Some Aspects of Magnetic Shielding of a Transformer Substation Using Alternative Shielding Techniques

SUMMARY The paper investigates efficiency of different shielding techniques. The study was performed on the basis of 3-D substation model design where the finite-element method for calculation of magnetic fields (the EMAS software) was used and measurements were performed. The study was designed to meet the following objectives: − to obtain a useful analytical tool for evaluation of magnetic fields in a transformer substation as well as induced currents and power losses in a case of passive or active loop shielding, − to develop general principles of magnetic field shielding in transformer substations based on a digital simulation of 3-D substation models, measurements and analytical solutions which could serve as effective guidelines for shielding design. The obtained shielding principles for various layouts of substations are used to demonstrate some practical problems of the power-frequency magnetic field shielding design. Research results present the shielding effectiveness as a function of shielding technique as well as shielding geometry, material selection, location, induced current and power losses. The results can be effectively implemented in the process of shielding design for substations where magnetic field reduction is required.