Faulty Branch Identification Method for DC Generation and Storage Systems With Multiple Series-Parallel Cells

摘要

Solar photovoltaic energy and electrochemical energy storage are key elements for the development of more sustainable and efficient electrical energy systems such as electric vehicles or microgrids. These systems require of multiple series-parallel cell connections that complicate enormously the location of possible ground faults. In this context, this article proposes a new method based on a low frequency periodical commutation of a grounding resistor placed in the midpoint of the DC source, that allows to discern the faulty branch by measuring the current at strategical positions of each string. The highest relative current variation when the system is grounded or ungrounded determines the faulty branch. The proposed method has been analyzed for three types of grounding connections by means of simulations and experimental tests using batteries, achieving successful results.