GE D90 Plus Instruction Manual page 399

CHAPTER 7: PROTECTION
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
The logic that determines the interaction of inputs, elements, schemes and outputs is field
programmable through the use of logic equations that are sequentially processed. The use
of virtual inputs and outputs in addition to hardware is available internally and on the
communication ports for other relays to use (distributed FlexLogic™).
FlexLogic™ allows users to customize the relay through a series of equations that consist
of operators and operands. The operands are the states of inputs, elements, schemes and
outputs. The operators are logic gates, timers and latches (with set and reset inputs). A
system of sequential operations allows any combination of specified operands to be
assigned as inputs to specified operators to create an output. The final output of an
equation is a numbered register called a virtual output. Virtual outputs can be used as an
input operand in any equation, including the equation that generates the output, as a seal-
in or other type of feedback.
A FlexLogic™ equation consists of parameters that are either operands or operators.
Operands have a logic state of 1 or 0. Operators provide a defined function, such as an
AND gate or a timer. Each equation defines the combinations of parameters to be used to
set a virtual output flag. Evaluation of an equation results in either a logic 1 state (=ON, flag
set) or logic 0 state (=OFF, flag not set). Each equation is evaluated at least four times every
power system cycle.
Some types of operands are present in the relay in multiple instances (for example, contact
and remote inputs). These types of operands are grouped together (for presentation
purposes only) on the faceplate display. The characteristics of the different types of
operands are tabulated below.
Table 22: Protection FlexLogic™ operand types
Type State
Contact On
input
Off
Contact Voltage on
output
Voltage off
Current on
Current off
Digital Greater than
counter
Equal to
Less than
Direct On
input
Element Pickup
(analog)
Dropout
Operate
Block
Example Characteristics (input is logic 1 or "on" if...)
Voltage is presently applied to the input
CONT IP1 ON
(external contact closed).
Voltage is presently not applied to the input
CONT IP1 OFF
(external contact open).
Voltage exists across the contact.
CONT OP1 VON
Voltage does not exist across the contact.
CONT OP1 VOFF
Current is flowing through the contact.
CONT OP1 ION
Current is not flowing through the contact.
CONT OP1 IOFF
The number of pulses counted is above the set
COUNTER 1 HI
number.
The number of pulses counted is equal to the
COUNTER 1 EQL
set number.
The number of pulses counted is below the set
COUNTER 1 LO
number.
The direct input is presently in the ON state.
DIRECT INPUT 1 ON
The tested parameter is presently above the
PHASE TOC1 PKP
pickup setting of an element which responds
to rising values or below the pickup setting of
an element which responds to falling values.
This operand is the logical inverse of the
PHASE TOC1 DPO
pickup operand.
The tested parameter has been above/below
PHASE TOC1 OP
the pickup setting of the element for the
programmed delay time, or has been at logic
1 and is now at logic 0 but the reset timer has
not finished timing.
The output of the comparator is set to the
PHASE TOC1 BLK
block function.
PROTECTION FLEXLOGIC™
389