The energy transition is accompanied by developing a digital decentralized low-carbon energy infrastructure with renewable-based generating plants as its main elements. In 2020, 15 photovoltaic power plants (PVPs) with an installed capacity of 364 MW were commissioned in Russia, which is 21.08% of the total installed PVP capacity of Russia. The findings of an analysis of Russia’s current regulatory and technical documents (RTD) concerning the frequency and active power flow control are presented. They indicate that all PVPs must participate in the general primary frequency control (GPFC). This requirement is due to large frequency deviations of transient processes resulting from an emergency active power shortage, which can shut down frequency-maintaining generating plants by relay or process protection devices and industrial consumers with significant damage to them. The requirements suggest full-scale tests of PVP to confirm their readiness for participation in GPFC. The program and results of checking the algorithm of change in the PVP active power, depending on frequency, are demonstrated with an example of one PVP. The full-scale tests confirmed the compliance of the certified PVP with this requirement. The plans for involving PVPs in the power flow control under various topology and operation conditions are considered.

Gas-fired reciprocating engine plants (GREPs) are widely used in power supply systems of industrial facilities, which allows for ensuring the operation of electrical loads in case of accidents in the power system. Operating experience attests to the fact that during islanded operations, GREPs are shut down by process protections or protective relays in the event of severe disturbances. This leads to complete load shedding, which is accompanied by losses and damage to industrial facilities. Severe disturbances include the following ones: large load surges on GREPs due to one of them being switched off, the group starting of electric motors, and load shedding (more than 50%) during short circuits or disconnection of process lines. Energy storage systems (ESS) have the ability to compensate for instantaneous power imbalances to prevent GREPs from switching off. The authors of this study have developed methods for intelligent control of the ESS that allow one to solve two problems: prevention of GREPs shutdowns under short-term frequency and voltage deviations as well as preservation of the calendar and cycling lifetime of battery storage (BS) of the GREP. The first method does not require performing the calculation of adjustments of control actions for active and reactive power on the ESS online but rather determines them by the value of frequency deviations and the voltage sag configuration, which greatly simplifies the system of automatic control of the ESS. The second method, which consists in dividing the steady-state power/frequency characteristic into sections with different droops that are chosen depending on the current load of the ESS and the battery state of charge, and offsetting it according to a specified pattern, allows for preventing the premature loss of power capacity of the ESS BS.

This paper analyzes the key defining features of modern electric power distribution networks of industrial enterprises. It is shown that the requirements set by industrial enterprises with respect to power quality parameters (PQPs) at the points of their connection to external distribution networks of utilities have been becoming increasingly strict in recent years. This is justified by the high sensitivity of critical electrical loads and distributed generation facilities to distortions of currents and voltages from a pure sine wave. Significant deviations of PQPs lead to significant damage at the consumer end due to the shutdown of electrical equipment by electrical and process protections as a result of overheating and increased wear and tear of individual elements of process lines. This necessitates the implementation of continuous monitoring systems at industrial enterprises, or sampling-based monitoring of PQPs at the boundary bus with an external distribution network. When arranging sampling-based monitoring of PQPs at certain time intervals, only those parameters that are critical for specific electrical loads should be calculated. We provide a rationale for the transition from the monitoring of a set of individual PQPs to a generalized PQP with the arrangement of simultaneous monitoring of several parameters. The joint use of the results of simulation and data from PQP monitoring systems for PQP analysis using the sampling-based procedure produces the desired effect. We present an example of a sequential decision-making process in the analysis of a generalized PQP based on Wald’s sequential analysis procedure. This technique makes it possible to adapt the PQP monitoring procedure to the features of a specific power distribution network of an industrial enterprise. We present the structural diagram of the device developed by the authors, which implements the sampling-based monitoring procedure of the generalized PQP. We put forward an approach for determining the average number of sampling data points required to make a decision about the power quality in the implementation of the sequential analysis procedure.

The creation of a decentralized low-carbon energy infrastructure is the main trend in the development of the electric power industry in many countries. Distributed generation facilities (DGs) based on gas reciprocating units (GRUs) are often built by industrial entities for the efficient utilization of secondary energy resources in order to minimize the environmental impact. Modern GRUs have some advantages, but they have design features that should be factored in when connecting them to the internal power systems of industrial entities. Incorrect consideration of possible operating conditions of GRU in their design can lead to their damage, excessive shutdowns, and disruptions in power supply to essential power consumers with significant damage and losses from undersupply of their products. Excessive shutdowns of GRUs are often caused by a non-selective choice of settings for relay protection devices or by load surges that exceed the allowable ones. With high availability factors, GRUs are disconnected five to eight times more often compared to large gas turbine and steam turbine power units. The large total power consumed by electric motors, as part of the load of an industrial entity, determines the nature and parameters of electromechanical transient processes during emergency disturbances. The presented analysis of issues facing real DG facilities relies on the acts of investigation into the causes of accidents. Calculations have shown that the action of the “Load Agreement Module” in the GRU excitation controller can provoke the occurrence of a voltage avalanche in the internal power system with a complete shutdown of the load. The paper presents recommendations on the choice of control algorithms and voltage settings for the GRU excitation controller. Technical solutions are given to prevent damage and excessive shutdowns of GRU in various operating conditions of the system, and to help ensure a reliable power supply to power consumers. The change in approaches to the design of DG facilities is substantiated in the light of their significant differences from other electric power facilities.

Modern gas-turbine units (GTUs) and gas-reciprocating units (GRUs) have found a wide use at power plants, including distributed generation facilities, running on gaseous fuel. The design features of these generating units have a considerable effect on the nature and parameters of transient processes due to emergency disturbances in the adjacent network. The study shows that single-shaft gas-turbine and gas-reciprocating units do not allow even short-term considerable frequency drops. These schemes and operating conditions arise due to emergency active power shortages when the connection between the power plant and the power system weakens due to repair conditions or islanded operation. The paper presents the results of transient process calculations for operating power plants (distributed generation facilities), which make it possible to identify the unfavorable properties of GTUs and GRUs. The results show that two-shaft (three-shaft) GTUs and GRUs can switch to out-of-step conditions even when short-circuits in the adjacent network are cleared with high-speed relay protection devices. The features of out-of-step conditions and the admissibility of their short-term duration for the spontaneous restoration of generators’ synchronization are considered. The findings suggest that considering the fundamental design features of generating units provides informed technical decisions on equipping power plants (distributed generation (DG) facilities) and the adjacent network with efficient emergency control systems.