GE C70 Instruction Manual page 187

CHAPTER 5: SETTINGS
Datasets used by TxGOOSE1, TxGOOSE2, and/or by reports also provide a chatter suppression service for their Boolean
members. Oscillation in a value, also known as chatter, can be caused by errors in logic programming, inadequate
hysteresis (deadband) on a threshold, or a failed station component. Chatter can flood a communications network with
GOOSE messages, degrading response time for all users. If chatter is detected in a Boolean member, TxGOOSE suspends
GOOSE event message triggering and report message triggering from that member for as long as the condition exists, and
for a minimum period of one second. While sending is suspended, a self-test message identifying the specific data item
detected as oscillating is activated.
Navigate to Settings > Product Setup > Communications > IEC 61850 > DataSets > DataSet01 to access the settings for
the first data set. The settings and functionality for the others are similar.
DataSet01 name
Range: 0 to 32 VisibleString characters
Default: DataSet01
The value entered sets the name of the data set, which is required to be unique within the UR for proper operation. An
ObjectReference to the data set consists of a string that is the concatenation of "<LDName>/LLN0$" and the DataSet01
name setting value. An ObjectReference to the data set is published in the datSet field of TxGOOSE messages, and it can
be used by subscribers to discriminate the messages of that TxGOOSE from other GOOSE messages. An ObjectReference
to the data set is optionally published in the DatSet field of Report messages. Valid characters are upper and lowercase
letters, digits, and the underscore (_) character. The first character must be a letter.
DataSet01 Member1
Range: End of List or any instantiated 61850 data object or data attribute with Functional Constraint ST or MX
Default: End of List
This setting specifies the first member in TxGOOSE1 messages. There is a similar setting for each of the up to 64
members that the UR allows in a Dataset. Only values of members before the first set to End of List are published.
Deadband settings
A deadband is a range in which no action occurs, expressed as a percentage.
The IEC 61850 panels contain hundreds of deadband settings, such as in the following panels: System Setup > Signal
Sources, FlexLogic, Grouped Elements, Control Elements, and GGIO4. Each panel is not outlined here.
Deadband setting names all end either with "DEADBAND" or .db. As they all work the same way, but each on a different
analog value, a single description applicable to all deadband settings is given here. The analog value that each deadband
setting applies to is usually obvious from the name of the setting. However, a tabulation of the analog values and their
associated deadband setting can be found in the UR Series Communications Guide.
GOOSE, buffered report, and unbuffered report messages are for the most part transmitted only when there is a value
change in one or more of their members. Most analog values continuously dither by an amount that is not significant.
Were a report to be sent each time an insignificant analog value change occurred, then the communications network
floods with GOOSE and report messages, degrading response time for all users.
To control this, a deadband setting is provided for each analog value. Also, in addition to the present actual value of each
analog ("instMag" in the following figure), there is a deadbanded value ("mag" in the figure), which is updated with the
present value only when the difference between the two exceeds the deadband setting (db in the figure). Changes to this
deadbanded value trigger transmissions when included in GOOSE and report data sets.
C70 CAPACITOR BANK PROTECTION AND CONTROL SYSTEM – INSTRUCTION MANUAL
Figure 5-21: Deadband settings with .db suffix
PRODUCT SETUP
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