Demand - GE L90 Instruction Manual

5 SETTINGS
The data logger samples and records up to 16 analog parameters at a user-defined sampling rate. This recorded data may
be downloaded to the enerVista UR Setup software and displayed with 'parameters' on the vertical axis and 'time' on the
horizontal axis. All data is stored in non-volatile memory, meaning that the information is retained when power to the relay is
lost.
For a fixed sampling rate, the data logger can be configured with a few channels over a long period or a larger number of
channels for a shorter period. The relay automatically partitions the available memory between the channels in use.
Changing any setting affecting Data Logger operation will clear any data that is currently in the log.
NOTE
• DATA LOGGER RATE: This setting selects the time interval at which the actual value data will be recorded.
• DATA LOGGER CHNL 1(16): This setting selects the metering actual value that is to be recorded in Channel 1(16) of
the data log. The parameters available in a given relay are dependent on: the type of relay, the type and number of CT/
VT hardware modules installed, and the type and number of Analog Input hardware modules installed. Upon startup,
the relay will automatically prepare the parameter list. A list of all possible analog metering actual value parameters is
shown in Appendix A: FlexAnalog Parameters. The parameter index number shown in any of the tables is used to
expedite the selection of the parameter on the relay display. It can be quite time-consuming to scan through the list of
parameters via the relay keypad/display – entering this number via the relay keypad will cause the corresponding
parameter to be displayed.
• DATA LOGGER CONFIG: This display presents the total amount of time the Data Logger can record the channels not
selected to "Off" without over-writing old data.
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PATH: SETTINGS PRODUCT SETUP

# DEMAND

#
MESSAGE
MESSAGE
MESSAGE
The relay measures current demand on each phase, and three-phase demand for real, reactive, and apparent power. Cur-
rent and Power methods can be chosen separately for the convenience of the user. Settings are provided to allow the user
to emulate some common electrical utility demand measuring techniques, for statistical or control purposes. If the
is set to "Block Interval" and the
DEMAND METHOD
is assigned to any other FlexLogic™ operand, Method 2a is used (see below).
DEMAND TRIGGER
The relay can be set to calculate demand by any of three methods as described below:
CALCULATION METHOD 1: THERMAL EXPONENTIAL
This method emulates the action of an analog peak recording thermal demand meter. The relay measures the quantity
(RMS current, real power, reactive power, or apparent power) on each phase every second, and assumes the circuit quan-
tity remains at this value until updated by the next measurement. It calculates the 'thermal demand equivalent' based on the
following equation:
where: d = demand value after applying input quantity for time t (in minutes)
D = input quantity (constant), and k = 2.3 / thermal 90% response time.
GE Multilin
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DEMAND
CRNT DEMAND METHOD:
Thermal Exponential
POWER DEMAND METHOD:
Thermal Exponential
DEMAND INTERVAL:
15 MIN
DEMAND TRIGGER:
Off
DEMAND TRIGGER
kt
–
d t ( ) (
D 1 e
= –
L90 Line Differential Relay
Range: Thermal Exponential, Block Interval,
Rolling Demand
Range: Thermal Exponential, Block Interval,
Rolling Demand
Range: 5, 10, 15, 20, 30, 60 minutes
Range: FlexLogic™ operand
Note: for calculation using Method 2a
is set to "Off", Method 2 is used (see below). If
)
5.2 PRODUCT SETUP
5.2.10 DEMAND
5
CRNT
(EQ 5.4)
5-23