Basler Electric BE1-700 - Manual (Page 14)

Each current sensing circuit is low burden and isolated. Neutral (residual) and negative-sequence current
magnitudes are derived from the three-phase currents. An independent ground current input is included
for direct measurement of the current in a transformer neutral, tertiary winding or flux balancing current
transformer.
Contact Sensing Inputs
Four programmable contact-sensing inputs (IN1, IN2, IN3, and IN4) with programmable signal
conditioning provide a binary logic interface to the protection and control system. Each input function and
label is programmable using BESTlogic. A user-meaningful label can be assigned to each input and to
each state (open and closed) for use in reporting functions.
Contact Outputs
Five programmable general-purpose contact outputs (OUT1, OUT2, OUT3, OUT4, and OUT5) provide a
binary logic interface to the protection and control system. One programmable, fail-safe contact output
(OUTA) provides an alarm output. Each output function and label is programmable using BESTlogic. A
user-meaningful name can be assigned to each output and to each state (open and closed) for use in
reporting functions. Output logic can be overridden to open, close, or pulse each output contact for testing
or control purposes. All output contacts are trip rated.
Protection and Control Functions
Protection functions, depending on the relay style ordered, may consist of overcurrent, voltage,
frequency, breaker reclosing, fuse loss and breaker failure protection and general purpose logic timers.
Setting groups and virtual control switches make up the control functions. The following paragraphs
describe each protection and control function.
Overcurrent Protection (BE1-700C)
Overcurrent protection is provided by six instantaneous overcurrent functions and three time overcurrent
functions. Digital signal processing filters out unwanted harmonic components while providing fast
overcurrent response with limited transient overreach and overtravel.
Each instantaneous overcurrent function has a settable time delay. Phase elements include 50TP and
150TP. Neutral elements include 50TN and 150TN. Negative-sequence elements include 50TQ and
150TQ.
Inverse time overcurrent functions are provided for phase, neutral and negative-sequence protection. A
51P phase element, 51N and 151N neutral elements, and a 51Q negative-sequence element are
provided. Time overcurrent functions employ a dynamic integrating timing algorithm covering a range
from pickup to 40 times pickup with selectable instantaneous or integrated reset characteristics. Time
overcurrent curves conform to the IEEE PC37.112 document and include seven curves similar to
Westinghouse/ABB CO curves, five curves similar to GE IAC curves, a fixed time curve and a user
programmable curve.
Voltage Protection (BE1-700V)
One volts per hertz protective element (24) provides overexcitation protection for a generator and/or
transformer.
Two phase overvoltage and two phase undervoltage elements provide over/undervoltage protection (27P,
59P). Phase overvoltage protection can be set for one of three, two of three or three of three logic. When
a four-wire voltage transformer connection is used, overvoltage protection can be set for either phase-to-
phase voltage or phase-to-neutral voltage.
Two auxiliary overvoltage and one auxiliary undervoltage element provides over/undervoltage protection
(27X, 59X, 159X). Auxiliary voltage protection elements can be set to individually monitor the auxiliary
voltage fundamental, third harmonic or phase 3V
0
voltages. Ground unbalance protection is provided
when the optional auxiliary voltage input is connected to a source of 3V
0
such as a broken delta VT.
With the optional auxiliary voltage input connected to the bus, one sync-check function provides
synchronism protection (25). Sync-check protection checks for phase angle difference, magnitude
difference, frequency difference (slip) and, optionally, if the three-phase VT frequency is greater than the
auxiliary VT frequency. One voltage monitor output (25VM1) provides independent dead/live voltage
closing logic.
One negative-sequence overvoltage element provides protection for phase unbalance or a reverse
system phase-sequence (47).
1-2 BE1-700 General Information 9376700990 Rev M