GE 750, Инструкция по эксплуатации

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13-
18
750/760 Feeder Management Relay GE Power Management
13.5 ANALOG INPUT 13 S6 MONITORING
13
13.5 ANALOG INPUT 13.5.1 DESCRIPTION
The relay can monitor any external quantity, such as transformer winding temperature, bus voltage, battery
voltage, station service voltage, transformer tap position, etc., via an auxiliary current input called the analog
input. Any one of the standard transducer output ranges 0-1 mA, 0-5 mA, 0-10 mA, 0-20 mA, or 4-20 mA can
be connected to the analog input terminals.
Two independent elements are available for monitoring the analog input level,
ANALOG THRESHOLD 1(2)
, each
having a user programmable name, pickup level, drop out ratio, and a time delay. For each element, when the
measured analog input quantity exceeds the pickup level for longer than the associated time delay, the relay
can be configured to cause a trip, an alarm, or signal an output contact. The element will drop out only when
the user programmed drop out ratio has been met. There are also two elements which measure the analog
input rate-of-change,
ANALOG IN RATE 1(2)
, which operate in a similar fashion.
13.5.2 ANALOG INPUT SETUP
Before the analog input can be used for monitoring, the value of the input must be converted to the quantity
that is being measured. The relay simplifies this process by internally scaling the transducer output, and dis-
playing and monitoring the actual measured parameter. Note the resolution that will result from the selection of
the minimum and maximum setpoints. For example, if 0 to 20
µ
A is to be represented via the 0 to 20 mA ana-
log input, an input of 4.5 mA will translate to a 5
µ
A actual value reading. This is due to the rounding up of the
value, since the analog input actual value is an F1 format. If a range of 0 to 200
µ
A was programmed to be rep-
resented via the 0 to 20 mA input, 4.5 mA will result in a 45
µ
A actual value.
■
ANALOG INPUT SETUP
■
[ENTER] for more
The
ANALOG INPUT SETUP
setpoints path is:
\ SETPOINTS \ S6 MONITORING \ ANALOG INPUT \ ANALOG INPUT SETUP
ANALOG INPUT NAME:
ANALOG INPUT
Range: Any Combination of 20 Alphanumeric Characters
Enter the name of the quantity being read. See Section 8.10: USER TEXT
MESSAGES on page 8–11 for a description of entering text from the front
panel. This name will be displayed instead of
ANALOG INPUT (which is the
factory default) in the actual value message
A2 METERING \ ANALOG INPUT \ ANA-
LOG INPUT
. If the quantity being read is the transformer winding temperature,
you may enter TRANSFORMER TEMP for this setpoint.
ANALOG INPUT UNITS:
µ
A
Range: Any Combination of 6 Alphanumeric Characters
Enter the units of the quantity being read. See Section 8.10: USER TEXT
MESSAGES on page 8–11 for a description of entering text from the front
panel. The 6 characters entered here will be displayed instead of
µA
(which is
the factory default) wherever the analog input units are displayed. If the quan-
tity being read is the transformer winding temperature in units of degrees Cel-
sius, you may enter
°C
for this setpoint.
ANALOG INPUT RANGE:
0-20 mA
Range: 0-1 mA, 0-5 mA, 4-20 mA, 0-20 mA, 0-10 mA
Enter the current output range of the transducer connected to the relay's ana-
log input. Any of the standard transducer output ranges are accommodated.
ANALOG INPUT MINIMUM
VALUE: 0
µ
A
Range: 0 to 65535 in steps of 1
Enter the value of the quantity which corresponds to the minimum output value
of the transducer. For example, if a temperature transducer which outputs 4 to
20 mA for temperatures 0 to 250°C is connected to the analog input, then
enter
0 . The relay will therefore interpret 4 mA as representing 0°C. Intermedi-
ate values between the minimum and maximum will be scaled linearly.