ABB REL300 Instruction Manual page 122

Check jumper #3 on the Microprocessor module for phase sequence ro-
tation ABC or ACB. Remove jumper #3 for system ABC rotation. Con-
nect Jumper #3 for ACB system.
5.1 CALCULATION OF REL300 SETTINGS
The following REL300 setting calculations correspond to the setting categories in the Installa-
tion Section (4). Assume that the protected line has the following data:
• 18.27 miles
• Line reactance 0.8 ohms/mile
• 69 kV, 60 cycles
• Positive and negative sequence impedances:
ZIL(Pri) = Z2L(Pri) = 15∠77° ohms
• Zero sequence impedance:
Z
0L
• Current Transformer Ratio (CTR):
RC = 1200/5 = 240
• Voltage Transformer Ratio (VTR):
RV = 600/1 = 600
• Relay secondary ohmic impedances are:
Z = Z
Z
1L
Z
0L
5.1.1 Ratio of Zero and Positive Sequence Impedances
ZR = Z
Section 5. SETTING CALCULATIONS
(pri) = 50∠73° ohms
(Set CTR = 240)
(Set VTR = 600)
x R /R
pri C V
= 15 ∠ 77 ° x 240/600 = 6 ∠ 77 ° ohms
= Z
2L
= 50∠73° x 240/600 = 20∠73° ohms
/Z = 20/6 = 3.33
0L 1L
!
WARNING
I.L. 40-385.7
5-1