Protective Function Configuration
5.6 Phase Time Overcurrent (51)
The Phase Time Overcurrent function uses a selected time overcurrent characteristic curve to determine the trip time for the applied phase currents. The defined characteristic curves are valid over a range of multiple of pickup values. The func- tion also includes the ability to select a customer defined curve. This function is always enabled. Refer to Appendix A for detailed trip curve information.
A1700 | Phase Time Overvurrent (51) | |
Address | Parameter | Option |
1702 | Curve | Inverse |
|
| Short Inverse |
|
| Long Inverse |
|
| Moderately Inverse |
|
| Custom |
|
| Very Inverse |
|
| Extremely Inverse |
|
| Definite Inverse |
|
| Slightly Inverse |
|
| I2T Without Limit |
1703 | Pickup | 5 A CTs: |
|
| 1 A CTs: |
|
| (0.1 A steps) |
1705 | Time Dial | |
1706 | Filter | rms or fundamental |
1709 | Reset | Instantaneous or Disk Emulation |
1710 | Freeze Wfm1 | on Pickup, on Trip, or None |
1711 | Freeze Wfm2 | on Pickup, on Trip, or None |
1712 | Blocked by | None, 50HS, 50HSN, or |
|
| 50HS & 50 HSN |
|
|
|
The Curve parameter (1702) allows the selection of the pre- programmed characteristic curve used by this function. The ISGS relay comes with nine standard and one custom over- current characteristic curves that can be adjusted with the Time Dial parameter. The custom curve is a
The range of the pickup value (1703) depends on the sec- ondary phase CT rating (1 A or 5 A) and the value is in sec- ondary amperes. The function begins timing when any individual phase current exceeds the pickup current setting.
Note: The pickup point is 1.06 of the pickup set- ting. Refer also to paragraph on Pickup in Section 5.1.
The Time Dial parameter (1705) used for the selected curve allows the
The Filter parameter (1706) sets the sensing method used by the function in its pickup calculations. The rms filter uses fun- damental current plus harmonics, while the fundamental filter ignores harmonics.
The Reset parameter (1709) offers instantaneous or disk emulation settings. Selecting Instantaneous causes the relay to clear the timer when the current drops below the pickup threshold. Selecting Disk Emulation causes the relay to simu- late the integrating disk characteristics of electromechanical relays, where the delay time decays over time. With disk emulation, a relay that continuously picks up and drops out will eventually trip. Set this parameter to Instantaneous when using a custom curve.
Each of the two waveform capture buffers (1710 and 1711) can be independently programmed to freeze snapshots on pickup or trip.
The function is able to actuate any binary output contact on pickup, and any trip or binary output contact on trip.
5.7 Neutral Time Overcurrent (51N)
The Neutral Time Overcurrent function uses a selected time overcurrent characteristic curve to determine the trip time for the applied current at the fourth current input. The defined characteristic curves are valid over a range of multiple of pickup values. The function also includes a customer defined curve. Refer to Appendix A for detailed trip curve informa- tion.
A1800 | Neutral Time Overcurrent (51N) | |
Address | Parameter | Option |
1801 | Function | Enabled or Disabled |
1802 | Curve | Inverse |
|
| Short Inverse |
|
| Long Inverse |
|
| Moderately Inverse |
|
| Custom |
|
| Very Inverse |
|
| Extremely Inverse |
|
| Definite Inverse |
|
| Slightly Inverse |
|
| I2T Without Limit |
1803 | Pickup | 5 A CTs: |
|
| 1 A CTs: |
|
| (0.1 A steps) |
1805 | Time Dial | |
1806 | Filter | rms or fundamental |
1809 | Reset | Instantaneous or Disk Emulation |
1810 | Freeze Wfm1 | on Pickup, on Trip, or None |
1811 | Freeze Wfm2 | on Pickup, on Trip, or None |
1812 | Blocked by | None, 50HS, 50HSN, or |
|
| 50HS & 50 HSN |
|
|
|
The Neutral or Ground Time Overcurrent function can be enabled and disabled (1801).
The Curve parameter (1702) allows the selection of the pre- programmed characteristic curve used by this function. The ISGS relay comes with nine standard and one custom over- current characteristic curves that can be adjusted with the Time Dial parameter. The custom curve is a
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