Uptime Management
- Automatic string level visual alarms
- Real time data collection
- Monitoring energy production (daily basis)
- Effective data interpretation
- Mismatch characterization
- Solar Resource Management and Prediction
- PV system monitoring systems
- Trending and Analytics for continuous improvement
- Critical and non-critical reactive repairs
- Spare parts and inventory management
General checks
While a solar plant is being installed, engineers at OHMS Energy prepare a schedule for
preventive maintenance. This includes, but is not limited to, adjustments, cleaning,
lubrication, repairs, replacements, and the extension of equipment life. At least twice a year,
O&M personnel conduct a general inspection of the installation-site.
During this inspection, technicians from OHMS Energy:
- Ensure roof drainage is adequate, roof drains are not clogged and confirm that there are no signs of water pooling near the array
- Ensure roof penetrations (if any) are watertight
- Check for ground erosion near the footings of a ground mount system
- Effective data interpretation
- Confirm electrical enclosures are only accessible to authorised personnel
- Check for corrosion on the outside of enclosures and the racking system
- Check for cleanliness throughout the site to ensure that there is no debris in the inverter pad area or elsewhere
- Check for loose hanging wires in the array
- Check for signs of animal infestation under the array
Specific checks
Apart from the basic checks, some specific checks are undertaken as part of the preventive maintenance:
- Modules
Modules need the maximum amount of preventive maintenance, and cleaning activities are majorly concentrated around them.
- Frequency of cleaning:
In normal conditions, when there isn’t too much dust or dirt,
cleaning is carried out on a fortnightly basis. However, in dusty areas such as Rajasthan, the
cleaning frequency is increased to once a week.
- Water Quality:
The cleaning of the modules is performed keeping in mind the TDS (total
dissolved solids) levels, water specifications and certain wiping details. In India, the TDS level
of the water needs to be at least below 250 parts per million (ppm). The chlorine (less than
250 ppm) and calcium (less than 250 ppm) level of the water, as well as the electrical
conductivity, is considered while carrying out the cleaning. Water quality is tested after
every six months to ensure that set standards are maintained.
- Quality of cleaning equipment:
Brushes without hard bristles (say fibre brushes) are used
for cleaning. A low-quality brush, like one with metal bristles, could negatively impact the
glass surface of the modules. In some cases where hard substances like bird droppings have
gotten stuck on the module, engineers use detergent to clean the surface. However, the
detergent is not highly concentrated and has very high-water content.
- Innovation in Cleaning:
Technicians at OHMS are currently in the process of developing
automated cleaning systems. In the sprinkle-type cleaning system, nozzles will be placed on
the module itself, and it will automatically start the system using remote monitoring,
pressurise the water, and pour it over modules. It would be particularly useful when it is
hard to install a water source at the site. However, this would be a costlier way to clean
when compared to deploying someone at the site.
- Post wash care:
Post extensive cleaning, modules are wiped off properly to ensure no stain
is left to avoid affecting the generation capacity. Since OHMS takes up the responsibility of
maintaining the plant, our engineers make arrangements for Ultra Poly Vinyl Chloride
(UPVC) conduit pipes to ensure water supply. After the system returns to steady-state
temperature (i.e. there is no remaining impact from the cooling effect of wash water), the
current produced is noted along with weather conditions including temperature, irradiance
etc. This maintenance work is recorded in the log book, and the production of the clean
system to the previous production values is compared.
- Inverter
Most German-make inverter manufacturers recommend servicing the
inverter on a quarterly basis. However, OHMS Energy carries out servicing on a monthly
basis as there is a lot more dust in India compared to other countries. The ventilation is
provided via a filter, and this filter needs to be frequently cleaned. Therefore, usage of
high-quality filters is advantageous. As part of preventive activities, our engineers check he voltage of the string inverter and record it in the periodic log book. This gives an
understanding of voltage fluctuations if any.
- MC4 Cabling Connector:
Under preventive measures, we ensure that there is no gap
between the male and female connector pipes. Any gap, irrespective of the size, could
cause a fire and damage the modules. Separately, off-takers can install a “check” meter of
equal or higher accuracy with reference to the main meter to cross-check the production
level on a monthly basis. All readings have to be, more or less equal, with a 2-3%
correction allowance.
- Transformer
For transformers at the site with installed capacity in megawatts,
parameters such as the operating temperature, OTI (oil temperature), WTI (winding
temperature), and oil level are monitored daily. If there is any internal disturbance in the
transformer, it reflects in these parameters which are monitored at least three times in a
day (at 11 AM, 02 PM and 04 PM as solar power is generated at its peak during these
slots). The transformer has to be cleaned thoroughly once in six months. OHMS Energy
conducts IR test and cable yearly to check the transformer performance.
- Protection from external elements:
To ensure that the plant is working smoothly (i.e.
without any shutdown), the same has to be sealed properly. Else, rats and other rodents
can enter, and get electrocuted. This, in turn, can cause a short circuit, and affect the
entire plant. Many people are not aware that even high-pressure water can damage the
modules. If the water stream is too strong, our team will place the outlet at a farther
distance.
- Remote monitoring:
solar power plant constantly needs to be monitored to detect
breakdowns and optimise its operation. The same function could be performed either
on-site or from a remote location wherein we retrieve all the data either from the inverter
or from communicating equipment (probes, meters etc.).