Electric power savers - Operating measurements of practical installations

The paper describes the principle, function and impact of operation of two types of electrical devices for power energy saving: device used for common types of electrical appliances and device used for public lighting. Measurements of practical installations by real customers were made and the goal of this paper is to describe the principle of measured energy savers, to analyse the behaviour of the saver from view of active and reactive power flow, to calculate the efficiency of energy saver, to calculate savings when energy saver is used and to determine the voltage impact of operation of energy savers on distribution grid. Energy saver is for the DNO a black box with unknown function and the customers ask the DNO´s advice when the DNO should or shouldn´t recommend the energy saver´s installation. Following measurements and studies were made from this view.