Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Photovoltaic Training - Session 4 - Plant Maintenance


Published on

Importance of good maintenance procedure in the plant operation.

Components to be maintained.
PV Panel.
Solar tracker.

Types of maintenance 

Corrective maintenance.
Preventive Maintenance.

Critical elements.

Management of spare parts and stock.

Types of inspections and reach 
Visual inspections.
Deep inspections.
Frequency of revisions.

Published in: Technology

Photovoltaic Training - Session 4 - Plant Maintenance

  1. 1. Photovoltaic Systems Training Session 4 ‐ Plant Maintenance Javier Relancio & Luis Recuero Generalia Group September 28th 2010 construction-operation-and-maintenance
  2. 2. PHOTOVOLTAIC SYSTEM Design, Execution, Operation & Maintenance PLANT MAINTENANCE Javier Relancio. Generalia Group.  28/09/2010 2
  3. 3. INDEX Importance of the plant maintenance during the operation Components to maintain Types of maintenance Spare parts & stock management 3
  4. 4. INDEX Importance of the plant maintenance during the operation Components to maintain Types of maintenance Spare parts & stock management 4
  5. 5. Operation & Maintenance Options (I) Types of maintenance Predictive: It tries to predict the plant performance in the future, to prevent possible malfunctions by certain actions. It is only used in plants with suntracking systems I.E: If an element life time is supposed to be X years, it can be programmed to be substituted the year X-1, in order to avoid a serious failure Preventive: It tries to set periodical tasks to guarantee the plant lifetime I.E.: Although the suntracker oil could last for 25 years, we can decide to change it every 5 years Corrective: It tries to repair incidences which have already happened and try to avoid their repetition. IE.: Atmospheric phenomenon (such us wind, storms, etc) can damage any element in the plant. Also, manufacturing defects. 5
  6. 6. Operation & Maintenance Options(II) Influence of the in-force legislation Every country can define within its own legislation any type of compulsory maintenance or control task for PV facilities If this is the case, this must be integrated in the plant maintenance program. If there is no legislation for PV facilities, the criteria to implement the maintenance program will be done according to our decisions, depending on the most important factors for each plant 6
  7. 7. Operation & Maintenance Options(III) There are many options to define how the plant maintenance should be done: It will depend on the plant size Key points Issue Options Maintenance The promoter or installer Responsible A specialized maintenance company Continuous presence Plant staff Intermittent presence Presence only if an incidence happens Control & Advanced monitoring system Supervision Simple monitoring system System Only inverter monitoring system Personal Surveillance Remote Surveillance System System Combination 7
  9. 9. Operation & Maintenance Costs (I) 1. Plant operation & maintenance staff The training of the maintenance supervisor is essential: The reparation of possible breakdowns must be done as efficient as possible The maintenance responsible must be independent In a functional level: enough skills to manage the maintenance of one or several plants by himself In a documentary level: skills to create and update the records of maintenance, records of incidents, etc; and to treat the information Its cost will depend fundamentally on the number of persons (half- NOTE: time/full-time) and their skills It is essential for 2. Spare Parts stock management the personnel's efficiency a A bad management of supplies can mean complete days of stop of an correct management of installation the spare parts It is essential to have an updated list of all the spare parts in the plant and consumables and to assure there is enough quantity 3. Consumable stock management: oil, paint, etc 9
  10. 10. Operation & Maintenance Costs(II) 4. Surveillance system The reparation, substitution of equipments and other possible defects in the plant due to thefts, can mean a high cost Even if we have an insurance: lost production, labor cost for reinstatements, etc This reverberates in the need to reduce to 0, as far as possible, this type of incidents Options: physical vigilance, TV - vigilance or combination of both 5. Monitoring system A well implemented supervision of the plant can mean huge savings in the corrective maintenance It is important to detect any possible incident before it causes a serious breakdown NOTE: for further information about these points: “Webinar 3: Plant Operation” 10
  11. 11. Operation & Maintenance Costs(III) 6. Insurance It is important to have an insurance that covers from all the effects of meteorological conditions it can suppose an important saving Also the risks of theft or possible damages due to vandalism There are insurances that they even cover the losses of production 7. Land renting contract It must clearly specify: The surface The terms The cost* 8. Supplies: Water, light, internet… * Including the increases 9. Taxes during the years Depending on each country, we have to consider the cost of the different taxes 11
  12. 12. Operation & Maintenance Costs(IV) Conclusion The annual maintenance & operation costs, referred to the plant cost can be considered: Solar plant without suntracker – 1 % Solar plant with suntracker – 1,3 % Solar Roof– 0,7 % Notes: It has not been taken into account the cost of physical surveillance, which can raise the operation costs, except for large plants where the unitary repercussion on the production is not so important. As a rough estimation, the cost per hour of a guard from an outsourcing company is around 11 € per hour in Spain 12
  13. 13. INDEX Importance of the plant maintenance during the operation Components to maintain Types of maintenance Spare parts & stock management 13
  14. 14. Components to be maintained: The PV module (I) It is the most massive element within the facility It has a guarantee for manufacturing defects during its first period of life Usually, from 3 to 5 years It has a guarantee for producing with a minimal performance during 25 years Due to these reasons, this element should never be repaired. We analyze the panel, if it has any defect, it is replaced by the manufacturer Panel Analysis: Manufacturing defects They should be detected visually Defective frames Yellowing (The panel becomes yellow) Defective connection boxes Broken glass 14
  15. 15. Components to be maintained: The PV module(II) Panel Analysis: Production defects (I) They are harder to be detected, as other components may be involved It is important to isolate the defect, and confirm it has been produced in the panels Testing mechanisms 1. To detect which array has the issue a. Within large facilities: The monitoring system could control each array separately b. Within small facilities: we have to do a manual testing for each array 15
  16. 16. Components to be maintained: The PV module (III) Panel Analysis: Production defects (II) 2. To detect the defective panels within the array: a. Test both the voltage and the current for each panel: The voltage may be reduced if a cell has any defects b. The hot spots may produce a voltage reduction: They can be detected visually, but a thermographic camera can help to find them out 16
  17. 17. Components to be maintained: The inverter (I) Type of inverter The maintenance strategy may vary depending on the type of inverter Small inverters: to be placed on the wall Big inverters: to be placed on the ground Small inverters maintenance We should have a number of inverters in stock, ready to replace any defective one When a malfunction is detected: The inverter is replaced by one in stock And it is sent to the factory for its reparation NOTE: This operation can be done really fast, so that we can avoid production losses, as if we have a stock we do not depend on third parties 17
  18. 18. Components to be maintained: The inverter (II) Big inverter maintenance We can find two options: Manufacturer maintenance Maintenance by our own company Pros No need of qualified personnel in the plant The reparation might be done faster Third party dependence when any incidence happens Need of qualified personnel in the plant,  Cons It might be profitable from a certain installed  power Try to avoid sending the inverter to be repaired in the  In this case, the spare parts stock  factory management is really important For large inverters, the cost of the spare parts  It may take more than a week to be repaired can be important Observaciones In the contract, it is essential to add a clause for indemnity  in case of production losses If the reparation takes more than a certain period, the  indemnity may be executed This period should be less than 48 hours (weekends  included) NOTE: in any case, if we want to guarantee a fast reparation we must have spare parts in the plant 18
  19. 19. Components to maintain: The suntracker The suntracker has software, mechanical & electrical devices Mechanical: Its preventive maintenance is very important: Motor lubrication Sensor state supervision Any corrective measure will be more expensive Control The software must be always updated to the last version The possibility to remotely update the software can reduce the time to update it locally NOTE: As in the inverters case, depending on the amount of units, it can be interesting either to outsource the maintenance of the suntrackers, or to employ qualified personnel to do it ourselves. 19
  20. 20. Components to maintain: Control cabinets, protections & cables (I) Control cabinets Preventive: Visual inspection is very important to know their state. Punctual: if they are in the open air, if it is important to check their state after bad weather conditions For example, after a hard storm, water could have gone inside the cabinet If the control cabinet has lost its capabilities, it must be replaced as soon as possible 20
  21. 21. Components to maintain: Control cabinets, protections & cables (II) Protections Preventive: Periodical tests to the protections that allow them will be done. Periodical inspections will be done, specially in the connections If any defect is detected, the device will be immediately replaced. The spare part stock is important NOTE: A bad connection can produce an electrical arc, that may raise the temperature and cause the device breakdown 21
  22. 22. Components to maintain: Control cabinets, protections & cables (III) Cable Preventive To check the connections between the different equipments To check those parts where the cable cover can be damaged Facilities without suntracker: once the cable installation has been verified, and its voltage and connection have been checked, the cable shouldn’t have any problems Facilities with suntracker: it is important to periodically check the cable route and test if there are any important mechanical tensions at any point, which may cause a serious problem in the future 22
  23. 23. Components to maintain: The meter The meters are solid devices They have a critical function Once they are installed and the plant has been commissioned, the electric company seals them to avoid being operated Anyway, a preventive maintenance should be done: To check if the data being sent by the meter is logical, and is the same as the one we can read at the display When handling any incidence, we must contact the electric company: They can send their own personnel They can allow us to operate the meter 23
  24. 24. INDEX Importance of the plant maintenance during the operation Components to maintain Types of maintenance Spare parts & stock management 24
  25. 25. Preventive Maintenance (I) The preventive maintenance must: Go as far as possible and as structured as possible. Be present in all steps: design, execution & operation Before the plant operation, the preventive maintenance must be taken into account: In the plant design In the components provisioning In the equipment guarantees In the components reception In the insurance contracting We cannot think about the plant maintenance as: “A man with his tools” 25
  26. 26. Preventive Maintenance (II) During the plant design (I): Have the parameters of radiation and tilt of the modules been well studied? Are we sure that we are not demanding to the plant operator a performance over the real capabilities of the plant, due to an optimistic study? Has the shadowing study been done properly, especially on those plants with suntracking systems? We always have to take into account a balance between the losses for shading versus the optimization of the plot Has a study of the wind been developed in the zone, in order to properly determine the suntracker specs? Have we taken into account the salinity and humidity of the local atmosphere that could influence the structure and screws? 26
  27. 27. Preventive Maintenance (III) During the plant design (II): Has the quality of the soil been studied to verify the absence of materials that attack the concrete and may debilitate the fixation to the soil? Have we checked that all the equipments have the minimal protection level, IP65, to be installed outdoor? Are the important components protected by voltage dischargers? In case of control cabinets or control rooms which contain various devices, such us inverter or transformers... Do they have an appropriate cooling system? 27
  28. 28. Preventive Maintenance (IV) During the plant design(III): Do the electrical cabinets have the enough dimensions to dissipate the heat of their components, specially during summer? Is the section of the cables adapted to avoid voltage drops below the desirable 0.5 - 1%? Have we tried to distribute the main elements in several isolated rooms, to avoid losing the whole production in case of fire or flood? 28
  29. 29. Preventive Maintenance (V) In the supply of components: The chosen modules … Are they certified by a certified laboratory? Do they fulfill the standard EN 61.215? Or the one applicable for each country? Are they a “class II”? The inverters … Do they a have reasonable European efficiency, between 94 and 96 %? Do they a have suitable galvanic protection? Are the structures galvanized with a minimum thickness of 80 microns (or equivalent treatment)? 29
  30. 30. Preventive Maintenance (VI) In the required guarantees for the devices (I) Nearly all the modules manufacturers guarantee a degradation of less than 20 % after 25 years, but … What guarantees does the chosen manufacturer offer for manufacturing defects? Is it over 2 years? Is it close to 5 years? Does the manufacturer guarantee a degradation of less than 10% after 10 years? NOTE: this point should be specially verified for thin-film modules: They do not always guarantee it They can suffer a strong initial degradation 30
  31. 31. Preventive Maintenance (VII) In the required guarantees for the devices (II) Is it either the manufacturer or the distributor the one who offers the guarantee? If it is the distributor … is he established in our country? If he is not… does he have the right to sell out of his country? Is it “guaranteed” the “chain of guarantees"? Does the contract detail all the guarantees adequately? For the inverters, have the guarantees been extended to the maximum number of years (at a reasonable cost)? Does the manufacturer offer a replacement service, within 24-48 hours? Does he have a hotline service? 31
  32. 32. Preventive Maintenance (VIII) At the component reception Have we done a visual inspection of the modules? Have we done a selection of the modules by power? It is not practical a “module by module” electrical measurement But the classification of the manufacturer " flash list “ can be very useful. NOTE: For module tolerances of around 5 %, two classifications can be enough Are the components stored in the suitable conditions during the period of assembly? Are this same conditions applied for the storage of the spare parts? 32
  33. 33. Preventive Maintenance (IX) At the insurance contract signature Has the insurance been contracted with the suitable coverage …? Atmospheric phenomena Electrical damages Thefts Production Losses Civil responsibility With reasonable excess 33
  34. 34. Preventive Maintenance (X) Preventive maintenance during the plant operation (I) Key points: Preventive maintenance Spare parts in the plant Training Meteorological predictions Incidence detection Grid connection breakdown (Electrical company side) Physical/Remote Surveillance 34
  35. 35. Preventive Maintenance (XI) Preventive maintenance during the plant operation (II) It is necessary to define the maintenance tasks and their periodicity And then create a record of preventive maintenance on every element, with the date of accomplishment. Example: Preventive maintenance calendar 20XX TASK PERIODICITY DATE Checking the cables state Yearly dd/mm/yyyy Retightening of the electrical connections Yearly dd/mm/yyyy … … … 35
  36. 36. Preventive Maintenance (XII) Preventive maintenance during the plant operation (III) List of tasks that generally require preventive maintenance: Earthing system checking in transformers and rest of the facility Retightening of the electrical connections in the control-cabinets Voltage dischargers checking Cable state checking Module dirtiness checking Suntrackers deviation according to the position of the sun Lubrication of the components of the suntrackers Retightening of the suntrackers screws Maintenance required by the electrical Companies in the Transformation Center * 36 * It is usually outsourced to the installer of the center
  37. 37. Preventive Maintenance (XIII) Preventive maintenance during the plant operation (IV) Maintenance tasks follow-up Every maintenance task must be logged in individual records for every device or component Example: Suntracker record DATE TASK OBSERVATIONS 15/02/2010 Cable checking Routine 06/03/2010 Suntracker lubrication Routine … … … 37
  38. 38. Preventive Maintenance (XIV) Preventive maintenance during the plant operation (V) Training This is really important specially if the final client has decided to do the plant maintenance by his own The person in charge of the plant maintenance must have an important electrical formation and reasonable knowledge on solar power. If the plant is with suntracker, he must also have electromechanical formation Meteorological predictions It is really important in plants with suntrackers. The wind may cause serious damages to the suntrackers It is a requirement for the suntracker to have protections against the wind: It can automatically be positioned horizontally when receiving a signal from the central anemometer It is recommended that each suntracker has its own wind sensor 38
  39. 39. Preventive Maintenance (XV) Preventive maintenance during the plant operation (VI) Incidence detection mechanisms As the detection of a fire in any building: Transformation center Meter room Grid isolating center Control & Supervision Room Grid breakdown detection (From the company side) Certain issues from the electrical company can cause the plant disconnection from the grid It is important to notify it to the responsible as soon as possible By an acoustic alarm By SMS. Specially important during the weekends NOTE: All these breakdowns could be unnoticed for the electrical company or, sometimes ignored, and if they are not demonstrable they might not be recognized or compensated 39
  40. 40. INDEX Importance of the plant maintenance during the operation Components to maintain Types of maintenance Spare parts & stock management 40
  41. 41. Stock & Spare Part Management Spare parts in the plant If the plant is larger than 500 kW, we have to store spare parts in situ The “List of Spare parts” must be done evaluating: If the element is critical (1 - 5) Malfunction probability (1 - 5) Delivery time (1 - 5) MALFUNCTION DELIVERY ELEMENT CRITICAL TOTAL PROBABILITY TIME INVERTER 5 1 3 15 MAGNETOTHERMIC 5 2 1 10 GEAR MOTOR 5 1 4 20 TRANSFORMER 3 1 3 9 … … … … 41
  42. 42. Stock & Spare Part Management Depending on: Material Material Each element evaluation Input Output SOLAR PLANT Each element price SUPPLIER A percentage of Devolution elements in stock is Reparation determined Between 0,5 to 2% Management Note: It can reach a 3% if the element price is very Stock low Time 42
  43. 43. End of Session 4 Thank you for attending construction-operation-and-maintenance 43