4.69
Date Code 20170814
Instruction Manual
SEL-700G Relay
Protection and Logic Functions
Group Settings (SET Command)
Collect the following information before calculating the volts/hertz element
settings:
➤
The generator manufacturer’s overexcitation limit curve
➤
The step-up transformer manufacturer’s overexcitation limit
curve on generator voltage base (if you want transformer
overexcitation protection)
Set E24 := Y to enable volts/hertz protection elements. If you do not need
volts/hertz protection, set E24 := N. When E24 := N, the 24TC, 24D1, 24D1T,
24C2, 24C2T, and 24CR Relay Word bits are inactive. The relay hides the
corresponding settings; you do not need to enter these settings.
The relay uses X-side frequency and the highest phase-to-phase voltage to
calculate the actual V/Hz level.
Use the Level 1 volts/hertz element as an overexcitation alarm. Set 24D1P
equal to or greater than 105 percent, but less than the minimum pickup of the
Level 2 element. Use a 24D1D time delay of 1.0 second to allow time for
correction of an overexcitation condition prior to an alarm.
The 24CCS setting defines the overexcitation tripping element time-delay
characteristic as shown in Figure 4.38. Set 24CCS := OFF if you do not
require Level 2 volts/hertz protection. When 24CCS := OFF, the other Level 2
settings are hidden and do not need to be entered.
➤
When 24CCS := DD, the element operates with a dual-level
definite-time characteristic with pickup and delay of 24D2Pn
and 24D2Dn (n = 1 or 2).
➤
When 24CCS := ID, the element operates with a composite
inverse-time and definite-time characteristic with pickup of 24IP
(inverse-time) and 24D2P2 (definite-time). The 24IC and 24ITD
settings define the inverse-time curve shape (see Figure 4.41
through Figure 4.43).
Table 4.13
Volts-Per-Hertz Settings
Setting Prompt
Setting Range
Setting Name :=
Factory Default
ENABLE V/HZ PROT
Y, N
E24 := Y
LVL1 V/HZ PICKUP
100–200 %
24D1P := 105
LVL1 TIME DLY
0.04–400.00 s
24D1D := 1.00
LVL2 CURVE SHAPE
OFF, DD, ID, I, U
24CCS := ID
LVL2 INV-TM PU
100–200 %
24IP := 105
LVL2 INV-TM CURV
0.5, 1, 1.0, 2, 2.0
24IC := 2
LVL2 INV-TM FCTR
0.1–10.0 s
24ITD := 0.1
LVL2 PICKUP 1
100–200 %
24D2P1 := 175
LVL2 TIME DLY 1
0.04–400.00 s
24D2D1 := 3.00
LVL2 PICKUP 2
101–200 %
24D2P2 := 176
LVL2 TIME DLY 2
0.04–400.00 s
24D2D2 := 3.00
LVL2 RESET TIME
0.00–400.00 s
24CR := 240.00
24 ELEM TRQ-CNTRL
SEL
OGIC
24TC
:=
1
Summary of Contents for SEL-700G Series
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