ABB REB670 Series, Applications Manual

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Section 10 Multipurpose protection
10.1 General current and voltage protection CVGAPC
IP14552-1 v2
10.1.1 Identification
M14886-2 v3
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
General current and voltage
protection
CVGAPC 2(I>/U<) -
10.1.2 Application
IP15008-1 v1
M13084-3 v5
A breakdown of the insulation between phase conductors or a phase conductor and earth
results in a short circuit or an earth fault respectively. Such faults can result in large fault
currents and may cause severe damage to the power system primary equipment. Depending
on the magnitude and type of the fault different overcurrent protections, based on
measurement of phase, earth or sequence current components can be used to detect these
faults. Additionally it is sometimes required that these overcurrent protections shall be
directional and/or voltage controlled/restrained.
The over/under voltage protection is applied on power system elements, such as generators,
transformers, motors and power lines in order to detect abnormal voltage conditions.
Depending on the type of voltage deviation and type of power system abnormal condition
different over/under voltage protections based on measurement of phase-to-earth, phase-to-
phase, residual- or sequence- voltage components can be used to detect and operate for such
incident.
The IED can be provided with multiple General current and voltage protection (CVGAPC)
protection modules. The function is always connected to three-phase current and three-phase
voltage input in the configuration tool, but it will always measure only one current and one
voltage quantity selected by the end user in the setting tool.
Each CVGAPC function module has got four independent protection elements built into it.
1. Two overcurrent steps with the following built-in features:
•
Definite time delay or Inverse Time Overcurrent (TOC/IDMT) delay for both steps
• Second harmonic supervision is available in order to only allow operation of the
overcurrent stage(s) if the content of the second harmonic in the measured current
is lower than pre-set level
• Directional supervision is available in order to only allow operation of the
overcurrent stage(s) if the fault location is in the pre-set direction (
Forward or
Reverse). Its behavior during low-level polarizing voltage is settable (Non-
Directional, Block, Memory)
• Voltage restrained/controlled feature is available in order to modify the pick-up level
of the overcurrent stage(s) in proportion to the magnitude of the measured voltage
• Current restrained feature is available in order to only allow operation of the
overcurrent stage(s) if the measured current quantity is bigger than the set
percentage of the current restrain quantity.
2. Two undercurrent steps with the following built-in features:
1MRK 505 370-UEN D Section 10
Multipurpose protection
Busbar protection REB670 225
Application manual