Reset Delay - DEMA 400 Series User Manual

4.3.2.2.7

Reset Delay

According to the menu settings, It was selected to count the DMT (constant time) reset time
(0.04 s) after the current has dropped below 5.00 In without exceeding 5.00 In and without
breaker tripping. Thus, after the current falls below the threshold, 40 ms will be counted. If
the threshold is not exceeded until the end of this period, the protection function trip time
counter will be reseted. Reset delay thresholds are in the range of (0-60).
4.3.2.2.8 RTMS
Reset Curves are the 'Reset Time Multiplier' used in the Universal Formula. The Reset Type
is activated when selected as IDMT. The setting range of the factor can be selected within the
range (0,025 - 5).
4.3.2.2.9 Measurement Mode
The measurement mode can be selected as RMS or Basic Sequence. The basic component
measurement is selected to use harmonic-free measured values. The RMS measurement is
selected to use the values calculated by taking the square root of the mean of the squares of
the measured values. This value is also called Active or Effective value.
49 – Thermal Overload Protection
4.3.2.3
Earth overcurrent protection settings are located under this sections: Main Menu> Protection
Settings> Current Protection Settings> Thermal Overload Protection.
The thermal overload protection operates according to the thermal protection curve. This
curve is located under the sections : Main Menu> Protection Settings> Protection and Reset
Curves> Thermal Overload Protection Curves.
Thermal overload protection function is a protection function which is important in
controlling the overloads of the transformers, motors and cables in the range of (1.0 - 1.5) Ir
and maintaining them at the specified load values.
When the I > thermal overload protection and I> overcurrent protections are properly
Θ
combined, it will be protected from unnecessary trips and also primary devices will be
protected precisely. It can prevent the system quickly from being forced by opening the
overcurrents over 1.5 I
The problems in the field such as temporary and low-value overloads result in power failure,
or transient loads that do not reach high values cause the conductors of electrical devices to
.
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