P.1.3
Date Code 20151029 Protection Manual SEL-411L Relay
Introduction and Specifications
Features
Relay features include the following:
NOTE: The -0 version of the relay
does not provide series-compensated
line protection logic.
Line Differential Protection. Use the line differential function to protect
two, three, or four terminals
1
. This function provides line protection,
even when an in-line transformer is present (three-pole tripping only
single pole tripping when no transformer). Charging current
compensation ensures element sensitivity, particular at higher voltage
levels.
Superior Distance Protection. Combine five zones of phase distance and
ground distance elements with directional overcurrent elements.
Patented Coupling Capacitor Voltage Transformer (CCVT) transient
overreach logic enhances Zone 1 distance element security. The Best
Choice Ground Directional Element
®
optimizes directional element
performance and eliminates many settings. Additional logic prevents
Zone 1 overreach on series-compensated lines.
NOTE: The -0 version of the relay
does not provide high-speed
directional elements and high-speed
distance elements.
High-Speed Tripping. The relay uses the HSDPS (High-Speed Directional
and Phase Selection) element and high-speed distance elements for
subcycle detection of power system faults.
Reclosing. Incorporate programmable single-pole and three-pole tripping
and reclosing of one and two circuit breakers into an integrated
substation control system. Synchronism and voltage checks from
multiple sources provide complete bay control.
Breaker Failure. The relay incorporates CT subsidence detection to
produce element dropout in 5/8 cycle. Apply the relay to supply three-
pole breaker failure for one or two breakers. Included is the necessary
logic for single-pole and three-pole breaker failure retrip and initiation
of transfer tripping.
Out-of-Step Blocking and Tripping. Select out-of-step blocking of distance
elements or out-of-step tripping during power swings. The relay
includes multizone elements and logic for detection of an out-of-step
condition.
Switch-Onto-Fault. Relay switch-onto-fault (SOTF) logic permits specific
protection elements to quickly trip after the circuit breaker closes,
protecting maintenance personnel and substation equipment.
Frequency Elements. Any of the six levels of frequency elements can
operate as either an underfrequency element or as an overfrequency
element. Because the relay tracks the frequency from 40.1 Hz to
65 Hz, the frequency elements are suited for applications such as
underfrequency load shedding and restoration control systems.
Fault Locator. Efficiently dispatch line crews to quickly repair line
problems.
Primary Potential Redundancy. Multiple voltage inputs to the relay
provide primary input redundancy. At loss-of-potential (LOP)
detection, configure the relay to use inputs from an electrically
equivalent source. Protection remains in service without
compromising security.
Dual CT Input. Apply with ring bus, breaker-and-a-half, or other two-
breaker schemes. Combine currents within the relay from two sets of
CTs for protection functions, but keep them separately available for
monitoring and station integration applications.
1
Four terminal application is available over 87L Ethernet communications only. Initial release is
without Ethernet and protects as many as three terminals using serial communications.
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