Page 410 - Practical Power System and Protective Relays Commissioning

398 Index

Z protection, 276f
Zero sequence, 165, 165f zero-sequence network of, 278f
circuits of transformers, 275 277, 276f, Zinc oxide
277f surge arrester, 148
impedance, 76 77, 166, 170 for surge arresters, 103, 104f
networks of two-winding transformers, Zone
169f extension scheme, 223 224, 224f
principle, 228 of protection, 192
Zigzag earthing transformers, 277 relay CH calculation, 317, 318f