7SR210 & 7SR220 Description of Operation
Unrestricted ©2018 Siemens Protection Devices Limited
Page 67 of 94
Voltage detectors
Voltage detectors determine the status of the line or bus. If the voltages on either the line or bus are below a set
threshold level they can be considered to be ‘dead’. If the voltages are within a setting around the nominal voltage
they are classed as ‘live’. Independent voltage detectors are provided for both line and bus.
If a voltage is in the dead band range then it will be classed as dead until it has reached the live band area.
Similarly, if a voltage is live, it continues to be live until it has reached the dead band area. This effectively allows
for variable amounts of hysteresis to be set. Figure 4.9.3-1 illustrates the voltage detector operation.
Note: the area between the dead and live zones is not indeterminate. When any voltage is applied to the relay it
will ramp up the software RMS algorithm and always pass through the dead zone first.
A wide range is provided for live and dead voltage detector levels but the live and dead zones must not overlap.
Figure 4.9.3-1
Voltage Detector Operation
Under-voltage detectors
The under-voltage detectors, if enabled, can block a close output command if either the line voltage is below the
25 Line Undervolts
setting value or the bus voltage is below the
25 Bus Undervolts
setting value. Both line and
bus have their own independent settings and are applied to the single-phase voltage inputs.
Differential voltage detectors
The differential voltage detector, if enabled, can block a close output command if the difference between the line
and bus voltages is greater than the differential voltage setting value.
Summary of Contents for Argus 7SR21
Page 1: ...Energy Management 7SR21 7SR22 Argus Overcurrent Relay Reyrolle Protection Devices ...
Page 2: ......
Page 4: ...Contents 7SR11 and 7SR12 Page 2 of 2 2018 Siemens Protection Devices Limited ...
Page 185: ...7SR210 Settings Guide Unrestricted 2018 Siemens Protection Devices Limited Page 61 of 61 ...
Page 277: ...7SR220 Settings Guide Unrestricted Page 72 of 107 2013 Siemens Protection Devices Limited ...
Page 382: ...7SR220 Technical Manual Chapter 4 Page 2 of 96 2017 Siemens Protection Devices Limited ...
Page 386: ...7SR220 Technical Manual Chapter 4 Page 6 of 96 2017 Siemens Protection Devices Limited ...
Page 398: ...7SR220 Technical Manual Chapter 4 Page 18 of 96 2017 Siemens Protection Devices Limited ...
Page 414: ...7SR220 Technical Manual Chapter 4 Page 34 of 96 2017 Siemens Protection Devices Limited ...
Page 466: ...7SR220 Technical Manual Chapter 4 Page 86 of 96 2017 Siemens Protection Devices Limited ...
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Page 470: ...7SR220 Technical Manual Chapter 4 Page 90 of 96 2017 Siemens Protection Devices Limited ...
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