MESSKO MTeC EPT202, Operating Instructions Manual

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14 BA 2076/02/01
When cooling stage ONAF1 was active for another 100 hours,
the relays are then changed again.
The same principle applies when 3 or 4 cooling stages are
assigned to load change operation.
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Switching Contacts ALARM and TRIP Switching Contacts ALARM and TRIP
Switching Contacts ALARM and TRIP Switching Contacts ALARM and TRIP Switching Contacts ALARM and TRIP
The EPT202 is equipped with 2 additional switching contacts
to generate an alarm message and to trip the transformer. By
assigning parameters, these contacts can be assigned to the
oil or the winding temperature and the hysteresis and delay
time can be set.
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Calculation of Life Consumption Calculation of Life Consumption
Calculation of Life Consumption Calculation of Life Consumption Calculation of Life Consumption
The life consumption calculation can be configured with 2
algorithms (calculation as per ANSI or as per IEC standard) or
can be masked out.
Both algorithms are a function of the hotspot temperature.
The calculation can only supply a realistic value when the
winding parameters are assigned correctly.
Both algorithms supply the life consumption as a percentage
of the expected lifespan. The expected lifespan must be
parameterized for this.
NO NO NO NO NOTE TE TE TE TE
The expected lifespan for the insulation system of a
transformer winding depends on the materials used and
the construction.
This value can be obtained from the manufacturer of the
transformer.
Calculation in accordance with ANSI standard Calculation in accordance with ANSI standard Calculation in accordance with ANSI standard Calculation in accordance with ANSI standard Calculation in accordance with ANSI standard
C57.91-1995 (+errata)
C57.91-1995 (+errata) C57.91-1995 (+errata) C57.91-1995 (+errata) C57.91-1995 (+errata)
Recommended for transformers whose construction is
dominated by the US American standards ANSI or IEEE.
The cooling stages are called COOLING 0 to COOLING 4 on
the EPT202. The parameter record of the last cooling stage is
always active and thus provides the basis for the calculation
of the winding temperature and life management
consumption.
The parameter records of the cooling stages are linked with
the switching contacts as shown below.
•
No switching contact switched - COOLING 0 active
•
Switching contact S1 switched - COOLING 1 active
•
Switching contact S2 switched - COOLING 2 active
•
Switching contact S3 switched - COOLING 3 active
•
Switching contact S4 switched - COOLING 4 active
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Load Change Oper Load Change Oper
Load Change Oper Load Change Oper Load Change Operation
ation
ation ation ation
The load change function permits the fans or pumps
connected to the switching contacts to be loaded equally.
Each switching point can be individually assigned to load
change operation. During load change operation the relays of
the assigned switching contacts are switched in sequence
after the adjustable load change internal has expired. The LED
display and the winding parameters of the active cooling
stage remain as they were before.
The load change function will now be explained using the
following example.
Cooling stage 1 of a transformer is ONAF1. The left fan group
is turned on with switching point S1 and the related
parameter record of the COOLING1 cooling stage is activated.
Cooling stage 2 is ONAF2. The right fan group is switched
through with switching point S2 and the related parameter
record of the COOLING2 cooling stage is activated.
Without load change operation, the runtime of the left fan
group (active during COOLING1 and COOLING2) would be
greater than that of the right fan group (only active during
COOLING2).
Switching points S1 and S2 are now assigned to the load
change operation and a load change interval of 100 hours is
parameterized. If cooling stage ONAF1 was now active for a
total of 100 hours (the left fan group has run 100 hours
alone), switching contacts S1 and S2 then change the relays.
Switching contact S1 now switches with the actual relay of
switching contact S2 and vice versa. This turns off the left
fan group and turns on the right fan group. The status of the
LED display and the parameter record of the active cooling
stage (COOLING1 in our example) are not affected by this.
When activation is performed by switching point S2 (ONAF2
or COOLING2), then S2 switches the left fan group through
with the actual relay of S1.
5 Funktion Description
CAUTION CAUTION CAUTION CAUTION CAUTION
The calculation of life consumption of the EPT202 is based
on the thermal aging of a transformer winding in
accordance with ANSI or IEC standards. Remember that
the value calculated here may not reflect actual
conditions.
Life consumption only refers to the insulation system of a
transformer winding and not to the complete transformer.