Use of non-contact voltmeter to quantify potential induced degradation in CdTe modules

Hamza Ahmad Raza, Farrukh Ibne Mahmood, Govindasamy TamizhMani

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Potential induced degradation (PID) is a significant reliability issue for photovoltaic modules in the field. Conventionally, to detect the PID-affected modules, all the modules in a string are individually disconnected and measured using I-V (current–voltage) tracers. It is extremely time-consuming, expensive and unsafe (if the module connectors are field aged) approach. In our approach, we aim detecting the PID-affected modules quickly, inexpensively and safely without disconnecting individual modules in the string. In this study, contactless electrostatic voltmeter's (ESV) strength was explored to detect the PID-affected cadmium telluride (CdTe) modules in a string. These contactless measurements on high-voltage PV strings could make this technique unique and preferable to detect PID-affected modules in a string compared to the I-V curve method. In this work, a CdTe module was stressed for PID using the Aluminum (Al) foil method in a walk-in environmental chamber, which resulted in a reduction of module's peak current (Imax), peak voltage (Vmax), and fill factor (FF), and hence power (Pmax). Outdoor light I-V, EL, and ESV measurements were performed pre- and post-PID to determine the effectiveness of the non-contact ESV technique. The ESV technique successfully detected the change in Vmax, and hence Pmax, compared to the pre-and post-PID conditions. A difference of less than 2% was observed in the results of the non-contact and non-interruptive method compared to the conventionally used interruptive voltmeter or I-V tracer method. This technique and the test results demonstrate a significant promise to identify poor-performing modules in PV string without disconnection of individual modules in the string.

Original languageEnglish (US)
Pages (from-to)284-290
Number of pages7
JournalSolar Energy
StatePublished - Mar 1 2023


  • Electrostatic voltmeter
  • Non-contact method
  • Peak voltage
  • Potential induced degradation
  • Thin film characterization

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • General Materials Science


Dive into the research topics of 'Use of non-contact voltmeter to quantify potential induced degradation in CdTe modules'. Together they form a unique fingerprint.

Cite this