Main Challenges faced while maintaining Seasonal Tilt Solar Power Plants

Main Challenges Faced While Maintaining Seasonal Tilt Solar Power Plants

Main Challenges faced while maintaining Seasonal Tilt Solar Power Plants

Main Challenges faced while maintaining Seasonal Tilt Solar Power PlantsSeasonal Tilt work carried under the aegis of Avi Solar Energy Expert Team

Module cleaning challenges:

When modules are tilted to near zero angles the water will not trickle down due to the low gradient. Here comes our expert analytical team which provides cost-effective techniques to make sure that all the dirt and accumulated water is cleared off the module.

Hydraulic/Mechanical Jack:

Use of modern yet economical techniques like hydraulic jacks or mechanical Jacks so that the chances of module breakages can be minimized or eliminated while doing seasonal tilt along with the reduction in the number of laborers making the entire process of tilting safe, timely and cost-effective.

Due Diligence for precise tilt angle and start of seasonal tilt activities:

The tilt work is generally planned for not more than 30 days from an identified date during the season. It can be further varied up to a few days before or after as suggested by the expert analytical team from Avi Solar Energy for an optimal generation.

String breakage during annual tilt work:

This usually happens if Y connectors are used. Avi Solar Energy has expert engineers capable of solving such issues mainly due to a robust process orientation and their vast experience.

Minimal Ground Clearance during higher tilt angle:

Mainly grass levels are to be maintained at minimal levels else there are chances of this impacting generation mainly due to string level faults or overgrown grass causing shadow effects.

 

Information Courtesy: Avi Solar Energy Pvt Ltd

avisolar's roof top OMS Hubs

Avi Solar’s Rooftop OMS Hubs

Continuously growing & geographically well spread out rooftop solar projects in India is in need of a quick and professional OMS services at its doorstep.

Understanding this need and leveraging its expertise and experience of handling O&M services for more than 700MW solar power plants across India, Avi Solar Energy has created its O&M hubs at different strategical locations with complete O&M resources to provide quick and professional O&M services for rooftop solar projects.

Avi solar Energy is geared up to fully to provide professional O&M services for rooftop projects in its already existing and also in its upcoming rooftop O&M hubs as depicted below.

avisolar's roof top OMS Hubs

For more details and enquiries, please feel free to contact us as

Email: sales@avisolar.com

Website: www.avisolar.com

 

PLC SCADA VS IOT SCADA

PLC SCADA vs IOT BASED SCADA

 

SCADA stands for Supervisory Control And Data Acquisition; it is a computer-based control system used to gather and analyse the real-time data in industries. The purpose is to monitor and control of process and equipment. First generation SCADA comprised of rugged hardware called PLCs which connected to various sensors and collected data in digital format for further processing.

A Solar PV Power Plant doesn’t need much of controlling, it is all about monitoring. Hence you do not need a complex PLC based SCADA system. There are thousands of panels, kms of cables, tons of connectors which if monitored gives information on health and performance of the PV plant.

All you need is an IOT platform. EagleSun SCADATM from Avi solar is one such simple, low cost, effective monitoring system designed specifically for Solar PV plants.

If you are using a PLC-based SCADA – Switch to Ultra low-cost IOT based EagleSun SCADA now!

PLC SCADA VS IOT SCADA

 

For any technical queries Email- eaglesun@avisolar.comPLC SCADA VS IOT SCADA

For Solar PV Monitoring Products and O&M services  visit  www.avisolar.com

SOLAR ROOFTOPS – O&M Challenges

SOLAR ROOFTOPS – O&M Challenges

 

Indian Government has set an ambitious target to install 100 GW of solar capacity by 2022, out of which 40 GW has to come from rooftop projects. However, the country has managed to set up just over 2 GW of solar rooftop capacity so far, while the target for the financial year 2017-18 was 5 GW, according to the data from MNRE.
Experts are raising concerns that Rooftop projects can’t be added in that quantity as a lot of roof structures especially residential are not designed to carry the additional loads of Solar PV Panels. However Small businesses, which contribute about a one third to India’s $2 trillion economy, suffer from high power tariffs and erratic supply causing them to fall back on expensive and polluting diesel generators to keep the lights on. This is where we see a potential for PV rooftop projects. Government establishments and commercial buildings like malls or even warehouses have the capacity to install significant capacities of Solar PV.

SOLAR ROOFTOPS – O&M Challenges

Once installed on roofs, It will be imperative for all players in the Solar Energy domain to come up with a suitable strategy to optimize power generation as well as tune-in operational efficiency.  Maintenance at regular intervals is crucial for extending the life and generation performance of solar plants of any size.

Avi Solar one of the leading O&M Service Provider for utility PV plants is now gearing up to serve the rooftop market in India. Unlike utility plant, it is not viable to have dedicated engineers for rooftops; hence Avi solar has created “O&M Service Hubs” at strategic locations across the country. These hubs will have a workforce and spares that will cater to a bunch of rooftops.

 

Few challenges specific to operation & maintenance of Rooftops are listed below:

Work Permit:  Most industrial rooftops have a permit system to work akin to a factory set up and O&M provider has to plan well in advance for any maintenance activity.

Planned schedules: Plant maintenance is a repeated activity with standard operating procedures to be followed for Preventive Maintenance (PM) and Corrective/ Break down maintenance (CM).

Reporting: Every scale of developer/Investor/Corporate owner of a solar PV Installation is interested in timely reports of Power generation and Health parameters of the Plant. The fairly recent advances in monitoring solutions have not penetrated the rooftop market. Reporting and analytics are not organized as much as Ground mounted plants.

Scattered sites: Ground Mounted plants may have a full-fledged SCADA monitoring system whereas many Industrial rooftop plants have to invest in third-party software (portals) to collate data from various sites.

Safety: As the Rooftop plants are at elevated places, the safety of workers is of paramount concern. Safe working practices and PPEs are a must in this industry.

 

SOLAR ROOFTOPS – O&M Challenges

 

Practical approach to O&M issues:

Based on extensive field operations experience and feedback from customers, Avi Solar O&M team has devised indigenous ways to address the above issues.  Micro-level operation management, Spare management, Optimization of resources based on requirements in each city and state is devised. Macro-level planning, safety training, and monitoring ensures the smooth functioning of the business.

Technical solution from Professionals in the field:

Avi Solar Energy Private Limited has developed a software tool SPIDAR (Solar Plant Intelligent Data Acquisition and Reporting), a simple application software that connects owner/client of a PV plant with the real-time generation reports and performance data gathered by engineers/technicians at the site.

India's Top PV Monitering System

Is Your PV Remote Monitoring/SCADA System Functional?

Have you invested in a best in class Solar PV SCADA and now unable to monitor your PV Plant? You are not alone! There are several Solar PV Plant owners repenting their decision on the choice of PV Monitoring system/SCADA.

At Avi Solar Energy, our Analytics & Monitoring team studied and analysed over 1GW of Solar PV plants across India. Here is the summary of our analysis:

For a Solar Plant Developer, getting the Inverter up and pumping power to the grid has been the focus when a new plant is built. SCADA is the last item in punch list, because even if it is not functional, the generation is still ON! Its only after couple of years after the plant is commissioned, when the O&M team reports issues at the site, plant owner realizes that monitoring is important to figure out the performance of the plant.

Here are some of the major issues with SCADA / Remote Monitoring systems that we have experienced in field

1.  Leased line connections not working.

Most SCADA needs a high bandwidth internet connection like leased lines, which are very expensive to maintain.

2.  Developers have not renewed the AMC with SCADA supplier

Many suppliers sold their system at low prices initially, but owners didn’t know that you need to pay a heavy premium every year.

3.   Cables connecting the SCADA systems are damaged.

Most traditional SCADA systems were interconnected using Kilometres of Fibre Optic / Copper cables, which have been damaged by unskilled labourers at the plant.

4.  No Service / Support engineers visit the plant

Many leading SCADA suppliers provide you telephonic support. But to resolve major issues you need to depute service engineers at these sites which are usually in remote areas.

5.  SCADA is limited to control room only.

Many plants have a monitoring system at the control room, which means you are at the mercy of site engineer. Data accuracy and relevance could be at stake if the plant can’t be monitored remotely.

6.  No String Level Monitoring.

Data collection is limited to Inverter monitoring only.

String level faults cannot be detected.

The good news is that, there are retrofit solutions available which can replenish your existing SCADA and bring the plant data to your remote monitoring centre. IoT being the buzz word today, there are several options to get the data from your plant to the cloud in a cost-effective manner. There are several IoT platforms which can monitor data from PV plants. EagleSun SCADA™ is one such platform exclusively developed for Solar PV Plants.

As the PV plant gets older, one needs to watch for performance degradations, losses due to aging of plant BOS like connectors, cables and terminations. Your SCADA needs to be operational and you need to have the plant data. It is strongly recommended that you monitor all the equipment, mainly the Inverter, Weather Station, String Combiner Box, Transformers, VCB and Energy Meters. If cost concerns exist for string-level monitoring, Zonal level monitoring solution can be considered.

The history of your plant will not only give insight into the performance parameters, it can also help you a great deal in forecasting & scheduling.

EagleSun SCADA™ is one of the cost-effective solution to retrofit your remote monitoring system. Service support is equally important. Avi Solar team being the leading provider of O&M services for Solar PV assets, with their professional team of engineers and technicians can provide local support for the EagleSun SCADA™ across India.

 

 

Snail Trails on Solar Panels – an aesthetic issue or a performance limiter?

Snail Trails on Solar Panels– an aesthetic issue or a performance limiter?

As Solar Plants age, Developers must reckon many problems. Modules do degrade over time and may underperform. Microcracks may develop as modules are exposed to the elements all through their life time. Some modules may inherently have had micro cracks from the time it was shipped and can extend over larger cross-sections during operations. Over & above thermal cycling can affect metal contacts, solder interconnections & causes thermal stresses in the module. This can have serious consequences and may result in catastrophic failure in the long term.

Since 2012 a phenomenon has been observed across many Solar plants, of small dark brownish lines or partial discoloration being caused on PV modules. These were termed “snail trails” and research started on its occurrence and the impact it can have on power generation.

After studying patterns across many plants, it was broadly concluded that mere existence of snail trails by itself does not affect power generation. However, snail trails seen where micro cracks run across cells may affect power generation. Even this must be assessed to be sure.

What are snail Trails: 

Snail trails are discolouration of the panel, which usually builds up over couple of years of power production on the field. Moisture can enter through the back sheet and diffuse to the cell surface. Here the silver from the grid contact fingers may get dissolved and the silver ion migration to the EVA (Ethyl Vinyl Acetate) foil encapsulation can set in the snail trail formation – mainly Silver nanoparticles showing a typical brownish colour.

It has been ascertained that this discolouration happens due to the formation of silver acetate, that is synthesized by silver carbonate (Ag2CO3) originating from the reaction of Ag ions and carbon dioxide and acetic acid that originates from the degradation of the EVA encapsulation. The effect of this reaction is that it can reach the front of the panel from the back and causes a chemical breakdown on the front of the panel of the grid fingers. This becomes visible as snail trails and was possibly thought to bring in a reduction in the panel’s performance as it can cut irradiance if these trails run across the cell. Though it is not true it is surely an indicator for cracks within the cells. The snail trails are almost always located at cell edges or along micro cracks that can run across the cells in the panel and these are ones that can possibly lower power production. So, it is more of chance that the cracks are deep enough that may result in more stresses building up and thereby a deterioration in performance by creating potential hot spots.

In view of the perception that snail trail affected modules can have adverse impact on generation, Developers are a worried lot that the solar plant should not affect their Return on Investment (RoI) and reduce the life of the modules.

 

It is better to ascertain the impact by conducting tests on samples of snail trail affected modules. 

Various tests are possible such as

  • Thermal Imaging
  • Electroluminescence
  • I-V tests                        
  • Raman Spectroscopy.

Figure 1: Snail trail affected module

Figure 2: Thermal Imaging of Snail Trails on Module

To assess performance differences between snail trail affected and unaffected modules the string currents were measured during peak generation time. Data is shown for two sample sets.

No conclusion could be drawn about underperformance of snail trail affected modules.  Observation was that the values of current and voltage continued to be in the same range for both sets of modules

The technical team recommended that one of the best methods to assess the impact of Snail trail affected modules is to carry out Electroluminescence (EL) tests to gauge the structure and depth of the microcracks within the module from the EL images alongside I-V characteristics of the modules. Some samples were taken for EL tests/I-V tests. The Fill Factor (FF) of one of the modules recorded a drop of 6% against data sheet specifications. Considering the age of the plant to be 4 years, a 6% drop in FF in one of the modules translates to an annual average deterioration of 1.5%, slightly above usual thresholds of degradation. This could possibly relate to the microcracks in the snail trail module affecting performance. The values of the Series resistance of the cell showed up higher for such affected cells than other unaffected modules.

Figure 3: EL image of Module with micro-cracks

A clear picture will emerge after performing Electroluminescence tests and I-V characteristics tests. The intensity of the cracks, if any, can easily be seen and the Fill Factor data from the I-V tests will be an indicator of any performance dip or quality problems in the module. If the results match the manufacturer specifications or indicate minor problems, then it can be concluded that the performance aspects are intact, otherwise these affected modules are the ones to observe for deterioration in future.

 

Another way to understand the effects of snail trail affected modules is to analyze the monthly plant generation recorded during the previous year and compare it during the same month in the present year. If the generation difference is <0.8-1% a year later under non-break down conditions and normalized to insolation levels, it is well within limits of degradation – very usual of plants ageing and the performance ratios dipping year on year. Otherwise, it can be gathered that the module degradation has set in for the affected modules.

Replenish your Non-functional Solar PV Plant SCADA

Replenish your Non-functional Solar PV Plant SCADA 

Have you Invested in a world-class Solar PV SCADA and now unable to monitor your PV Plant?

You are not alone! There are several Solar PV Plant owners repenting their decision on the choice of SCADA supplier.

Avi Solar Energy Pvt Ltd., with their experience of managing over 1 GW of Solar PV plants across India has analyzed and understood why most of the SCADA systems are not functional.

Here are top 4 reasons:

  1. Leased line connections not working.
    • Most SCADA needs a high bandwidth internet connection like leased lines, which are very expensive to renew.
  2. Developers have not renewed the AMC with SCADA supplier
    • Many suppliers sold their system at low prices initially, but owners didn’t know that you need to pay a heavy premium every year.
  3. The cables connecting the SCADA systems have damaged.
    • Most traditional SCADA systems were interconnected using KMs of Fiber Optic / Copper cables, which have been damaged by unskilled labours at the plant.
  4. No Service / Support engineers visit the plant
    • Many leading SCADA suppliers provide you telephonic support. But to resolve major issues you need to depute service engineers at these sites which are usually in remote areas.

Don’t we have a solution? can’t we restore the Remote monitoring SCADA?

You can!

Switch to EagleSun SCADATM, which is a wireless remote monitoring system designed & developed by Technical Solutions Group (TSG) of Avi Solar. These developers mostly coming from the IT industry who have developed products for multinationals, gather knowledge from Avi Solar’s O&M engineers who have REAL field experience on all different PV technologies. They understand what works & what does not at PV plants.

EagleSun

EagleSun SCADA is a low cost solution , can inter operate with your existing SCADA with no/minimal changes to your existing SCADA system

Call us today on +91 70229 49911 / 99806 98001 or email sales@avisolar.com for more details on how you can get your plant data on your smartphone or PC.

For any technical queries write to eaglesun@avisolar.com 

Solar PV Forecasting & Scheduling – Integrated with EagleSun SCADA

Forecasting and Scheduling (F&S) regulations for renewable energy generators, specifically for Solar PV plant owners has been communicated by SLDC and the industry has started gearing up for its impact! The effective dates for DSM penalty are in place for many states.

The requirement is to submit  day-ahead power generation  which can be done using different ways shown below:

  1. Energy generators (IPPs) can submit the F&S directly to SLDC
  2. Third party (FSS) on behalf of Energy generators (IPPs) can submit the F&S directly to SLDC
  3. QCA can submit the aggregated F&S to SLDC
  4. Aggregator (Agg) can submit the aggregated F&S to SLDC

Avisolar Energy is also one of the QCA and is already submitting F&S in the states of Andhra Pradesh (AP), Telengana (TS) and Karnataka. With our experience managing over 1GW of Solar PV plants, the Technical Solutions Group (TSG) has developed a robust forecasting algorithm which generates week ahead and day ahead generation.

This easy to use forecasting tool can be integrated with Avisolar’s wireless remote monitoring system -EagleSun SCADA.

 

 

 

 

 

EagleSun SCADA gets real time data from  Inverter. The key parameter needed for F&S is AC Power . This data is continuously monitored, compared with the forecasted power and the deviation is calculated instantaneously.

For more details & a free demo of the F&S tool pl write to sales@avisolar.com

Challenges in Operations and Maintenance of a solar plant

 

Preventive Maintenance:

Preventive Maintenance includes routine inspection and servicing of all plant equipment. It is a necessary activity to prevent breakdowns and reduce energy yield losses. Following the Standard Operating Procedures (SOPs) and standard Checklists helps ensure consistency and quality of work.

Condition Monitoring:

Condition based Monitoring involves monitoring of equipment condition and plant operation on real time basis and addresses potential problem at a very early stage to prevent breakdown. A significant change in condition can be indicative of a likely fault that can occur.

Corrective Maintenance:

Corrective maintenance activities begin in the event of a fault.  The goal should be to clear the faults and restore operation of the equipment within the limits of contractual Plant availability.

O&M Budget:

Minimum budget within which to manage the smooth operations of a solar plant is one of the biggest challenges.

Here the site management strategy should be comprehensive for a better performance minimum cost along with customer satisfaction.

Documentation:

To maintain the record of each activity at the site and provide this information on time without any delay to the client. This is one of the best practice in O&M services.

Spare Management:

“Keeping Machines in fit condition calls for right spare parts at right time in right quantity”

Inventory management system is one of the best ways to track stock, warranty, and spares maintenance to ensure smooth operations in a plant.

Skilled Manpower:

Skills Training is most important for improving workmanship and a productive work environment.

Behavioral and Technical skills may be honed on the job so that the O&M provider helps

  • Maintain a healthy work environment and can enhance the quality of work
  • Minimize accidents on the job
  • Minimize breakdown time
  • Standardization in Plant and internal process

 

Plant Performance:

To achieve the plant performance in terms of Performance Ratio (PR) and Operational Performance Ratio(OPR), Generation units, reduce Breakdown and ensure smooth operation, following tasks are important for the on-site team:

(1) Module Cleaning as per desired frequency and site conditions

(2) Vegetation control as required

(3) Spares Management

(4) Manpower optimization

(5) Quality Maintenance work

(6) SCADA Monitoring

Safety:

When working at a Project site, it is in the interest of people and property to maintain the safety protocol and use (Personal Protective Equipment) PPE’s and the right methods during the work for protection from any kind of hazards.

Factors Affecting Solar PV Power Plant Performance

Solar Photo Voltaic Power Plants are designed to last 25 years or more. However, during the life time of a Solar PV Power Plant there are many factors that can affect Plant performance. During the Plant design stage, a study is done using Simulation software (viz PVSYST) to arrive at the likely monthly and yearly Generation possible at a site using reference irradiance data available from NASA/Meteonorm databases.

Typical factors that are covered during the Simulation study are factors that affect performance of plants during the day-to-day operations and during the life of the plant. Some factors are controllable while some of them are Non-controllable during the working of the Plant.

Typical Factors affecting Plant performance:

  • Soiling Losses
  • Vegetation growth causing shadows
  • Higher Temperatures – temperatures reaching greater than Nominal Cell operating temperature(NOCT) can de-rate performance by 0.45% for every degree rise in temperature beyond NOCT.
  • Incident Angle Modifier (IAM) Losses inherently defined during simulation can vary mainly due to improper or fragile nature of the Antireflective coatings for AR coated Modules
  • Light Induced degradation intrinsic to the module and linked to the quality of the wafer during manufacturing
  • Cable Losses between DC field and Inverter and losses between Inverter and Point of injection to Grid
  • Inverter Losses (Efficiency related)
  • AC Ohmic Losses

Other Factors likely to affect performance and warrant attention are:

  • Build up of Hot Spots due to thermal effects within the module
  • Module Efficiency (current category) differences– Usually Manufacturers have different and superior current class modules that invariably works in low irradiation unlike lower current category of same power rating
  • Snail Trails and its correlation to micro-cracks in cells may adversely affect performance
  • Potential Induced Degradation (PID) effect – Factors related to the Module including ingredients in glass and the means of encapsulation have an impact on PID. Ungrounded systems usually are affected with PID. It is generally reversible, and losses can be controlled.
  • Bus Bar Rusting – Lesser the redundancy of busbars, the chances of deterioration are more
  • Tilt angle being disturbed during Preventive maintenance activities or while doing seasonal tilt changes
  • Higher total dissolved solids(TDS) in water that is used for Module cleaning can cause scaling and thereby affect performance adversely
  • High UV radiation at a place correlated to degradation

It is evident that the quality of the Module right from the time it has left the production floor has to be consistent – these need to weather the environmental changes well and conform to the design specifications. If the designated or allowed yearly degradation levels are breached, then there will be a noticeable dip in performance.

The O&M service provider needs to address all the controllable factors quickly to reduce generation losses. Regarding the non-controllable factors, the client must be apprised about the impact of these on generation and request them to take suitable action. If the factors pertain to Module deficiencies client should have discussions with the Module Manufacturers to help resolve issues and touch on warranty aspects. Laboratory testing of a few sets of Modules may be required to be carried out to be sure of performance aspects.

—  Contributed by Ganesh H , AVP – Technical Solutions Group