TCPSB undertook an economic comparison of the available transformers, which considered the capital cost of the transformer and the annual cost of the fixed (iron) and load (copper) losses. Table 1 tabulates the results for the comparison of the 50-kVA distribution transformers.
The results of the comparison for 100-kVA units indicate that the amorphous core transformer financially is the preferred choice-the low iron loss more than compensates for the high capital cost. TCPSB uses an accounting life or depreciation period of at least 20 years for distribution transformers. Therefore, the utility realizes a long-term financial benefit when amorphous core 50-kVA and 100-kVA transformers are used for rural electricity network renovation. Figure 2 shows the Chinese-manufactured 100-kVA 10/0.4-kV pole-mounted amorphous core transformer for rural network applications.