Table of Contents
Advertisement
Introduction
1.3 Characteristics
Teleprotection Supplement (optional)
• Different schemes which may be set:
• Transfer trip (direct, via pickup or a separately settable overreach zone)
• Comparison schemes (permissible overreach transfer trip = POTT or blocking schemes with separate over-
reach zone or directional pickup)
• Pilot wire comparison/reverse interlocking (with direct current for local connections or extremely short lines)
• suitable for lines with two or three ends
• Phase segregated transmission possible in lines with two ends
• Signal exchange between the devices via binary outputs and binary inputs, either directly via the device con-
tacts or via the protection data interface(s)
Earth Fault Protection (optional)
• Time overcurrent protection with a maximum of three definite time stages (DT) and one inverse time stage
(IDMT) for high resistance earth faults in earthed systems
• For inverse-time overcurrent protection a selection from various characteristics based on several standards
is possible
• The inverse time stage can also be set as fourth definite time stage
• High sensitivity (from 3 mA on, depending on the version)
• Phase current restraint against error currents during current transformer saturation
• Second harmonic inrush restraint
• Optional earth fault protection with voltage-dependent tripping time or with zero sequence power inverse
time tripping
• Each stage can be set to be non-directional or directional in forward or reverse direction
• Single-pole tripping enabled by integrated phase selector
• Direction determination with automatic selection of the larger of zero sequence voltage or negative se-
quence voltage (U
transformer starpoint current (I
power (3I
0
• One or more stages may function in conjunction with a teleprotection scheme; also suited for lines with three
ends
• Instantaneous tripping by any stage when switching onto a fault
Sensitive Earth Fault Detection (optional)
• for compensated or isolated networks
• Detection of the displacement voltage
• Determination of grounded phase
• Sensitive earth fault directional determination
• Angle error correction for current transformers
30
, I
or U
), with zero sequence system quantities (I
0
Y
2
, I
), with negative sequence system quantities (I
0
Y
· 3U
)
0
, U
), with zero sequence current and
0
0
, U
) or with zero sequence
2
2
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
Advertisement
Table of Contents
