Functional Scope - Siemens SIPROTEC 7SD600 System Manual

Numerical line differential protection SIPROTEC 7SD600 V3.0
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Functional scope

The numerical line differential protection 7SD600 of
fers the following functions:
Differential protection
D Absolutely discriminative protection for all kinds of
short circuits in earthed, isolated-neutral or reso
nant-earthed systems,
D Stabilization against current transformer transfor
mation errors in the event of external short-cir
cuits,
D Additional dynamic stabilization in the event of dif
ferent degrees of current transformer saturation,
D Stabilization with second harmonic is possible,
thus enabling incorporation of a transformer or
compensation reactor,
D In the event of single-end infeed, optional discon
nection of only the infeed line end or, via the trans
fer trip function, also at the non-infeed
line end,
D Measured value transmission via a symmetrical
pair of pilot wires,
D Compensation of pilot wire resistances necessary,
no computational adaptation of sensitivity
D Continuous monitoring of pilot wires with a keyed
AF signal (optical)
D Combination of differential protection-trip com
mand with an overcurrent release is possible,
D The differential protection-trip command can be
maintained until manual reset via a binary input or
local operation (Lockout function).
Siemens AG January 1999
Introduction
System manual Order no. E50417-G1176-C069-A1
Direct and remote tripping
D Tripping of local CB by external signal with settable
delay and drop-off time,
D Tripping at the remote line end by an external si
gnal, e.g. from a circuit-breaker failure protection
(version with pilot wire monitoring).
The functional scope also includes the following
D Continuous monitoring of the internal measuring
circuits, the auxiliary power supply, as well as all
protection hardware and software; thus increased
reliability,
D Measuring and test routines during normal load
operation, measurement of operational, differential
and stabilizing current,
D Event storage for the last three system faults (sy
stem disturbances), with real-time tag,
D Data storage for disturbance recording:
thus fast fault analysis, detailed fault logging,
D Commissioning aids, such as connection check,
pilot wire resistance and angle measurement,
D Monitoring of differential current below the diffe
rential protection pick-up value in order to detect
any interruptions in the current transformer cir
cuits.
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