• Series capacitor becomes nearly completely bridged by MOV when the line currentbecomes higher than 10-times the protective current level (I £ 10· kp· INC).8.1.2.10 Impact of series compensation on protective IED of adjacent linesVoltage inversion is not characteristic for the buses and IED points closest to the seriescompensated line only. It can spread also deeper into the network and this way influencesthe selection of protection devices (mostly distance IEDs) on remote ends of lines adjacentto the series compensated circuit, and sometimes even deeper in the network.en06000616_ansi.vsd~~ZLFZLAZLBEAEBVAVBVDIBIAIF-jXCFABDZSAZSBANSI06000616 V1 ENFigure 92: Voltage inversion in series compensated network due to fault currentinfeedVoltage at the B bus (as shown in figure 92) is calculated for the loss-less systemaccording to the equation below.( ) ( )= + × = + × - + ×B D B LB A B LF C B LBV V I jX I I j X X I jXEQUATION1998-ANSI V1 EN (Equation 63)Further development of equation 63 gives the following expressions:( )1= × + + × -é ùæ öê ç ÷ úè øë ûAB B LB LF CBIV jI X X XIEQUATION1999-ANSI V1 EN (Equation 64)( )01= = ++LBC B LFABXX V XIIEQUATION2000-ANSI V1 EN (Equation 65)Equation 64 indicates the fact that the infeed current IA increases the apparent value ofcapacitive reactance in system: bigger the infeed of fault current, bigger the apparentseries capacitor in a complete series compensated network. It is possible to say that1MRK 506 369-UUS - Section 8Impedance protectionLine distance protection REL670 2.2 ANSI 193Application manual
