Terai Distribution Network Expansion

A distribution program spread across eight districts needs a different procurement logic from a single substation. The challenge is to turn hundreds of individually small installations into one maintainable network.

A program measured in hundreds

The published construction scope divides the low- and medium-voltage work into three geographic lots. In total, the lots call for 500 distribution transformers together with roughly 950 circuit-kilometres of 11 kV line and 1,000 circuit-kilometres of 400 V line.

1. Saptari and Siraha: 150 transformers, 250 circuit-km of 11 kV line and 320 circuit-km of 400 V line.
2. Dhanusa, Mahottari and Sarlahi: 175 transformers, 360 circuit-km of 11 kV line and 350 circuit-km of 400 V line.
3. Rautahat, Bara and Parsa: 175 transformers, 340 circuit-km of 11 kV line and 330 circuit-km of 400 V line.

One transformer specification will not fit every feeder

Transformer ratings should follow the feeder forecast, voltage-drop study and local load pattern rather than an equal division of total capacity. A market centre, an irrigation load and a rural residential spur can share the same voltage class while imposing very different peak loading, phase balance and future-growth requirements.

Standardise the interfaces, not the engineering assumptions

• Use a controlled range of kVA ratings and one approved accessory schedule.
• Keep vector group, tapping range, terminal arrangement and protection philosophy consistent across each network package.
• Record no-load and load-loss data by serial number so acceptance and lifetime loss evaluation remain traceable.
• Package poles, surge arresters, cut-outs, LV distribution hardware and earthing details as repeatable field assemblies.

For delivery planning, the useful unit is not “one transformer”; it is a complete site kit assigned to a location, installation drawing and commissioning record. That approach reduces missing components in the field and makes progress measurable district by district.