Comparative analysis of calculations of induced voltage in low voltage installations caused by lightning current

Abstract:
This article refers to the problem of estimating the expected values of voltages induced in internal conductive installations due to the magnetic field accompanying the lightning current spreading through the lightning protection system. In everyday practice, it is either an omitted element of the design and the protection measures are selected by feel, or if the designer decides to make this type of estimation, he usually uses the formula that is the content of the IEC 62305-4 lightning protection standard. Considering its degree of simplification, it is difficult to unambiguously treat the obtained result as a basis for selecting protective measures or abandoning their installation. This is a common argument about why someone did not make such calculations. Therefore, the article’s authors compared this method with a method based on modelling and simulations in various variants of the current model and conductive loop geometry. Since this scientific approach uses various methods to describe the shape of the lightning current, e.g. the double exponential function, the Heidler function or the average value of steepness, the article briefly characterizes their advantages and disadvantages. Its central part describes the studies based on which the results were obtained, collated and compared. On this basis, the conclusions were presented.