Study of transmission line SCS: NPCC may send engineers as Chinese team not coming

ISLAMABAD: The National Power Control System (NPCC) is likely to despatch its two engineers to China to study Stability Control System (SCS) of north and south transmission line, as Chinese company M/s PMLTC has refused to send its engineers citing security concerns after the Dasu Project attack, well-informed sources told Business Recorder.

Sharing details, sources said, Stability Control System for HVDC system has been installed by M/s PMLTC as a main control system that operates in reaction to the disturbance in HVDC system and stabilizes the system by tripping generation and load in the network.

PM reaches out to Chinese engineers working on Dasu project

The SCS operates and is based on a strategy table which is designed after conducting detailed simulation studies. These simulations determine the safe power transfer limits from south to north transmission system employing necessary generation and load tripping scheme to ensure system stability during Bipole block conditions.

According to NPCC, it is imperative that these studies be conducted periodically to assess the stable south to north power transfer limit of the parallel HVDC/HVAC transmission corridor as new generators and grid stations are added in the system.

As per Amendment No. 1 of the Transmission Service Agreement (TSA) of Matiari-Lahore HVDC Line Project, M/s PMLTC is required to conduct the SCS study for limited scenarios after the CoD and train NTDC engineers to conduct simulations for the rest of the project’s lifespan.

Later, it was decided between NTDC and PMLTC that the PMLTC’s simulation expert will conduct SCS studies for summer of 2024 in Pakistan and stationed there until the study is completed.

However, on April 6, 2024 M/s PMLTC communicated that due to security concerns, specifically the recent event in the Dasu Project, no Chinese engineer will be dispatched to Pakistan and considering the criticality of Stability Control System (SCS) studies for the upcoming period, M/s PMLTC has proposed to send two engineers and the PSS/E Software, from Pakistan to China.

The revised proposal was given by M/s PMLTC to ensure that the required study can be conducted in a timely manner and the SCS Strategy can be designed accordingly for Summer and Winter 2024-25.

In this regard, NPCC has intimated that the power flow base cases of system conditions of summer, prepared by NTDC, have already been shared with M/s PMLTC, whereas the base cases for system conditions of winter 2025 are near completion and shall be shared with M/s PMLTC in the coming week.

NPCC is of the view that as per the timeline provided by M/s PMLTC, the system studies for summer and winter scenarios will be completed at the end of August 2024.

The timeline strictly depends upon the movement of at least two engineers as proposed by M/s PMLTC from NPCC/NTDC to China, as the advanced level analysis will be conducted in China along with capacity building of engineers enabling them to carry out such studies independently.

In addition, NPCC has intimated that the system studies to develop plan for maximum power transfer limit from south to north in the parallel HVDC/HVAC transmission system is presently underway by M/s CESI, Italy. The final report is expected to be completed by end July 2024.

Afterwards, deliberations, on the results and findings of the system studies with updated south to north power transfer limits to be established by M/s PMLTC for the coming year 2024-25 and also with plan proposed by M/s CESI for maximum power transfer limit from south to north in future, may be done in the month of September 2024 before intimation to the PM Office.

Copyright Business Recorder, 2024