Technical Documentation
KSR-V –Capacitor-Bank Protection Relay
6
2.2 Data collection
The waveforms of the signals (=voltage) on the input channels are sampled by the data collection logic of the
KSR-V. This presents the software with enough information to calculate all the values.
The sampling of the input signal needs to be synchronized to the input signal. The KSR-V
uses voltage L1-N for this purpose. If this voltage is too small or even disconnected, the
device can not do calculations synchronously. In this case, a frequency of 50 Hz/cps is
assumed and the data acquisition works accordingly.
The data collection circuitry for the voltage channels uses seven terminals (L1, L2, L3, N, V1-4), which have
to be connected in accordance to the connection diagram. As a minimum, the L1/L2/L3 terminals have to be
connected while N can be left floating. In this case, N is artificially generated inside the device by three
resistors in a star-connection. Connection of the N-terminal overrides the internal high-impedance resistor
circuit. The voltages can be connected directly (with respect to the maximum rating) or via transformers. In
this case, a factor between 1 and 4000 can be presented to the KSR-V, which resembles the voltage
conversion factor of the measurement transformers. The device will use this factor to provide corrected
readings for all voltages.
Always make sure, you don’t exceed the maximum ratings of the voltage channels. The ratings and a
connection diagram are available on the labels on the back of the device and in the "Technical Data"
chapter. If these ratings are exceeded, severe damage may be done to the KSR-V!
Each input channel contains a high precision input filter with a 3dB-cutoff-frequency in the range of 2.5kHz -
3 kHz. This protects the system from being damaged by transients with high frequencies like voltage spikes
and ensures the synchronisation of the measurement system to the input signal in presence of high
frequency harmonics.
