Protection System Considerations for 400 kV Series Compensated Transmission Lines of the Central Western Network in Venezuela

The main aspects considered in the protection system associated with the Series Compensation Project of the Central Western 400 kV network in Venezuela are presented. Previous studies had determined that, for some fault conditions, phenomena such as voltage reversal and subsynchronous resonance would take place in that series compensated network. Those phenomena could affect the performance of conventional distance protections. New protection equipments, capable of an appropriate operation in networks with series compensation, were used to replace conventional distance protections. In addition, to guarantee correct relay performance, existing solid state distance relays LZ96, belonging to the 765 kV line Arenosa Yaracuy, were adapted through the installation of special modules. It was necessary to use particular criteria to set the new distance protections, being the main aspects a considerable reduction of first zone settings in some critical lines and an increasing dependency of communication channels for fault clearing