Sel 751A, Инструкция по эксплуатации

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D.9
Date Code 20100129 Instruction Manual SEL-751A Relay
DNP3 Communications
DNP3 in the SEL-751A
NOTE:
Most RTUs that act as
substation DNP3 masters perform an
event poll that collects event data of
all classes simultaneously. You must
confirm that the polling configuration
of your master allows independent
polling for each class before
implementing separate classes in the
SEL-751A.
For event data collection you must also consider and enter appropriate settings
for dead band and scaling operation on analog points shown in
Table D.7 . You
can either:
➤
set and use default dead band and scaling according to data
type, or
➤
use a custom data map to select dead bands on a point-by-point
basis.
See Configurable Data Mapping on page D.13 for a discussion of how to set
scaling and dead-band operation on a point-by-point basis. Dead bands for
analog inputs can be modified at run-time by writing to object 34.
The settings ANADBA n , ANADBV n , and ANADBM n control default dead-
band operation for each type of analog data. Because DNP3 Objects 30 and 32
use integer data, you must use scaling to send digits after the decimal point
and avoid rounding to a simple integer value.
With no scaling, the value of 12.632 would be sent as 13. With a scaling
setting of 1, the value transmitted is 126. With a scaling setting of 3, the value
transmitted is 12632. You must make certain that the maximum value does not
exceed 32767 if you are polling the default 16-bit variations for Objects 30
and 32, but you can send some decimal values using this technique. You must
also configure the master to perform the appropriate division on the incoming
value to display it properly.
You can set the default analog value scaling with the DECPLA n , DECPLV n ,
and DECPLM n settings. Application of event reporting dead bands occurs
after scaling. For example, if you set DECPLA n to 2 and ANADBA n to 10, a
measured current of 10.14 amps would be scaled to the value 1014 and would
have to increase to more than 1024 or decrease to less than 1004 (a change in
magnitude of ± 0.1 amps) for the device to report a new event value.
The SEL-751A uses the NUMEVE n and AGEEVE n settings to decide when
to send unsolicited data to the master. The device sends an unsolicited report
when the total number of events accumulated in the event buffer for master
n
reaches NUMEVE n . The device also sends an unsolicited report if the age of
the oldest event in the master n buffer exceeds AGEEVE n . The SEL-751A has
the buffer capacities listed in Table D.6 .
Binary Controls
The SEL-751A provides more than one way to control individual points. The
SEL-751A maps incoming control points either to remote bits or to internal
command bits that cause circuit breaker operations.
Table D.14 lists control
points and control methods available in the SEL-751A.
A DNP3 technical bulletin ( Control Relay Output Block Minimum
Implementation 9701-002 ) recommends that you use one point per Object 12,
control block output device. You can use this method to perform Pulse On,
Pulse Off, Latch On, and Latch Off operations on selected remote bits.
Table D.6 SEL-751A Event Buffer Capacity
Type Maximum Number of Events
Binary 1024
Analog 100
Counters 32