Basler Electric BE1-BPR - Manual (Page 13)

9272000990 Rev J BE1-BPR General Information 1-1
SECTION 1 • GENERAL INFORMATION
DESCRIPTION
BE1-BPR Breaker Protection Relays are three-phase and neutral, microprocessor based relays designed
to provide power systems with protection and security against monitored breaker failure or to initiate
multiple shot breaker reclosings.
These relays incorporate a powerful means of programming internal relay logic to satisfy a wide range of
user requirements without making any relay hardware changes. Microprocessor based design provides
the basic features of a programmable logic controller (PLC) combined with an instantaneous overcurrent
module. Cased in a 19 inch rack-mount or a vertical panel mount, the relay offers installation versatility. A
wide temperature, 2 lines by 16 character display provides diagnostic and setup information. Two RS-232
serial ports (one each front and rear) and one RS-485 serial port (rear) provide remote communication
and relay control.
Built-in diagnostics and monitoring features provide information for both the health of the relay and the
health of the breaker being monitored. Relay diagnostics include continuous background monitoring of the
power supplies, analog-to-digital (A/D) converter, random-access memory (RAM), read-only memory
(ROM), and electrically-erasable programmable ROM (EEPROM). A dedicated alarm (ALM) relay output
provides power supply, microprocessor, and software alarm status. Breaker diagnostics include a timing
diagnostic log, breaker contact duty monitoring, breaker resistor protection, and breaker arc detection.
Other monitoring features include oscillographic fault records and fault summary logs. BE1-BPR relays
use the Inter-Range Instrumentation Group (IRIG), Format B for high timing accuracy and resolution.
APPLICATION - STANDARD MODELS
Breaker Failure
BE1-BPR relays are intended to provide a preprogrammed solution for most breaker failure relaying
applications. Breaker failure relaying is the use of a current monitoring relay to determine whether or not
current continues to flow into a faulted circuit after a breaker has been instructed to interrupt the circuit. If
current continues to flow into the faulted circuit after a defined period of time has elapsed (sufficient for
the breaker to have interrupted the current), the circuit breaker is considered to have failed. Steps must
then be taken to trip the next set of breakers in the power system to prevent system damage. Breaker
failure schemes must be designed to isolate both the faulted circuit and the failed breaker.
Several reasons why a breaker fails to clear a fault are:
• Trip circuit is open (broken wire, blown fuse, open trip coil).
• Interrupting mechanism stuck, leaving a single phase of a three-phase circuit connected.
• Interrupter flash-over due to the loss of dielectric strength through contamination or damage.
• Operating mechanism failed to operate.
Breaker failure relays detect these conditions and initiate backup procedures.
Breaker failure relays are applied on a per breaker basis. That is, one breaker failure relay for each
breaker in the substation. BE1-BPR relay outputs must be arranged to initiate the tripping of all the circuit
breakers necessary to isolate the fault if the protected circuit breaker fails to operate. The relay may also
need to initiate transfer tripping of remote breakers to accomplish this task. Transfer tripping of the remote
line end for a breaker failure should also block reclosing of the remote circuit breakers. External lockout
relays are typically used to trip and block reclosing of the backup breakers because they normally require
a positive operator action to reset them.
Typically, breaker failure protection is applied to transmission and sub-transmission systems. However,
breaker failure protection may be applied to any portion of the power system where failure of a circuit
breaker to operate properly could result in severe system damage or instability. Breaker failure protection
can also be used to selectively clear a failed breaker in a station with multiple buses without clearing the
entire station.
Breaker Reclosing
BE1-BPR relays can be configured as multiple shot reclosing relays that operate in parallel and
independently from the breaker failure function.