Schweitzer Engineering Laboratories SEL-700G Series, Инструкция по эксплуатации

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4.127
Date Code 20170814 Instruction Manual SEL-700G Relay
Protection and Logic Functions
Group Settings (SET Command)
If setting:
ORDERm := OFF
then all of the ground directional elements are inoperable. Note in Figure 4.83
and Figure 4.84 that setting ORDER := OFF effectively makes the residual-
ground and neutral-ground overcurrent elements nondirectional (the
directional control outputs of Figure 4.83 and Figure 4.84, respectively, are
continuously asserted to logical 1).
50PDIRPY—Phase Directional Element Three-Phase Current Pickup.
The 50PDIRPY setting is set to pick up for all three-phase faults that need to
be covered by the phase overcurrent elements. It supervises the positive-
sequence voltage-polarized directional elements FDIRP and RDIRP (see
Figure 4.87).
If the load-encroachment logic is enabled (enable setting ELOADY := Y),
then setting 50PDIRPY is not made or displayed, but is fixed internally at:
0.5 A secondary (5 A nominal phase current inputs,
IAY
,
IBY
,
ICY
)
0.1 A secondary (1 A nominal phase current inputs, IAY , IBY , ICY )
Z2F/Z2R—Forward/Reverse Directional Z2 Thresholds.
Z2F and Z2R
are used to calculate the Forward and Reverse Thresholds, respectively, for the
negative-sequence voltage-polarized directional elements (see Figure 4.77 and
Figure 4.89).
If enable setting EDIR := Y, you calculate and enter the settings Z2F and Z2R
(negative-sequence impedance values), but setting Z2R must be greater in
value than setting Z2F by 0.1

secondary.
If enable setting EDIR := AUTO, the relay uses the positive-sequence line
impedance magnitude setting Z1MAG as follows to calculate the settings Z2F
and Z2R (negative-sequence impedance values) automatically:
Z2F := Z1MAG/2 (

secondary)
Z2R := Z1MAG/2 + z

secondary; z listed in Table 4.35 below)
NOTE:
If the calculation of Z2F or
Z2R exceeds the setting range, the
quantity is set to the upper limit of the
setting range.
Figure 4.91 and Figure 4.92 and supporting text concern the zero-sequence
impedance network, the relay polarity, and the derivation of settings Z0F and
Z0R. The same general approach outlined for deriving settings Z0F and Z0R
can also be applied to deriving settings Z2F and Z2R in the negative-sequence
impedance network, although the preceding method of automatically making
the settings Z2F and Z2R usually suffices.
50QFP/50QRP—Forward/Reverse Directional Negative-Sequence
Current Pickup.
The 50QFP setting (3I
2
current value) is the pickup for the
forward fault detector 50QF of the negative-sequence voltage-polarized
directional elements (see Figure 4.74). Ideally, the setting is above normal
load unbalance and below the lowest expected negative-sequence current
magnitude for unbalanced forward faults.
Table 4.35 z Constant for Z2R Setting
Relay Configuration z (

Secondary)
5 A nominal current 0.2
1 A nominal current 1.0