Solar Project Developers/EPC /Electrical Contractors/MNRE/SECI/NSM

1. Presentation on Best Practice for
Electrical Equipment Installation and Safety
of Product(Earthing & Protection)
INDIA belive Power From Sun + Battery(HESB)
Green Power/Silent Power/Econmical Power
Sabco Bijlee Milegi Hum Dekarke Rahenge

2. Solar PV Plant and India
Target /Projection behind with Reality
Safety and Efficiency Missing due to un Practical
Decision by Some Developer forcing Component
Supplier to Reduce Prices and also threating for un
Practical Financial Long Credit Period Terms.
Payment against Generation.
Poor O&M
We should not use water for cleaning of PV Panels
practice dry cleaning of Friendly Chemicals.
Add Hybrid Source of Generation Like Wind Machine
or High Energy Storage Battaries.

4. Solar PV PUMP Programme
CFA
Pattern
• 30% capital subsidy
to farmers through
SNA
• 40% through banks
coupled with Loan
Implementi
ng
Agencies
• State Nodal Agencies
• NABARD and other
banks
• State Drinking Water
Department

5. 1,08,766 Solar Pumps
Sanctioned
Rs.353.50 Crore was released
various agencies.
63,436 pumps sanctioned to
States (Irrigation)
30,000 was sanctioned to NABARD
15,330 nos. sanctioned to States
(Drinking Water.

6. G
M
Generation Transmission Distribution Load
Battery Power Generation Transmission Distribution Consumption
Electric Power Systems Lets us work till dark is away from Each Home

7. Why and how it make sense to go with
higher DC system voltage?• As entire solar Industry across the globe is facing heat in competitive bid recent years that is because of
drastically fall of overall project cost of Solar PV plant and along with other factors i.e. Radiation,
financing, credit worthyness of Offtaker etc. The drastically downfall of overall Solar PV system cost due
to drastically change in Solar PV Module price (~0.80%-1.10%/Month since March 2015) and innovation
,optimization in BoS i.e. Solar Inverter, block size (smart block arrangement), optimized DC overloading,
Structure design.Lets checkout- How Solar Industry shifted in Higher voltage installation on DC side
• Why did the industry move from 600 volt solar arrays to 1000 volt solar arrays? The answer is simple, to
reduce system costs. The value of increased system voltages is realized in infrastructure savings, reduced
installation costs, and end-to-end efficiency improvements. That is the same reason that the industry is
now moving from 1000 volt systems to 1500 volt systems. Although 1000VDC-rated BOS equipment was
generally more expensive than 600VDC equipment, those costs were more than offset by the cost
reductions throughout the overall system. As the volume of the higher voltage rated components and
wire increased, the installed costs were reduced even further. Again, the story is repeated with the move
towards 1500VDC systems. The primary reason is the 31% to 37% decrease in DC current for the same
power.

8. • Lets talk about advantages first
• Lower DC Losses - Higher the system voltage lower the system current, for the same
resistance ohmic losses will be lower
• Less Strings
• Reduced string cable length and Array cable length - Due to higher no. of module in series in
case of 1500 V dc system compare to 1000 Vdc
• Reduction of String Combiner boxes
• Capex & Opex Saving
• Bigger Block Size - Concept of the bigger is better
• Understand the challenge
• O e ight ask h stop at 5 VDC? Wh as ’t it V? The short a s er is the solar
pa el, s it hgear, fuse, a d ir uit reaker a ufa turers ere ’t read to ork ith a
increase of 1000V, so the acceptable challenge was a 500V step above the 1000VDC rating.
1500V rated wire is not the problem. Switchgear, fuses, surge protectors, circuit breakers
and other BOS components are still being introduced and certified. The reduction of current
is the advantage, but the corresponding disadvantage is the conductor spacing (creep).
Spacing must be greater for the higher voltages so the equipment gets correspondingly
bigger and takes up more room. Internal arcing becomes a bigger concern so the design
standards for these components become more complex and costly.
• 1500VDC fuses and 1500VDC disconnect switches, molded case switches, contactors, surge
protective devices and sensors . Other manufacturers have joined in and the competition to
supply the industry with the full range of 1500VDC rated components has both kept prices in
check and increased the range of available product options. However, the list is still limited
compared to those rated for 1000VDC. The good news is that at any given power capacity,
with the increase in voltage, the current is reduced. Inverters are power conditioning units
that esse tiall , push urre t at a fi ed oltage. The higher the urre t, the higher the heat
and the higher the stress on current carrying components and switching devices. So a
redu tio i urre t is, i ge eral, a good thi g fro the i erter’s perspe ti e

9. Efficiency and cost considerations for
1500Vdc PV Systems
• Efficiency and cost considerations for 1500Vdc PV Systems
• Higher output power levels can be obtained from essentially the same IGBT
stacks if the current is reduced.The catch is that to work at the higher
voltages, IGBTs have to be rated at the higher peak operating voltages. This
means more expensive devices and higher switching losses. Some inverter
manufacturers have had to accept lower efficiencies (usually .5% lower)
compared to 1000VDC inverters. Sungrow has been able to maintain the
same CEC energy conversion efficiencies in their line of 1500VDC inverters
as they do in their line of central and string 1000VDC inverters (98.5%).
• There are cost savings on the AC side of the inverter as well. With the
increase in DC input voltage, the inverter can be designed for a higher AC
output voltage. This reduces the AC current and allows for smaller gauge
wire to be used for the wire runs from the inverters to the transformers. For
example, a change from an output voltage of 480VAC to 600VAC reduces
the current by 20%. For the same distance between the inverter and the
point of connection to the transformer, this can mean a reduction of two
wire sizes in most cases .

10. • Way forward- What does 1500 Vdc mean for Solar Industry in future
• So where are the real savings?
• If there is a premium for 1500VDC rated solar panels, and the 1500VDC
rated BOS components have a premium, will that offset the savings in wire,
labor, and other installation costs? If the inverter has a lower CEC weighted
efficiency that results in a lower energy throughput, then the answer will be
a resounding there will definitely be a reduction in the cost of the installed
system. This is verified by the fact that virtually all utility scale project
developers and EPCs are going with 1500VDC systems.

11. • A recent survey by IHS showed that the over-all savings estimates for
1500VDC system installations by experienced EPCs were in the range of 20%
to 25% compared to 1000VDC systems. The variables include the cost of the
wire (changes with the market price of copper), the local labor rates, union
or non-union, system architectures, use of trackers, and the choice of
inverters
• 2. So where will the industry go from here?
• It may move to even higher DC voltages, but the costs required to design
and manufacture key components that can handle say, 2000VDC, may be
too daunting. Most, if not all of the innovations and design changes have
been incorporated based on their ability to reduce costs somewhere in the
BOS components, installation, or O&M processes. Large volume orders and
competition among 1500VDC component suppliers will continue to drive
BOS costs down.

12. Fuse Selection Criteria of SMB (String
Monitoring Box) in case of Solar
System Design

13. • Fuse Selection Criteria of SMB (String Monitoring Box) in case of Solar
System Design
• In case of electrical system design anywhere as per standard practice we
select fuse/breaker size with the help of the below formula:
• Fuse/Breaker rating size = Current X 1.2 or 1.3 times
• Suppose we selected 280Wp module, as per datasheet Isc is 8.68Amps so
Selected Fuse = 8.68Amps X 1.25 = 10.85Amps so selected fuse say 12Amps
• But in case of solar system design this formula many times fail to provide
correct rating of fuses or fuses burnt frequently at site in the period of
summer season.
• Before starting we all have to know about this fact that in case of solar
modules, irradiation is proportional to module current as well as
temperature is proportional to module current (minutely) also, which
means when irradiance & temperature will increase than module current
will also increase from its rated current.
• Reasons for burning of fuses (my own practical experience) :
• As noted in datasheet All electrical parameter specified at STC 25degC cell
temperature & 1000W/m2 irradiance, in summer season radiation will
increase from 1000W/ m2 to 1100 to 1200W/m2 also temperature will
increase.
• Say at 1100W/m2 and 40deg ambient temperature Isc will become from
8.68Amps to 9.62 Amps

14. • Now when inner Box temp of SMB is 65degC (fuse holder) then as per
derating of say fuse, fuse current carrying capacity will become from
12Amps to 9.5Amps at 65degC.
• Particularly at this instance fuses will blown, also in summer season this
will happen frequently at site.
• So in case of fuses they will define selection of fuses as per below formula:
• Fuse rating = Isc X 1.56 times
• Fuse rating = Isc(8.68Amps) X 1.56 times(very safer side) = 13.54Amps so
selected fuse say 15Amps
• Conclusion: Before selecting fuse rating, solar designer has must to know
about following informations:
• Maximum Irradiation and ambient temperature of site in summer
• Selection of SMB based on internal temperature rise calculation of each
components.

15. Thanks
Mahesh Chandra Manav