Off-grid PV system design Procedure Step By Step Including Practical Standalone PV Project: To determine the correct number of PV solar panels To determine the correct capacity and sizing of DC batteries To specify the correct specification for P solar panels To specify the correct specification for battery bank To assign the collected data for PV solar power grid design To Establish the step procedure for off grid or standalone PV system To design 10 KWp hybrid PV power system

3. • To determine the correct number of PV solar panels
• To determine the correct capacity and sizing of DC
batteries
• To specify the correct specification for P solar panels
• To specify the correct specification for battery bank
• To assign the collected data for PV solar power grid
design
• To Establish the step procedure for off grid or
standalone PV system
• To design 10 KWp hybrid PV power system

5. The designing of PV solar system is to :
 determine the required PV solar panels,
Specify capacity/sizing of DC batteries ,
Assign rating of wiring and protection devices and
 the configuration and arrangement among PV
components, DC batteries bus and power converter
source
Make line diagram for DC and AC sides
Sitting PV components on the available area
Definition: what means by PV designing ??

6.  Step 1: estimate the average irradiation, available area in m2 – see lecture 1
 Step 2: estimate the daily consumption and peak sun shine ..see lecture 2
 Step3:Apply the PV design equations
 Step 4:Apply the DC batteries equations
 Step 5: Arrange PV solar Panels
 Step 6: Select the inverter Size and solar panel rate (AT DATA COLLECTED STEP)
 Step 7: select The proper sized for DC and AC cables
 Step 8: select the proper DC and AC Protection
 Step 9:select the proper surge arrestors for DC and AC sides
 Step 10:draw wiring diagram for PV solar panels, DC side, AC sides and over all line
diagram
Photovoltaic Power Grid Procedure:

8.  Et : energy consumption =38.5kwh/day…see lecture 2 for
more details and summary in next page
 PSH = solar irradiation = 5.57 …..see lecture 2 for more
details and summary in next page
 Hanwha solar Panel 315Wp available in local marker
 Infisolar 10KWp hybrid inverter available in local market
 Ritar 12 V DC batteries 200Ah@C10 available in local
market or NARAD REX 200
 Preliminary Parameters:/

9.  Step 1: GET PSH or Solar Irradiation:/

10.  2. Determine the PSH. Peak sun shine :
• PSH ( 𝑃𝑒𝑎𝑘 𝑠𝑢𝑛 ℎ𝑜𝑢𝑟𝑠
ℎ𝑟𝑠
𝑑𝑎𝑦
=
𝑎𝑣𝑔.𝐷𝑎𝑖𝑙𝑦 𝐼𝑟𝑟𝑖𝑑𝑖𝑎𝑡𝑖𝑜𝑛(
𝐾𝑊ℎ
𝑚2
.𝑑𝑎𝑦)
𝑃𝑒𝑎𝑘 𝑠𝑢𝑛(
1𝐾𝑊ℎ
𝑚2
)
)
=
5.57
𝑘𝑤ℎ
𝑚2
/𝑑𝑎𝑦
1𝑘𝑤ℎ/𝑚2
=5.57 hour
 Step 1:GET PSH or Solar Irradiation:/

11. 1. Asset the daily consumption by tabulated connected load
before electrical conservation tools
Power Consumption
Load Connected #No power rate Running hours Total Notes
#No w hour kwh
Light lamps 22 40 12 10.56Transformer light coil
PC computers 8 85 10 6.8
Scanner and printers 2 40 2 0.16
Air Conditions 12000 btu solit unit 1 1350 8 10.8Without inverter
Television 1 850 4 3.4
kitchen kettle 1 3000 4 12
Refirigerator 1 450 20 9
Summation 52.72
losses 10 % 5.272
total 57.992
 Step 2 : Get Et-Total electrical energy consumption:/

12. Optimizing Power Consumption
Load Connected #No power rate Running hours Total Notes
#No w hour kwh
Light lamps 22 20 12 5.28 Install new Led lamps
PC computers 8 85 10 6.8 No change
Scanner and printers 2 40 2 0.16 No change
Air Conditions split unit with inverter 1 1095 8 8.76Replace with inverter type
40 inch LED TV 1 40 4 0.16 Install LED type
kitchen kettle .. 1 1200 4 4.8 Install smart one
Refrigirator 1 450 20 9
Replace with inverter type
Summation 34.96
losses and safety factor 10 % 3.496
total 38.456
2. Apply the potential conservation tools to reduce losses as
below:
 Step 2 : Get Et-Total electrical energy consumption:/

13.  Step 2 : Get Et-Total electrical energy consumption:/

14. 𝑃𝑃𝑉 =
𝐸 𝐿
𝜂 𝑉.𝜂 𝑅.𝑃𝑆𝐻
∗ 𝑆𝑓 …………………….(1)
where :
• 𝑃𝑃𝑉: The total capacity in a rating in kilowatts peak (kWp)
• EL (Total energy consumption per day )KWh/day;
• PSH ( 𝑃𝑒𝑎𝑘 𝑠𝑢𝑛 ℎ𝑜𝑢𝑟𝑠
ℎ𝑟𝑠
𝑑𝑎𝑦
=
𝑎𝑣𝑔.𝐷𝑎𝑖𝑙𝑦 𝐼𝑟𝑟𝑖𝑑𝑖𝑎𝑡𝑖𝑜𝑛(
𝐾𝑊ℎ
𝑚2
.𝑑𝑎𝑦)
𝑃𝑒𝑎𝑘 𝑠𝑢𝑛(
1𝐾𝑊ℎ
𝑚2
)
)
• 𝜂 𝑅……….efficiency of charge regulator;
• 𝜂 𝑉………. efficiency of inverter ;
• 𝑠 𝐹……….(the safety factor, for compensation of resistive and PV-cell temperature
losses = 1.3) based on your initial cost , material efficiencies and losses, and
extension loads
 Step 3: Determine The # of PV solar Panels By Eq.(1)

15. • Number of PV solar Panels Np:
𝑃𝑃𝑉 =
38.5
0.92.0.92.5.57
∗ 1.3
𝑃𝑃𝑉 = 10.6 𝐾𝑊𝑝
Solar Panel rate is 315 watt from Hanwha
𝑁 𝑃 =
𝑃𝑝𝑣
𝑠𝑜𝑙𝑎𝑟 𝑝𝑎𝑛𝑒𝑙 𝑟𝑎𝑡𝑒
=
10.6
315
=33 solar panels
 Step 3: Determine The # of PV solar Panels By Eq.(1)

16. Total PV = PV Array = 33 solar panels
# of PV String=#of Parallel PV =33/17=1.9 =2 ;; why
divide on 17 ???
** String PV is the number of solar panels connected in
series to achieve one unit line
 NO of Parallel strings = 2….the inverter has two
separate inputs ( Read Technical Data)
 The string Number =17 solar panels
 String Operating voltage =17*45=765 Vdc within
acceptance range
 Step 4: specify #PV in each string and arrange parallel PV strings

17.  Step 4: specify #PV in each string and arrange parallel PV strings

18. • String 1 = 17 * 45 V=765V
• String 2 = 17 * 45 V=765 V
• How Much DC power from
PV solar Panels
• =34*315=10710 W
• Max.DC power at input
inverter = 14000 W
• PV solar DC power less than
14000..Accept
• PV solar 17 in series bus
voltage = less than 800 VDc…
Accept
• How much the required area
???
 Step 4: Verification Design for PV solar Panels

19. • Batteries should be capable of meeting both the power and energy
requirements of the system
• .𝐶𝐴𝐻 =
𝐸 𝐿
𝑉 𝐵.𝜂 𝑉.𝜂 𝐵.𝐷𝑂𝐷
∗ 𝑇𝑎𝑢𝑡 …………(2)
• 𝐶𝐴𝐻 battery capacity, specified for an appropriate discharge rate x, in
ampere hours (Ah)
• 𝑇𝑎𝑢𝑡 number of days of autonomy (no solar available)
• 𝑉𝐵 nominal voltage of the d.c. bus (i.e. battery voltage), in volts (V),
normally 48 vdc at off grid/standalone topology
• 𝐷𝑂𝐷 design maximum depth of discharge of the battery, expressed as a
percentage %
• 𝐸𝐿 total design daily energy demand KWh after optimizing
• 𝜂 𝑉. 𝜂 𝐵:efficiencies for inverter and DC batteries , respectively.
 Step 5: Determine The # of DC batteries By Eq.(2)

20. • Batteries should be capable of meeting both the power and energy
requirements of the system
• .𝐶𝐴𝐻 =
𝐸 𝐿
𝑉 𝐵.𝜂 𝑉.𝜂 𝐵.𝐷𝑂𝐷
∗ 𝑇𝑎𝑢𝑡
• .𝐶𝐴𝐻 =
38.5𝑘𝑤ℎ
48∗0.95∗0.92.∗0.5
∗ 2=3670 Ah
 Step 5: Determine The # of DC batteries By Eq.(2)

21. • Our Design is 12 V @ 200 AH, The more parallel
batteries string is the more difficult to keep all
the banks properly charged and equally string
voltage
• How we can use only one string ??
You can use only one string if you select DC
battery with high Ah such as 2V @ 1800Ah, and
the required number of DC batteries are 24 DC
batteries .(Initial cost is very high)
=24 X 2V = 48 Vdc@1800 Ah
 Step 5: Determine The # of DC batteries By Eq.(2)

22.  Step 5: Determine The # of DC batteries By Eq.(2)
Battery Bank arrangement: DC
battery 6 Vdc
Battery Bank arrangement: DC
battery 12 Vdc

23. Step 6: Specify DC and AC overcurrent devices and rate current
• Over current protection devices (OCPD) :
• Must be designed for PV systems also each fuse must be in fuse
holder
• Must be installed for both AC input & output of the inverter
• Must be double pole protection for easy to replace (Touch-safe Fuse
holder).
• IEC60269-6 and UL2579 certified.
• IP20 Finger-Safe Holder with Indication
• AC/DC MCCB Circuit breakers (B - curve):
• Mounting on DIN top hat rail EN 60715
• IP20 or IP40 Protection category
• Resistance to vibration according to IEC 60068-2-6;EN 61373
• Covers all common PV system voltages and currents
• High ambient temperatures

24.  Check I rate current from off grid inverter
 Select safety factor = 1.25 ( from experience)
 Multiply Irate X1.25 = fuse or breaker rate
 Select the available cross section from table C.B on the right
1. Fuse or breaker after PV string:
Irate=1.25*9=12 A … select fuse or breaker 16 A
2. Fuse or breaker after DC batteries :
Irate=1.25*200=250 A … select fuse or breaker 250 A
3. AC breaker overcurrent at AC output of inverter:
Irate=1.25*14.5=18A … select fuse or breaker 20 A
4. AC breaker overcurrent at AC Input of inverter:
Irate=1.25*40=50A … select fuse or breaker 50 A
Step 6: Specify DC and AC overcurrent devices and rate current

25. DC Protection Device
Scematic Diagram and location:/

26.  Install at the DC bus and after PV string
 DC surge arrestor (surge protection device) Type II
 Must be Double pole protection 1000VDC , 40kA
 Ul1449 and IEC 60364-7-712 certified.
 Must include Visual Status Indication.
 Short-Circuit Interruption (SCI) over current Protection.
• <25ns Response Time [tA]
• IP20 Degree of Protection
• Example =Mersen Type 2; 1000 Volt
Step 7: Specify DC and AC surge arrestors devices
DC surge arrestor:/

27. DC SURGE ARRESTOR
Scematic Diagram and location:/

28.  Install at the AC common bus and after Inverter
 AC surge arrestor Type II + III (combined) arrestor and
circuit breaker, 40kA,
 Three phase 400VAC TT system (according to your
grounding system in your country TN-S,),
 Pluggable with Standards:IEC61643-1:2005; EN61643-
11:2007 and CE, TUV, KEMA certified.
• Example =Scheinider- iPF K 40 modular surge arrester - 3 poles + N OR
• Mersen STP T12 - 12K 275V - 4PG
Step 7: Specify DC and AC surge arrestors devices
AC surge arrestor:/

29. AC SURGE ARRESTOR
Scematic Diagram and location:/

30.  Note: the allowable voltage drop for solar DC cables between Pv and
inverter less than 1 %
 Operation temperature for DC cables should be between - 25 ºC to +90
ºC
 PV / DC cables must be of type FG21M21 double insulator flexible
conductor core
 Connectors must be typical MC4 PV connector (no cut of PV cable).
 Wires jacket shall be flame retardant, halogen free, e-beam cross linked, UV-
resistant
 Wires between PV arrays and other system components (inverter, junction
box, etc.) must protected by UV PVC tubes or ducts.
• DC CROSS SECTION AT LEAST 4 MM2; rated DC voltage 1000V min
Step 8: Specify and calculate DC and AC cable dimention
DC cable type and specification:/

32.  The DC cable three phase 2x4 mm2 will be installed as DC
out from solar panel to combiner box and to inverter, and
the current rate at IN 1x9 A
According The Table 1-1 : Select 4 mm2
 The DC cable three phase 2x120 mm2 will be installed as
DC out , from DC batteries to input inverter for
discharging DC batteries, and the current rate at IN
inverter is 40 A
According The Table 1-1 : Select 2 x 120 mm2
DC cable type and specification:/

33.  Voltage drop must be less than 1% between grid inverter and load.
 AC Cable to achieve less than 1% Power Loss not less then 10 mm2
based on Ampacity and voltage drop ( inverter rate is 10 KW)
 For systems operating at not more than 0.6 kV between a conductor to earth or 1 kV
between conductors at maximum conductor temperatures of 90 °C for continuous
normal operation and 250 °C for short circuit
 Conforms to IEC 60502-1 Standard: and EC 60228, Class 1 or Class 2.
 Double insulated, multi- core, rated AC voltage 0,6/1KV .XLPE
 Warranty should be at least 10 years for All Cables.
 Wires must be fixed on cable trays
• AC CROSS SECTION AT LEAST 10 MM2
Step 8: Specify DC and AC cable dimension and specification
AC power cable:/

34.  The AC cable three phase 5x10 mm2 will be installed as
AC out from inverter to Distribution Boards, and the
current rate at IN inverter is 3x17A from inverter data
According The Table 1-1 : Select 10 mm2
 The AC cable three phase 5x10 mm2 will be installed as
AC IN from utility grid to input inverter for charging DC
batteries, and the current rate at IN inverter is 40 A from
inverter data
According The Table 1-1 : Select 16 mm2
Step 8: Specify DC and AC cable dimension and specification

35. Step 9: Draw Overall line diagram
https://www.linkedin.com/groups/12107513

36. Check Isc short circuit current from PV solar
panel
Select safety factor = 1.56 ( from experience)
Multiply Isc X1.56 = ampacity in ampere
Select the available cross section from
table 1-1 according to the ampacity
Isc = 9 A PV panel technical data
Amp=9x1.56= 14 A
Cross section 4 mm2 achieve and carry that
ampacity 14 A
PV cables:/

37. Check I rate current from DC battery
Select safety factor = 1.25 ( from experience)
Multiply Irate X1.25 = ampacity in ampere
Select the available cross section from table 1-1
according to the ampacity
Irate = 200 A
Amp=200x1.25= 250 A
Cross section 120 to achieve and carry that
ampacity 250 A
DC batteries cables:/

38.  Check I rate current from off grid inverter
 Select safety factor = 1.56 ( from experience)
 Multiply Irate X1.56 = ampacity in ampere
 Select the available cross section from table 1-1 according to
the ampacity
1. AC cable to D.board: see technical data at inverter
- I.rate =14.5 A
Amp=14.5x1.56= 24 A
Cross section 6 or 10 to achieve and carry that ampacity 24 A
2. AC cable from utility grid to input inverter: see technical data at
inverter
- I.rate =40 A
Amp=40x1.56= 63 A
Cross section 16 mm2 to achieve and carry that ampacity 63 A
AC cables:/

39. https://www.linkedin.com/groups/12107513

40. 1. PV solar panel
2. DC batteries storage system
3. PV mounting structure
4. DC and AC wiring
5. DC and AC protection devices
6. DC and AC surge arrestor
7. Monitoring and Metering devices
8. Grounding/earthing system
9. DC and AC distribution boards

41. Hanwha Solar is one of the top 10 photovoltaic
module manufacturers in the world
company of Hanwha Group, one of the largest
business enterprises in South Korea
PV solar Panel Hanwha Solar_HSL 72S/320 watt
Next lecture will discuss the quality and brands for
PV solar panel in world

42. A. Hanwha solar Panel :schamtic diagram

43. B. Hanwha solar Panel :Technical Data

44. Voltronic Power is one of the top in Palestine and
Pakistan
A smart hybrid inverter for off-grid, backup and grid-
tied solar energy systems.
Utilizes solar power, AC utility, and battery storage
power to supply continuous power to Loads and Mains,
through grid-connected and off-grid operation 3 X 1.
User-selectable Usage Priority to set power usage
priority among generating solar electricity, self-
consumption and battery energy storage, for
maximizing your benefit
Hybrid inverter infinisolar
Next lecture will discuss the quality and brands for PV
solar panel in world

45. :
A. infinisolar Hybrid Inverter: schamtic diagram infinisolar

46. B. Infino Hybrid Inverter :Technical Data infinisolar
:

47.  RITAR POWER, the safe and intelligent power. Produce the VRLA
Battery for Solar, Deep Cycle application, Telecom, E-vehicle, UPS
,Inverter, Forklift etc.
 OPzV series is a Valve Regulated Lead Acid battery that adopts
immobilized GEL and Tubular Plate technology to offer high reliability
and performance.
 The Battery is designed and manufactured according to DIN standards
and with die-casting positive grid and patent formula of active
material.
 OPzV series exceeds DIN standard values with more than 20 years
floating design life at 25℃ and is even more suitable for cyclic use
under extreme operating conditions.
 Ritar OPzV , 12 VDC,200Ah@C10
 Next lecture will discuss the quality and brands for PV solar panel in
world

48. A. Ritar DC battery : schematic diagram

49. 5.8 DC Batteries 12V-200Ah@C10
A. Ritar DC battery :Technical Data

50. https://www.linkedin.com/groups/12107513

51. Table 1-1:Cross section cable

52. • Designing standalone PV grid is based on the daily consumption and autonosy days
• Divide the daily consumption by factor 0.3 to get the required total capacity of
photovoltaic solar panels
• Divide the daily consumption by 1.2 factor to get the required total capacity of DC
batteries in Kwh and then divide to system voltage such as 48 vdc to get the capacity of
DC batteries in A.h
• For only one array, Divide total capacity of PV solar panels by 155 to get the required
area in m2.
• @ AC bus-of standalone PV power grid: Each 1KW provides 4.5 A for single phase and
1.5 A per phase for 3.phase

53. Next Lecture

54. References