Effect of Numerous PV Inverters on Power Quality Connected to the Same LV Network in a Suburban Area

Abstract

Abstract. The number of the domestic power plants is increasing rapidly. Most of these are photovoltaic (PV) systems. It is worth examining the effects of the PV units on the network, because the spreading of these units is expected. This paper presents a solution how the effect of numerous photovoltaic inverters on the power quality can be simulated and examined if these are connected to the same low voltage (LV) network. The harmonic effect of domestic PV systems is discussed with the application of the so called Double Domain Simulation method. However the distribution network is modelled in the frequency domain, the PV systems are simulated in the time domain. The calculations are performed by different polluted upstream network configuration. Our goal was to build an adequate simulation environment and to examine the effect of numerous PV systems on the power quality of the LV network. Key wordsPower Quality, Harmonics, PV Systems, Computer Simulation, Double Domain Simulation Brief introductionNowadays the renewable energy supply is increasing rapidly. The electrical energy can be generated dispersedly by domestic power plants, which are becoming more and more widespread. According to the Hungarian standards a power plant is called domestic power plant if it is connected to the low voltage public grid and its power not exceeds 50 kVA. These can be connected to the single-phase or the three phase network. Electrical power -that produced by domestic power plant -can be supplied into the public grid or can be used to cover the power demand of a household. In Hungary the Electric Energy Law prescribes that the generated power should be received and transmitted by the distribution system operator (DSO). [1] [5] The distribution network was built traditionally for oneway distribution, but the spreading of the domestic power plants causes bidirectional electrical energy flow in the distribution network. Moreover the domestic power plants inject harmonic currents into the grid because these systems are connected to the grid through a power electronic device. Therefore these effects raise new problems to the DSO. The domestic power plant can generate electrical power from wind-solar-or other renewable energy. This research is focusing only on the PV devices. First a simulation environment is described, and then the simulation results are detailed. We assumed that ten PV inverters are connected to the same LV network. We would like to examine the effect of this on the power quality of the LV network. Our research would like to answer the issue of the DSO, what would happen if numerous PV units are installed. Applied ModelsFor the double domain simulation, the distribution network is modelled in the frequency domain, while the PV systems are simulated in the time domain. A. The model of the distribution systemThe system is based on a real LV transformer zone with overhead wire system from the suburb of Budapest, capital of Hungary. The model has been performed after the layouts of the streets are supplied by the tran...

Designing of Hybrid Integrated Constrained PSO Algorithm for Two Converters in Solar PV System

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