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I.L. 40-385.1B
T3P = 0.8 and T3G = 0.8
NOTE: T3P and T3G are separate timers; they
can be set at a different time settings.
c. For out-of-step block (OSB), if applied, the OSB
override timer setting (OSOT) is determined by the
power system operation. Its range is 400 to 4000 ms,
in 16 ms steps. For example, set MDAR OSOT =
500 if OSB override time of 500 ms is required.
d. For single-pole trip application only, the single
phasing limit timer setting (62T) is for preventing
thermal damage to rotating machines, due to the I
component during single phasing. Its range is 300 to
5000 ms. in 50 ms steps. The setting should be
2 )
based on the poorest (I
in service. For example, set MDAR 62T = 1550, if
3PT is required before 1.55 seconds and after one
pole has been open and the breaker does not or can-
not reclose.
e. For the blocking system only, the channel coordi-
nation timer setting (BLKT) is based on the following
application criteria:
BLKT > (Slowest remote carrier start time + channel
time + margin) - (the fastest local 21P/21NP pickup
time)
Where channel time includes the transmitter and re-
ceiver times, and the times which occur between
these devices, e.g., wave propagation, interfacing
relays, etc.
For MDAR:
fastest 21P/21NP pickup time
slowest carrier start time
suggested margin time
For example, the MDAR channel coordination timer
should be determined as shown below, if the chan-
nel time is 3 ms.
BLKT = (4 + 3 + 2) - 14= -5
i.e., set BLKT
5.2
SELECTION OF MDAR SETTINGS
The following settings are determined by the appli-
cation. They do not require calculation.
5.2.1 The OSC setting is for selecting one of the 4
ways (TRIP/Z2TR/Z2Z3/∆I∆V) to initiate the oscillo-
graphic data taken, where:
TRIP --- start data taken only if trip action
5-4
2
constant of the machines
t
= 14 ms
=
4 ms
=
2 ms
= 0
occurs.
Z2TR --- start data taken if Zone 2 units pick up, or
any trip action occurs.
Z2Z3 --- start data taken if Zone 2 or Zone 3 units
pick up, or any trip action occurs.
∆I∆V --- start data taken if ∆I, ∆V, Zone 2 or Zone 3
units pick up, or any trip action occurs.
NOTE: The setting of ∆I, ∆V, for OSC is not rec-
ommended.
5.2.2 The FDAT setting is for selecting one of the
3 ways (TRIP/Z2TR/Z2Z3) to initiate the fault data
taken, where:
2
TRIP --- start to store fault data only if trip action
occurs.
Z2TR --- start to store fault data if Zone 2 units pick
up or any trip action occurs.
Z2Z3 --- start to store fault data if Zone 2 or Zone 3
units pick up or any trip action occurs.
5.2.3 The current transformer ratio setting
(CTR) is used for the load current monitoring, if it is
selected to be displayed in primary amperes. It has
no effect on the protective relaying system. For this
example, set CTR = 240.
5.2.4 The voltage transformer ratio setting
(VTR) is used for the system voltage monitoring, if it
is selected to be displayed in primary volts. It has no
effect on the protective relaying system. For this ex-
ample, set VTR = 600.
5.2.5 The frequency setting (FREQ) should be
selected to match the power system operating fre-
quency. For example, select FREQ = 60 if the power
system operating frequency is 60 Hertz.
5.2.6 The current transformer type setting (CT-
YP) provides the flexibility for 5 Amp or 1 Amp rated
current transformer selection. For example, select
and set CTYP = 5 if a 5 Amp current transformer is
used.
The setting of CTYP affects all the distance unit and
overcurrent unit setting ranges. The ranges will be
automatically changed as listed in Table 5-1.
5.2.7 The read primary setting (RP) should be
set at YES if all the monitoring ac voltages and cur-
rents are selected to be displayed in primary KV and
KA values, respectively.
5.2.8 The ohms per unit distance of the line re-
actance setting (XPUD) is the multiplier for fault
distance display. It has a range of 0.3 to 1.5 in 0.001
(5/92)
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