Protection and control functions, Setting groups, Differential protection – Basler Electric BE1-CDS240 General Information User Manual
Page 5: Overcurrent protection, Voltage protection, Frequency protection, Protection and control functions -3

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Each output is programmable using BESTlogic (assign any virtual output to any physical output
relay) and can be given a user meaningful name for the variable and for each state (open and
closed) for use in reporting functions.
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Output logic can be overridden to open, close or pulse each output contact for testing, or control
purposes.
Protection and Control Functions
Setting Groups
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Four (4) settings groups allow adaptive relaying to be implemented to optimize the relay settings
for various operating conditions.
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Automatic and external logic can be employed to select the active setting group.
Differential Protection
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Three-phase percentage restrained differential protection with harmonic restraint: 87. Protection
can be set to monitor two, three, or four windings. Unused inputs can be used for overcurrent
protection.
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Two restricted earth fault ground differential protection elements with independent ground (IG)
input (and C-phase, IG2, of Current Circuit 4): 87ND and 187ND.
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Tap compensation for the differential protection can be automatically calculated by the relay
based upon user settings of CT ratio, MVA and kV base values.
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Ground differential between calculated residual of any winding and the phase C current input of a
fourth and unused winding (IG2).
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Each winding can be independently set for a phase relationship (relative to winding 1) of 0 to 360
degrees in steps of 30 degrees.
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Each winding can be set for IEC standard transformer connections.
Overcurrent Protection
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Instantaneous overcurrent with settable time delay for each operating quantity (A, B, C, N (using
IN or IG) and Q. Eight (8) sets Phase, Five (5) sets Neutral, Four (4) sets Negative-Sequence.
Each function is individually assignable to any of the current input circuits. Functions are: 50TP,
150TP, 250TP, 350TP, 450TP, 550TP, 650TP, 750TP, 50TN, 150TN, 250TN, 350TN, 450TN,
50TQ, 150TQ, 250TQ, and 350TQ.
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Inverse time overcurrent functions with integrating or instantaneous reset. Four (4) for Phase, five
(5) for Neutral, and four (4) for Negative-Sequence. Each function is individually assignable to
any of the current input circuits. Functions are 51TP, 151TP, 251TP, 351TP, 51TN, 151TN,
251TN, 351TN, 451TN, 51TQ, 151TQ, 251TQ, and 351TQ.
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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.
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Time overcurrent curves conform to IEEE PC37.112 and include seven curves similar to
Westinghouse/ABB CO curves, five curves similar to GE IAC curves, four IEC curves, a fixed
time curve, and a user programmable curve.
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Digital signal processing filters out unwanted harmonic components while providing fast
overcurrent response with limited transient overreach and overtravel.
Voltage Protection
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Voltage control or restraint for 51P (51V protection)
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One (1) volts per hertz protective element (24) provides overexcitation protection for a generator
and/or transformer.
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Two phase (2) undervoltage elements, 27P and 127P, provide phase undervoltage protection.
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Two phase (2) overvoltage elements, 59 and 159, provide phase overvoltage protection.
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One (1) negative-sequence overvoltage element (47) provides protection for phase unbalance or
a reverse system phase-sequence.
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One (1) zero sequence overvoltage element (59X) provides protection for ground faults on
ungrounded systems using calculated 3VO.
Frequency Protection
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Six (6) over/underfrequency protection elements are provided: 81, 181, 281, 381, 481, and 581.
9365200990 Rev M
BE1-CDS240 General Information
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