| 摘要 |
<p>A method in a three-terminal differential protection comprises measuring a terminal phase current ( I T 1( y ) , I T 2( y ) , I T 3( y ) ), at each terminal (T1, T2, T3) of a protected zone of the differential protection in each phase (L1, L2, L3) to be protected and determining a bias current ( I b ( y ) ) of the phase on the basis of the terminal phase currents ( I T 1( y ) , I T 2( y ) , I T 3( y ) ). The bias current determination comprises subtracting phasor values of the terminal phase currents of two terminals from the phasor value of the terminal phase current of one terminal. The terminal phase current being a minuend in the phasor difference computation is selected on the basis of the phase angles or amplitudes of the terminal phase currents.</p> |
