●Route & Zones
a CP zone is an electrical circuit — pipe, junctions, CP devices and CP linesAreas & zones
- SGPCSui Gas Processing Complex 3 zones
- Z-01 SGPC–Tipu Trunk
- Z-02 Tipu Gathering
- Z-03 Grub Wellheads
- MARIMari Field 3 zones
- Z-05 Mari–Daharki Trunk
- Z-06 Mari Export
- Z-07 Tank Farm 2200
- ZSZarghun South 1 zones
- Z-09 ZS Flowline Network
- SJWSujawal 2 zones
- Z-11 Sujawal Loop North
- Z-12 Sujawal Loop South
- KDKKandhkot 1 zones
- Z-14 Kandhkot Trunk
Z-01 SGPC–Tipu Trunk — potential along chainage
unprotected KP 10.0–14.0
TP-0101GB-01TP-0102TP-0104TR-01TP-0106TP-0108HV crossingTP-0110DC-2201 34% IRTR-04TP-0114TP-0116
KP 0.0KP 4.1KP 8.2KP 12.3KP 16.4
Test post Rectifier Groundbed Coating defect AC interference
●Zone Register
DC protection and AC interference are separate failure modes — both are reported| Zone | Name | Structure | km | Test posts | Rectifier | Coating | Worst inst-OFF | DC state | AC risk |
|---|---|---|---|---|---|---|---|---|---|
| Z-01 | SGPC–Tipu Trunk | PL-06" SGPC–TIPU | 16.4 | 16 | TR-01 / TR-04 | 3LPE | -698 mV | Unprotected | 18 A/m² low |
| Z-02 | Tipu Gathering | PL-04" TIPU Gathering | 6.2 | 8 | TR-07 | Coal tar | -848 mV | Unprotected | 41 A/m² elevated |
| Z-03 | Grub Wellheads | MPCL-SGPC-GRUB-WHS1/2 | — | 4 | TR-14 | FBE | -612 mV | Unprotected | 6 A/m² low |
| Z-05 | Mari–Daharki Trunk | PL-10" MARI–DAHARKI | 48.3 | 42 | TR-09 / TR-11 | 3LPE | -824 mV | Unprotected | 112 A/m² significant |
| Z-06 | Mari Export | PL-16" MARI Export | 31.7 | 28 | TR-27 | 3LPE | -979 mV | Protected | 22 A/m² low |
| Z-07 | Tank Farm 2200 | TK-2201 / TK-2202 | — | 6 | TR-29 | Bitumen | -806 mV | Unprotected | 9 A/m² low |
| Z-09 | ZS Flowline Network | ZS-Flowline Network | 14.0 | 18 | TR-16 | Tape wrap | -831 mV | Unprotected | 35 A/m² elevated |
| Z-11 | Sujawal Loop North | PL-08" SUJAWAL Loop | 9.8 | 12 | TR-18 | Coal tar | -781 mV | Unprotected | 14 A/m² low |
| Z-12 | Sujawal Loop South | PL-08" SUJAWAL Loop | 7.4 | 10 | TR-19 / TR-31 | Coal tar | -744 mV | Unprotected | 27 A/m² low |
| Z-14 | Kandhkot Trunk | PL-12" KANDHKOT Trunk | 22.6 | 24 | TR-22 / TR-24 | 3LPE | -885 mV | Protected | 76 A/m² elevated |
AC bands per EN ISO 18086 (supersedes EN 15280): < 30 A/m² low risk · 30–100 elevated · > 100 significant. A line can sit comfortably at −1050 mV on DC and still lose metal to AC interference near an HV crossing — Z-05 is exactly that case. Mitigation per NACE SP21424.