Photovoltaic Training - Session 2 - Construction and Start-Up


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* Civil works. Preparation of infrastructure.
* Mechanical assembly.
* Electrical Installation: Ground‐mounted PV facilities. Rooftop installations. Wiring. Cabinets. Ground net.
* Environmental aspects and waste management.
* Quality. Critical aspects in the development of the installation.
* Testing. Key issues. Inverter tests. Maximum power of the PV generator. Evaluation of the Performance Ratio real.

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Photovoltaic Training - Session 2 - Construction and Start-Up

  1. 1. Photovoltaic Systems Training Session 2 ‐ Execution and  Commissioning Javier Relancio & Luis Recuero Generalia Group September 16th 2010 construction-operation-and-maintenance
  2. 2. PHOTOVOLTAIC SYSTEM Design, Execution, Operation & Maintenance EXECUTION AND COMMISSIONING Javier Relancio. Generalia Group.  16/09/2010 2
  3. 3. INDEX Civil works. Infrastructure preparation Mechanical works Electrical works Environmental issues Quality. Critical issues during execution Safety & Labor risks Commissioning tests. Key points 3
  4. 4. INDEX Civil works. Infrastructure preparation Mechanical works Electrical works Environmental issues Quality. Critical issues during execution Safety & Labor risks Commissioning tests. Key points 4
  5. 5. 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
  6. 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 6
  7. 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: 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
  8. 8. 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
  9. 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 9
  10. 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 10
  11. 11. INDEX Civil works. Infrastructure preparation Mechanical works Electrical works Environmental issues Quality. Critical issues during execution Safety & Labor risks Commissioning tests. Key points 11
  12. 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 &  Higher cost (Both for structure &  mounting) mounting) Photo: Krannich 12
  13. 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 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
  14. 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 tile Source: SoportesSolares 14
  15. 15. 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)
  16. 16. 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
  17. 17. INDEX Civil works. Infrastructure preparation Mechanical works Electrical works Environmental issues Quality. Critical issues during execution Safety & Labor risks Commissioning tests. Key points 17
  18. 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 18
  19. 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 19
  20. 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. 20
  21. 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 21
  22. 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. EARTH CABLE The section of this cable is to be calculated during the design 22
  23. 23. INDEX Civil works. Infrastructure preparation Mechanical works Electrical works Environmental issues Quality. Critical issues during execution Safety & Labor risks Commissioning tests. Key points 23
  24. 24. 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
  25. 25. 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
  26. 26. 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
  27. 27. 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
  28. 28. Example: Environmental management during the project execution 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
  29. 29. Example: Environmental management during the project execution 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
  30. 30. Example: Environmental management during the project execution 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
  31. 31. INDEX Civil works. Infrastructure preparation Mechanical works Electrical works Environmental issues Quality. Critical issues during execution Safety & Labor risks Commissioning tests. Key points 31
  32. 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 32
  33. 33. Quality: Critical aspects 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
  34. 34. Quality: Critical aspects 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
  35. 35. 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
  36. 36. 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
  37. 37. INDEX Civil works. Infrastructure preparation Mechanical works Electrical works Environmental issues Quality. Critical issues during execution Safety & Labor risks Commissioning tests. Key points 37
  38. 38. 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
  39. 39. Labor risks evaluation plan 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
  40. 40. Labor risks evaluation plan 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
  41. 41. Labor risks evaluation plan 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
  42. 42. INDEX Civil works. Infrastructure preparation Mechanical works Electrical works Environmental issues Quality. Critical issues during execution Safety & Labor risks Commissioning tests. Key points 42
  43. 43. 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
  44. 44. Plant production checking 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
  45. 45. Plant production checking 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
  46. 46. Plant production checking 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
  47. 47. 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
  48. 48. 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
  49. 49. End of Session 2 Thank you for attending construction-operation-and-maintenance 49