Abstract
A power amplifier is used to supply sinusoidal currents of different frequencies for measuring eddy-current losses of a 25 kVA single-phase transformer under short-circuit condition. Measured data show that eddy-current loss is a linear function of frequency with power of 2 and the eddy-current loss coefficient P EC-Rlinear is computed. New measurement techniques are applied to determine the derating of single-phase transformers with full-wave diode and thyristor rectifier loads. The derating of transformers has been defined such that for the (apparent, real) power transfer of a transformer the total losses are identical to the rated losses at rated temperature. A relation between apparent power, derating and K-factor is given taking into account iron-core and stray-power losses. Measured derating values are compared with computed results based on the eddy-current losses, iron-core losses, stray-power losses, and K-factors. The eddy-current loss coefficient P EC-Rnonlinear is computed from harmonics caused by diode/thyristor bridge loads.
| Original language | English |
|---|---|
| Pages (from-to) | 148-154 |
| Number of pages | 7 |
| Journal | IEEE Transactions on Power Delivery |
| Volume | 15 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 2000 |
| Externally published | Yes |
Funding
Manuscript received February 27, 1998; revised August 21, 1998. This work was supported by the Electric Power Research Institute, Palo Alto, CA, under Contract RP 2951-07. E. F. Fuchs and D. Yildirim are with the University of Colorado, Boulder, CO 80309. W. M. Grady is with the University of Texas, Austin, TX 78712. Publisher Item Identifier S 0885-8977(00)00664-6.
| Funders | Funder number |
|---|---|
| Electric Power Research Institute | RP 2951-07 |
Keywords
- Eddy-current loss
- K-factor
- Nonlinear load
- Transformer derating