Investigation on Impact of Solar PV penetration on the Operation of Protective Relays in a Distribution System using Python

The integration of renewable energy into the existing distribution system results in the development of an active, interconnected system. PV generation is one of the widely integrated renewable energy sources. As the level of PV penetration increases the challenges will also increase. This paper presents the impact of PV in distribution systems in terms of voltage profile, power flow and short circuit analysis. This change in the short circuit current level and power flow direction will affect the coordinated operation of the protection system of the electrical network. Test systems representing distribution systems are modelled in the Python platform. Python is an open-source software platform with excellent community support, machine learning and data analysis features. A case study is conducted on an IEEE 33 bus distribution system to analyse the impact of PV penetration on protective devices and protection issues. The results show that when high PV penetration occurs the systems short circuit current level and direction of power flow changes which will affect the operation of the protective devices. Further, when PV penetration increases up to 40 % the short circuit current level may vary up to 7 times the standard value which will affect the performance of the protective device as the device setting is primarily dependent upon the short circuit current value.