ISLAMABAD: The National Electric Power Regulatory Authority (NEPRA) has expressed reservations against National Transmission and Despatch Company (NTDC) for not implementing its recommendations on partial system collapse of October last year.
The Regulator had constituted its own inquiry committee to find out facts of partial system collapse which also made recommendations and directed NPCC/NTDC and K-Electric to comply with its recommendations but the concerned Organizations did not pay heed to implement those recommendations.
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According to a letter written by Additional Director General, Iftikhar Ali Khan, the Inquiry Committee suggested following recommendations/remedial measures to avoid events involving subject incidents in future: (i) existing interim arrangement may immediately be reinforced with standard hardware;(ii) aging factor of conductor, quality of material, proper workmanship during the execution of interim arrangement must be ensured;(iii) periodic maintenance/monitoring activities, especially in respect to the interim arrangement designed forK2/K3 Circuits, must be ensured as per SOP;(iv) pending work of dedicated transmission lines for evacuation of power from K2 and K3 plants must be completed on top priority;(v) VAR compensations study shall be carried out and required measures in light of study shall be taken to avoid power swing in future;(vi) fully functional SCADA facility for complete system related to NTDC, GENCOS, IPPs and DISCOs is essentially required for system operator in order to ensure the online monitoring of system parameters in all respects for sake of system security, stability and analysis of events through GPS synched time event recorder; (vii) to ensure the healthiness of Power System Stabilizers (PSS) at power plants to damp intra-area oscillations;(viii) to ensure the installation of modern technologies device such as Wide Area Management (WAM) including Phasor Management Units (PMU) to detect oscillations instability which can be mitigated by Remedial Action Scheme (RAS); (ix) availability of required professionals and staff as per approved yard stick, along with required T&P including Thermo vision camera, especially in southern region must be arranged on urgent basis in order to ensure timely maintenance of existing network for system stability, reliability and security;(x) it must be ensured that all transmission line approved projects are completed as scheduled.
The work on delayed projects shall be accelerated on priority basis in order to evacuate cheaper power generation stably; (xi) NTDC Telecom department deficiencies must be addressed to ensure proper communication of inter-grid signals and avoid transmission of false signals; and (xii) execution work of dedicated transmission lines shall be completed before the energisation of transformation equipment (or) COD of power plants in order to avoid the LDs resultantly reducing the basket price for end consumer
According to NEPRA during the meeting with Thar Energy Power (TEL) Plant team it is learnt that PSS is active. NPCC has confirmed that PSS is in-active at TEL, and necessary verification in this regard is essential.
The power sector regulator argues that implementation of coordinated over-frequency/over-speed trip schemes on newly synchronized generating units (i.e. Lucky Energy, Shanghai Electric, Thal Nova and TEL) after system study shall be expedited in order to ensure the system reliability.
The Nepra’s Inquiry Committee recommended that automatic tripping to be implemented through SCS on Lucky Energy Ltd, Shanghai Electric, ThalNova and TEL in case of outage on mono-pole bi-pole HVDC system at Matiari Converter Station; and in addition Protocols/SOPs to be developed in order to streamline the operational co-ordination between KE and NPCC.
The Regulator further recommended that quantum of load to be shed through under-frequency and ROCOF schemes in South region needs to be increased for survival of the region whenever the region experiences under-frequency situation.
The NEPRA team noted that the practice of switching off transmission lines to control the over voltage on system is neither prudent nor recommended. Therefore, the Committee recommended a study be undertaken to install additional Shunt Reactors at appropriate locations, ie, may be on Grid Station Busbar.
The NEPRA has directed NTDC/NPCC to implement its recommendations forthwith in letter and spirit and the compliance report in this regard is required to be submitted to it within thirty days’ of receipt of the letter.
Copyright Business Recorder, 2023