The figure below shows how the pick-up settings and the measured frequency affect the pick-up level
of the volts-per-hertz protection function.
Figure. 5.3.21 - 172. Effect of pick-up settings and the measured frequency to the overvoltage function's pick-up level.
Volts-per-hertz protection is based on the ratio between the maximum phase-to-phase voltage and the
measured system frequency. The blocking signal and the setting group selection control the operating
characteristics of the function during normal operation, i.e. the user or user-defined logic can change
function parameters while the function is running.
The outputs of the function are the START, TRIP and BLOCKED signals. The non-
directional overcurrent function uses a total of eight (8) separate setting groups which can be selected
from one common source.
The operational logic consists of the following:
• input magnitude selection
• input magnitude processing
• threshold comparator
• block signal check
• time delay characteristics
• output processing.
The inputs for the function are the following:
• operating mode selections
• setting parameters
• digital inputs and logic signals
• measured and pre-processed voltage magnitudes.
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Q-G215
-G215
Instruction manual
Version: 2.04
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