GE N60 Instruction Manual page 256

5.5 FLEXLOGIC
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 out-
put. 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 parame-
ters to be used to set a Virtual Output flag. Evaluation of an equation results in either a 1 (=ON, i.e. flag set) or 0 (=OFF, i.e.
flag not set). Each equation is evaluated at least 4 times every power system cycle.
Some types of operands are present in the relay in multiple instances; e.g. contact and remote inputs. These types of oper-
ands are grouped together (for presentation purposes only) on the faceplate display. The characteristics of the different
types of operands are listed in the table below.
Table 5–15: N60 FLEXLOGIC OPERAND TYPES
5
OPERAND TYPE
Contact Input
Contact Output
(type Form-A contact
only)
Direct Input
Element
(Analog)
Element
(Digital)
Element
(Digital Counter)
Fixed
Remote Input
Virtual Input
Virtual Output
5-138
STATE EXAMPLE FORMAT
On Cont Ip On
Off Cont Ip Off
Current On Cont Op 1 Ion
Voltage On Cont Op 1 VOn
Voltage Off Cont Op 1 VOff
On DIRECT INPUT 1 On
Pickup PHASE TOC1 PKP
Dropout PHASE TOC1 DPO
Operate PHASE TOC1 OP
Block PHASE TOC1 BLK
Pickup Dig Element 1 PKP
Dropout Dig Element 1 DPO
Operate Dig Element 1 OP
Higher than Counter 1 HI
Equal to Counter 1 EQL
Lower than Counter 1 LO
On On
Off Off
On REMOTE INPUT 1 On
On Virt Ip 1 On
On Virt Op 1 On
N60 Network Stability and Synchrophasor Measurement System
CHARACTERISTICS
[INPUT IS '1' (= ON) IF...]
Voltage is presently applied to the input (external contact
closed).
Voltage is presently not applied to the input (external
contact open).
Current is flowing through the contact.
Voltage exists across the contact.
Voltage does not exists across the contact.
The direct input is presently in the ON state.
The tested parameter is presently above the 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 above PKP
operand.
The tested parameter has been above/below 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 block function.
The input operand is at logic 1.
This operand is the logical inverse of the above PKP
operand.
The input operand has been at logic 1 for the 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.
The number of pulses counted is above the set number.
The number of pulses counted is equal to the set number.
The number of pulses counted is below the set number.
Logic 1
Logic 0
The remote input is presently in the ON state.
The virtual input is presently in the ON state.
The virtual output is presently in the set state (i.e.
evaluation of the equation which produces this virtual
output results in a "1").
5 SETTINGS
GE Multilin