7SR210 & 7SR220 Description of Operation
Unrestricted ©2018 Siemens Protection Devices Limited
Page 53 of 94
3.16 Voltage Protection: Under/Over Frequency (81) – 7SR22
Six under/over frequency elements are provided in the 7SR22 relay.
The relay utilises fundamental voltage measurement values for this function. The frequency calculation is based
on the highest input voltage derived from the voltage selection algorithm.
Frequency elements are blocked if all phase voltages fall below the
81 U/V Guard
setting.
The sense of the element (under-frequency or over-frequency) is set by the
81-n Operation
setting.
81-n Setting
sets the pick-up voltage level for the element.
An output is given after elapse of the
81-n Delay
setting.
The
81-n Hysteresis
setting allows the user to vary the pick-up/drop-off ratio for the element.
Operation of the under/over frequency elements can be inhibited from: -
Inhibit 81-n
A binary or virtual input, function key or remote data Comms.
81-n U/V Guarded
Under voltage guard element.
or
> <
General Pickup
81-n
Inhibit 81-n
81-n Hysteresis
81-n Delay
c
&
81-n Setting
81-n Operation
81-n Element
Enabled
Disabled
81-n U/V Guarded
Yes
&
Voltage
Selection
VL1
VL2
VL3
F
<
&
81 U/V Guard
Setting
<
<
Inhibit 81-n
General Pickup
81-n
Figure 3.16-1 Logic Diagram: Under/Over Frequency Detector (81)
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 ...
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