O&M Services for Solar Power Plants

High quality and timely servicing increases the productivity of solar power plants and reduces maintenance and repair costs. Compared to other power generating equipment, PV-stations are simple and unpretentious in maintenance, however, their effectiveness and return on investment depend on how professionally the construction is carried out, subsequent maintenance, and monitoring of the functioning of individual elements of the system. High-quality operation and maintenance (O&M) are one of the main ways to ensure the most highly efficient operation of a solar power plant.

Photo 1. Inspection of the state of photovoltaic modules.
Photo 1. Inspection of the state of photovoltaic modules.

What are the Solar Power Plants’ malfunctions causes?

Environmental Impact and Operational Damage. Pests (rodents, birds), lightning strikes, and power surges can cause a fire or electric shock. Often this leads to a fire in a large area of ​​the power plant. In addition, during the operation of the power plant, equipment malfunctions are also possible: “hot spots” and microcracks on the surface of solar modules, string commutation failure and inverter equipment, weakening of terminal contacts, damage to insulation, etc. Any damage to the power generating equipment leads to a decrease in the efficiency of the station, therefore, constant monitoring of the status of devices and wiring is necessary.

Warranty Cases. This is a certain group of failures that occurs due to the fault of the manufacturer, supplier, and installer of the equipment. These include internal defects of individual elements of equipment or solar panels, which are manufacturing defects, damage during transportation or installation.

It is worth noting that the failure of just a few silicon cells in one photomodule significantly reduces the productivity of a solar power plant. The timely replacement of the problem module helps to avoid this decrease.

At the first stages of the station’s operation, a guarantee for equipment and materials provided by suppliers, so the presence of an official representative of the manufacturer in Ukraine will be an additional guarantee for the quick replacement of a solar installation defective element.

Monitoring of plant parameters and regular inspection help identify hidden manufacturing defects in equipment and materials timely.

Critical Project Omissions. They arise when equipment selected improperly (cross-section of conductors, poor-quality connectors, poor-quality grounding, etc.) or when the design and construction did not take into account factors affecting the efficiency of the power plant. Among these factors, the greatest effect exerted by:

  • geographical location;
  • orientation and angle of solar panels inclination;
  • temperature characteristics;
  • shading.

For example, the temperature regime of PV-modules significantly affects the generation capacity, especially in summer days (Fig. 1). Therefore, when placing PV-station on the roofs of buildings, a gap usually left between the solar modules and the roof, providing additional air circulation, which allows lowering the temperature and slowing down the degradation of the modules.

Fig. 1. Modeling the effect of various temperatures on the output characteristics of a solar module. Source: “Modeling of solar cells based on various semiconductors”, Refdb.ru.
Fig. 1. Modeling the effect of various temperatures on the output characteristics of a solar module. Source: “Modeling of solar cells based on various semiconductors”, Refdb.ru.

Solar Power Plants Operating and Maintenance

A professional set of operation and maintenance (O&M) services for solar power plants ensures that the photovoltaic system will maintain a high level of technical and, therefore, economic performance over the entire life cycle. At present, all stakeholders recognize that high-quality operations and maintenance services reduce potential risks and positively affect return on investment.

Photo 2. Wiring and transformers fire on the territory of the photovoltaic station in the Kherson region because of a short circuit in the power grid.
Photo 2. Wiring and transformers fire on the territory of the photovoltaic station in the Kherson region because of a short circuit in the power grid.

Solar Power Plants’ Key Indicators Monitoring. After the commissioning of a solar power plant, systematic monitoring of its condition is required to notice and eliminate possible failure or malfunctions in time. Including remote online monitoring by using special service programs. Measured indicators:

  • General indicators (voltage, current, performance);
  • Amount of electricity generated;
  • Amount of electricity consumed;
  • Status of connections and switches;
  • Damage and emergency status of individual system elements;
  • Solar energy conversion efficiency;
  • Charge-discharge batteries.

Measurements allow us to determine that the power plant is stable and does not need additional adjustment. In addition, in case of system incorrect operation detection, it is possible to change the settings for energy distribution remotely, as well as update the equipment software. For details on methods of voltage control within systems of transmission and distribution of electric power, see the Reactive Power Control in Utility-Scale PV Plants.

Fig. 2. Thermographic image of solar modules defects.
Fig. 2. Thermographic image of solar modules defects.

Solar Station Equipment Operation and Maintenance. The service includes regular inspection and situational (unscheduled) support, which involves the departure of the emergency team, diagnostics and repair work:

  • Checking the condition of cables and equipment
  • Thermal inspection of connection boxes and power circuits
  • Measurement of insulation resistance of cables and equipment
  • Conducting an audit of contact compounds
  • Grounding resistance measurement
  • Temperature measurement of PV modules and inverter power section
  • Internal cleaning of the inverter from dust and dirt
  • Check bolt connections
  • Inspection of all equipment and insulation for mechanical damage
  • Carrying out maintenance
  • Processing of indicators and electronic layout transfer
  • Indicators reconciliation acts drawing up

In recent years, many different methods for testing PV-modules developed and a significant part of them applied in practice. O&M companies very interested in these methods, but often face the problem of choosing the most effective method.

Fig. 3. Schematic representation of various PV-modules testing methods. Source: Scientific and economic comparison of outdoor characterization methods for photovoltaic power plants, Sciencedirect.com.
Fig. 3. Schematic representation of various PV-modules testing methods. Source: Scientific and economic comparison of outdoor characterization methods for photovoltaic power plants, Sciencedirect.com.

However, visual inspection is the most trivial and quite effective method. Specially trained personnel can detect module malfunctions with a simple external examination. Although many changes in performance are invisible and require more sophisticated detection methods, nevertheless, an external inspection allows identifying defects such as: Hot Spot, Shadowing effects, Yellowing, Glass Breakage, Delamination, Ruptured Backsheet.

Photo 3. Visual modules inspection (from left to right): Hot Spot, Shadowing effects, Yellowing, Glass Breakage, Delamination, Ruptured Backsheet. Source: Scientific and economic comparison of outdoor characterization methods for photovoltaic power plants, Sciencedirect.com.
Photo 3. Visual modules inspection (from left to right): Hot Spot, Shadowing effects, Yellowing, Glass Breakage, Delamination, Ruptured Backsheet. Source: Scientific and economic comparison of outdoor characterization methods for photovoltaic power plants, Sciencedirect.com.

Solar Power Plant Servicing and Security. The solar power plant needs servicing, which includes an overview of the integrity of the fence, mowing grass, cleaning the surface of photovoltaic modules, caring for sewers, and much more. Regular cleaning of modules surface prevents the debris and dirt accumulation and helps maintain optimal solar panel performance 24/7. A dirty solar panel loses up to 25% of its energy potential.

Solar Power Plant Malfunctions

Qualified solar power plant maintenance technicians inspect the entrusted facilities make sure everything is working properly. Equipment is repaired or replaced in the case of malfunctions. The most common problems presented in table 1:

Table 1. Main types of faults and their impact on the operation of a solar power plant
Types of faults Impact on the operation of the solar station
Fasteners Lack or Weakening and Corrosion This defect can lead to individual modules mechanical damage or even the entire system.
Inverters Overheating or Damage Despite the inverters are designed for outdoor operation, clogged and not cleaned filter will lead to еру inverter overheating and malfunction, which will lead to voltage fluctuations and reduce solar power plant performance.
Photovoltaic Modules Faulty or Ineffective Can lead to many problems and reduce system performance. Failure of one module at least can significantly reduce the power of PV-plant.
Poor Grounding The absence of voltage removal at the ground, unreliable contacts, or damaged insulation can cause not only a decrease in performance but also multiple damages throughout the system.
Clogged Ventilation Lack of air circulation leads to solar modules overheating, reducing their performance, and accelerating degradation.
Shading by Tree Branches and Modules Pollution Reduces the insolation level and the solar power plant efficiency.
Production Defect Defective equipment degrades performance and can cause power plant outages.
Damage from Pests Small animals sometimes gnaw the cable insulation, and birds make nests in solar arrays, all this creates the danger of fire and electric shock.

Performer Choosing for Operation & Maintenance

Personnel for Maintenance and Operation of solar power plants require training, skills, and abilities. With market growth and the solar investment portfolios globalization, expectations for service quality are growing rapidly.

If the equipment purchased from trusted suppliers, then a full warranty service package is available to the customer.

What must check with installers interested in providing O&M services is two points:

  1. Can installers perform monitoring, analytics, root cause detection, and other reporting functions?
  2. Are there qualified specialists, operation and maintenance managers, software/IT specialists, financial and accounting employees?

Maintenance of solar power plants best left to qualified installers or service specialists who familiar with PV devices and their safety procedures. Typically, maintenance services providers deal with a wide range of O&M photovoltaic systems, which include:

  • Real-time interpretation and data collection;
  • Ongoing energy production monitoring;
  • Critical as well as non-critical repairs;
  • Trend and KPI analysis to continuous performance improvement ensure;
  • Minimize costs and the best system performance ensure;
  • Inventory and spare parts management;
  • Remote or local sensing of environmental conditions affecting solar power plant;
  • Security issues identifying.

Companies that take responsibility for monitoring and maintenance of photovoltaic stations provide round-the-clock customer support through their network operations center. They offer working business ideas in the form of additional services for their corporate and industry clients.

Витрати на обслуговування та експлуатацію сонячних електростанцій

Витрати, пов’язані з обслуговуванням та експлуатацією фотоелектричних систем є незначними у порівнянні з іншими джерелами струму. Деякі з основних факторів, що впливають на рівень витрат на The maintenance costs of solar power plants are negligible compared to other power generating devices. The solar PV systems maintaining and operating costs depend on several factors (Table 2).

Table 2. Factors that determine the level of costs for the operation and maintenance of solar power plants
Factors Description
Location Proximity to the service provider, remote access or brigade exit to the facility.
Solar system type Ground-mounted, rooftop, stationary or track, etc.
Photovoltaic components Totalizers and solar modules number, inverters type and number, transformers number, etc.
Environmental conditions Such as salty air, humidity, heat, pollen, sandy place, bird population, industrial emissions, level of insolation, the presence of construction sites nearby, etc.

 

Utilities and other companies producing solar energy are paying increasing attention to the highest level of solar asset productivity and reliability achieving. Therefore, when assessing the business case for a photovoltaic installation, in addition to initial costs of solar power plant calculating, a plan and budget for the operation and maintenance (O&M) determine.

Рис. 4. Directions of expenses that should be taken into account when calculating the budget for the service and maintenance of a solar power plant. Source: Solar Photovoltaic Plant Operating and Maintenance Costs, Scottmadden.com.
Рис. 4. Directions of expenses that should be taken into account when calculating the budget for the service and maintenance of a solar power plant. Source: Solar Photovoltaic Plant Operating and Maintenance Costs, Scottmadden.com.

Currently, the O&M services demand is growing, and the market is actively developing. There are several solar power station service companies in Ukraine whose engineers have undergone intensive training and well equipped to O&M services providing. Regular solar power plant monitoring allows quick fix problems and prevents a decrease in electricity production. O&M teams take care of all aspects of solar PV-system maintenance, ensuring that it works following international standards.

AVENSTON pays great attention to staff training and O&M service development. We offer service support for both types of equipment: purchased from our company and purchased from other leading global manufacturers. Our highly qualified specialists can prevent and eliminate problems of any complexity in the shortest possible time.