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
Thresh.R.Endu.<
is generated.
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:
mechan.TRIP A=
). They act as counters
which count only the trips whose tripping currents are below the value of the current criterion.
Ι
2
t-Procedure
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
nom
2
). As with the other procedures, a threshold logically combines the three sums via an OR
operation and evaluates them.
The calculated squared tripping currrent integrals are added to the existing statistic values. Subsequently,
threshold comparison is started using threshold
ΣI^2t>
, and the new statistic values are output. If one of the
values lies above the threshold, the message
Thresh. ΣI^2t>
is generated.
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.
Motor Statistics
General
There are two different types of statistical motor data:
•
Operational information and
•
Startup information.
The statistical operational information contains the
•
Total number of motor startups
•
Total number of the motor operating hours (including startup conditions)
•
Total number of motor shutdown hours
•
Percentage of motor operating time and the total megawatt hours (if the device has a voltage trans-
former).
For every motor startup
•
The duration
•
The startup current
•
The startup voltage (if the device has a voltage transformer) are stored in the startup information.
Motor Operation Information
The motor operation statistic is newly calculated in a 600 ms cycle. In the statistics buffer, its image is
decreased to a resolution of one hour.
Motor Startup Information
The motor startup current and the startup voltage (if the device has a voltage transformer) are indicated as
primary values.
The measurement of these statistical values is initiated upon energization of the motor. This is recognized as
soon as the threshold value of the circuit breaker position detection (parameter 212 BkrClosed I MIN) is
2.25.2.3
Functions
2.25 Auxiliary Functions
326 SIPROTEC 4, 7SJ62/64, Manual
C53000-G1140-C207-8, Edition 08.2016
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