CPGHC Plant Hub Choki, Balochistan

Project Overview

At CPGHC Plant Hub Choki, Balochistan, our team conducted comprehensive high-voltage diagnostic testing on a 75 MVA, 10.5/500 kV power transformer. The objective was to assess insulation health, verify winding characteristics, and confirm dielectric strength to ensure safe and reliable operation under NTDC protocols and IEC standards.

Testing Scope

The scope of work included the following tests:

• Insulation Resistance Test (HV, LV, and WV windings)
• Winding Resistance Measurement (Primary and Secondary)
• Transformer Turns Ratio (TTR) Test (HV Winding)
• Short Circuit Impedance Test
• Vector Group Verification
• Demagnetization of Core
• Voltage Withstand Test:
  • HV Winding at 68 kV
  • LV1 Winding at 28 kV
  • LV2 Winding at 28 kV
  • WV Winding at 28 kV

Key Testing Procedures

• Insulation and winding tests were performed using Omicron – Austria Testrano 600 and CPTD-1 for high accuracy and automated data acquisition.
• Insulation Resistance test was carried out using Kyoritsu – Japan KEW-3125.
• AC Withstand Testing of HV, LV, and WV windings was carried out with NXZR-400KVA test system, applying resonance frequency voltage levels for one minute as per IEC standards.
• Demagnetization was executed post-testing to eliminate residual magnetism and ensure accurate future diagnostics.

Project Documentation and Impact

All testing data was recorded and analyzed using Omicron PTM software, enabling detailed assessment and trend monitoring. The results confirmed the transformer’s insulation integrity, winding health, and operational reliability. This project has significantly contributed to strengthening the stability of the CPGHC Plant’s transmission system, ensuring safe integration into the national power grid station.