GE 845, Instruction Manual

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4–348 845 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
FLEXLOGIC CHAPTER 4: SETPOINTS
FlexElements
There are 8 identical FlexElements™. A FlexElement is a universal comparator, that can be
used to monitor any analog actual value measured or calculated by the relay, or a net
difference of any two analog actual values of the same type. Depending on how the
FlexElement is programmed, the effective operating signal could be either a signed signal
(“Signed” selected for Input Mode), or an absolute value (“Absolute” selected for Input
Mode).
The element can be programmed to respond either to a signal level or to a rate-of-change
(delta) over a pre-defined period of time. The output operand is asserted when the
operating signal is higher than a threshold or lower than a threshold as chosen by the user.
When programming a FlexElement, one must keep in mind the following limitations:
1.
The analog inputs for any FlexElement must be from the same “gender”:
–
current and current (in any combination, phase-symmetrical, phase-phase, kA-A,
differential, restraint, etc.)
– voltage and voltage (as above)
– active power and active power (Watts and Watts)
– reactive power and reactive power (Vars and Vars)
– apparent power and apparent power (VA and VA)
– angle and angle (any, no matter what signal, for example angle of voltage and
angle of current are a valid pair)
– % and % (any, for example THD and harmonic content is a valid pair)
– V/Hz and V/Hz
– °C and °C
– I
2
t and I
2
t
– FlexElement actual and FlexElement actual
For all the other combinations, the element displays 0.000 or N/A and will not assert
any output operand.
2. The analog value associated with one FlexElement can be used as an input to another
FlexElement “Cascading”.
Figure 4-140: FlexElement logic diagram
894017$1.CDR
FUNCTION:
SETTING
Enabled = 1
SETTINGS
INPUT COMPARISON
MODE:
OPERATING MODE:
DIRECTION:
PICKUP:
RATE OF CHANGE TIME
UNIT (dt):
RATE OF CHANGE TIME:
RUN
INPUT 1(+):
SETTINGS
Actual Value FLEXLOGIC OPERANDS
FE 1 OP
FE 1 PKP
INPUT 2 (-):
Actual Value
+
-
FE 1 Op Signal
ACTUAL VALUE
Disabled = 0
BLOCK:
SETTING
Off = 0
AND
t
PKP
t
DPO
SETTINGS
DROPOUT DELAY:
PICKUP DELAY:
HYSTERESIS: