UNI-T UT381PV Solar Farm Inspection and Maintenance Guide Malaysia
UNI-T UT381PV Solar Farm Inspection and Maintenance Guide Malaysia
Content
Solar farms require regular inspection to identify shading, contamination, incorrect panel alignment and performance differences between PV arrays.
The UNI-T UT381PV Solar Irradiance Meter allows maintenance technicians to measure solar irradiance, panel temperature, ambient temperature, inclination and azimuth using one portable instrument.
These measurements help technicians document the site conditions present when electrical performance is tested.
Why Irradiance Must Be Recorded
PV output changes with the amount of solar energy reaching the panels. Electrical readings taken without irradiance information can be difficult to interpret.
The UT381PV measures solar irradiance from 0 to 1400 W/m².
During an inspection, position the instrument in the same plane as the solar panels. Record the irradiance at approximately the same time as the string voltage, current or power measurement.
Irradiance information helps distinguish between:
- Low output caused by weak sunlight
- Low output caused by partial shading
- Temperature-related performance reduction
- Differences between PV strings
- Possible electrical or module faults
When comparing different arrays, complete the measurements within a short period because sunlight can change rapidly.
Compare Different Sections of the Solar Farm
A large solar farm may experience different conditions across the site.
One section may be affected by:
- Moving cloud cover
- Dust accumulation
- Vegetation
- Shadows from structures
- Uneven terrain
- Different panel orientations
- Localised panel damage
Measure irradiance at several representative locations instead of assuming that the entire site receives identical sunlight.
If two sections show different electrical output, compare their irradiance and temperature before concluding that one section has an electrical fault.
Monitor Panel Temperature
Solar panels operating under strong sunlight can reach high surface temperatures.
The UT381PV measures temperatures from −40°C to 120°C. Its supplied suction-cup temperature probe can be attached to the panel surface during inspection.
Higher panel temperature may contribute to lower voltage and reduced power output. Temperature comparison is particularly useful when one row or array performs differently from another under similar irradiance.
Check for localised conditions such as:
- Restricted airflow
- Different mounting clearances
- Heat accumulation near roof or ground surfaces
- Damaged or discoloured modules
- Uneven vegetation growth
- Hot areas requiring further thermal inspection
The UT381PV records surface temperature but does not replace a thermal camera when detailed hotspot detection is required.
Verify Panel Inclination
The UT381PV provides inclination measurement from −90° to +90°.
Use this function to compare panel rows and confirm that the mounting angle remains consistent with the installation design.
An abnormal angle may be caused by:
- Loose mounting hardware
- Structural movement
- Installation inconsistency
- Ground settlement
- Wind-related movement
- Previous maintenance work
Record the angle of the affected row and compare it with nearby rows. Visible misalignment should be inspected before it causes additional stress or performance loss.
Check the Azimuth Direction
The UT381PV measures azimuth from 0° to 360°.
Azimuth measurement helps verify that panel rows face the intended direction. It is also useful when documenting a new solar site or checking whether a mounting structure has shifted.
Before measuring:
- Complete compass calibration
- Keep away from strong magnetic sources
- Avoid large metal structures where possible
- Allow the reading to stabilise
- Repeat the reading for confirmation
Azimuth results should be evaluated together with the installation plan and site layout.
Use Data Logging for Site Monitoring
The UT381PV stores up to 12,800 measurement sets. The recording interval can be adjusted from one second to 60 minutes.
Data logging can support:
- Morning-to-afternoon irradiance monitoring
- Temperature trend analysis
- Shading investigations
- Comparison between panel rows
- Before-and-after cleaning checks
- Maintenance documentation
- Investigation of intermittent output complaints
Bluetooth connection to the UNI-T iENV mobile application allows technicians to review and manage the collected readings.
Solar Farm Inspection Workflow
A practical inspection sequence is:
- Review the site performance records.
- Identify low-performing strings or arrays.
- Inspect the panels for dirt, damage and shading.
- Measure irradiance at representative locations.
- Record panel and ambient temperatures.
- Compare inclination between panel rows.
- Verify the azimuth direction when misalignment is suspected.
- Compare environmental readings with electrical results.
- Continue with electrical, insulation or I-V curve testing where required.
- Record all findings in the maintenance report.
The UT381PV can also be integrated with the UNI-T UT541 15kW Photovoltaic I-V Curve Analyzer when more detailed PV performance analysis is required.
Limitations of Irradiance Measurement
The UT381PV provides important environmental and installation measurements, but it does not directly diagnose every PV fault.
Additional instruments may be required to test:
- Open-circuit voltage
- Short-circuit current
- String current
- Insulation resistance
- Earth continuity
- I-V curve performance
- Connector temperature
- Module hotspots
- Inverter condition
The best results come from combining irradiance information with appropriate electrical and thermal measurements.
For assistance selecting the UNI-T UT381PV for solar farm inspection and maintenance in Malaysia, contact MTM Precision.
MTM Precision Sdn Bhd
Showroom & Service Centre: No. 29-1 & 29-2, Jalan Bandar 18, Pusat Bandar Puchong, 47160 Puchong, Selangor, Malaysia
Tel: 03-8080 7172
WhatsApp: +6016-660 7346
Email: mtmpre@yahoo.com
Website: www.mtmpre.com.my
30 Sep 2026
