Potential induced degradation (PID) is a serious threat for the photovoltaic (PV) industry. The risk of PID may increase with increasing operating voltage of PV systems. Although PID tests are currently standard tests, the expansion of floating PV power plants and installation in humid climates show that PID-free modules are still sensitive to this type of degradation. Therefore, a method that can detect PID in the initial phase before standard tests reveal it, is necessary to increase the reliability of PV systems and maintain their lifetime. One possible tool for revealing early-stage PID manifestations is impedance spectroscopy and I-V dark curves measurements. Both IS and dark current measurement methods are sensitive to cell shunt resistance (R_SH), which is strongly influenced by PID before significant power loss and can act as an early stage PID detection mechanism. The paper describes the differences of the common P-type PV module parameters both during the degradation process and also during the regeneration process when diagnosed by conventional and IS and dark current measurement methods.

There exist many photovoltaic (PV) power plants which are based on thin-film technology. Unlike PV power plant with crystalline silicon technology, the diagnostic possibilities of thin-film PV modules are limited due to seasonal effects and problematic utilization of thermography. The main problem of degradation of these PV plants is the area degradation which affects even PV power plants with transformer inverters. Although there exist measurement methods based on I–V curve measurement, these methods require specific climatic conditions (clear sky, sufficient irradiance) and time. Here, we present the novel approach to diagnose thin-film modules affected with degradation which provides quick results with low-cost equipment.

A special, by microprocessor controlled source, designed and made for power supply of electromagnets used in magnetotherapy, is written in this paper. The source makes and breaks the adjusted dc current in coil of electromagnet, so called applicator, with random time of switching. The therapeutically used magnetic field generated in applicator has a character of rectangular pulses and these pulses represent the random signal with large width of the frequency spectrum in this case. Some properties and basic parameters of the integrated system realized by this source and special flat plastic applicator are written as well.

Internal short circuit (ISCr) detection in the electrochemical cell is very difficult. The internal short circuit may cause a thermal runaway. This thermal runaway (TR) can even cause an explosion of the cell. That is why it is very important to timely detect internal short circuit. The cause of the internal short circuits is a manufacturing defect, overcharge or overdischarge. There are several methods of analysis. This work focuses on the detection of an internal short circuit while the cell is being charged. This work then focused on calculating ISCr from capacity of battery.