Voltage Protection - ABB Relion 650 Series Product Manual

Line distance protection
REL650
Product version: 1.0
CCRBRF function can be programmed to give
a three-phase re-trip of the own breaker to
avoid unnecessary tripping of surrounding
breakers at an incorrect initiation due to
mistakes during testing.
Stub protection STBPTOC
When a power line is taken out of service for
maintenance and the line disconnector is
opened the voltage transformers will mostly
be outside on the disconnected part. The
primary line distance protection will thus not
be able to operate and must be blocked.
The stub protection covers the zone between
the current transformers and the open
disconnector. The three-phase instantaneous
overcurrent function is released from a
normally open, NO (b) auxiliary contact on
the line disconnector.
Pole discordance protection
CCRPLD
Circuit breakers or disconnectors can due to
electrical or mechanical failures end up with
the different poles in different positions (close-
open). This can cause negative and zero
sequence currents which gives thermal stress
on rotating machines and can cause
unwanted operation of zero sequence or
negative sequence current functions.
Normally the own breaker is tripped to
correct such a situation. If the situation
persists the surrounding breaker should be
tripped to clear the unsymmetrical load
situation.
The pole discordance function operates based
on information from the circuit breaker logic
with additional criteria from unsymmetrical
phase current when required.
Broken conductor check BRCPTOC
Conventional protection functions can not
detect the broken conductor condition.
Broken conductor check (BRCPTOC)
function, consisting of continuous current
unsymmetry check on the line where the IED
is connected will give alarm or trip at
detecting broken conductors.
16
1MRK 506 308-BEN -
Issued: September 2009
Directional over/underpower
protection GOPPDOP/GUPPDUP
The directional over-/under-power protection
(GOPPDOP/GUPPDUP) can be used
wherever a high/low active, reactive or
apparent power protection or alarming is
required. The functions can alternatively be
used to check the direction of active or
reactive power flow in the power system.
There are number of applications where such
functionality is needed. Some of them are:
• detection of reversed active power flow
• detection of high reactive power flow
Each function has two steps with definite
time delay. Reset times for every step can be
set as well.
Negative sequence based
overcurrent function DNSPTOC
Negative sequence based overcurrent
function (DNSPTOC) is typically used as
sensitive earth-fault protection of power
lines, where incorrect zero sequence
polarization may result from mutual
induction between two or more parallel lines.
Additionally, it is used in applications on
underground cables, where zero sequence
impedance depends on the fault current
return paths, but the cable negative sequence
impedance is practically constant.
DNSPTOC protects against all unbalance
faults including phase-to-phase faults. Always
remember to set the minimum pickup current
of the function above natural system
unbalance level.

6. Voltage protection

Two step undervoltage protection
UV2PTUV
Undervoltages can occur in the power system
during faults or abnormal conditions. Two
step undervoltage protection (UV2PTUV)
ABB