MV design guide - Schneider Electric
MV design guide - Schneider Electric
MV design guide - Schneider Electric
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Switchgear<br />
definition<br />
Voltage transformer<br />
Transformation ratio (Kn)<br />
Upr<br />
Kn = = for a TT<br />
Usr<br />
N1<br />
N2<br />
Voltage ratio error<br />
This is the error that the transformer introduces into the voltage<br />
measurement.<br />
voltage error (%) =<br />
(kn Usr - Upr)•100<br />
Upr<br />
Kn = transformation ratio<br />
Phase error or phase-shift error<br />
This is the phase difference between the primary voltage Upr and the<br />
secondary voltage Usr. IT is expressed in minutes of angle.<br />
The thermal power limit or rated continuous power<br />
This is the apparent power that the transformer can supply in steady state<br />
at its rated secondary voltage without exceeding the temperature rise<br />
limits set by the standards.<br />
<strong>Schneider</strong> <strong>Electric</strong><br />
Merlin Gerin <strong>MV</strong> <strong>design</strong> <strong>guide</strong><br />
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