Lightning Protection Improvement and Economic Evaluation of Thailand’s 24 kV Distribution Line Based on Difference in Grounding Distance of Overhead Ground Wire

Table 8

Economic feasibility.

Grounding distance (m)	Total investment cost (USD) (h)	O&M cost (USD); 3% of column h (i)	DPP (year)	NPV (USD)	IRR (%)	PI	Conclusion
40	755,666.70	22,670	15.12	143,321.87	12	1.15	Accepted
80	377,833.35	11,335	>25	−252,164.29	2	0.48	No
120	251,888.90	7,556.67	>25	−218,965.25	−1	0.32	No
160	188,916.67	5,667.50	>25	−168,167.37	−1	0.30	No
200	151,133.34	4,534	>25	−129,262.51	−1	0.33	No