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.
Parameters
Figure 3 - 9 shows the control panel of the over-voltage relay model. The following parameters can be modified:
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 | 60 |
| Ubase | V | The base voltage (L-L) at the measurement location | 500000 |
Operating | N/A | Two types of operating quantity are provided in this | Phase-Neutral |
| 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 |
| Reset | Input (binary) | The reset signal for the relay. The relay will be reset when |
| Q | Output (binary) | The output of over-voltage relay. By default it is 0, if an |
| Q_n | Output (binary) | The complementary value of Q. |