<p>In many countries, there are isolated energy districts with different types of consumers that are not connected to a centralized power supply system. Historically, the main sources of electricity in such energy districts were diesel power plants (DPP) based on diesel generator sets (DGS) of various types and capacities. Taking into account the global trend towards decarbonization of the electric power industry in isolated energy districts, the structure of generating capacities has been changing in recent years. This is due to the phased decommissioning of obsolete morally and physically DGS and the commissioning of facilities based on renewable energy sources (RES), including hybrid energy complexes. Photovoltaic power plants (PVPP) play an important role in this process. All power plants are connected to the electric grid via inverters. Most power plants use network inverters, which need a reference voltage from the mains to control their operating modes. Inverters have the ability to participate in frequency control in certain ranges. These capabilities are provided by algorithms embedded by manufacturers in their automatic control systems (ACS). The article presents the requirements for the participation of PVPP in frequency regulation, information on the protection settings of inverters, as well as the possibilities of their operation in emergency modes. Recommendations are given on the choice of algorithms of operation and settings of inverters of PVPP. In order to increase the effectiveness of the PVPP participation in frequency regulation in isolated energy districts, the need for the use of electricity storage systems as part of the PVPP is justified.</p>