Time Delayed Measured Earth Fault Protection (51G); Figure 3-6 Logic Diagram: Measured Time Delayed Earth Fault Element - Siemens 7SR45 Argus User Manual

Table 3-5
Parameters Description
50G-n
50G-n Block
Element
50G-n Setting Current Set point
50G-n Delay Delay time
3.6

Time Delayed Measured Earth Fault Protection (51G)

One instantaneous time delayed measured earth fault element is provided in the 7SR45 self powered overcurrent
and earth fault relay.
51G-1
51G-n Setting sets the pick-up current level.
A number of shaped characteristics are provided. An inverse definite minimum time (IDMT) characteristic is
selected from IEC and ANSI using 51G-n Char. A time multiplier is applied to the characteristic curves using the
51G-n Time Mult setting. Alternatively, a definite time lag (DTL) can be chosen using 51G-n Char.
When DTL is selected the time multiplier is not applied and the 51G-n Delay (DTL) setting is used instead.
The 51G-n Reset setting can apply a definite time delayed reset, or when the operation is configured as an IEC
or ANSI if the reset is selected as IEC/ANSI (DECAY), reset the associated reset curve will be used. The reset
mode is significant where the characteristic has reset before issuing a trip output.
A minimum operate time for the characteristic can be set using 51G-n MinOperate setting.
A fixed additional operate time can be added to the characteristic using 51G-n Follower setting.
Operation of the time delayed measured earth fault elements can be inhibited by assigning binary inputs.
Inhibit 51G-n
Figure 3-6
© 2017 Siemens Protection Devices Limited
Instantaneous Measured Earth Fault Protection (50G-n)
Default Value
Disabled
1xIn
0
A binary input.
Logic Diagram: Measured Time Delayed Earth Fault Element
7SR45 Description of Operation
Min Max Step Change
- - -
0.2xIn 20xIn 0.01
0 s 600 s 0.01
Chapter 1 Page 21 of 34