ISLAMABAD: National Power Control Centre (NPCC), the System Operator (SO), has proposed system impact assessment study and a facility assessment study, covering system stability and network reinforcement for establishment of solar PV projects at two RLNG-fired projects in Punjab, well informed sources told Business Recorder.
A report prepared by NPCC titled “operational studies for solar PV projects planned to be developed at Jhang/ Trimmu and Layyah/ Haveli Bahadur Shah” provides an overview of the operational impact of interconnecting solar parks near Jhang/ Trimmu and Layyah/ Haveli Bahadur Shah.
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According to NPCC a load-flow analysis has been conducted for each location to determine the maximum power evacuation from the solar park under summer peak load conditions, a summary of 500 MW solar park at 220-kV near Jhang Trimmu is as follows: (i) the network capacity for power evacuation from Trimmu Solar and Trimmu CCPP is 1100-MW under normal network conditions and 900-MW under N-I contingency conditions; (ii) daily start-up and shutdown of Trimmu CCPP during the solar hours is not possible as the number of starts for the steam turbine is restricted to 56 per year; (iii) since the minimum operating point for Trimmu CCPP in combined cycle mode is 560-MW, Trimmu Solar would be restricted to 340-MW when Trimmu CCPP is operating; (iv) to increase the capacity of Trimmu solar without risking curtailment, the solar park should also be interconnected to the 132KV networks of FESCO and/ or MEPCO. Further analysis of 132kV interconnections may be taken up with the transmission planning departments of the relevant Discos. On 1000-MW solar park at 500kV near Layyah/ Haveli Bahadur Shah, NPCC has submitted following observations: (i) while there is sufficient capacity on the 500kV transmission lines, the 200/ 220kV step-down transformers at 500kV Multan and 500kV Muzaffargarh are overloaded under N-I contingency conditions resulting in temporary curtailment; (ii) this problem can be mitigated by either reinforcing the transformation capacity at Multan & Muzaffargarh, or by extending 500KV Layyah to 220kV or 132kV voltage levels.
Copyright Business Recorder, 2023