Setting Notes - Siemens 7SC80 Manual

values to be displayed and the evaluation to be started using the specified threshold. If one of the new values
lies above the threshold, the message
Three additional phase-selective statistic values are provided to determine the portion of purely mechanical
trips among the results of the remaining lifetime (e.g. for phase A:
which count only the trips whose tripping currents are below the value of the current criterion.
2 t-Procedure
Ι
During the Ι 2 t-procedure the squared fault current integral occurring per trip is added up phase-selectively.
The integral is derived from the squared instantaneous values of the currents occurring during arc time of the
circuit breaker. This results in:
T CB arc = (parameter 266 T 52 BREAKTIME) – (parameter 267 T 52 OPENING).
The three sums of the calculated integrals are represented as statistic values referred to the squared device
nominal current (Ι
operation and evaluates them.
The calculated squared tripping currrent integrals are added to the existing statistic values. Subsequently,
threshold comparison is started using threshold
values lies above the threshold, the message
Commissioning
Usually, no measures are required for commissioning. However, should the protection device be exchanged
(e.g. old circuit breaker and a new protection device), the initial values of the respective limit or statistical
values must be determined via the switching statistics of the respective circuit breaker.
2.26.2.3

Setting Notes

Reading/Setting/Resetting the Counters
The counters can be read via the Web Monitor or using DIGSI. The procedure using DIGSI is explained in the
SIPROTEC 4 System Description. Setting or resetting of these statistical counters takes place under the menu
item MESSAGES —> STATISTICS by overwriting the counter values displayed.
Circuit Breaker Maintenance
Under address 172 52 B.WEAR MONIT one of the alternatives ΣΙ
Disabled can be set. All parameters relevant to this function are available at parameter block P.System
Data 1 (see Section
The following setting values are important input values the subfunctions require in order to operate correctly:
The CB Tripping Time is a characteristic value provided by the manufacturer. It covers the entire tripping
process from the trip command (applying auxiliary power to the trip element of the circuit breaker) up to arc
extinction in all poles. The time is set at address 266 T 52 BREAKTIME.
The CB Operating Time T 52 OPENING is equally a characteristic value of the circuit breaker. It covers the
time span between the trip command (applying auxiliary power to the trip element of the circuit breaker) and
separation of CB contacts in all poles. It is entered at address 267 T 52 OPENING.
The following diagram illustrates the relationship between these CB times.
SIPROTEC Compact, 7SC80, Manual
E50417-G1140-C486-A8, Edition 07.2017
Thresh.R.Endu.< is generated.
2 ). As with the other procedures, a threshold logically combines the three sums via an OR
nom
2.1.3 Power System Data 1
mechan.TRIP A= ). They act as counters
ΣI^2t> , and the new statistic values are output. If one of the
Thresh. ΣI^2t> is generated.
x procedure, 2P procedure, Ι
).
Functions
2.26 Auxiliary Functions
2 t procedure or
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