ABB ret650 - Page 8

Example how to connect delta connected three-phase
CT set to the IED....................................................................48
Example how to connect single-phase CT to the IED............ 51
Relationships between setting parameter Base Current, CT
rated primary current and minimum pickup of a protection IED.. 53
Setting of voltage channels......................................................... 53
Example................................................................................. 53
Examples how to connect, configure and set VT inputs
for most commonly used VT connections.............................. 54
Examples on how to connect a three phase-to-earth
connected VT to the IED........................................................ 55
Example on how to connect a phase-to-phase
connected VT to the IED........................................................ 57
Example on how to connect an open delta VT to the IED
for high impedance earthed or unearthed networks...............59
Example how to connect the open delta VT to the IED
for low impedance earthed or solidly earthed
power systems....................................................................... 62
Section 5 Local HMI....................................................................... 65
Display..............................................................................................66
LEDs.................................................................................................68
Keypad............................................................................................. 69
Local HMI functionality..................................................................... 71
Protection and alarm indication................................................... 71
Parameter management .............................................................72
Front communication................................................................... 73
Section 6 Differential protection..................................................... 75
Transformer differential protection T2WPDIF and T3WPDIF .......... 75
Identification................................................................................ 75
Application................................................................................... 75
Setting guidelines........................................................................ 76
Restrained and unrestrained differential protection................76
Elimination of zero sequence currents................................... 79
Inrush restraint methods.........................................................80
Overexcitation restraint method............................................. 80
Cross-blocking between phases............................................ 81
External/Internal fault discriminator........................................ 81
Differential current alarm........................................................ 83
Open CT detection................................................................. 83
Switch onto fault feature.........................................................84
Setting example...........................................................................84
Introduction.............................................................................84
Table of contents
2 Transformer protection RET650 2.2 IEC
Application manual