Transformer losses

What are the losses in transformers? An electrical transformer is a static device, in any electrical machine; ‘loss’ can be defined as the difference between input power and output power. Like any electrical device, a transformer does have load losses due to several factors. These losses appear in the form of heat and produce an increase in temperature and a drop in efficiency. Transformer losses are similar to losses in a DC machine, except that transformers do not have mechanical losses. How can we calculate the losses in transformer? Generally, power losses of the transformer determine by the Open-circuit test and Closed-circuit test. These tests help to determine the voltage regulation, circuit constant, and efficiency of the transformer. These tests are performed without the actual loading and because of this reason the very less power is required for the test. The open circuit and the short circuit test give a very accurate result as compared to the full load test. The open-circuit test is to determine the no-load current and losses of the transformer because of which their no-load parameters are determined. This test is performed on the primary winding of the transformer. The Closed-circuit test is determines the copper loss occur on the full load and equivalent to resistance, impedance, and leakage reactance. The copper loss is used for finding the efficiency of the transformer. The short circuit test is performed on the secondary or high voltage winding of the tra...

Transformer Price and Losses The Connection Losses and purchase price should be considered when deciding which transformer to purchase. The purpose of this technical article is to present a uniform approach that can be used to determine the dollar value of these losses over the life of the transformer. Load, no-load and auxiliary losses at 50 MVA for the 30/40/50 MVA transformer will be evaluated as follows: • No-Load Losses $/kW 2450 • Load Losses $/kW 1304 • Auxiliary Losses $/kW 756 The cost of losses for each transformer will be calculated by multiplying the appropriate dollars/kW values above by the guaranteed load losses at 55°C rating and 100% voltages. This cost will be added to the bid price for evaluation.” Let’s see an example // Using the loss evaluation factors given above, determine which manufacturer’s transformer has the lowest evaluated cost including losses. 161/34.5 kV, 30/40/50 MVA Transformer Manufacturer A’s Transformer Manufacturer B’s Transformer Bid price $424,500 $436,000 No -load losses 59 kW 53 kW Load losses at 50 MVA (at 55°C temperature rise) 224 kW 218 kW Auxiliary losses (at 50 MVA 55°C temperature rise) 2.0 kW 2.5 kW … and play with numbers // Manufacturer A’s Transformer Manufacturer B’s Transformer Bid Price = $424,500 = $436,000 Total cost of No-load Losses 59 kW (2450 $/kW) = $144,550 53 kW (2450 $/kW) = $129,850 Total cost of Load Losses 224 kW (1304 $/kW) = $292,096 218 kW (1304 $/kW) = $284,272 Total cost of Auxiliary Losses 2.0 kW ...

The electrical machine consists of multiple devices like an electrical transformer, electric motor (AC/DC), In an earlier article, I have explained the I will also explain the different types of losses occurs in different parts of the transformer. Even though we are talking about the transformer losses, let me tell you that the transformer is more power-efficient and has very low losses. Why is transformer energy efficient? Usually, the electrical machine has more losses as there are multiple moving parts like rotor. The transformer is one of the static device in electrical machine. Due to the static device (not having any moving parts), mechanical loss (friction loss, bearing loss) does not occur. Only winding or core loss occurs in the transformer. Due to this, very small losses occur in transformer as compare to the other devices in the electrical machine. This is also one of the reasons that the transformer is more power-efficient. Let’s study, what are the types of losses in transformer? Table of Contents • • • • • • • • 4 Types of Losses in Transformer Describing each of them in detail. How can we calculate the losses in transformer? Generally, power losses of the transformer determine by the Open-circuit test and Closed-circuit test. These tests help to determine the voltage regulation, circuit constant, and efficiency of the transformer. Under the construction and working, transformer power losses are divided into two forms. • Variable loss • Constant loss Transfor...

\[\begin\] Depending on what is known, efficiency may be calculated in several ways as shown by equations (1) and (2). Regardless of which form is used, only the real power should be used to calculate efficiency. Maximum Efficiency of a Transformer At full-load The maximum efficiency of a transformer at a given power factor occurs when the copper losses are equal to the core losses. Obviously, the absolute maximum efficiency occurs when the power factor of the load is unity.

All electronic gadgets today employ high frequency Switch Mode Power Supplies. As the number of such gadgets is increasing rapidly, the focus is on improving the efficiency of power conversion and better utilization of energy. It is always a challenge for the practicing power supply engineers to exactly apportion and evaluate the total losses in the power converters. While it is relatively easy to compute and measure the power losses in semiconductor devices, it is practically difficult to measure the power losses in magnetic components. The data sheets provided by the manufacturers, for core loss and thermal resistance, do act as a starting point in the design stage but, always the designers felt the need to know the exact power loss in the ferrite high frequency transformers and their thermal resistance values. The data sheets provide thermal resistance values only for the cores and it is necessary to quantify value for a fully wound transformers. Copper losses in high frequency transformers are very significant and too involved to compute. In this paper, we propose a simple and practical technique, which precisely depicts the actual power loss in a high frequency ferrite core transformer. With this technique various ferrite cores can be characterized for their hysteresis losses at varying flux densities and frequencies. We can also precisely compute the thermal resistance of the Ferrite transformers. Electronics has become an indispensable part of all facets of human li...

The U.S. electric transmission and distribution system is among the most efficient in the world. Yet, according to the A Utilities historically have been unable to financially justify comprehensive distribution transformer replacement programs based exclusively on efficiency improvement. The same applies regarding transmission and distribution lines where a complex number of design and installation parameters affect conductor, dielectric, reactive current, and sheath losses. Aggregate losses are greatest for distribution networks and in contrast with the trend of undergrounding distribution systems for reliability reasons, studies show underground cable losses are often higher than overhead conductor loses. Regulatory policies in many states complicate the utility efficiency investment picture by imposing energy efficiency resource standards that only allow end-use efficiency to count toward program targets. The result, while positive in some respects, is resources are focused on helping customers implement energy efficiency initiatives, while no incentives exist for transmission and distribution investments, which could have the same or greater impact of reducing electrical losses, and accordingly, energy use. Improving T&D Efficiency Despite the regulatory situation and the magnitude of the challenge of replacing legacy infrastructure with the highest electrical losses (distribution conductors and transformers), utilities are doing quite a bit to improve T&D efficiency, ...