1. CIGRE SC-B5 Colloquium 2005 Sept.14-16 Calgary Canada PS3:Protection & Control of Series Compensated networks Q3:Are there any experiences of other unique series compensation distance relay applications where special adjustments to settings and/or logic are required to ensure correct protection performance? Zhao Xicai NARI-RELAYS CHINA Xczhao@nari-relays.com

2. Protection for SC T/L Main Ⅰ –Pilot distance relay –Pilot zero sequence directional relay –Under-reach DPFC distance relay –Three zones phase distance relay –Three zones ground distance relay –Two delayed zones of zero sequence directional over- current relay Main Ⅱ –Phase-segregated current differential relay –Zero sequence differential current relay –Under-reach DPFC distance relay –Three zones phase distance relay –Three zones ground distance relay –Two delayed zones of zero sequence directional over- current relay

3. DPFC Distance Relay DPFC-Deviation of Power Frequency Component

4. Distance Relay Polarizing Voltage –Positive sequence voltage and –Memory voltage

5. Distance Relay Two Relays with Different Memory Decay time Operate simultaneously-Forward fault Operate one after another-Backward fault

6. Distance Relay Uplv= Protection Voltage of MOV.

7. Zero-Sequence Directional Relay Additional Source Impedance Introduced