Siemens ISGS SG8158-00 - Manual (Page 34)

Protective Function Configuration
28 Siemens Energy & Automation, Inc.
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 time-delayed trip if the system line fre-
quency rises above a set level.
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.
A2500 Overfrequency (81O)
Address Parameter Option
2501 Function Enabled or Disabled
2502 Pickup Nominal frequency
60.1-65.0 Hz (0.1 Hz steps)
2504 Time Delay 0-100 s (0.01 s steps),
or infinity
2505 Blocked at 40-120 V (at VT input)
(1 V steps)
2510 Freeze Wfm1 on Pickup, on Trip, or None
2511 Freeze Wfm2 on Pickup, on Trip, or None
5.16 Underfrequency (81U)
The Underfrequency (81U) function has only a definite time
characteristic and causes a time-delayed trip if the system
line frequency drops below a set level. This function can be
useful for load shedding applications.
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.
A2500 81U Underfrequency
Address Parameter Option
2551 Function Enabled or Disabled
2553 Pickup Nominal frequency
55.0-59.9 Hz (0.1 Hz steps)
2554 Time Delay 0-100 s (0.01 s steps),
or infinity
2556 Blocked at 40-120 V (at VT input)
(1 V steps)
2560 Freeze Wfm1 on Pickup, on Trip, or None
2561 Freeze Wfm2 on Pickup, on Trip, or None
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