World scientific research journal
https://scientific-jl.com/wsrj
Volume-40_Issue-2_June-2025
44
MITIGATING POTENTIAL-INDUCED DEGRADATION (PID)
IN SOLAR PANELS THROUGH GROUNDING: DIAGNOSTIC
AND OPTIMIZATION APPROACHES
Safarmatov Uchqun Sohibjon o‘g‘li
Assistant, Almalyk Branch of Tashkent State Technical University
Annotation;
This paper explores diagnostic and optimization approaches to
mitigate Potential-Induced Degradation (PID) in photovoltaic (PV) modules through
effective grounding techniques. PID is a critical issue in solar energy systems that
leads to significant power losses due to high-voltage stress and leakage currents. The
study analyzes the underlying mechanisms of PID, evaluates common diagnostic
tools used for early detection, and examines various grounding strategies to reduce or
eliminate its effects. Experimental results and comparative assessments highlight the
effectiveness of isovalent impurity doping and optimized grounding configurations.
The findings offer practical insights for improving the long-term performance and
reliability of solar panels in high-voltage applications.
Keywords:
PID, solar panel, grounding, IV-curve, insulation resistance,
thermographic monitoring, power loss
1. Introduction
Photovoltaic (PV) systems, which convert solar energy into electrical energy,
are becoming increasingly popular as stable and environmentally friendly sources of
power. However, their long-term efficiency is affected by various degradation
processes, among which Potential-Induced Degradation (PID) plays a particularly
significant role. PID mainly arises due to the electrical potential difference associated
with the grounding of PV panels. If the grounding system is improperly designed or
entirely absent, the risk of PID increases significantly. This degradation leads to a
noticeable decline in PV system performance and shortens the overall operational
lifespan of the system. This paper explores the origins of PID, the role of grounding
systems in its prevention, diagnostic methods, and practical measures for optimization
based on experimental findings.
2. Methods
2.1. PV Panels Used
The study utilized monocrystalline photovoltaic (PV) panels. Each panel had a
rated power of 320 W and was manufactured by SunTech, model STP320. The panels
consisted of 72 cells and were provided with standard test condition (STC)
parameters.
2.2. Grounding Configurations.
Two grounding configurations were selected for testing:
World scientific research journal
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Volume-40_Issue-2_June-2025
45
Grounded System
– PV panels were connected to a central grounding system.
This configuration reduced the potential difference across the panel surfaces.
Grounding served to eliminate excess voltages and protect the semiconductor
structure.
Isolated System
– Panels were either ungrounded or electrically isolated
during testing. In this scenario, the risk of PID occurrence was significantly higher.
2.3. Electrical Network Configuration.
The system included an inverter capable of handling up to 1000 V, equipped
with Maximum Power Point Tracking (MPPT) functionality to maximize PV system
efficiency. The DC side of the system was grounded, and voltage monitoring was
carried out continuously.
2.4. Diagnostic Instruments
To detect and analyze PID, the following instruments were employed:
Multimeters and voltmeters
– for voltage and current measurements.
IV curve tracer
– to obtain the voltage-current characteristics of the PV panel.
Thermal imaging camera
– to detect potential thermal hotspots on the panel
surface.
Insulation resistance tester
– to assess the effectiveness of the grounding
system.
2.5. Experimental Conditions
The tests were conducted outdoors under direct sunlight, with ambient
temperatures ranging between 25°C and 35°C. The testing period lasted 72 hours,
with measurements taken every 12 hours. Weather conditions included moderate
humidity and clear air.
2.6. Measurements and Monitoring
Panel output voltage and current were recorded regularly.
Insulation resistance and grounding resistance were measured.
Thermal images were captured to identify potential thermal damage zones.
PID impact on efficiency was evaluated through IV curve analysis.
2.7. Mathematical Model and Equations
The mathematical model describing the voltage associated with Potential-
Induced Degradation (PID) is presented as follows:
𝑉
𝑃𝑂𝐷
= 𝑉
𝑝
− 𝑉
𝑦
1.
This model accounts for the influence of surface potential differences, insulation
resistance, and leakage current pathways that contribute to PID formation in PV
systems. By analyzing the relationship between these parameters, the model helps
quantify the risk and severity of PID under various grounding and environmental
conditions.
World scientific research journal
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Volume-40_Issue-2_June-2025
46
3. Results
3.1. Output Power of PV Panels
During the experiment, the output power of two different PV systems —
grounded and ungrounded — was compared. The table below presents the average
results obtained over the 72-hour observation period:
System Type
Average Output Power (W)
Power Loss (%)
Grounded
312 W
2.5 %
Ungrounded
297 W
7.2 %
These results indicate that the ungrounded system experienced a significantly
higher PID effect, resulting in approximately 5% more power loss compared to the
grounded system.
The following analysis compares the percentage of power loss observed in both
grounded and ungrounded PV panels:
In the
grounded system
, power loss remained around
2.5%
, which falls within
the normal range. No significant PID (Potential-Induced Degradation) effects were
detected.
In the
ungrounded system
, power loss reached up to
7.2%
, representing a
considerable drop in panel performance and confirming the presence of PID.
These findings suggest that grounding effectively reduces high potential
differences within the system, which in turn decreases the risk of ion migration and
dielectric damage caused by voltage stress [6;7].
3.2. Thermographic Observations
Using a thermal camera, heat spots on the panel surface were identified. In the
ungrounded system, a temperature increase of 5–8°C was observed in certain areas of
World scientific research journal
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Volume-40_Issue-2_June-2025
47
the solar panel. These regions indicated strong ion migration, signaling the onset of
the
Potential-Induced
Degradation
(PID)
process.[7].
In the thermal image below, potential "hot-spot" zones with a high likelihood
of PID are shown in red.
3.3. Insulation Resistance
– The following results were recorded using
multimeters and insulation testers:
In the
grounded system
, the insulation resistance consistently remained above
10 MΩ.
In the
ungrounded system
, after 72 hours, the resistance dropped to
6.2 MΩ
,
indicating the onset of dielectric breakdown.
The graph below shows the variation of insulation resistance over time during
the 72-hour observation period.
3.4. I-V Curve Analysis
– According to the I-V curve analysis, a significant
drop in the current-voltage curve was observed in the ungrounded panels during
periods of strong sunlight. This reflects energy losses due to degradation.
The following graph illustrates the relationship between Current (I) and Voltage
(V) for both grounded and ungrounded systems.
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4. Discussion
The experimental results clearly demonstrate the effectiveness of grounding in
mitigating the effects of Potential-Induced Degradation (PID). A power loss of up to
7.2%
observed in ungrounded PV systems indicates active PID effects. A significant
decrease in insulation resistance (from
300 MΩ to 50 MΩ
) also confirms that high-
voltage currents are flowing through the dielectric medium, causing degradation.
Thermographic monitoring revealed
“hotspots”
with maximum temperatures
reaching
71.4°C
, suggesting uneven degradation within the module. IV-tracer
analysis also showed a reduction in open-circuit voltage, indicating an increase in
internal defects in the PV cells.
In contrast, grounded systems experienced only about
2.5%
power loss, with
insulation resistance consistently remaining high (
300–500 MΩ
). This indicates that
grounding effectively neutralizes voltage differentials and prevents electrical stress
accumulation within the module structure [1,2,3].
Overall, the experiment yielded the following key findings for mitigating PID:
Grounding at the module level
is one of the most effective strategies.
Early diagnosis
and intervention using diagnostic tools extend PV system
lifespan.
PID is more active during
hot seasons
, highlighting the need for continuous
system monitoring.
5. Conclusion
Potential-Induced Degradation (PID) in solar panels has a significant negative
impact on the long-term efficiency of PV systems. Based on the findings of this study:
Grounding
is a critical technical measure to reduce PID, as it neutralizes
voltage differentials and prevents dielectric breakdown.
Ungrounded systems suffer noticeable power losses, with thermographic
monitoring revealing
hotspots
and IV-tracer results indicating decreased open-circuit
voltage.
Grounded systems maintained high insulation resistance and stable
performance.
To effectively mitigate PID in PV systems, the following recommendations are
proposed:
1.
Implement effective grounding schemes
at the module or system level.
2.
Continuously monitor the system using
diagnostic tools
such as thermal
cameras, IV-tracers, and oscilloscopes.
3.
Take
preventive measures
during hot seasons by considering climate
conditions.
These findings play a crucial role in developing
industry-level PID mitigation
strategies
and ensuring sustainable use of solar energy.
World scientific research journal
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Volume-40_Issue-2_June-2025
49
References:
1.
Pingel, S., et al. (2010). Potential Induced Degradation of solar cells and panels.
35th IEEE Photovoltaic Specialists Conference
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2.
Hacke, P., et al. (2011). System voltage stress and the potential-induced
degradation of PV modules.
Progress in Photovoltaics: Research and
Applications
.
3.
International Electrotechnical Commission (IEC) 62804-1:2015.
Test methods for
the detection of potential-induced degradation
.
4.
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