ABB Relion 670 Series Product Manual page 44

Bay control REC670
Version 2.2
currents, is used to exactly calculate the fault position.
The fault can be recalculated with new source data at
the actual fault to further increase the accuracy.
Especially on heavily loaded long lines, where the source
voltage angles can be up to 35-40 degrees apart, the
accuracy can be still maintained with the advanced
compensation included in fault locator.
Event counter with limit supervison L4UFCNT
The Limit counter (L4UFCNT) provides a settable
counter with four independent limits where the number
of positive and/or negative flanks on the input signal
are counted against the setting values for limits. The
output for each limit is activated when the counted
value reaches that limit.
Overflow indication is included for each up-counter.
Running hour-meter TEILGAPC
The Running hour-meter (TEILGAPC) function is a
function that accumulates the elapsed time when a
given binary signal has been high.
The main features of TEILGAPC are:
• Applicable to very long time accumulation (≤ 99999.9
hours)
• Supervision of limit transgression conditions and
rollover/overflow
• Possibility to define a warning and alarm with the
resolution of 0.1 hours
• Retain any saved accumulation value at a restart
• Possibilities for blocking and reset
• Possibility for manual addition of accumulated time
• Reporting of the accumulated time
Estimation of transformer winding insulation life
LOLSPTR
Estimation of transformer winding insulation life
(LOLSPTR) is used to calculate transformer winding hot
spot temperature using the empirical formulae. It is also
used to estimate transformer loss of life from the
winding hot spot temperature value. The transformer
winding insulation is degraded when the winding hot
spot temperature exceeds certain limit. LOLSPTR gives
warning and alarm signals when the winding hot spot
temperature reaches a set value.
Hot spot temperature calculation requires top oil
temperature at a given time. This value can either be a
measured value taken through sensors or the one
calculated by the function. This decision is made based
on the top oil temperature sensor quality. Top oil
temperature calculation is done using the method
explained in IEC 60076-7 standard.
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Inputs required for hot spot temperature calculation
are:
• Transformer oil time constant
• Winding time constant
• Loss ratio at different tap positions
• Ambient temperature around the transformer
The oil and winding time constants can be calculated by
the function based on transformer parameters if the
inputs are not available from the transformer
manufacturer.
Ambient temperature to the function can either be
provided through the sensor or monthly average
ambient temperature settings. This decision is made
based on the ambient temperature sensor quality.
Additionally, LOLSPTR function provides difference
between measured value and calculated value of the top
oil temperature.
Additionally, the function calculates loss of life in form
of days and years. This information is updated at
settable intervals, for example, hourly or daily.
Transformer winding percentage loss of life is
calculated every day and the information is provided as
total percentage loss of life from the installation date
and yearly percentage loss of life.
Through fault monitoring PTRSTHR
The through fault monitoring function PTRSTHR is used
to monitor the mechanical stress on a transformer and
place it against its designed withstand capability.
During through faults, the fault-current magnitude is
higher as the allowed overload current range. At low
fault current magnitudes which are below the overload
capability of the transformer, mechanical effects are
considered less important unless the frequency of fault
occurrence is high. Since through fault current
magnitudes are typically closer to the extreme design
capabilities of the transformer, mechanical effects are
more significant than thermal effects.
For other power system objects, for example, an over-
head line, this function can be used to make a log of
primary quantities of a protected line.
Current harmonic monitoring CHMMHAI
Current harmonic monitoring function CHMMHAI is used
to monitor the current part of the power quality of a
system. It calculates the total harmonic distortion (THD)
with respect to fundamental signal amplitude, and the
total demand distortion (TDD) with respect to maximum
demand load current. These indices indicate the current
signal quality factor.
Additionally, the function is used to calculate the
numerical multiple of rated frequency harmonics
amplitude and harmonic distortion upto the 5
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