1-2 G60 Generator Management Relay GE Multilin1.2 UR OVERVIEW 1 GETTING STARTED1 1.2UR OVERVIEW 1.2.1 INTRODUCTION TO THE URHistorically, substation protection, control, and metering functions were performed with electromechanical equipment. Thisfirst generation of equipment was gradually replaced by analog electronic equipment, most of which emulated the single-function approach of their electromechanical precursors. Both of these technologies required expensive cabling and auxil-iary equipment to produce functioning systems.Recently, digital electronic equipment has begun to provide protection, control, and metering functions. Initially, this equip-ment was either single function or had very limited multi-function capability, and did not significantly reduce the cabling andauxiliary equipment required. However, recent digital relays have become quite multi-functional, reducing cabling and aux-iliaries significantly. These devices also transfer data to central control facilities and Human Machine Interfaces using elec-tronic communications. The functions performed by these products have become so broad that many users now prefer theterm IED (Intelligent Electronic Device).It is obvious to station designers that the amount of cabling and auxiliary equipment installed in stations can be even furtherreduced, to 20% to 70% of the levels common in 1990, to achieve large cost reductions. This requires placing even morefunctions within the IEDs.Users of power equipment are also interested in reducing cost by improving power quality and personnel productivity, andas always, in increasing system reliability and efficiency. These objectives are realized through software which is used toperform functions at both the station and supervisory levels. The use of these systems is growing rapidly.High speed communications are required to meet the data transfer rates required by modern automatic control and moni-toring systems. In the near future, very high speed communications will be required to perform protection signaling with aperformance target response time for a command signal between two IEDs, from transmission to reception, of less than 3milliseconds. This has been established by the IEC 61850 standard.IEDs with the capabilities outlined above will also provide significantly more power system data than is presently available,enhance operations and maintenance, and permit the use of adaptive system configuration for protection and control sys-tems. This new generation of equipment must also be easily incorporated into automation systems, at both the station andenterprise levels. The GE Multilin Universal Relay (UR) has been developed to meet these goals.
