Sel 411L - Page 847

P.14.23
Date Code 20151029 Protection Manual SEL-411L Relay
SELOGIC Control Equation Programming
SEL
OGIC Control Equation Elements
In free-form programming, the relay evaluates the counter at execution of the
counter Input SEL
OGIC control equation (PCNnnIN or ACNnnIN). If you
enter an expression for the counter Reset (PCNnnR) or the counter Preset
(PCNnnPV), the values for Reset and Preset that the relay uses are the last
values the relay calculates before the input SEL
OGIC control equation
calculation. Because the relay uses the last values for Reset and Preset in this
manner, we recommend for most applications that you enter the Preset, Reset,
and Input statements together in the order shown in Example 14.9. You can
view the current value of the counter by assigning the protection counter
current value, PCVnnCV, to a protection math variable or by assigning the
automation counter current value, ACVnnCV, to an automation math variable.
View the math variable values by issuing the appropriate MET PMV or
MET AMV commands.
The current value count is stored in volatile memory. Elapsed time resets to
zero for both protection and automation sequential timers when relay power
cycles, you change settings or settings groups, or you perform any function
that reboots the relay.
EXAMPLE 14.9 Counter Programming
The free-form programming equations that follow demonstrate how
to enter settings to control a protection counter in protection free-
form SEL
OGIC control equation programming. Programming for an
automation counter is similar.
Protection Counter 1 counts close operations of the circuit breaker
associated with the 52AA1 element. Initially, the current value,
PCN01CV, is zero. The relay increments the current value each time
the circuit breaker closes. The relay increases the count value,
PCN01CV, each time the circuit breaker closes and the element 52AA1
value changes from 0 to 1 (a rising edge). When the count reaches
1000, the timer automatically resets and begins counting again.
# Example protection counter programming
#
# This example counts how many times a three-pole circuit breaker closes
# The counter automatically resets every 1,000 operations
PCN01PV := 1000
PCN01R := PCN01Q
PCN01IN := 52AA1
The SELOGIC control equations below provide multiple-change
detection counting both close and open operations of the circuit
breaker. The intermediate value PSV01 turns on for one processing
interval each time the circuit breaker closes. The intermediate value
PSV02 turns on for one processing interval each time the circuit
breaker opens. The OR combination of PSV01 and PSV02 contains a
rising edge for each circuit breaker operation, open or closed, that
Protection Counter 1 counts.
# Example protection counter programming
#
# This example counts how many times a three-pole circuit breaker operates
either open or closed
#
# Detect OPEN and CLOSE and combine
PSV01 := R_TRIG 52AA1 # Pulse for each close
PSV02 := F_TRIG 52AA1 # Pulse for each open
PSV03 := PSV01 OR PSV02 # Pulse for each open or close