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. |