Ashida ADR233B - Under;Over Voltage

ADR233B
Doc ID : ADR233B/IM/01
Ref ID : ADR233B/IM/PS
Rev No. : 05
Page No. : 147 of 479
4.14 Under/Over Voltage (27/59)
Overvoltage and under voltage conditions are generally related to Over load condition or loss of
load conditions, where the supply voltage increases or decreases in magnitude. If the regulating
equipment is unsuccessful in restoring healthy system voltage then, the under voltage or
overvoltage element is required to trip the circuit breaker for the stable operation of Electrical
power system.
ADR233B relay provides over and under voltage protections with definite time delay setting.
Protection functions can be programmed for alarm signal or trip signal through programmable
logic.
V<
+
-
&
Voltage
V<= Enabled
DT Delay
V<T
V<P
Figure 24: Logic Diagram for the Under Voltage Function (on Enabled)
The logic diagram fig.24 is work for Under voltage protection function when V< Enabled
parameter is selected as Enabled (Disabled/Enabled).
The Under voltage protection logic checks whether the voltage goes below the Threshold value
and the set time delay calculated from definite time (tV< DT Delay) then the IED generates
Under Voltage trip.
+
-
&
Voltage
DT Delay
V> P
V> T
V> =
Enabled
V>
Figure 25: Logic Diagram for the Over Voltage Function (Enabled Selection)
The logic diagram fig.25 is work for over voltage protection function when Over Voltage
parameter is selected as Enabled (Disabled/Enabled).