Basler Electric BE1-BPR Breaker Protection Relay

Introduction

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