Case Study 1: 50MW Solar Farm — Rajasthan
| Detail | Information |
| Client | Large-scale IPP — utility scale, name confidential |
| Location | Rajasthan, Western India |
| Plant size | 50MW ground-mounted, crystalline silicon modules |
| Plant age at inspection | 4 years operational |
| Challenge | Plant generating 6.5% below P90 baseline for three consecutive months. SCADA showed no string-level alerts. IV curve tracing by O&M contractor on selected strings was inconclusive. |
| Elion commissioned to | Identify cause and location of underperformance across the full 50MW array |
What Elion Did
We conducted a full-array drone thermography inspection over four days in November, following post-monsoon inspection protocols. Irradiance was maintained above 650 W/m2 for all inspection days. 640×512 thermal sensor with 13mm lens, simultaneous RGB capture. The 50MW plant consists of approximately 165,000 modules arranged in 330 strings across 12 inverter zones.
What We Found
| Finding Type | Count | Severity | Estimated Generation Impact |
| Hotspot cells — bypass diode failures | 87 modules | Class 2 to 3 | 2.1% of total plant generation |
| PID — systematic string-edge pattern | 14 strings across 3 inverter zones | Class 2 | 1.8% of total plant generation |
| Open-circuit string faults | 6 complete strings | Class 3 | 0.9% of total plant generation |
| Soiling — localised bird dropping patches | 234 modules | Class 1 | 0.4% of total plant generation |
| Delamination — early stage | 12 modules | Class 1 | Negligible current impact, monitor |
| TOTAL estimated generation loss | All findings combined | Mixed | Approximately 5.2% of total plant generation |
Result
The O&M contractor replaced the 87 modules with bypass diode failures, cleaned the 234 soiled modules, repaired the 6 open-circuit string faults (5 failed string fuses, 1 loose MC4 connector), and initiated a grounding review to address PID across the three affected inverter zones.
Post-repair generation monitoring showed a 5.1% improvement in plant output relative to the pre-inspection baseline — recovering approximately INR 2.4 crores per year in additional generation revenue at a tariff of INR 2.85 per unit. The Elion inspection cost was recovered from the first month of improved generation.
Case Study 2: 220km Transmission Corridor — Central India
| Detail | Information |
| Client | State Transmission Corporation — name confidential |
| Location | Central India — mixed terrain including flat and forested sections |
| Line details | 220kV double circuit, approximately 220km corridor, 440 towers |
| Line age | 18 years operational |
| Challenge | Two unexplained circuit trips in 6 months. Ground patrol completed but no visible cause found. Client needed to identify thermal anomalies before the summer demand peak. |
| Elion commissioned to | Complete full corridor drone thermography and identify all thermal anomalies above 5 degrees delta-T |
What Elion Did
We deployed two drone units simultaneously on different sections of the corridor to complete the 220km inspection in 8 days. NOTAM filed with AAI for three sections near aerodromes along the corridor. Coordination with state utility load dispatch centre to freeze switching operations during each day’s inspection window. 640×512 thermal sensor with 25mm telephoto lens, maintained 30-metre standoff from live conductors throughout.
What We Found
| Finding Type | Count | Severity | Towers Affected |
| Splice joint overheating delta-T above 10 degrees | 43 locations | Class 2 to 3 | Distributed across 38 towers |
| Splice joint critical delta-T above 20 degrees | 8 locations | Class 3 — urgent | 8 towers — recommended emergency outage |
| Clamp and hardware hotspots | 27 locations | Class 2 | 22 towers |
| Insulator string thermal anomalies | 15 strings | Class 1 to 2 | 12 towers |
| Earth wire conductor breaks thermal signature | 4 locations | Class 2 | 4 towers — visible in RGB also |
| Vegetation encroachment — thermal contrast mapping | 11 spans | Operational risk | Flagged for ROW clearance team |
Result
The 8 critical splice joints were replaced in an emergency outage coordinated with the state load dispatch centre within 3 weeks of report delivery. Post-repair thermal imaging was conducted on the repaired sections to confirm normal operating temperature. The remaining Class 2 findings were incorporated into the utility’s 12-month planned maintenance schedule.
No further circuit trips occurred in the 12 months following the inspection and repairs. The utility has since commissioned Elion for annual inspection of this corridor.