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Electrical Design
Published in Anthony J. Pansini, Electrical Distribution Engineering, 2020
Energy losses in a transformer are generally of two kinds:No-load loss (also known as iron or core loss) results from the magnetizing or exciting current flowing in the primary coil regardless of the load carried. Its value of about 0.5 percent at rated full load may vary substantially at voltages above or below rated values. Although small as a power loss, it goes on constantly, accumulating into significant annual energy losses (in kilo-watt-hours).Full-load losses (earlier known as copper losses) result from the load current passing through the resistance of both primary and secondary coils. This I^R loss varies with the square of the current carried and therefore depends on the shape of the load curve. Since the current flowing in a circuit is inversely proportional to the voltage, the copper loss is inversely proportional to the square of the voltage; hence, for the same-size transformer, the losses in the primary coil are substantially less as the voltage ratings increase.
Transformer Testing
Published in Leonard L. Grigsby, Electric Power Transformer Engineering, 2017
Shirish P. Mehta, William R. Henning
Transformer no-load loss, often called core loss or iron loss, is the power loss in a transformer excited at rated voltage and frequency but not supplying load. The no-load loss comprises three components: Core loss in the core materialDielectric loss in the insulation systemI2R loss due to excitation current in the energized winding
Core
Published in Fang Zhu, Baitun Yang, Power Transformer Design Practices, 2021
When the transformer is energized, the core steel and the circuit through which exciting current circulates produce loss called no-load loss. The watts consumed by the core are in the form of heat, which contributes to core and oil temperature rises. The no-load loss is always produced when the transformer is energized regardless whether it carries a load or not. No-load loss is usually guaranteed below a limit. The no-load loss consists of several components discussed in this section.
Optimal Design and Performance Analysis of Three-phase Distribution Transformer with Variable Loading
Published in Electric Power Components and Systems, 2022
Osamah Al-Dori, Betül Şakar, Atilla Dönük
The no-load loss in an efficient distribution transformer should be smaller than the load losses to improve all-day efficiency [7, 19]. Therefore, distribution transformers should not just be designed to operate at full load with maximum efficiency, but more importantly, at a load much lower than the full load [7]. The ratio of the transformer load power to the rated load power is denoted by as shown in Eq. (11). When the transformer is operating at its full load, = 1.