59 - Overvoltage Relay

Summary

The over-voltage relay (59) 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. Two types of operating quantities are available: Phase-Neutral Voltage and Phase-Phase Voltage. The model works for 50 Hz or 60 Hz systems.

Icons and diagrams

Model overview
The over-voltage relay trips electrical equipment under its protection whenever the line or phase 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 illustrated in Figure 3 - 9, 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.

Over-voltage relay characteristics

Parameters

Figure 3 - 9 shows the control panel of the over-voltage relay model. The following parameters can be modified:

Relay parameter panel

The following parameters are tunable:

Parameters tab of 59 Relay

Name	Unit	Description	Sample value
Frequency	Hz	The frequency of the measured current signals. Both 50 and 60 Hz are supported within the model.	60
Ubase	V	The base voltage (L-L) at the measurement location	500000
Operating Quantity	N/A	Two types of operating quantity are provided in this model: maximum Phase-Neutral Voltage or maximum Phase- Phase Voltage among three phases.	Phase-Neutral Voltage
Level 1	pu	Overvoltage level 1.	1.05
Level 2	pu	Overvoltage level 2.	1.1
Level 3	pu	Overvoltage level 3.	1.15
Level 4	pu	Overvoltage level 4.	1.2
Level 5	pu	Overvoltage level 5.	1.25
Time 1	s	Time delay associated with Level 1.	2
Time 2	s	Time delay associated with Level 2.	.5
Time 3	s	Time delay associated with Level 3.	.4
Time 4	s	Time delay associated with Level 4.	.3
Time 5	s	Time delay associated with Level 5.	.2

Input and output signals
The module has 2 inputs and 2 outputs:

59 Relay I/O

I/O name	Type (unit)	Description
Vabc	Input (V)	A 3-dimension voltage input for three-phase voltages, in the order of Va, Vb and Vc.
Reset	Input (binary)	The reset signal for the relay. The relay will be reset when this signal becomes 1.
Q	Output (binary)	The output of over-voltage relay. By default it is 0, if an over-voltage scenario is detected, it becomes 1.
Q_n	Output (binary)	The complementary value of Q.