Siemens EF 73E Series Instrukcja Użytkownika Pobierz pdf (Strona 4)

Siemens Protection Devices Limited 4

46BC Phase Unbalance/Broken Conductor

Element has settings for pickup level and DTL delay. With

the circuit breaker closed, if the NPS:PPS current ratio is

above setting this could be due to a broken conductor.

50BF Circuit Breaker Fail

The circuit breaker fail function may be triggered from an

internal trip signal or from a binary input. Line currents

and earth currents are monitored following a trip signal

and an output is issued if any current is still detected,

above setting, after a specified time interval.

Alternatively, if the trip is from a mechanical protection

the circuit breaker position can be used to determine a

failure. A second time delay is available to enable another

stage to be utilized if required. An input is also available

to bypass the time delays when the circuit breaker is

known to be faulty.

50/51 Phase Fault

50 INST/DTL and 51 IDMTL/DTL elements provide

overcurrent protection, each with independent settings

for pickup current, time-multiplier (51) and time-delays.

User can select IEC or ANSI time current characteristics.

The IDMT stage has a user programmable reset

characteristic, either DTL or shaped current ~ time reset

characteristic, to improve grading with electromechanical

protection.

50G/51G/50N/51N Earth Fault/ Earth Fault

Two earth fault measurement modes are available. One

mode directly measures the earth current from an

independent CT, or the residual connection of the 3 line

CTs. This input can be ordered as either earth fault or

sensitive earth fault (50G/51G).

The second mode derives the earth current internally

from the 3 phase CT inputs to give earth fault (50N/51N).

50 INST/DTL and 51 IDMTL/DTL elements provide

overcurrent protection, each with independent settings

for pickup current, time-multiplier (51) and time-delays.

User can select IEC or ANSI time current characteristics.

The IDMT stage has a user programmable reset

characteristic either DTL or shaped current ~ time reset

characteristic to improve grading with electromechanical

protection.

0.1

100

1000

110

Current (multiples of setting)

Time

(sec)

2 3 4 5 6 8 20 30 40 50 60 80

100

Long Time Inverse

Normal Inverse

Very Inverse

Extremely Inverse

Fig 2. IEC Overcurrent Curves

0.1

100

1000

110

Current (multiples of setting)

Time

(sec)

2 3 4 5 6 8 20 30 40 50 60 80

100

Moderately Inverse

Extremely Inverse

Very Inverse

Fig 3. ANSI Overcurrent Curves

Description of Functionality

1 2 3 4 5 6 7 8 9 ... 15 16

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