Use of Special Protection Systems to Meet the Reliability Criteria During the Double Generators or Double Circuits Outage in the WECC Major Southwest Network Hub

This paper presents the technical analysis of utilizing the special protection systems (SPS) such as (1): a direct load tripping scheme (DLT) during the two major generating units outage to mitigate the post-transient voltage instability problem and (2): a direct generator tripping scheme (DGT) in the event of double circuits outage to maintain transient stability performance to meet the reliability criteria. Implementation of these SPS can minimize the adverse impact and prevent from further system wide spread cascading outages on the existing system and therefore will maximize system power transfer capability. This paper discuss the planning studies and the associated technical advantages that can be achieved by utilizing these two types of special protection systems in the WECC major southwest network hub