59 - Overvoltage Relay (1-ph)

Summary

The over-voltage relay (59-OV) operates when the voltage it monitors exceeds a set of threshold values. There are five levels of settings available in this relay. Each level corresponds
to a predefined over-voltage level and a tripping delay time. The operating quantity of the relay can be the RMS value of phase voltage, or the positive, negative or zero sequence of a three-phase voltage signals. The operating quantity can be either in per unit or actual value.

Icons and diagrams

Model overview

The over-voltage relay trips electrical equipment under its protection whenever the line voltage exceeds the selected setting. A time-delay is normally used to enable it to ride through momentary spikes and thus prevent nuisance tripping. The five-level over-voltage relay characteristics are presented below. For instance, if we use the default values as illustrated above, Level 1 voltage is 1.05 pu and tripping time is 2 sec. It means that when the input voltage is higher than 1.05 pu and continues to be higher than 1.05 pu for more than 2 seconds, the over-voltage relay will be asserted. If the voltage is higher than 1.05 pu for any time that is less than 2 seconds, its timer will be reset and will not restart until the voltage reaches the level 1 voltage threshold again. All voltage levels and delay times are tunable parameters.

Parameters

The below figure shows the control panel of the 59-OV relay.

The following parameters are tunable:

Parameter tab of 59-OV Relay

Name	Unit	Description	Sample value
Level 1	pu or V	Overvoltage level 1	1.05
Level 2	pu or V	Overvoltage level 2	1.10
Level 3	pu or V	Overvoltage level 3	1.15
Level 4	pu or V	Overvoltage level 4	1.20
Level 5	pu or V	Overvoltage level 5	1.25
Time 1	sec	Time delay associated with level 1	2
Time 2	sec	Time delay associated with level 2	0.5
Time 3	sec	Time delay associated with level 3	0.4
Time 4	sec	Time delay associated with level 4	0.3
Time 5	sec	Time delay associated with level 5	0.2

Input and output signals
The module has 1 input and 1 output:

59-OV Relay I/O

I/O Name	Type (Unit)	Description
V	pu or V	A single dimensional signal, it should be the RMS value of phase voltage, or the positive, negative or zero sequence of a three-phase voltage signals.
Trip	Binary	The output of overvoltage relay. By default it is 0, if an over-voltage scenario is detected, it becomes 1.