Transformer and AC Line Reactor FEA Design Software Delivers Radical New R&D Productivity for Electrical Manufacturers

Oxford — The development of new generations of transformers and line reactors is radically simplified and accelerated by a powerful new automated software toolbox from the Vector Fields Software product line of Cobham Technical Services.

A new 3D Transformers Environment (TE3D) provides a graphical user interface for rapidly designing transformers and reactors using Cobham’s renowned Opera-3d finite element electromagnetic simulation package. TE3D makes it extremely simple for users to employ advanced and precise finite-element analysis simulation to evaluate design ideas. The software will prove popular with both new and experienced transformer engineers, as it demystifies the process of entering design data for industry standard transformer designs and interpreting results.

Users are presented with simple dialog boxes and drop-down menus to define a new transformer or reactor design. After entering this data - which typically takes just a few minutes - the software automatically creates a three-dimensional finite element model of a reactor or transformer, together with independent drive and load circuits within the circuit editor for subsequent simulation and analysis.

The software allows a very wide variety of common transformer types to be created, including three-phase, three- and five-leg core, and single-phase two- and three-leg core. The software accommodates both racetrack and solenoid type single and multiple layer windings, and most of the commonly used winding connections specified in the international IEC 60076-1 standard for power transformers. All aspects of transformer design - such as lamination configuration, core clamping structures, steel support plates and clamp bolts - can be modelled through the environment, including multiple air gaps and placement of the core inside a conductive tank. Users are also offered the option to modify the device and circuits following the initial build to enable precise matching of their designs, and the analysis options available within the environment can be used to analyse devices not constructed within it.

The simulation analysis phase is also automated. User options include performing open-circuit, short-circuit and inrush current tests on transformers, and mutual inductance tests on reactors. Once an analysis has been completed, the TE3D environment automatically sends the results to the Opera Manager to be solved. In the case of the inrush current test, for example, the calculated results include the Lorentz forces on the primary and secondary windings, eddy currents in any support structures, iron losses in the transformer core, and transformer efficiency. All results can be displayed graphically, presenting users with a clear and unambiguous portrayal of design changes.

The TE3D environment offers fine control of the Finite Element Analysis (FEA) mesh size and distribution within each device, which can be specified by the user before or after the model has been built, to help balance speed with accuracy. The standard Modeller mesh tolerances are converted automatically when any changes are made to length units.

TE3D will also model a diverse range of reactor types, including three-phase three leg, five leg and both horizontal and vertical air core, and single-phase two leg, three leg and air core. Power systems designers will appreciate the benefits of using TE3D from the outset. By modelling the transformer or reactor they can visualise the shape of stray flux and the areas with the highest local loss concentration. Design data can be changed in seconds, allowing ‘What-if?’ type scenarios to be investigated quickly, so that users can home-in on the optimal design solution to an application more efficiently.

To support design optimization, TE3D is also fully integrated with Opera-3d’s powerful Optimizer tool. This further accelerates design by selecting and managing a comprehensive family of goal-seeking algorithms automatically. This is ideal for designers looking to move performance characteristics such as efficiency to new levels, as even a small improvement can bring significant long-term economic and environmental benefits. The reduction of electrical losses involves a huge number of design trade-offs, which can take considerable time to evaluate fully. By supporting multiple design goals, even when they compete with one another, the Optimizer software minimises the number of simulation runs that are needed and provides an extremely efficient path to design optimization.

As Jeremy Howard-Knight of Cobham Technical Services points out, “This new tool offers a simple means of automating the design optimization process, and is particularly relevant at a time when transformer manufacturers are subject to huge demands for technological innovation from the marketplace. The toolbox will prove extremely useful to designers trying to visualise the transient behaviour of devices in detail. Aside from standard device characteristics it will enable rapid identification of regions of high field or excessive losses.”

TE3D follows other successful Opera-3d design environments for rotating machines (ME2D & ME3D) - which are in use worldwide by commercial companies, research centres and academic institutions alike.