GE Multilin G650, Manual

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GEK-113285A G650 Generator Protection & Control System C-19
APPENDIX C C.8 ANALOG INPUTS
C
C.8ANALOG INPUTS
It is important to note that 16-bit and 32-bit variations of Analog Inputs are transmitted through DNP as signed numbers.
Even for analog input points that are not valid as negative values, the maximum positive representation is 32767. This is a
DNP requirement.
The deadbands for all Analog Input points are in the same units as the Analog Input quantity. For example, an Analog Input
quantity measured in volts has a corresponding deadband in units of volts. This is in conformance with DNP Technical
Bulletin 9809-001 Analog Input Reporting Deadband. The scale factors apply also to deadbands. For example if Current
Scale Factor is set to 0.001, and it is desired that a specific Analog Input point (that is of type current) trigger an event when
its value changes by 1 kA, then the deadband for this point should be set to 1000. Relay settings are available to set default
deadband values according to data type. Deadbands for individual Analog Input Points can be set using DNP Object 34.
Units for Analog Input points are as follows:
Current: kA Apparent Power: MVA
Voltage: kV Energy: MWh, Mvarh
Real Power: MW Frequency: Hz
Reactive Power: Mvar Angle: degrees
ANALOG INPUT POINTS
Static (Steady-State) Object Number:
30
Change Event Object Number:
32
Request Function Codes supported:
1 (read), 2 (write, deadbands only), 22 (assign class)
Static Variation Reported when variation 0 requested:
1 (32-Bit Analog Input)
Change Event Variation reported when variation 0 requested: 1
(Analog Change event without Time)
Change Event Scan Rate: defaults to
500ms.
Default Class for all points:
1