ISLAMABAD: The report prepared by a three-member committee, headed by Muhammad Mustafa, General Manager (Technical), NTDC, about the power breakdown that on October 13, 2022 gripped the southern part of the country and some parts of Punjab for the whole day, discloses that 25-year-old worn out conductor was used as a temporary arrangement for transmission of electricity from K2 and K3 nuclear power plants.
It further highlights that both breakdowns occurred at Tower No26A installed around three years ago, which was devised as an interim arrangement for power transmission from K2 and K3 nuclear power plants. “The failure of the transmission line (TL) hardware and accessories within three years of commissioning is a question mark on the quality of material and workmanship.”
It also mentions that the connectors used at locations 26, 26A &17 were not standard transmission line hardware items but were deployed as an improvised arrangement, meant for interim interconnection arrangement. So much so that despite the criticality of the interim arrangement, O&M (operation and maintenance) was not carried out as per SOP by the relevant Asset Management Formation.
Though the report doesn’t mention that nuclear power plants of K2 and K3 are responsible for the breakdown, the spokesman of the Pakistan Atomic Energy Commission (PAEC), in response to media reports appeared on various channels, rejected the impression that nuclear plants were responsible for the electricity collapse. In fact, it is the NTDC system that tripped and caused the power breakdown.
According to the inquiry report, at 09:14 hrs, no loss of generation and load was observed after tripping of 500 kV NKI-K2/K3 Circuit. At 09:16 hrs, after tripping of 500 kV Jamshoro-K2/K3 Circuit-] & II, the system responded through under frequency, cross trip & rate of change of frequency protection schemes.
The report mentions that the partial blackout was caused due to mechanical failure of Line Hardware of 500 kV NKI-K2/K3 and 500 kV Jamshoro-K2/K3 Circuit-I but that could have been contained if PSS at Lucky and Thar Energy Limited had been commissioned to sustain the system disturbance like Port Qasim and Engro Thar Power Limited. The 500 kV link between Gatti and Barotha could have withstood but its tripping aggravated the already compromised system. The operation of Existing System Protection schemes such as Under Frequency Loadshedding, Cross Trips, Rate of Change of Frequency & Out of Step responded timely and played a major role to save the system from total collapse.
The implementation status of the recommendations of previous inquiry reports was collected from relevant stakeholders and reviewed by the inquiry committee. It was revealed that the majority of those were found either implemented or under the implementation stage.
Based on the visual inspection and documentary evidence, the inquiry committee is of the opinion that if deemed necessary, disciplinary action under the relevant rules may be initiated against the technical teams from Project Delivery South, involved in the execution of interim arrangement and Asset Management South for lack of O&M activities as per SOP keeping in view the criticality of said arrangement. “The top decision-makers in Power Division have kick-started the proceedings against those responsible for the power breakdown,” a senior official said.
The inquiry committee also came up with 11 recommendations to avert such breakdowns in future saying that during the planning and design phases, the condition of aged Transmission Lines shall be assessed while interconnecting with new power plants. During the execution stage, the quality of material and workmanship shall be ensured as per international standards. O&M activities of Transmission Lines including thermography needs to be carried out per SOP with available resources.
It also recommended that ongoing projects of permanent networks for evacuation of power in general and in particular from K2 and K3 should be completed instead of relying on interim arrangements. “Implementation of SCADA-III shall be ensured as per timelines to enhance the live visibility of system parameters to the system operator. Phasor Measurement Units are required to be installed to timely indicate the oscillations in the system.” “Stability Control System shall be activated at the earliest to enhance the system stability.”
For more effective maintenance of transmission lines, a yardstick for the creation of new Transmission Line Divisions/Subdivisions is developed so that with the addition of new transmission lines, the requisite posts be got sanctioned accordingly.
Transmission Line maintenance staff shall be equipped with proper PPEs, T&P, spare materials, and hardware and vehicles to ensure the healthiness of NTDC’s transmission lines as per NTDC maintenance SOPs. It also asked that condition assessment of the section of old 500 kV transmission lines near coastal/polluted areas should be carried out on a war footing basis and remedial measures may be taken accordingly.