Siemens SENTRON PAC5100, Device Manual, Page: 29 / 266

4 Measurands and Recording
4.1 Measuring and Recording System
29 SENTRON PAC5100/5200, 7KM5212/5412, Device Manual
E50417-H1040-C568-A1, Edition 03.2015
Overvoltage of the Mains Voltage
• The basic measurement of the RMS value V
rms
of overvoltage is the determination of the RMS value
V
rms
(1/2) for each single measuring channel. The limiting value for overvoltages is a percentage value of
Udin.
• The factory setting of the hysteresis is 2 % of Udin. It can be set from 1 % to 6 %.
• In multi-phase systems, all channels are independently synchronized in the zero point of the voltage.
• In 1-phase systems, overvoltage begins when the voltage V
rms
rises above the threshold of the
overvoltage. Overvoltage ends when the voltage V
rms
falls below the threshold value of the overvoltage
minus the hysteresis.
• In multi-phase systems, overvoltage begins when the voltage V
rms
rises above the threshold of the
overvoltage in one or more channels. Overvoltage ends when the voltage V
rms
falls below the threshold
value of the overvoltage minus the hysteresis in all measured channels.
• The overvoltage threshold value and the hysteresis were parameterized according to the measuring task.
• Overvoltage is characterized by the data pair Maximum value of overvoltage and duration (t) :
The maximum value of an overvoltage is the highest voltage value of V
rms
which is measured in a channel
during overvoltage.
Voltage Interruption
• In 1-phase systems, a voltage interruption begins when the voltage V
rms
falls below the threshold of the
voltage interruption. The voltage interruption ends when the voltage V
rms
rises above the threshold value
of the voltage interruption plus the hysteresis.
• In multi-phase systems, the voltage interruption begins when the voltages V
rms
fall below the threshold of
the voltage interruption in all channels. The voltage interruption ends when the voltage V
rms
rises above
the threshold value of the voltage interruption plus the hysteresis in any of the measured channels.
• The voltage interruption threshold value and the hysteresis are parameterized according to the measuring
task.
• The factory setting of the hysteresis is 2 % of Udin. It can be set from 1 % to 6 %.
Unbalance of the Mains Voltage
• The mains voltage unbalance is determined using the method of the symmetrical components. In case of
unbalance, the negative-sequence component U
2
is determined in addition to the positive-sequence
component U
1
. The fundamental component of the voltage is measured over a 10-period time interval for
50-Hz distribution systems and over a 12-period time interval for 60-Hz distribution systems.
Harmonics of the Mains Voltage
• interruption-free 10-/12-period measurement of a harmonics subgroup U
sg,n
according to
IEC 61000-4-7.
• The total distortion is calculated as the subgroup total harmonic distortion (THDS) according to IEC 61000-
4-7.
• Measurements are performed up to the 40th harmonics order.