Siemens ISGS SG8158-00 - Manual (Page 41)

Control & Communications
Siemens Energy & Automation, Inc. 35
The Trip Source Impedance parameter (8301) can be
enabled or disabled. When enabled, the circuit periodically
monitors the trip supply voltage (auxiliary voltage, station bat-
tery) and will perform an action (for example, close a binary
output) should the voltage drop below ANSI minimum val-
ues. Monitoring the trip source (auxiliary power) to detect
bad connections and weak batteries is done by periodically
drawing a small current from the trip supply and monitoring
the subsequent sag in the voltage. Using averaging tech-
niques, the trip source impedance can be estimated. Based
on this estimate, an error message is given if the source volt-
age drops below ANSI minimum values during a trip event.
When the function is enabled, it can cause the actuation of
any of the output contacts. This circuit can function only in
true DC trip systems. It should be disabled and the inputs left
disconnected when the device is used in AC trip systems.
The Trip Source Fail parameter of the Trip Source Impedance
function (8302), when set to yes, allows the relay fail contact
to be asserted when the monitoring function detects an error.
When set to no, the relay fail contact is not affected.
The Trip Coil Continuity function (8303), when enabled,
senses a trip coil continuity error, causes an action to be
taken, and logs the event if the 52a and 52b switches are
ever both open at the same time for more than 100 ms. No
other time delay is implemented. When the function detects
the error, the function is considered to be in pickup until the
condition is no longer present.
The Trip Coil Fail parameter of the Trip Coil Continuity func-
tion (8304), when set to yes, allows the relay fail contact to
be asserted when the monitoring function detects an error.
When set to no, the relay fail contact is not affected.
Because the 52b switch does not need to interrupt the cur-
rent through the trip coil, it provides a reliable indication of
breaker position: when it is open, the breaker is considered
closed. The practice (in DC trip systems) of placing a red sta-
tus indicator lamp in series with the trip coil allows a conve-
nient method for monitoring the continuity of the trip coil.
When the circuit breaker is closed, the 52a switch is closed
and the voltage across them and the trip coil is small
because most of the voltage drop occurs across the indicat-
ing lamp circuit. If the trip coil is open or the a-switch is
defective, an error condition exists and an alarm can be gen-
erated. An exception is a breaker withdrawn for servicing.
The Breaker Mechanism function (8305), when enabled,
senses an error in the mechanism that controls the position
of one or both switches (breaker mechanism error), causes
an action to be taken, and an event to be logged if the
switches are ever both closed for more than 100 ms. No
other time delay is implemented. When this function detects
an error, it is considered to be in pickup until the condition is
no longer present.
The ISGS relay considers the b-switch to be more reliable. If
it senses the switches both open at the same time, the
breaker is considered to have a trip coil continuity error or to
be withdrawn. The 52a switch closed and the 52b switch
open are interpreted as a closed breaker. If the relay senses
the 52a switch open and the 52b switch closed, the
breaker is considered to be open. Refer also to Table 6.1.
6.7 Logs and Breaker Monitor Reset
With the Reset function, the user can independently reset
logs and breaker monitoring functions. Performing the reset
operation for an individual category will reset all values within
that category to zero, but new values are tracked immedi-
ately. The Resets address block also includes functions to
set the number of breaker operations and the sum of inter-
rupted current on each phase.
The Trip Log reset function (8201) can be set to yes to reset
the values in all trip logs. This function requires a password.
When the parameter is activated by setting it to yes, the LCD
displays the message “IN PROGRESS” followed by the mes-
sage “SUCCESSFUL”.
Resetting the minimum and maximum logs with the Min/Max
Values reset function (8202) discards all current values, but
new minimum and maximum values are tracked immediately.
The Energy reset function (8203) resets all demand values.
The Breaker Operations reset function (8204) resets the
breaker operations counter.
The sum of interrupted current reset function resets the sum
of interrupted current for each phase (8205).
The Breaker Operations (Counter) reset function (8211) sets
the number of breaker operations, for example, when mov-
ing the breaker to a cubicle protected by an ISGS relay
where the previous breaker had a different operations count.
The Sum of Interrupted Current for phases A, B, and C reset
functions (8212, 8213, 8214) can be set from 0 to 99999 kA.
8200 Resets
Address Function Option/Display
8201 Trip Log yes, in progress, successful
8202 Min/Max Values yes, successful
8203 Energy yes, successful
8204 Breaker Ops yes, successful
8205 Sum I interrupted yes, in progress, successful
8211 Breaker Ops
(Counter)
0-65535
8212 Sum IL1 0-99999 kA (0.01 kA steps)
8213 Sum IL2 0-99999 kA (0.01 kA steps)
8214 Sum IL3 0-99999 kA (0.01 kA steps)
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