Analog Input; Demand Metering - GE Multilin 745 Instruction Manual

745
Transformer Management Relay

Analog Input

! ANALOG INPUT

Demand Metering

! DEMAND METERING [!]
5–36
PATH: SETPOINTS !" S2 SYSTEM SETUP
[!] ANALOG INPUT NAME:
Analog Input
ANALOG INPUT UNITS:
MESSAGE
µ
A
ANALOG INPUT RANGE:
MESSAGE
0-1 mA
ANALOG INPUT MINIMUM
MESSAGE
VALUE:
ANALOG INPUT MAXIMUM
MESSAGE
VALUE:
The 745 provides a general purpose DC current input for use in monitoring any
external parameter. Any standard transducer output may be connected to the
analog input for monitoring.
• ANALOG INPUT NAME: Press ENTER to begin editing the name of the analog
input. The text may be changed from "Analog Input" one character at a time,
using the VALUE keys. Press the ENTER key to store the edit and advance to the
next character position. This name will appear in the actual value message
METERING ANALOG INPUT
!"
• ANALOG INPUT UNITS: Enter the units of the quantity being read by editing
the text as described above. The 6 characters entered will be displayed instead
of Units wherever the analog input units are displayed.
• ANALOG INPUT RANGE: Select the current output range of the transducer
that is connected to the analog input. The units are defined by the
setpoint.
UNITS
• ANALOG INPUT MINIMUM/MAXIMUM: Enter the value of the quantity
measured which corresponds to the minimum/maximum output value of the
transducer. The units are defined by the
PATH: SETPOINTS !" S2 SYSTEM SETUP
CURRENT DEMAND METER
TYPE: Thermal
THERMAL 90% RESPONSE
MESSAGE
TIME: 15 min.
TIME INTERVAL:
MESSAGE
20 min.
This section assigns the demand setpoints for monitoring current demand on all
three phases of each windings. Current demand on the 745 is performed one of
three ways: Thermal, Rolling Demand or Block Interval.
• CURRENT DEMAND METER TYPE: Select the method to be used for the
current demand metering.
Select "Thermal" to emulate the action of an analog peak-recording thermal
demand meter. The 745 measures the current on each phase every second, and
assumes the circuit quantity remains at this value until updated by the next
measurement. It calculates the 'thermal demand equivalent' as follows:
where d = demand after applying input for time t (in minutes)
D = input quantity (constant)
k =
--------------------------------------------------------------------------------------- -
Thermal 90% Response Time
http://www.GEindustrial.com/multilin
!" ANALOG INPUT
Range: 18 alphanumeric characters
Range: 6 alphanumeric characters
Range: 0-1 mA, 0-5 mA, 4-20 mA, 0-20
Range: 0 to 65000 in steps of 1
µ
0 A
Range: 0 to 65000 in steps of 1
µ
1000 A
.
ANALOG INPUT UNITS
!" DEMAND METERING
Range: Thermal, Block Interval, Rolling
Range: 5, 10, 15, 20, 25, 30, 60 min.
Range: 5, 10, 15, 20, 25, 30, 60 min.
kt
–
d t ( ) D 1 e ( )
= –
2.3
S2 System Setup
mA.
A2
ANALOG INPUT
setpoint.
Demand
(see note below)
(EQ 5.3)
GE Multilin