Modelling and Analysis of a Multifunctional Microcontroller based Relay for Protection of Solid State Transformer

In Modern power systems the Solid State Transformer (SSTs) is an emerging technology, where it acts as the interface between MV AC and the LV AC/DC micro grid. Due to the faults that occur in the system, the SSTs are subjected to different electrical stresses. Therefore a suitable protective scheme has to be developed. This paper is aimed at proposing a suitable protective scheme has to be developed. This paper is aimed at proposing a multifunctional protective schemes to protect the Solid State Transformers against Over Voltage, Under Voltage and the Over Load by using Arduino Uno Microcontroller. The protective schemes are modeled and analyzed by using Proteus software and a software program has been developed using Proteus package C-language. The microcontroller monitors the network voltage and current, therefore it energizes the relay in case that system voltage, and current exceeds the preset value. The performance of OV/UV relay is investigated by performing different conditions at Instantaneous, Momentary and Temporary categories according to IEEE 1159 standards. The Over Load relay operates whenever the current in the system exceeds the pickup value and it is compared with theoretical calculations, therefore the performance of the relay is investigated.