Development of a new test method for alpha plane differential protection characteristic using IEC61850 Standard based numerical relays

Abstract

This paper focuses on three-terminal Alpha Plane differential protection to develop a complete test method using the OMICRON test universe software essentially defining security, dependability, and sensitivity of the Alpha Plane characteristic. It analyses the three-terminal alpha plane characteristic and the existing primitive test method and develops an improved test method using the IEC 61850 standard. The primitive method is time-consuming and results in unnecessarily prolonged outages. The primitive test method is discussed and improved by implementing the IEC 61850 standard. First, the standard IED Capability Description (ICD) file is modified by developing new logical nodes using AcSELerator Architect and XML Maker software. Then the developed logical nodes, Three-Terminal differential protection Alpha Plane characteristic with its additional infeed/outfeed check logic, and the developed test method are tested simultaneously using Test Universe software. A laboratory test bench is built using three SEL311L relays, two CMC 356 Omicron injection devices, PC, MOXA Ethernet switch, CMIRIG-B time synchronizing unit, SEL 2407 satellite synchronized clock, and a DC power supply. The developed test method vindicates the benefits of IEC 61850 standard over hardwired systems. Prolonged outage times due to test set preparation using hard wires are drastically reduced