Protective Function Configuration
5
When the curve is set to inverse, the Max Time parameter (2456) sets an absolute maximum amount of time that the function will remain in pickup regardless of the inverse curve. The value ranges from 1 to 250 seconds and can be set in steps of 1 second.
Blocking (2457) can be set from 40 to 120 V. Regardless of the setting, the function is automatically blocked if the volt- age drops below 40 V. An event will be generated when this function is blocked due to an undervoltage condition.
Each of the two waveform capture buffers (2460 and 2461) 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.
5.15 Overfrequency (81O)
The Overfrequency function has only a definite time charac- teristic and causes a
A2500 | Overfrequency (81O) | |
Address | Parameter | Option |
2501 | Function | Enabled or Disabled |
2502 | Pickup | Nominal frequency |
|
| |
2504 | Time Delay | |
|
| or infinity |
2505 | Blocked at | |
|
| (1 V steps) |
2510 | Freeze Wfm1 | on Pickup, on Trip, or None |
2511 | Freeze Wfm2 | on Pickup, on Trip, or None |
|
|
|
The Overfrequency function can be enabled or disabled (2501).
The function begins timing when the frequency exceeds the pickup frequency setting (2503).
The time delay (2504) represents the time between pickup and trip. The delay can be adjusted from 0 to 100 seconds in steps of 0.1 second. The delay can also be set to infinity so that the function never times out.
Blocking (2506) can be set from 40 to 120 V. Regardless of the setting, the function is automatically blocked if the volt- age drops below 40 V. An event will be generated when this function is blocked due to an undervoltage condition.
Each of the two waveform capture buffers (2510 and 2511) 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.
5.16 Underfrequency (81U)
The Underfrequency (81U) function has only a definite time characteristic and causes a
A2500 | 81U Underfrequency | |
Address | Parameter | Option |
2551 | Function | Enabled or Disabled |
2553 | Pickup | Nominal frequency |
|
| |
2554 | Time Delay | |
|
| or infinity |
2556 | Blocked at | |
|
| (1 V steps) |
2560 | Freeze Wfm1 | on Pickup, on Trip, or None |
2561 | Freeze Wfm2 | on Pickup, on Trip, or None |
|
|
|
The Underfrequency function can be enabled or disabled (2551).
The function begins timing when the frequency drops below the pickup frequency setting (2553).
The time delay (2554) represents the time between pickup and trip. The delay can be adjusted from 0 to 100 seconds in steps of 0.1 second. The delay can also be set to infinity so that the function never times out.
Blocking (2556) can be set from 40 to 120 V. Regardless of the setting, the function is automatically blocked if the volt- age drops below 40 V. An event will be generated when this function is blocked due to an undervoltage condition.
Each of the two waveform capture buffers (2560 and 2561) 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.
5.17 Breaker Failure (50BF)
The Breaker Failure function responds to a fault condition where any phase current being measured by the CTs does not drop below a programmable level. Whenever another protective function activates the contact identified by the breaker parameter, (usually Trip 1), this function will wait until the set amount of time has expired. Then it checks the phase currents. If they are not equal to or less than the set pickup value, the function executes its defined actions.
28 | Siemens Energy & Automation, Inc. |
