GE D90 Plus Instruction Manual page 485

CHAPTER 8: AUTOMATION
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 logic).
Automation logic 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.
An automation logic 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
(=ON, flag set) or logic 0 (=OFF, flag not set). Each equation is evaluated at the automation
scan rate.
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 33: Automation logic operand types
Type State
Digital On
input
Off
Digital Voltage on
output
Voltage off
Current on
Current off
Digital Greater than
counter
Equal to
Less than
Direct On
input
Element Pickup
Dropout
Operate
Fixed On
Off
Remote On
input
Virtual On
input
Example Characteristics (input is logic 1 or "on" if...)
Voltage is presently applied to the input
DIG IP1 ON
(external contact closed).
Voltage is presently not applied to the input
DIG IP1 OFF
(external contact open).
Voltage exists across the contact.
DIG OP1 VON
Voltage does not exist across the contact.
DIG OP1 VOFF
Current is flowing through the contact.
DIG 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 output operand is at logic 1.
DIG ELEM 1 PKP
This operand is the logical inverse of the
DIG ELEM 1 DPO
pickup operand.
The input operand has been at logic 1 for the
DIG ELEM 1 OP
programmed pickup delay time, or has been
at logic 1 for this period and is now at logic 0
but the reset timer has not finished timing.
Logic 1.
ON
Logic 0.
OFF
The remote input is presently in the on state.
REMOTE IN 1 ON
The virtual input is presently in the on state.
VIRT IP 1 ON
AUTOMATION LOGIC
475