9-4 G60 Generator Management Relay GE Multilin9.1 SETTING EXAMPLE 9 APPLICATION OF SETTINGS99.1.7 LOSS OF EXCITATIONFor the example system, we have the following values:(EQ 9.7)(EQ 9.8)(EQ 9.9)(EQ 9.10)(EQ 9.11)(EQ 9.12)(EQ 9.13)(EQ 9.14)The voltage supervision setting will be determined by a system study and may be disabled on either element if required. VTfuse failure should supervise this element.The choice of source is not critical for this application. The NEUTRL source is chosen for the following setting changes.Make the following changes in EnerVista UR Setup or through the SETTINGS ÖØ GROUPED ELEMENTS ÖØ SETTING GROUP1 ÖØ LOSS OF EXCITATION menu:9.1.8 REVERSE POWERThe reverse power element should be set at ½ the rated motoring power. The pickup is calculated as follows:(EQ 9.15)For the example system:Z b sec( )base kV 2base MVA--------------------------- CT ratioVT ratio---------------------× 18 kV( )2211.765 MVA------------------------------------ 1600157.5---------------× 15.54 Ω= = =X d′(sec) X d′ Z b(sec)× 0.216 15.54 Ω× 3.36 Ω= = =X d sec( ) X d Z b sec( )× 1.967 15.54 Ω× 30.57 Ω= = =CENTER 1 Z b sec( ) X d′(sec)+2------------------------------------------------- 15.54Ω 3.36Ω+2------------------------------------------- 9.45 Ω= = =RADIUS 1 Z b sec( )2-------------------- 15.54 Ω2---------------------- 7.77 Ω= = =PICKUP DELAY 1 0.06 seconds=CENTER 2 X d sec( ) X d′(sec)+2------------------------------------------------- 30.57Ω 3.36Ω+2------------------------------------------- 16.97 Ω= = =RADIUS 2 X d sec( )2--------------------- 30.57 Ω2---------------------- 15.28 Ω= = =S min12--- Rated Motoring Power (primary watts)3 Phase CT Primary Phase VT Ratio Phase VT Secondary×××--------------------------------------------------------------------------------------------------------------------------------------------------------------------------×=S min12--- 22 10 6× W3 8000 A 157.5× 66 V××---------------------------------------------------------------------× 0.044 pu= =
