--- title: "Quotation for a power transformer" subject: "Power Plant Design" chapter: 4 key: "semester_8/power_plant_design:power-transformer-quotation" source: https://www.bctengineer.com/q/semester_8/power_plant_design/power-transformer-quotation site: BCT Engineering --- # Quotation for a power transformer Power Plant Design · Chapter 4: Electric System Design of a Power Plant - Asked in: 2078 Kartik, 6 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/power-transformer-quotation - Whole chapter: https://www.bctengineer.com/md/semester_8/power_plant_design/chapter-4 ## Question Make a tentative an example type quotation of a "Power Transformer" for power evacuation purpose from switch yard of a general medium size hydropower project situated in hilly region. ## Short answer For a 2x12 MW plant, step-up to 132 kV: specify 16 MVA, 11/132 kV, YNd11, ONAN/ONAF, 10% impedance, with hill transport measures. Indicative total cost for two units with spares and erection is about NPR 10,79,15,000 including VAT. ## Answer A **tentative quotation** for a power transformer gives the main technical particulars, scope, price and terms so that the developer can budget and compare offers. Assumed project: a medium hydropower plant of 2 × 12 MW in a hilly region (altitude about 1500 m), evacuating at 132 kV. One step-up transformer per unit. Rating: $S = 12/0.85 = 14.1$ MVA, so a standard **16 MVA** unit is chosen. #### Main technical particulars offered | Item | Offered value | |---|---| | Type | 3-phase, oil-immersed, outdoor, two-winding step-up | | Rating | 16 MVA ONAN / 20 MVA ONAF | | Voltage ratio | 11 / 132 kV, off-circuit taps ±2 × 2.5% on HV | | Vector group | YNd11 (HV neutral solidly earthed) | | Impedance | 10% ± IEC tolerance | | Frequency | 50 Hz | | Insulation level (HV) | BIL 650 kVp, power frequency 275 kV (corrected for altitude) | | Losses (guaranteed) | No-load ≤ 12 kW; load loss ≤ 85 kW at 75 °C | | Temperature rise | Oil 50 K, winding 55 K (reduced for altitude above 1000 m, IEC 60076-2) | | Accessories | Buchholz relay, PRV, OTI/WTI, MOG, silica gel breather, HV/LV bushings, bushing CTs, radiators, fans, marshalling box | | Hill transport | Shipping weight limited to about 30 t; may ship oil-filled or $N_2$-filled, radiators separate | | Standard | IEC 60076 | #### Price schedule (indicative) | S.N. | Description | Qty | Unit price (NPR) | Amount (NPR) | |---|---|---|---|---| | 1 | 16/20 MVA, 11/132 kV power transformer as above, with first oil filling | 2 | 4,50,00,000 | 9,00,00,000 | | 2 | Mandatory spares (bushings, gaskets, Buchholz relay) | 1 lot | – | 15,00,000 | | 3 | Transport to site, supervision of erection and commissioning | 1 lot | – | 40,00,000 | | | **Subtotal** | | | **9,55,00,000** | | | VAT 13% | | | 1,24,15,000 | | | **Grand total** | | | **10,79,15,000** | #### Commercial terms - Delivery: 7–9 months after LC; FOR site; route survey by supplier. - Tests: routine tests (ratio, vector group, losses, impedance, insulation) witnessed by the owner; type test reports (temperature rise, impulse) submitted. - **Loss capitalisation:** bids are compared with the capitalised value of guaranteed losses; a penalty applies for excess losses. - Warranty: 24 months after commissioning; payment by LC; validity 120 days. 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. How is the 16 MVA transformer rating chosen for a 12 MW unit? A. 12/0.85 = 14.1 MVA, next standard size 16 MVA B. 12 x 0.85 = 10.2 MVA C. 12 MVA exactly D. Twice the MW Answer: A. S = P/pf = 14.1 MVA, so the next standard size is 16 MVA. (Key point: Rating selection) 2. Which vector group is offered for the GSU? A. Yy0 B. YNd11 C. Dyn11 D. Dd0 Answer: B. YNd11 with HV neutral solidly earthed. (Key point: Vector group) 3. What is the role of loss capitalisation in comparing bids? A. Capitalised value of guaranteed losses is added to compare bids, with penalty for excess losses B. It reduces warranty C. It sets the voltage D. It fixes delivery Answer: A. Lower losses have a capitalised value that affects the evaluated bid price. 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