Voltage Based Inverse Definite Minimum Time Characteristics - ABB RELION REX640 Technical Manual

1MRS759142 C
11.3
11.3.1
REX640
Technical Manual
Voltage based inverse definite minimum time
characteristics
IDMT curves for overvoltage protection
In inverse-time modes, the operate time depends on the momentary value of the
voltage, the higher the voltage, the faster the operate time. The operate time
calculation or integration starts immediately when the voltage exceeds the set value of
the Start value setting and the START output is activated.
The OPERATE output of the component is activated when the cumulative sum of the
integrator calculating the overvoltage situation exceeds the value set by the inverse
time mode. The set value depends on the selected curve type and the setting values
used. The user determines the curve scaling with the Time multiplier setting.
The Minimum operate time setting defines the minimum operate time for the IDMT
mode, that is, it is possible to limit the IDMT based operate time for not becoming too
short. For example:
General function block features
Section 11
1691