Sympathetic Tripping in a Field Case Study

Sympathetic tripping refers to the operation of a protective device in a healthy section of the network due to a fault on another section, resulting in unnecessary loss of power supply to the customers of an unfaulted line.The objective of this paper is to study the causes of sympathetic tripping phenomena observed by the Hellenic Electricity Distribution Network Operator on the distribution network of the city of Thessaloniki, Greece. For this purpose, several simulation scenarios are performed using the EMTP-RV software to investigate the performance of the protection system in different cases and assess the general state of the network.