Photovoltaic Training - Session 2 - Construction and Start-Up

Photovoltaic Systems Training

Session 2 ‐ Execution and
Commissioning

Javier Relancio & Luis Recuero
Generalia Group

September 16th 2010

http://www.leonardo-energy.org/training-pv-systems-design-
construction-operation-and-maintenance

PHOTOVOLTAIC SYSTEM
Design, Execution, Operation & Maintenance

EXECUTION AND COMMISSIONING

Javier Relancio. Generalia Group. 16/09/2010
www.generalia.es
2
http://www.leonardo-energy.org/training-pv-systems-design-construction-operation-and-maintenance

INDEX

Civil works. Infrastructure preparation

Mechanical works

Electrical works

Environmental issues

Quality. Critical issues during execution

Safety & Labor risks

Commissioning tests. Key points

3

INDEX


Mechanical works

Electrical works





4

Civil Works: Infrastructure preparation

Rooftop projects
We may find little civil works, but it will be reduced to the trench
opening for the connection of the inverters and the meters

Ground projects
Civil works are very important
A good definition for the civil works could mean an important
saving in the project.

Main civil works are:
Terrain leveling
Accesses and inside roads/paths
Trench opening (AC & DC)

5

Terrain leveling

It might be avoided as much as possible in order to reduce the environmental impact
Only required works should be done:

Selecting a flat terrain may avoid its leveling
Selecting a structure type which can be fixed to the terrain by a “ground anchor”, instead
of a concrete base
Depending on the solution design, the choice between fixed or suntracking project can be
determinant

Source: QHOELET

6

Internal roads & paths

It is recommended to use already existing paths
We must take into account that the roads or paths have to allow the circulation of
trucks. Truck turning radius must be considered:

Length Minimum radius for Minimum radius
Vehicle Type Nomenclature Height Width Length between external front- for internal back-
axis wheel wheel
Light vehicle VL 1,30 2,10 5,80 3,40 7,30 4,20
2-Axis Omnibus B2 4,10 2,60 9,10 6,10 12,80 8,50
3-Axis Omnibus B3 4,10 2,60 12,10 7,60 12,80 7,40
2-Axis simple truck C2 4,10 2,60 9,10 6,10 12,80 8,50
3-Axis simple truck C3 / C4 4,10 2,60 12,20 7.6 12,80 7,40
4,00 /
Trailer (Semi) T2S1/ 2 / 3 4,10 * 2,60 15,20 12,20 5,80
7,00
4,90 /
Trailer (Semi) T3S1 / 2 / 3 4,10 2,60 16,70 13,70 5,90
7,90
3,80 /
2 Axis trailer + 1 Double C2 - R2 / 3 4,10 2,60 19,90 6,10 / 13,70 6,80
6,40
3,80 /
C3 - R2 / 3 /
3 Axis trailer + 1 Double 4,10 2,60 19,90 6,10 13,70 6,80
4
/6,40

7

Internal roads & paths

Once the installation has been commissioned, internal paths & roads will not be used too
much, so a 25 cm depth path of a mixture 75% gravel, 25 % river sand, may be enough.

Minimal turning radius for
B3/C3 vehicles

Accesses and roads/paths detail
75% gravel, 25 % river sand

Natural terrain

8

Trenches

In a PV project, all the cable must be buried underground
Each 40 meters or each direction change, a manhole will be placed to ease the cable
laying
The project design might try to use the same section for all the trenches

9

Trenches

The trenches will have:

A river sand base

Space for the pipes

Backfill of sifted soil and soft sand

Cable caution tape

In the case it is a vehicle passing
area, it will have a concrete layer
at the top

10

INDEX


Mechanical works

Electrical works





11

Mechanical works

Structure type Weight Anticorrosion protection Mechanical
performance
Galvanized steel Resistant rooftops 8 years (non salty atmosphere) Good
Hot galvanized steel Resistant rooftops More than 25 years Good
Anodizing Aluminum Light rooftops More than 20 years Medium
No structure Light rooftops ‐ ‐

For fixed installations, the structure can be set parallel to the surface
where it is to be installed (flat), or with the optimum tilt for each
latitude (Tilted)

Flat Tilted
No wind action Important wind action

Worse cooling Best natural cooling

Lower cost (Both for structure & Higher cost (Both for structure &
mounting) mounting)

Photo: Krannich

12

Mechanical works

The structure anchor for a ground installation may
have the following possibilities:

Ground anchor
These screws have an average length
between 1 -1,6 meters
Easy to be dismounted
They can be adapted to the terrain orography
Source: Conectavol
They can’t be used in a rocky terrain

Concrete basement
Above or under the ground
It requires a flat surface
Easy to be dismounted (if it is above the
ground)

13

Roof anchorage

Metal roof anchors:
We have two options:
Direct to purlins anchorage
Specially designed anchors to be fixed directly to the roof
sheathing

It is recommended to use the direct to purlin anchorage. If
tilted structure is being used, other choice could be risky.

Tile roof anchorage:
A typical solution is using a “U” shaped piece which is
anchored directly to the roof, avoiding to drill the tile
It is necessary to move the tiles (danger of leaks)
With a special piece we can go through the tile
Danger to break the tile
Source: SoportesSolares

14

PV Roofs

Roof state:
The following aspects are to be evaluated:
Safety
We have to verify if the roof is safe. If not, we may install “lifeline”, “skylight
network”
Roof type
Asbestos (Uralita) roofs are the most difficult ones, as it may be cracked by
stepping on it, producing leaks, or it could even be broken, being really risky for
the installers. In this case, it is recommended to change the whole roof to metal
roof.
Sealing
It is important to use the most indicated sealing to avoid
leaking. This sealers must have great elasticity and good
mechanical resistance. They may be complemented by
EPDM* bands

15 * a type of synthetic rubber (ethylene propylene diene Monomer)

PV Roofs

Loads on the roof

Material weight (average weight by square meter)

Element Weight

Structure 2KG

Crystalline panels 15KG

Thin film glass‐glass panel 22KG

Thin film laminated panel 6KG

Wind effect
During the design, both panel height and exposed surface must be considered
Extra loads during the execution: such us tools, workers, materials…
Accesses: The accesses will be distributed all along the roof surface, guaranteeing the
worker safety and allowing them to carry up small materials and tools

16

INDEX


Mechanical works

Electrical works





17

Electrical works

Cable for the panel strings

• We usually use the cable included by the panel manufacturers.
Important to confirm with the manufacturer that this cable is included
• This cable are composed of copper: 4mm; 0,6/1kV
• This cables usually are ended in “fast connectors”: Multicontact,
Tyco, etc

Source: Eastech Solar

18

Electrical works

Roof installations

Cable canalization might be done under hot galvanized cable tray or tubular conduit

Cable tray canalization simplifies mounting works, and eases the maintenance tasks.

Indoor, plastic(or metallic) cable tray might be used, as well as halogen-free cable

19

Electrical works

Ground installations

Electrical works will be done in the trenches, so the cable must be designed for this use.
It is recommended to use anti-mice cable, inside a tubular conduit.

Cable trenches might be really long, so the
trench design, number of cables by pipeline,
extra space by pipeline, manholes, etc.. could
be decisive to optimize the electrical works
duration
The cable should be previously marked in order
to avoid connecting issues
It is important to avoid corners or any element
which may cause any damage in the cable
isolation.

20

Electrical cabinets

Depending on its location, a different IP may be required
• For outdoor installations, at least IP 65 will be required
• For indoor installations, IP 21 could be enough (except for special conditions: water,
powder…)
It is really important to pay attention at the element connections, and the
identification of each cable & component in the project documentation
The thermal study of the cabinet is also important, verifying the minimal required volume
for the heat dissipation, and raising additional solutions as the incorporation of a heat
resistance in case of outdoor installations in very cold zones

21

Earthing system

The following elements must be earth connected

PV panel frameworks
Structure
Metal cable tray
Metal elements in electrical cabinets
PV inverters

For small facilities, the earthing system would be quite
simple: 2 – 3 pegs, depending on the soil resistivity

For bigger facilities, a cable grid is usually implemented,
using the trench already opened for the energy cables, placing
an uncovered copper cable below the energy cables. EARTH
CABLE

The section of this cable is to be calculated during the design

22

INDEX


Mechanical works

Electrical works





23

Our solar facility and the environment

Nowadays we can find

A change in the social sensibility for the environmental impacts. The society begins to
have a greater conscience and a harder implication.

This will be the real engine for the new environmental initiatives to be managed in a
suitable way.

The ISO Certification 14001, allows us to take and to show the others, our
environmental commitment.

For all this, the solar power companies should demonstrate the coherence with their
ecological message, developing a good environmental policy

24

Environmental aspects & impacts

Definitions (ISO 14001):

Environmental aspect: Any element of the activities, products or services that is
causing some type of impact on the environment can be considered as an
environmental aspect.

Environmental impact: Any change in the environment, either adverse or beneficial,
resulting from the activities, products and services of an Organization.

Residue: Any substance or object from which his holder detaches or has the obligation
to become detached following the European rules & standards

25

Environmental aspects & impacts

We must take into account the environmental management of our solar facility

a. To know the in force legislation
b. To know the environmental aspects that concern our business
c. To evaluate the impact that has on the environment
d. To propose indicators that give us a tangible evidence about the measured aspects,
and their impacts, and to use them to develop new preventive and corrective
measures
e. To have an emergency plan derived from the knowledge of the different environmental
aspects
f. To do the suitable management of the generated residues

The environmental management becomes necessary in the execution, as well as the operation
of the solar plant, therefore, an individual analysis of every project will be required

26

Example: Environmental management during
the project execution

1. List of aspects and impacts

Activity Aspect N/E Impact

Atmospheric contaminations
Electric energy consumption N
Visual Impacts
PV installations (and Fuel consumption N Atmospheric pollution
Suntrackers, in case Powder generation N Atmospheric pollution
of being used) Residues generation N Space in the dumpsite
Atmospheric pollution
Fire E
Impact on the fauna & flora.
N: Normal; E: Extraordinary

2. Emergency classification

Significant
Aspect P S A
YES=Y; NO=N

Fire 2 4 8 Y

P: Probability; S: Seriousness; A: Assessment

27


3. Aspect classification (Normal aspects)

SIGNIFICANT
ASPECTS F S C A
YES/ NO
Electrical energy consumption 5 2 2 20 YES
Dangerous residues generation 3 2 2 12 NO
Urban residues generation 4 1 2 12 NO
Noise generation 3 1 1 6 NO
Fuel consumption 3 2 2 12 NO
Powder generation 3 1 1 6 NO
Paper consumption 5 1 2 15 YES
Packages 4 1 2 12 NO

F: Frequency; S: Seriousness; C: Consequence; A: Assessment

28


4. Emergency plan

EVENT/ EMERGENCY: FIRE
Preventive measures Adaptation to the electrical and construction regulations. Fire‐extinguishers.
• The work manager is the person in charge of the extinction of fire.
• In case of non‐controllable emergency, the work manager will take charge of
warning the external emergency services.
Actuation plan
• The work responsible is the person in charge of giving the alarm and
controlling the evacuation of the whole staff. He must check that the
evacuation has been completed
Practice Fire
The response time will be measured for the following aspects:
• The fire warning.
Practice description
• Staff evacuation.
• The checking that the evacuation has been completed.
Frequency Yearly

29


5. Residue management general process:

In every moment, we must:
To develop a study of the residues that are being produced, in the execution and the
operation of the solar power facility;

To quantify the quantity of each one, and to do a management of the residue
according to its type.

Urban residues Dangerous residues

Paper Toner with metallic components

Plastic Batteries

Tins & Cans Fluorescents

Toner without metallic components Oils (Vehicles / Motors)

30

INDEX


Mechanical works

Electrical works





31

Quality: Critical aspects

The critical aspects referred to quality in the phase of execution are:

Materials
Checking that we have received the goods that have been requested
Inspection of the goods at their arrival to check possible material faults/defects
This process will be developed for a certain number of samples previously defined by the
quality department
The checking of the electrical and mechanical parameters of the material, to avoid early
breakdowns

Work execution
Correct planning of the work: in order to avoid delays, dead times of the workers,
managing the activities in “critical way”
Updated documentation for the works: It is important to check that the workers have the
latest edition of the information

32


Work
Manager

1.Checking that the ordered material fits
with the projects real requirements
2.Checking that the real project conditions
matched with the project design
3.Managing the material administration and
reception

Material Administration Material Reception

1.Checking that the items indicated in 1.Checking that the items that have
the delivery notes corresponds with arrived correspond to the items of
the ordered ones the delivery note
2. Checking any lacking item in the 2.Visual checking
order and claiming for it 3.Checking of electrical and
3. Checking the payments mechanical characteristics

33


Work Manager

1. Fulfillment of the planning deadlines
2. Checking the documentation of the
work orders
3. Checking the quality in the
intermediate milestones of the project Worker
4. Checking the management of the
residues during and at the end of the
project 1. Work execution according to the

5. Final checking of the work work order
2. To notify incidents in the
accomplishment of the works
3. Accomplishment of the checking
indicated in the work order

34

Panel inspections

Samples
selection
VISUAL ELECTRICAL THERMAL

Packages
OF Panel arrays Panels
Panels

The electrical
• Frame defects characteristics differ from Cell defects

• Glass defects the technical specs, used Hot spots
DETECTION
• Connection box defects for the design and they Cell bubbles
OF
• Cable & connector defects are out of the required
range

Although it might be true that the panels are the most expensive element in
the installation, a similar table should be done for the rest of the elements
35

Thermography

The Thermography is a simple method to detect defaults in the solar panels

The checking of the installation is developed in a rapid and visual form

It saves time, as it identifies directly the problematic panel without having to do
complex checks in the different strings

36

INDEX


Mechanical works

Electrical works





37

Labor risks evaluation plan

1. Introduction

Within every company it is obligatory to have a labor risk evaluation plan.
Even in the case that we subcontract other companies, it is necessary to check that each
company has its labor risk evaluation plan adapted to our activity.

Knowledge of the particularities
of the company activities

Risk analysis for each activity

Actions depending on the risks

38


2. Activitie characteristics

PV on the roof PV on the ground (Fix) PV on the ground (Suntracking)

Small facilities: From 2‐3 KW to 100KW
Larger facilities: >100 KW Larger facilities: >100 KW
(Or even more)

Working at great heights Working on the ground Working on the ground

Different types of roofs Earth movements Earth movements

Different tilts of roofs Trench openings Trench openings

Sharing the work with the industry
Larger number of workers Larger number of workers
where our plant is located

Electrical cabling and inverter Usage of cranes to fix the panel structure
Possibility of using cranes
commissioning to the Suntrackers

Electrical cabling and inverter Electrical cabling and inverter
commissioning commissioning

39


3. Activity risks

PV on the roof PV on the ground (Fix) PV on the ground (Suntracking)

Falls from the roof Falls into trenches Falls into trenches

Accidents due to material falling To be run over by working vehicles To be run over by working vehicles

Risk from the industry where the
Electrocution risk Electrocution risk
plant is located

Electrocution risk Accidents due to material falling Accidents due to material falling

Accident due to collision with the suntracker

40


4. Activitie summary

To analyze the photovoltaic activities, to know and to evaluate the risks of every job
inside every activity.

To train the staff on the risks depending on their job or workstation

To distribute the equipments of individual protection adapted to every workstation

To designate a person in charge of checking the correct execution of the prevention
plans

To develop an emergency and evacuation plan

41

INDEX


Mechanical works

Electrical works





42

Project commissioning

Technical documentation
Project design

Plans Operation &
Engineering Maintenance
Technical datasheets
Equipment manuals Preventive maintenance plan
Suntracker manual Corrective maintenance plan
Commissioning Monitoring system manual

Execution
Commissioning checklist
Plant production checking
Project modification Generator production checking
Done inspections Inverter production checking
Element identification

43


As the aim that we pretend is to maximize the productive capacity of the photovoltaic solar
plant, we need to check, from time to time, a test of the plant productive capacity (i.e. every
three years)

If the plant is very large, it could be worthy to do a test every year

The plant performance can be measured up by the instantaneous response to:
Cell temperature (Depending on the outdoor temperature, wind, irradiance)
Irradiance

We will evaluate:
The power, in alternating current at the plant output (meter)
Global and direct irradiance in a calibrated cell (from a similar technology to the one used
for the generator and parallel with it)
Cell temperature: sticking a thermal sensor to the calibrated cell

44


Outdoor temperature For the capture of the indicated
(Optional)
variables we will need to have:

Irradiance
A meteorological station
where the information of
Temperature and irradiance
will be registered

Source: Geonica A meter (with integrated
communications) from which

AC Power (at the we can read the output
meter output) power

TEMP. PANEL FV

45


In the case of using suntrackers, we have to verify the equipment performance every
hour by testing the shadow projected by a rod perpendicular to the plane of the
generator

Minimal measure period: 5 consecutive days dawn - dusk

Condition: The minimal period of irradiance over 600W/m2 must be at least 12 hours

Periodicity of the measure of output power - irradiance-temperature: 10 mins

The obtained measures of output power-irradiance-temperature are compared to the
expected ones and the deviations between both are analyzed

If the legislation allows it in the future, the modernization or extension of the plant for
repowering might be recommended

46

Testing of PV Generator electrical
characteristics

Objective: To determine the electrical characteristics under
the “Standard metering conditions”, defined by:
• Irradiance: G = 1000 W/m2
• Cell temperature: CT=25ºC.

We obtain the C-V curve from the generator and the
I
one from a standard module, and both are compared
under the conditions above-mentioned

These tests have to be done two hours before and after V
the local midday and the global irradiance has to be a
over 700W/m2

Nowadays we can find specific equipments to obtain the
C-V curve of a PV generator and move it into standard
conditions

47

Testing of the inverter electrical characteristics

Is the second most important element in a PV facility

Objective: To determine the characteristics which define the
energetic performance of an inverter:
• Efficiency
• Maximum Power Point Tracking

The European efficiency of the inverter, has to be
verified with the measures commented in the previous
slides, attaching the power measure and the voltage
in the DC side

Furthermore, it must be verified the inverter capacity
to track the Maximum Power Point (MPP)

Source: SMA

48

End of Session 2

Thank you for attending

http://www.leonardo-energy.org/training-pv-systems-design-
construction-operation-and-maintenance

49

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