Sel 411L - Page 446

P.3.338
SEL-411L Relay Protection Manual Date Code 20151029
Protection Functions
Protection Application Examples
Stub bus protection is not necessary for this application.
ESTUB := 0 Enable Stub Bus Protection (SEL
OGIC control equation)
87 In-Line Transformer. We would have the following at all relays:
87MVA:= 200 Transformer Max Power Capacity (1–5000 MVA)
The transformer connection is YDAB. The LV voltage leads the HV voltage
by 30 degrees (ABC phase rotation).
We would have the following at relays S and R:
87CTCWL:= 1 Terminal W CT Conn Comp. (0–12)
We would have the following at Relay T:
87CTCWL:= 0 Terminal W CT Conn Comp. (0–12)
We would have the following at relays S and R:
87VTWL:= 345.00 Terminal W Line-to-Line Voltage (1.00–1000 kV)
We would have the following at Relay T:
87VTWL:= 69.00 Terminal W Line-to-Line Voltage (1.00–1000 kV)
The transformer full load current is 377 A at the 345 kV terminal and 1883 A
at the 69 kV terminal.
We would have at the following at relays S, R, and T:
XFMRM = MIN(377/1000, 1883/2000) = 0.38
87XFMRM:= 0.38 Lowest ratio of XFMR full load/CT primary current
(0.35-3.50)
The relay will generate the following tap values:
We would have the following at Relay S:
Equation 3.127
87TTAPW:= 1.88 Tap Value for Terminal W (1.75–17.5)
We would have the following at Relay R:
Equation 3.128
87TTAPW:= 2.35 Tap Value for Terminal W (1.75–17.5)
We would have the following at Relay T:
Equation 3.129
87TTAPW:= 0.94 Tap Value for Terminal W (0.35–3.5)
The following settings apply at Terminal R because it is a master and runs the
differential element.
We would have the following at Relay R:
E87HR:= N Enable Harmonic Restraint Diff. Element (Y, N)
E87HB:= Y Enable Harmonic Blocking Diff. Element (Y, N)
Tap
225 1000
3345 200
------------------------------------ 1.88==
Tap
225 1000
3345 160
------------------------------------ 2.35==
Tap
225 1000
369 2000
------------------------------------ 0.94==