1 / 19

Example 1

Example 1.

baruch
Télécharger la présentation

Example 1

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Example 1 A 9375 kVA, 13,800 kV, 60 Hz, two pole, Y-connected synchronous generator is delivering rated current at rated voltage and unity PF. Find the armature resistance and synchronous reactance given that the filed excitation voltage is 11935.44 V and leads the terminal voltage by an angle 47.96°.

  2. Example 2 A cylindrical rotor machine is delivering active power of 0.8 p.u. and reactive power of 0.6 p.u. at a terminal voltage of 1 p.u. If the power angle is 20°, compute the excitation voltage and the machine’s synchronous reactance.

  3. Announcement • Quiz I : Next Tuesday (April 5, 2011) at 12:00 in H11 • Assignment I: will be posted today and due Next Tuesday (April 5, 2011) at 12:00 in H11

  4. Power Transformers

  5. Transformation ratio Primary (supply) Secondary (Load)

  6. Transformers at no load Ic E1 IF Qc E1 If Im f IF Ic Im The no load current If is needed to supply the no load losses and to magnetize the transformer core.

  7. Transformer losses • The transformer losses are divided into electrical losses (copper losses) and Magnetic losses (Iron losses). • Copper losses in both the primary and secondary windings. • Magnetic losses, these losses are divided into eddy current losses and hysteresis losses.

  8. Loaded Transformer Z2’ is the load impedance referred to the primary

  9. Equivalent circuit V1: Primary voltage (supply) I1 : Primary current. V2: Secondary voltage (load) I2: : Secondary current

  10. Exact Circuit

  11. Approximate Circuit (a) (b) The no load current ranges from 1% to 3% of the full load current. Therefore, the circuit can be simplified to circuit (b).

  12. Phasor Diagram

  13. Performance Measures • The percent regulation • The transformer efficiency

  14. Voltage Regulation

  15. Efficiency • The efficiency of the transformer is the ratio of output (secondary) power to the input (primary) power. Formally the efficiency is η: Where, P1 : The input power (Primary) = V1I1 cosf1 P2 : The output power (Secondary) = V2I2 cosf2 Where, PL is the power loss in the transformer = Pcopper + Piron

  16. Example A 100-kVA, 400/2000 V, single-phase transformer has the following parameters R1 = 0.01 R2 = 0.25 ohms X1 = 0.03 ohms X2 = 0.75 ohms The transformer supplies a load of 90 kVA at 2000 V and 0.8 PF lagging. • Calculate the primary voltage and current using the simplest equivalent circuit. • Find also the V.R. and efficiency for the transformer

  17. Solution

  18. Voltage Regulation

  19. Efficiency

More Related