 Sungrid SG-175M5 -V – Voltage Temperature Coefficient Adjusted Model ... 19

18.1.5 PVsyst Model Parameters .................................................................................. 21

19 Appendix G ...................................................................................................................24

19.1 PVsyst Shading Study ...............................................................................................24

20 Appendix I ....................................................................................................................25

20.1 AS 5033 Compliance Notes ......................................................................................25

21 Appendix J ....................................................................................................................28

21.1 Solar Unlimited Cable Calculations ..........................................................................28

21.2 Solar PV Cable Calculations .....................................................................................31

22 Appendix K ...................................................................................................................37

22.1 Shading Study Photos for May 22 2011 ....................................................................37

11 am .....................................................................................................................................39

12 noon..................................................................................................................................40

1 pm ......................................................................................................................................41

2 pm ......................................................................................................................................42

3 pm ......................................................................................................................................44

4 pm ......................................................................................................................................45

23 Appendix L ...................................................................................................................46

ii

23.1 Afternoon Shading Study for December 2011 ..........................................................46

Figures

Figure 59 Existing Sunny Porta display..................................................................................... 9

Figure 60 SMA FlashView screenshots ................................................................................... 10

Figure 64 SMA SMC 6000A main parameters ........................................................................ 12

Figure 65 SMA SMC 6000A secondary parameters ............................................................... 12

Figure 66 SMA SMC 6000A efficiency curve parameters ...................................................... 13

Figure 67 SMA SMC 6000A physical parameters .................................................................. 13

Figure 68 Kyocera KD135GH-2P basic data ........................................................................... 14

Figure 69 Kyocera KD135GH-2P model parameters – Shunt and series resistances ............. 14

Figure 70 Kyocera KD135GH-2P model parameters – shunt resistance characteristics ......... 15

Figure 71 Kyocera KD135GH-2P model parameters – Power temperature coefficient

characteristics ........................................................................................................................... 15

Figure 72 Kyocera KD135GH-2P Physical characteristics, diode and system voltage

parameters ................................................................................................................................ 16

Figure 73 Sungrid SG-175M5 basic data ................................................................................. 16

Figure 74 Sungrid SG-175M5 model parameters – Shunt and series resistances ................... 17

Figure 75 Sungrid SG-175M5 model parameters – shunt resistance characteristics ............... 17

Figure 76 Sungrid SG-175M5 model parameters – Power temperature coefficient


Figure 77 Sungrid SG-175M5 Physical characteristics, diode and system voltage parameters

.................................................................................................................................................. 18

Figure 78 Sungrid SG-175M5-V basic data ............................................................................ 19

Figure 79 Sungrid SG-175M5-V model parameters – Shunt and series resistances ............... 19

Figure 80 Sungrid SG-175M5-V model parameters – shunt resistance characteristics .......... 20

Figure 81 Sungrid SG-175M5-V model parameters – Power temperature coefficient


Figure 82 Sungrid SG-175M5-V Physical characteristics, diode and system voltage

parameters ................................................................................................................................ 21

Figure 83 Inverter and module inputs for installation one ....................................................... 21

Figure 84 Inverter and module inputs for installation two, with stings of 11 panels .............. 22

iii

Figure 85 Inverter and module inputs for installation two, with stings of 12 panels .............. 22

Figure 86 Thermal losses and NOCT factor used in simulations ............................................ 23

Figure 87 PVSyst hourly shading study for 28th

June 2011 from 8am to 4pm ........................ 24

4

1 Appendix B

1.1 Establishment of Data Logging System

One of the objectives for this project was to establish a reliable data logging system where

information from the inverters and meteorological sensors can be stored and accessed for

analysis and educational purposes. The SMA WebBox provides a FTP Push protocol where

daily data collected from the SMA equipment is stored. Through the help of Will Stirling of the

School of Engineering and Energy, this has been established and is currently operational.

The data stored is in the form of individual 5 minute averages of measured parameters in a XML

file format which is embedded within multiple layers of compressed folders. This has posed

problems with data accessibility which, through the work of Caleb Duggan of IT Services, a

script has been created to extract these files.

Further issues have been encountered with the importation and handling of the files due the

inability of Microsoft Excel to be able to import the files without error. For these reasons,

weekly manual downloading of data from the WebBox has been undertaken throughout the

project, and is recommended to continue. The manually downloaded data is in the form of a

single Comma Separated Variable (CSV) file each day which is easily handled by MS Excel or

other spreadsheet programs or mathematical analysis software such as Matlab. It is not possible

for this to be done automatically and a reminder should be set to ensure this is done.

It is possible through access to the WebBox via the internet and the WebBox’s IP address, to

access the data from anywhere with an internet connection, with additional accessibility on

campus through direct file access over the network. Access details for both these methods are

provided on the supplied CD rom.

1.2 Data Downloading Steps

On Campus Access

Manual downloading of data while on campus can be achieved by direct FTP access to the

WebBox by double clicking on the My Network Places icon on the desktop, or My Computer. In

the address bar, enter the following address:

ftp://user:[email protected]/

ftp://user:[email protected]/

5

This will bring up the internal Data folder. Double click on this and the enclosed sub-folder

which contains the data files which can then be simply copied to your computer or external

drive.

Internet Access

After opening a web browser, enter the following URL to the address bar:

http://134.115.91.42/

This will take you to the web interface of the WebBox. Entre the password: sma

This password is case sensitive.

NB: For security reasons, it may be advisable to have the password changed once access is

gained. If this is done, advise the Office of Commercial Services and anyone else who has access

of the new password. This will also affect the ftp access noted above and the sma in the address

will need to be substituted with the new password.

Within the home page, click on WebBox

http://134.115.91.42/

6

Then click on Recording

Then click on Download to download all the available files for the month.

7

If files of the past month are required, click on the drop menu to the left of the download button

to select the previous month and then click Download.

Data Handling

It is recommended that due to the process involved, data should be imported in batches to avoid

repetitive work when not needed. A months data is easily handled and takes little more time to

process.

Once the data is downloaded and ready to be analysed, double click on My Computer, then C

drive.

Create a new folder named CSVs (if one hasn’t already been created) and place the downloaded

CSV files within it. If previously edited files are in an old folder, remove these and archive them

or rename the old file.

8

Open the MS Excel file names MACROS, this file contains all the scripts used to get the data

into a more useable format.

Then open a second blank workbook which the files will be stored in.

If macros functionality has not been enabled on this computer, this will need to be done

When enabled, click on the View tab, then Macros.

This will bring up the Macros for the data processing.

The Macros are in order of execution beginning with AMultiCSVImport. When this macro has

completed successfully, delete the final sheets not named with dates. If not, the following

macros will hit errors.

When macro D (D1dataCullEU and D2dataCullEZ), inspect the worksheets to ascertain the

final column the data is stored in. It will either be column EU or EZ. Then use the corresponding

macro.

Once macro ECombinedData has been executed, STOP. The remaining macros should only be

run for specific reasons which are explained by highlighting the macro and clicking Edit.

9

Once data is downloaded and processed, the original CSV files should be archived for possible

future use or data recovery.

Data Displaying

Finding an alternative method for displaying information regarding the array was another task of

the project. The existing Sunny Portal data display is simple, static and provides little

information for people entering the library foyer

Figure 1 Existing Sunny Porta display

(lImage: SMA Sunny Portal, URL:

http://www.sunnyportal.com/Templates/PublicPageOverview.aspx?page=3c53adf2-dae5-4080-a51b-

e0a02819c968&plant=a26c7f29-3188-4db7-9a9a-a2c1392b286b&splang=en-US, Accessed 17/06/11)

http://www.sunnyportal.com/Templates/PublicPageOverview.aspx?page=3c53adf2-dae5-4080-a51b-e0a02819c968&plant=a26c7f29-3188-4db7-9a9a-a2c1392b286b&splang=en-US

http://www.sunnyportal.com/Templates/PublicPageOverview.aspx?page=3c53adf2-dae5-4080-a51b-e0a02819c968&plant=a26c7f29-3188-4db7-9a9a-a2c1392b286b&splang=en-US

10

SMA has produced an alternative free software package specifically for this purpose called

FlashView.

Flashview is a dedicated display application which provides live information direct from the

WebBox, with finer information resolution and animations.

Figure 2 SMA FlashView screenshots

(Images: SMA, FlashView, URL: http://www.sma-australia.com.au/en_AU/products/software/flashview.html,

Accessed 17/06/11)

http://www.sma-australia.com.au/en_AU/products/software/flashview.html

11

It was hoped to have this software up and running by the completion of the project, however

approval was still being sought for it to be loaded on the dedicated display computer.

12

18 Appendix F

18.1 PVsyst Component Electrical Parameters

18.1.1 SMA SMC 6000A

Figure 3 SMA SMC 6000A main parameters

Figure 4 SMA SMC 6000A secondary parameters

13

Figure 5 SMA SMC 6000A efficiency curve parameters

Figure 6 SMA SMC 6000A physical parameters

14

18.1.2 Kyocera KD135GH-2P

Figure 7 Kyocera KD135GH-2P basic data

Figure 8 Kyocera KD135GH-2P model parameters – Shunt and series resistances

15

Figure 9 Kyocera KD135GH-2P model parameters – shunt resistance characteristics

Figure 10 Kyocera KD135GH-2P model parameters – Power temperature coefficient characteristics

16

Figure 11 Kyocera KD135GH-2P Physical characteristics, diode and system voltage parameters

18.1.3 Sungrid SG-175M5 – Default Model

Figure 12 Sungrid SG-175M5 basic data

17

Figure 13 Sungrid SG-175M5 model parameters – Shunt and series resistances

Figure 14 Sungrid SG-175M5 model parameters – shunt resistance characteristics

18

Figure 15 Sungrid SG-175M5 model parameters – Power temperature coefficient characteristics

Figure 16 Sungrid SG-175M5 Physical characteristics, diode and system voltage parameters

19

18.1.4 Sungrid SG-175M5 -V – Voltage Temperature Coefficient Adjusted Model

Figure 17 Sungrid SG-175M5-V basic data

Figure 18 Sungrid SG-175M5-V model parameters – Shunt and series resistances

20

Figure 19 Sungrid SG-175M5-V model parameters – shunt resistance characteristics

Figure 20 Sungrid SG-175M5-V model parameters – Power temperature coefficient characteristics

21

Figure 21 Sungrid SG-175M5-V Physical characteristics, diode and system voltage parameters

18.1.5 PVsyst Model Parameters

Figure 22 Inverter and module inputs for installation one

22

Figure 23 Inverter and module inputs for installation two, with stings of 11 panels

Figure 24 Inverter and module inputs for installation two, with stings of 12 panels

23

Figure 25 Thermal losses and NOCT factor used in simulations

24

19 Appendix G

19.1 PVsyst Shading Study

Figure 26 PVSyst hourly shading study for 28th

June 2011 from 8am to 4pm

25

20 Appendix I

Appendix I can be found on the attached CD Rom as the digital Appendices.

Headings have been kept as reference and for the table of contents.

20.1 AS 5033 Compliance Notes

§ 1.1 Scope

The MULPVS falls in under the 600 V scope and is therefore not affected.

Table 2.1 Number of parallel strings without OC protection

Current standards use IMOD REVERSE , with recommendations for the use of the maximum fuse

rating.

Installation 1:

Limiting reverse current is stated as 15 A and has been assumed to refer to the max fuse rating,

with the short circuit current being 8.37 A. Using table 2.1 and 2 parallel strings per inverter, we

obtain:

Therefore, OC protection is NOT required.

Installation 2:

Short circuit current rating is 5.48 A, with a Series fuse rating of 10 A (assuming this is fuse max

rating), with 3 parallel strings per inverter, we obtain:

Therefore, OC protection is required as two times the short circuit current is greater than the

reverse current carrying capacity of the modules.

OC protection, as well as DC isolation and fuse protection, is installed as one component, being

an ABB DC isolation switch (ABB S802PV, S20, 800 Vdc) installed on each string and

therefore complies.

1 ISC IFUSEMAX 2 ISC

8. 37A 15A 16. 74A

2 ISC IFUSEMAX 3 ISC

10. 96A 10A 16. 44A

26

§ 2.5.4 ELV Segmentation

Installation 1 has been installed with M/C connections every 5 panels, limiting voltage at STC to

110.5 V.

Installation 2 is not clear on whether or not ELV sectionalisation has been incorporated into the

system. However, module cables with removable connectors may be considered acceptable.

§ 3.3.3 Temperature Rise

As recommended by AS4502, PV arrays are assumed to operate at 25°C above ambient.

However, data obtained from the array Sensorbox shows temperatures regularly reaching well in

excess of 70°C (with a maximum of 77°C), more than 30°C above ambient, with occasions

greater than 40°C above ambient.

When factoring this into module performance,

Kyocera (using -0.42%/°C)

Sungrid (using -0.47%/°C)

So the reduction in cell performance is regularly between 19% and 22%.

Two factors play a key part to this. The first being that the array is fixed on top of the metal roof

sheeting, which provides minimal air ventilation to the rear of the panels. The second being the

arrays sheltered position from cooling breezes. As the array faces north, with many buildings

surrounding the Bush Court area, wind is substantially lower than experienced at the Murdoch

Meteorological (MET) station, with differences up to 5.3 m/s (19 km/h) seen, at an average of

1.4 m/s (5.2 km/h). It should be noted that the Sensorbox, with the wind anemometer, ambient

and module temperature sensors, is located on the eastern end of the library roof where it has

more exposure from southerly to south easterly winds.

Temperature Derating Tmod TSTC PDeratingFactor

Temperature Derating 70 25 0. 42%

Temperature Derating 18. 9% max 21. 84% at 77°C

Temperature Derating 70 25 0. 47%

Temperature Derating 21. 15%max 22. 44% at 77°C

27

This may result in lower ambient and also cell operating temperatures than the majority of the

modules installed. Modules mounted centrally on the library roof would experience less breeze

and reduced ventilation, as well as higher temperatures from radiation and convection from

surrounding modules. This has the potential to result in temperatures above 80°C on a regular

basis through summer months, giving losses in the order of:

Kyocera (using -0.42%/°C)

Sungrid (using -0.47%/°C)

So as can be seen, temperature regulation plays a key role in maximising the performance of

roof mounted PV arrays.

§ 4.5 Fuses

Both installations uses a combination DC isolator, OC protection and fuse in one unit per string.

Temperature Derating 80 25 0. 42% 23. 1%

Temperature Derating 80 25 0. 47% 25. 85%

28

21 Appendix J

21.1 Solar Unlimited Cable Calculations

Data is not available for connector cables on SunGrid panels. Information has been requested

from the manufacturer and calculations will be done when received.

Cable Technical Data

DC Circuit breakers = 20 A/sub-array No. of strings = 2 Strings/sub-array No. of string cables/sub-array = 4 No. of cables Total = 30 DC String Cable Used = 6mm2 Cu Single Core at 90°C DC Sub-Array Cable Used = 10mm2 Cu Single Core at 90°C AC Circuit Breaker = 32 A AC Cable Used = 4mm2 Cu Twin Core at 90°C

String Cables

Assumptions:

All cables are spaced from surface

Cable type according to AS3008.1.1:2009 = X90

All cables bunched. Worst case, 4 cables when close to junction boxes, giving derating of

0.65

Thermal derating for X90 (90°C) cable operating at 60°C, giving a derating of 0.73

Longest cable run = 43.28 m (Solar Unlimited)

Calculations based on short circuit current

Current Carrying Capacity

Current carrying capacity of 4m m2 (nearest to 3.3mm

2) X90 spaced from surface = 48 A

Derating for 4 cables at 60°C:

(Assuming: ‘Bunched on a surface or enclosed’ according to AS3008.1.1, Table 22)

Therefore, cables are adequately sized for current capacity.

Icable,derated Tderating ncable,derating Icable,rating 0. 73 0. 63 48 22. 0752A

Istring,max 1. 25 Isc 1. 25 8. 37 10. 4625A

29

Maximum operating temperature for cables:

Using Table 27 of AS3008.1.1 gives Tmax = 80 °C

With module operating temperature approaches 80°C, this still should be considered acceptable

as cables are shaded from direct sun and should operate below module operating temperature.

Sub-Array Cables

Assumptions:

All cables are enclosed in conduit/ducting


All cables bunched. Worst case, 8 cables when close to inverters, giving derating of 0.52


Longest cable run = 11.75 m (Solar Unlimited)

Calculations based on circuit breaker rating, short circuit current and max power point

current


Current carrying capacity of 10mm2 X90 enclosed in air = 65 A





Dtemp,max Istring,max

nderatingIrated 1.258.37

0.6348 0. 346


Isubarray,max 1. 25 2 Isc 1. 25 2 8. 37 20. 825A


nderatingIrated 28.37

0.5265 0. 495

30

Using Table 27 of AS3008.1.1 gives: 70 < Tmax < 75 °C



Voltage Drops and Power Losses

Calculations carried out by Solar Unlimited were conducted using higher resistance cables than

X 90 from AS 3008. Therefore, are a worse case and are adequate.

Losses were calculated at 0.992 % and therefore conform to Australian Standards and Clean

Energy Council Guidelines.

31

21.2 Solar PV Cable Calculations

Data is not available for connector cables on SunGrid panels. Information has been requested

from the manufacturer and calculations will be done when received.

Cable Technical Data

DC Circuit breakers = 10 A/string No. of strings = 3 Strings/sub-array No. of cables/sub-array = 6 No. of cables Total = 30 DC String Cable Used = 4mm2 Cu Single Core at 90°C AC Circuit Breaker = 32 A AC Cable Used = 6mm2 Cu Twin Core at 90°C

Assumptions:

All cables are enclosed in conduit/ducting


All cables bunched. Worst case, 30 cables when close to inverters, giving derating of

0.38


Longest cable run = 70 m (based on longest run from Solar Unlimited being 43.28 m)

Calculations based on circuit breaker rating, short circuit current and max power point

current







Istring,max 1. 25 I_sc 1. 25 5. 48 6. 85A

32


Using Table 27 of AS3008.1.1 gives Tmax = 75°C



Voltage Drops

Resistance of 4mm2 X90 at 90°C = 5.88 Ω/km

Reactance of 4mm2 X90 at 90°C = 0.131 Ω/km

R>>X, therefore X ignored

Resistance for longest run:

Circuit breaker current voltage drop:

Short circuit current voltage drop:

Max power point current voltage drop:

Voltage at max power point: = 11 x Vmpp = 11 x 35.2 = 387.2 V

%voltage drop for 11 panels (worst case):

Percentage voltage drop at circuit breaker rated current:


nderatingIrated 6.85

0.3838 0. 474

Rmax 5.888

100070 0. 4116Ω

Vdrop,cb Icb R 10 0. 4116 4. 116V

Vdrop,sc Isc R 5. 48 0. 4116 2. 256V

Vdrop,mpp Impp R 4. 97 0. 4116 2. 046V

Vmpp,array Vmpp npanels 35. 2 11 387. 2V

33

Percentage voltage drop at short circuit current:

Percentage voltage drop at maximum power point:

Power Loss

Circuit breaker current power loss:

Short circuit current power loss:

Max power point current loss

% power loss for 11 panels per string (worst case):

Power losses at circuit breaker rated current:

Power losses at short circuit current:

Power losses at maximum power point:

%Vdrop,cb Vdrop,cb

Vmpp,array 100% 4.116

387.2 100% 1. 063%

%Vdrop,sc Vdrop,sc


387.2 100% 0. 538%

%Vdrop,mpp Vdrop,mpp


387.2 100% 0. 528%

Ploss,cb Icb2 R 102 0. 4116 41. 16W

Ploss,sc Isc2 R 5. 482 0. 4116 12. 36W

Ploss,mpp Impp2 R 4. 972 0. 4116 10. 17W

%Ploss,cb Ploss,cb

nPrated 100% 41.16

11175 100% 2. 138%

%Ploss,sc Ploss,sc

nPrated 100% 12.36

11175 100% 0. 642%

%Ploss,sc Ploss,sc

nPrated 100% 10.17

11175 100% 0. 528%

34

Using both short circuit current and maximum power point losses, the cable selection is

considered acceptable.

Inverter to Switchboard

Cable installed is 6mm2 Cu Twin Core at 90°C

Assumptions:

Cable length assumed as 12 m as must run overhead to switchboard

All inverter cables run in same conduit, therefore 10 cables with derating of 0.54

As cable is indoor, maximum operating temperature should not exceed 35°C, giving a

derating factor of 1.05





As inverter output is 6.0 kW, current output is:

Therefore cable selection is only just adequate. However, normal temperature is expected to be

less than 35°C, which would increase current carrying capacity.

Voltage Drops

Resistance of twin core 6mm2 X90 at 45°C = 3.38 Ω/km

Reactance of twin core 6mm2 X90 = 0.114 Ω/km

R>>X, therefore X ignored


Imax Pinverter,max

Vgrid 6000

240 25A

35

Resistance of cable (12m)

Voltage Drops:

Circuit Breaker (32A):

Inverter max (25A):

Percentage voltage drop for CB:

%Voltage drop for Inverter:

Power Loss

Circuit Breaker (32A):

Inverter max (25A):

%Power loss for CB:

%Power loss for Inverter max:

Rmax 3.38

1000 12 0. 04056Ω

Vdrop,cb Icb R 32 0. 04056 1. 298V

Vdrop,Inv,max IInv,max R 25 0. 04056 1. 014V

%Vdrop,cb Vdrop,cb

Vgrid 100% 1.298

240 100% 0. 541%

%Vdrop,Inv,max Vdrop,Inv,max

Vgrid 100% 1.014

240 100% 0. 423%

Ploss,cb Icb2 R 322 0. 04056 41. 53W

Ploss,Inv,max IInv,max2 R 252 0. 04056 25. 35W

%Ploss,cb P loss,cb

PInv,rated 100% 41.53

6000 100% 0. 692%

%Ploss,cb Ploss,Inv,max

PInv,rated 100% 25.35

6000 100% 0. 423%

36

Totals

Total %voltage drop at mpp:

Total %power loss at mpp:

Therefore, the cable selections are adequate and conform to Australian Standards and Clean

Energy Council Guidelines.

%Vdrop,mpp,total %Vdrop,mpp,array %Vdrop,mpp,invsb 0. 528 0. 423 0. 951%

%Pdrop,mpp,total %Pdrop,mpp,array %Pdrop,mpp,invsb 0. 528 0. 423 0. 951%

37

22 Appendix K

22.1 Shading Study Photos for May 22 2011

9am (photos from 23 May 2010 due to cloud cover at 9am may 22 2010)

38

10 am

39

11 am

40

12 noon

41

1 pm

42

2 pm

43

44

3 pm

45

4 pm

46

23 Appendix L

23.1 Afternoon Shading Study for December 2011

Documents

School of Engineering and Energy ENG460€¦ · School of Engineering and Energy ENG460 Engineering Thesis 2011 Performance Evaluation, Simulation and Design Assessment of the 56