Basler Electric BE1-BPR - Manual (Page 15)

9272000990 Rev J BE1-BPR General Information 1-3
Figure 1-1. Breaker Failure Timing Diagram
Because timing is such an important part of breaker failure protection, the BE1-BPR relay provides timing
diagnostics to assist in determining if the timer settings are optimal and to allow other aspects of the
protection system to be checked. This timing diagnostic is a Timer Log or TLOG. An example of its use is
to create a log of the margin remaining between when a fault is cleared and when a breaker failure would
occur. After a normal breaker operation clears a fault, the time remaining from when the BE1-BPR
overcurrent fault detector drops out and the breaker failure delay timer would have timed out is the
MARGIN. This time can be recorded by saving the time left on the delay timer when the fault detector
drops out by using the program timer log alarm (PTLOG) command. The time logged will correspond to
the MARGIN value in Figure 1-1. If there is a discrepancy between the calculated and actual margin value
stored in the TLOG, corrective action can be taken to correct the protection timing before a serious
problem occurs. If the MARGIN is too small or too large, the delay timer setting can be adjusted for
optimal operation. The PTLOG command also allows an alarm time to be programmed so that if the
MARGIN drops below a pre-determined value, the Alarm output (ALM) can be automatically closed to
signal the operator that immediate attention is required. Timing diagnostics can be programmed for each
of the six timers available.
Breaker Arc Detector
An important breaker diagnostic feature is the detection of low level arcing across an open breaker
(flashover). Flashover might occur because lightning struck and a surge suppressor failed or air pressure
in an air blast circuit breaker is lost. If left undetected, severe damage to the breaker contacts could
result. BE1-BPR relays can detect this type of fault using an extra low level phase overcurrent pickup and
a long moving average filter. These features have been provided as standard features in the BE1-BPR
relays. Used with the programmable logic, a breaker arc detector can be programmed to provide a
breaker close output to close the breaker and extinguish the arc. Additional interlocks may be added to
the logic to inhibit the breaker close signal if the breaker is isolating a faulted line.
IRIG Standard Time Format
The IRIG function allows the BE1-BPR relay to synchronize the on-board real time clock with a standard
IRIG demodulated time signal. Synchronization is automatic and the BE1-BPR initiates synchronization at
regular intervals (approximately 20 seconds) in order to maintain the one millisecond overall accuracy.
APPLICATION - ENHANCED MODELS
Enhanced BE1-BPR models have all of the features of standard models plus the additional features
described in the following paragraphs.
Breaker Contact Maintenance and Resistor Protection
Enhanced model BE1-BPR relays can perform two protection diagnostic functions other than the breaker
failure function. One, they can estimate breaker contact duty (wear) and signal when preventative
maintenance is needed. Two, they can estimate breaker opening resistor heating and provide a block
reclose signal to protect the breaker resistor when the resistor heating could exceed the maximum
resistor rating.