photovoltaic training - session 2 - construction and start-up

Photovoltaic Systems Training

Session 2 ‐ Execution and Commissioning

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

Javier Relancio & Luis RecueroGeneralia Group

September 16th 2010

PHOTOVOLTAIC SYSTEM

Design, Execution, Operation & Maintenance

EXECUTION AND COMMISSIONING

Javier Relancio. Generalia Group. 16/09/2010www.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


INDEX


Mechanical works

Electrical works






5

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)

Civil Works: Infrastructure preparation


6

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


7

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:

Vehicle Type Nomenclature Height Width LengthLength

between axis

Minimum radius for external front-

wheel

Minimum radius for internal back-

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

Trailer (Semi) T2S1/ 2 / 3 4,10 * 2,60 15,20 4,00 / 7,00 12,20 5,80

Trailer (Semi) T3S1 / 2 / 3 4,10 2,60 16,70 4,90 / 7,90 13,70 5,90

2 Axis trailer + 1 Double C2 - R2 / 3 4,10 2,60 19,903,80 / 6,10 / 6,40

13,70 6,80

3 Axis trailer + 1 Double C3 - R2 / 3 / 4 4,10 2,60 19,90

3,80 / 6,10 /6,40

13,70 6,80


8

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.

Internal roads & paths

Minimal turning radius for B3/C3 vehicles

Accesses and roads/paths detail75% gravel, 25 % river sand

Natural terrain


9

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


10

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


INDEX


Mechanical works

Electrical works






12

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 & mounting)

Higher cost (Both for structure & mounting)

Photo: Krannich


13

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

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)

Source: Conectavol


14

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 tileSource: SoportesSolares


15

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.

PV Roofs

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

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

16

Loads on the roof

Material weight (average weight by square meter)

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

PV Roofs

Element Weight

Structure 2KG

Crystalline panels 15KG

Thin film glass‐glass panel 22KG

Thin film laminated panel 6KG


INDEX


Mechanical works

Electrical works






18

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


19

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


20

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.


21

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

22

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.

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

EARTH CABLE


INDEX


Mechanical works

Electrical works






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

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Our solar facility and the environment


25

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

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

26

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

Environmental aspects & impacts


27

1. List of aspects and impacts

2. Emergency classification

Activity Aspect N/E Impact

PV installations (and

Suntrackers, in case

of being used)

Electric energy consumption NAtmospheric contaminations

Visual Impacts

Fuel consumption N Atmospheric pollution

Powder generation N Atmospheric pollution

Residues generation N Space in the dumpsite

Fire EAtmospheric pollution

Impact on the fauna & flora.

N: Normal; E: Extraordinary

Example: Environmental management during the project execution

Aspect P S ASignificant

YES=Y; NO=N

Fire 2 4 8 Y

P: Probability; S: Seriousness; A: Assessment


3. Aspect classification (Normal aspects)

ASPECTS F S C ASIGNIFICANT

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

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EVENT/ EMERGENCY: FIRE

Preventive measures Adaptation to the electrical and construction regulations. Fire‐extinguishers.

Actuation plan

• 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.

• 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

Practice description

The response time will be measured for the following aspects:

• The fire warning.

• Staff evacuation.

• The checking that the evacuation has been completed.

Frequency Yearly

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4. Emergency plan



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.

30

Urban residues Dangerous residues

Paper Toner with metallic components

Plastic Batteries

Tins & Cans Fluorescents

Toner without metallic components Oils (Vehicles / Motors)



INDEX


Mechanical works

Electrical works






32

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


33

Work Manager


Material Administration Material Reception

1.Checking that the items that have

arrived correspond to the items of

the delivery note

2.Visual checking

3.Checking of electrical and

mechanical characteristics

1.Checking that the items indicated in

the delivery notes corresponds with

the ordered ones

2. Checking any lacking item in the

order and claiming for it

3. Checking the payments

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


34

Work Manager

Worker

1. Work execution according to the

work order

2. To notify incidents in the

accomplishment of the works

3. Accomplishment of the checking

indicated in the work order

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

4. Checking the management of the

residues during and at the end of the

project

5. Final checking of the work



Samples selection

VISUAL ELECTRICAL THERMAL

Packages

PanelsOF

DETECTION OF

Panel arrays Panels

• Frame defects

• Glass defects

• Connection box defects

• Cable & connector defects

The electrical

characteristics differ from

the technical specs, used

for the design and they

are out of the required

range

Cell defects

Hot spots

Cell bubbles

35

Panel inspections

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


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

Thermography


INDEX


Mechanical works

Electrical works






38

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

Labor risks evaluation plan


39

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

(Or even more)Larger facilities: >100 KW Larger facilities: >100 KW

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

where our plant is locatedLarger number of workers Larger number of workers

Electrical cabling and inverter

commissioningPossibility of using cranes

Usage of cranes to fix the panel structure

to the Suntrackers


commissioning


commissioning



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

plant is locatedElectrocution risk Electrocution risk

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






Commissioning

Execution

Project design

Operation & Maintenance

PlansEngineeringTechnical datasheetsEquipment manualsSuntracker manual

Project modificationDone inspectionsElement identification

Preventive maintenance planCorrective maintenance planMonitoring system manual

Commissioning checklistPlant production checkingGenerator production checkingInverter production checking

Technical documentation

43

Project commissioning


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

44

Plant production checking

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


45

Source: Geonica


Outdoor temperature

(Optional)

Irradiance

AC Power (at the meter output)

TEMP. PANEL FV

For the capture of the indicated

variables we will need to have:

A meteorological station

where the information of

Temperature and irradiance

will be registered

A meter (with integrated

communications) from which

we can read the output

power


46

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



47

I

V

Testing of PV Generator electrical characteristics

We obtain the C-V curve from the generator and the

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

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

Objective: To determine the electrical characteristics under the “Standard metering conditions”, defined by:

• Irradiance: G = 1000 W/m2 • Cell temperature: CT=25ºC.


48

Is the second most important element in a PV facility

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)

Testing of the inverter electrical characteristics

Source: SMA

Objective: To determine the characteristics which define the energetic performance of an inverter:

• Efficiency• Maximum Power Point Tracking


49

End of Session 2


Thank you for attending

photovoltaic training - session 2 - construction and start-up

Technology

little civil works

main civil works

index civil works

axis trailer

key points11 http

flat terrain

internal paths roads

critical issues