Increasing the energy efficiency of modes of distribution networks with photovoltaic stations

Abstract

Purpose. Establishing the regularities of changes in influence of power quality indicators caused by the operating modes of photovoltaic (PV) station inverters on the operating modes of distribution networks’ equipment to improve their energy efficiency by reducing power losses. Methodology. To solve the scientific problems, the following methods are used such as: the method of harmonic analysis (Fourier integral); decomposition of the current spectrum by amplitude-frequency component using Mdaq-14 hardware and software platforms and LabVIEW software; the method of data correlation analysis to determine the higher harmonic current dependence on the load of an on-grid inverter; mathematical and physical modeling in the development of a way to improve the energy efficiency of on-grid inverters of PV stations. Findings. The conducted studies on electromagnetic compatibility indicators of grid photovoltaic station inverters in stationary and dynamic operation modes made it possible to establish the characteristic regularities of changes in the spectrum and amplitudes of higher harmonic components depending on the level of inverter loading. Hyperbolic dependences of the change in the sinusoidal signal distortion coefficients of the harmonic component on the level of inverter loading were experimentally established. A method has been developed for reducing the electromagnetic interference levels caused by photovoltaic station converters by implementing a circuit solution and algorithm for loading on-grid inverters in non-stationary modes in order to improve their electromagnetic compatibility and increase the energy efficiency of distribution networks with appropriate decentralized sources. Originality. The regularities are established of influence of the operating mode’s parameters of photovoltaic station inverters on the indicators of electromagnetic compatibility in their power supply system, including taking into account special circuit solutions, which allows increasing the energy efficiency of distribution network modes. Practical value. The method for reducing the electromagnetic interference levels generated by photovoltaic station inverters by implementing the proposed circuit solution and algorithm for loading the on-grid inverters in non-stationary modes is universal and can be applied to any photovoltaic station. This will help to reduce the power losses and electromagnetic damage to equipment from the action of higher harmonic components. Granting the established regularities of higher harmonics influence will allow one to take into account the impact of the relevant indicators on the additional insulation heating of power supply system elements and to assess the corresponding electromagnetic damage, to provide recommendations for consideration of the modes in calculating methods and PV equipment selection.