ABB RELION RED670 Series Product Manual page 38

Line differential protection RED670 2.2
Product version: 2.2
Stub protection STBPTOC
When a power line is taken out of service for maintenance
and the line disconnector is opened in multi-breaker
arrangements 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 (STBPTOC) 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 CCPDSC
An open phase can cause negative and zero sequence
currents which cause 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 breakers
should be tripped to clear the unsymmetrical load situation.
The Pole discordance protection function (CCPDSC) operates
based on information from auxiliary contacts of the circuit
breaker for the three phases with additional criteria from
unsymmetrical phase currents when required.
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
a 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.
Broken conductor check BRCPTOC
The main purpose of the function Broken conductor check
(BRCPTOC) is the detection of broken conductors on
protected power lines and cables (series faults). Detection
can be used to give alarm only or trip the line breaker.
Voltage-restrained time overcurrent protection VRPVOC
Voltage-restrained time overcurrent protection (VRPVOC)
function can be used as generator backup protection against
short-circuits.
The overcurrent protection feature has a settable current level
that can be used either with definite time or inverse time
characteristic. Additionally, it can be voltage controlled/
restrained.
38
M12902-3 v10
M13269-3 v15
SEMOD175421-4 v7
SEMOD171446-5 v2
GUID-935E1CE8-601F-40E2-8D22-2FF68420FADF v6
One undervoltage step with definite time characteristic is also
available within the function in order to provide functionality
for overcurrent protection with undervoltage seal-in.
7. Voltage protection
Two-step undervoltage protection UV2PTUV
Undervoltages can occur in the power system during faults or
abnormal conditions. The two-step undervoltage protection
function (UV2PTUV) can be used to open circuit breakers to
prepare for system restoration at power outages or as a long-
time delayed back-up to the primary protection.
UV2PTUV has two voltage steps, each with inverse or definite
time delay.
It has a high reset ratio to allow settings close to the system
service voltage.
Two step overvoltage protection OV2PTOV
Overvoltages may occur in the power system during abnormal
conditions such as sudden power loss, tap changer
regulating failures, and open line ends on long lines.
Two step overvoltage protection (OV2PTOV) function can be
used to detect open line ends, normally then combined with a
directional reactive over-power function to supervise the
system voltage. When triggered, the function will cause an
alarm, switch in reactors, or switch out capacitor banks.
OV2PTOV has two voltage steps, each of them with inverse
or definite time delayed.
OV2PTOV has a high reset ratio to allow settings close to
system service voltage.
Two step residual overvoltage protection ROV2PTOV
Residual voltages may occur in the power system during
earth faults.
Two step residual overvoltage protection (ROV2PTOV)
function calculates the residual voltage from the three-phase
voltage input transformers or measures it from a single
voltage input transformer fed from an open delta or neutral
point voltage transformer.
ROV2PTOV has two voltage steps, each with inverse or
definite time delay.
A reset delay ensures operation for intermittent earth faults.
Overexcitation protection OEXPVPH
When the laminated core of a power transformer or generator
is subjected to a magnetic flux density beyond its design
limits, stray flux will flow into non-laminated components that
are not designed to carry flux. This will cause eddy currents
to flow. These eddy currents can cause excessive heating
and severe damage to insulation and adjacent parts in a
1MRK 505 379-BEN C
M13789-3 v12
M13798-3 v16
M13808-3 v11
M13319-3 v9
ABB