Multipurpose Protection; General Calculation; Secondary System Supervision; Current Circuit Supervision Ccsspvc - ABB REC670 Product Manual

Bay control REC670 2.2
Product version: 2.2.1
START signal triggers the individual event timer, which is the
continuous time spent within the given frequency band, and
the accumulation timer, which is the cumulative time spent
within the given frequency band. Once the timers reach their
limit, an alarm or trip signal is activated to protect the turbine
against the abnormal frequency operation. This function is
blocked during generator start-up or shut down conditions by
monitoring the circuit breaker position and current threshold
value. The function is also blocked when the system positive
sequence voltage magnitude deviates from the given voltage
band limit which can be enabled by
It is possible to create functionality with more than one
frequency band limit by using multiple instances of the
function. This can be achieved by a proper configuration
based on the turbine manufacturer specification.

9. Multipurpose protection

General current and voltage protection CVGAPC
The General current and voltage protection (CVGAPC) can be
utilized as a negative sequence current protection detecting
unsymmetrical conditions such as open phase or
unsymmetrical faults.
CVGAPC can also be used to improve phase selection for
high resistive earth faults, outside the distance protection
reach, for the transmission line. Three functions are used,
which measures the neutral current and each of the three
phase voltages. This will give an independence from load
currents and this phase selection will be used in conjunction
with the detection of the earth fault from the directional earth
fault protection function.

10. General calculation

Multipurpose filter SMAIHPAC
The multi-purpose filter function block (SMAIHPAC) is
arranged as a three-phase filter. It has very much the same
user interface (e.g. inputs and outputs) as the standard pre-
processing function block SMAI. However the main difference
is that it can be used to extract any frequency component
from the input signal. Thus it can, for example, be used to
build sub-synchronous resonance protection for synchronous
generator.

11. Secondary system supervision

Current circuit supervision CCSSPVC

Open or short circuited current transformer cores can cause
unwanted operation of many protection functions such as
differential, earth-fault current and negative-sequence current
functions.
Current circuit supervision (CCSSPVC) compares the residual
current from a three phase set of current transformer cores
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with the neutral point current on a separate input taken from
another set of cores on the current transformer.
A detection of a difference indicates a fault in the circuit and
is used as alarm or to block protection functions expected to
give inadvertent tripping.
Fuse failure supervision FUFSPVC
The aim of the fuse failure supervision function (FUFSPVC) is
to block voltage measuring functions at failures in the
secondary circuits between the voltage transformer and the
IED in order to avoid inadvertent operations that otherwise
might occur.
The fuse failure supervision function basically has three
different detection methods, negative sequence and zero
sequence based detection and an additional delta voltage
and delta current detection.
The negative sequence detection algorithm is recommended
for IEDs used in isolated or high-impedance earthed
networks. It is based on the negative-sequence quantities.
The zero sequence detection is recommended for IEDs used
in directly or low impedance earthed networks. It is based on
the zero sequence measuring quantities.
The selection of different operation modes is possible by a
setting parameter in order to take into account the particular
earthing of the network.
A criterion based on delta current and delta voltage
measurements can be added to the fuse failure supervision
function in order to detect a three phase fuse failure, which in
practice is more associated with voltage transformer
switching during station operations.
Fuse failure supervision VDSPVC
Different protection functions within the protection IED
operates on the basis of measured voltage at the relay point.
Some example of protection functions are:
• Distance protection function.
• Undervoltage function.
• Energisation function and voltage check for the weak
infeed logic.
These functions can operate unintentionally, if a fault occurs
in the secondary circuits between voltage instrument
transformers and the IED. These unintentional operations can
be prevented by fuse failure supervision (VDSPVC).
VDSPVC is designed to detect fuse failures or faults in voltage
measurement circuit, based on phase wise comparison of
voltages of main and pilot fused circuits. VDSPVC blocking
output can be configured to block functions that need to be
blocked in case of faults in the voltage circuit.
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