IMPACT OF THE LOAD OF DISTRIBUTION NETWORK ON THE VOLTAGE INCREASE AT THE POINTOF CONNECTION OF PV INVERTER

• Date: 2022
• Author Affiliations: О. Gaevskii — NTUU «Igor Sikorsky Kyiv Polytechnic Institute»; A. Gaevskaya — NTUU «Igor Sikorsky Kyiv Polytechnic Institute»; M. Konovalov — Institute of Renewable Energy of NAS of Ukraine
• Keywords: keywords
• Main Authors: Gaevskii, О., Gaevskaya, A., Konovalov, M.
• Format: Article
• Language: Ukrainian
• Published: Institute of Renewable Energy National Academy of Sciences of Ukraine 2022
• Subjects: PV plant; inverter; distribution grid; point of common connection; over-voltages; islanding; dual-fed supplying
• Online Access: https://ve.org.ua/index.php/journal/article/view/339
• Journal Title: Vidnovluvana energetika

The reasons for PV plant over-voltages in the electrical distribution grid caused by the impact of energy consumption drop compared to PV generation are considered. The over-voltages beyond the maximum allowable values at the point of common connection (PCC) ​​is a very important factor, because it leads to automatic disconnection of PV inverters from the distribution grid and interruption of power supplying. To analyze this factor, an equivalent dual-feed scheme (substation and PV inverter) is used. This circuit with reverse power flow includes the following serial components: inverter - cable connection - step-up transformer - equivalent load distribution line - transformer substation - high-voltage network. The power load was localized in a certain node of the distribution line and therefore the equivalent circuit was reduced to three node substitution schemes: “PV plant – consumption node – substation”. In the simulation process, different ratios of network consumption levels and PV generation were analyzed, as well as different load points in the radial distribution line. As shown by the calculations of the power system with dual power supply and variable consumption, the influence of the consumption level under fixed generation significantly affects the increase or decrease of voltage in PCC. The impact of energy consumption drop under constant PV generation level and fixed settings the on-load tap-changer in substation leads to an increase in PCC voltage, and this increasing greater the more the more equivalent total impedance of the grid equipment (distribution line and step-up transformer) and of the connecting cable between the inverter and the step-up transformer.