---
title: "Quotation for HV breaker of a 48 MW plant"
subject: "Power Plant Design"
chapter: 4
key: "semester_8/power_plant_design:hv-breaker-quotation-48mw"
source: https://www.bctengineer.com/q/semester_8/power_plant_design/hv-breaker-quotation-48mw
site: BCT Engineering
---

# Quotation for HV breaker of a 48 MW plant

Power Plant Design · Chapter 4: Electric System Design of a Power Plant

- Asked in: 2079 Shrawan, 4 marks
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_8/power_plant_design/hv-breaker-quotation-48mw
- Whole chapter: https://www.bctengineer.com/md/semester_8/power_plant_design/chapter-4

## Question

Make a tentative an example type quotation of a high voltage side "circuit breaker" for power evacuation purpose at switch yard of a hydropower project that has installed capacity about 48 MW and line length to grid point substation is about 15 km.

## Short answer

Assuming 132 kV evacuation, full load current 247 A gives 1250 A rating. Quote four 145 kV SF6 outdoor live-tank breakers, 31.5 kA, spring-charged, with spares and supervision, total indicative cost NPR 2,61,03,000 including VAT.

## Answer

A tentative quotation lists the technical data, quantity and price of the breaker so that the developer can budget and compare offers. Assumptions: 48 MW plant with 2 × 24 MW units, evacuation at **132 kV** over 15 km by a **double-circuit line**, so the switchyard has 2 transformer bays and 2 line bays.

Rated current check: $I_{FL} = \dfrac{48/0.85}{\sqrt{3} \times 132} = 247$ A, so a standard 1250 A rating is ample.

**QUOTATION** (example, indicative prices)

To: XYZ Hydropower Ltd., Kathmandu. Ref: 132 kV switchyard circuit breakers. Validity: 90 days.

| S.N. | Description | Qty | Unit price (NPR) | Amount (NPR) |
|---|---|---|---|---|
| 1 | 145 kV, 3-pole, outdoor **SF6 live-tank circuit breaker**, 1250 A, 31.5 kA for 3 s, making 80 kA peak, BIL 650 kVp, spring-charged mechanism, O-0.3 s-CO-3 min-CO, single-pole operation for auto-reclose (line bays), 110 V DC control, SF6 density monitor, support structure | 4 | 55,00,000 | 2,20,00,000 |
| 2 | Spares: trip/close coils, gas filling kit, density monitor | 1 lot | – | 5,00,000 |
| 3 | Supervision of erection and testing at site | 1 lot | – | 6,00,000 |
| | **Subtotal** | | | **2,31,00,000** |
| | VAT 13% | | | 30,03,000 |
| | **Grand total** | | | **2,61,03,000** |

Terms:
- Standards: IEC 62271-100; type test reports enclosed.
- Delivery: CIF Birgunj/site within 6 months of LC; packing for hill transport.
- Warranty: 24 months from commissioning; payment by LC (10% advance, 80% on delivery, 10% after commissioning).

Prices are only indicative for budgeting; actual prices come from competitive bids.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Which is the full-load current check for 48 MW at 0.85 pf, 132 kV?
   A. About 247 A
   B. About 2470 A
   C. About 24 A
   D. About 500 A
   Answer: A. I = (48/0.85)/(sqrt3 x 132) = 247 A, so a 1250 A breaker is ample. (Key point: Full-load current)

2. How is the grand total obtained?
   A. Subtotal plus 13% VAT
   B. Subtotal minus VAT
   C. Unit price times 13
   D. Subtotal only
   Answer: A. Subtotal 2,31,00,000 plus 13% VAT 30,03,000 gives 2,61,03,000. (Key point: Quotation totals)

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