Novel Objective Function Involving Integral Power Quality Criterion for Distributed Generation Planning

With the continuous development of social economy, the demand for electricity is increasing day by day. Power users have higher and higher requirements on the reliability of power supply. In case of grid failure, The impact on businesses and individuals is also growing. The reliability of medium voltage power supply system has been paid more and more attention. The reliability of medium voltage power supply has a direct impact on users’ satisfaction with electricity consumption. Power supply reliability has become an important index to reflect the continuous power supply capacity of enterprises. Power supply enterprises pay more attention to power supply reliability year by year. Improving the reliability of power supply for medium voltage users has become an important part of reliability management. The author summarizes the work experience, the main factors affecting the reliability of medium voltage supply are analyzed. The measures and methods to improve the reliability of medium voltage power supply are put forward.

A set of mathematical models for calculating the reliability indexes of structurally complex multifunctional combined installations in heat and power supply systems was developed. Reliability of energy supply is considered as required condition for the creation and operation of heat and power supply systems. The optimal value of the power supply system coefficient F is based on an economic assessment of the consumers’ loss caused by the under-supply of electric power and additional system expences for the creation and operation of an emergency capacity reserve. Rationing of RI of the industrial heat supply is based on the use of concept of technological margin of safety of technological processes. The definition of rationed RI values of heat supply of communal consumers is based on the air temperature level iside the heated premises. The complex allows solving a number of practical tasks for providing reliability of heat supply for consumers. A probabilistic model is developed for calculating the reliability indexes of combined multipurpose heat and power plants in heat-and-power supply systems. The complex of models and calculation programs can be used to solve a wide range of specific tasks of optimization of schemes and parameters of combined heat and power plants and systems, as well as determining the efficiency of various redundance methods to ensure specified reliability of power supply.

This research investigates the integration of renewable energy sources such as solar and wind into Nigeria’s power grid. The main objective is to develop a simulation model that examines how renewable energy systems affect power reliability and supply efficiency under different load and generation conditions using MATLAB. The simulation setup includes solar photovoltaic arrays and wind turbines connected to the grid through inverter systems and controlled using standard power system techniques. Changes in solar radiation and wind speed are introduced during the simulation to reflect real-life variations in renewable energy generation. The results show that, despite their variable nature, solar and wind systems can support the grid effectively when combined with proper control, forecasting, and storage technologies. The study demonstrates that integrating renewable energy into the grid can reduce power shortages, improve electricity access, support a more stable and reliable power supply as well as contribute to sustainable development goals by promoting the use of renewable energy in Nigeria.

Optimal economic-driven planning of multiple DG and capacitor in distribution network considering different compensation coefficients in feeder’s failure rate evaluation

Continuous operation in an electric and hydrogen hybrid energy storage system for renewable power generation and autonomous emergency power supply

The reason for the appearance of the first distributed generation in Russia was the high requirements to the reliability of power supply to power consumers of a special group of the first category of reliability. Diesel generating units were used to ensure uninterrupted operation. High costs for technological connection of consumers of the 1st and 2nd categories of reliability have strengthened the tendency to install a backup energy source in the enterprises' own power supply systems. However, setting reserves leads to a decrease in economic efficiency. There are additional costs for maintaining the reserve in a working condition. As a result, enterprises transfer the backup units to the mode of the main power source, and that of the backup function to the centralized power supply system. The creation of such industrial MiniGrid operating in a mode without power supply to the grid increases the cost of electricity for other consumers. Besides, with the departure of industrial enterprises from the centralized power supply, the share of communal and non-industrial consumers is growing. This requires an increase in the manoeuvrability of energy sources. The creation of balanced Energy Cells for energy supply to the population and small and medium-sized businesses that provide services to the population is not accompanied by the negative effects indicated above. In Russia, there are isolated examples of such systems, similarly operating in a mode without supplying power to the grid. Changes are needed to allow active consumers to supply excess capacity to the grid during peak hours in the UES of Russia, for which the grid companies need to be allowed to operate at least in a mode without supplying power to the grid, which will not lead to a decrease in grid companies' revenues from electricity transmission services. The introduction of these changes does not only lead not only to an increase in the reliability of power supply but also to an increase in the economic efficiency of the UES, which will reduce the price of electricity.

An evaluation method of distributed generation credible capacity based on island partition

18 - Electric power systems

Power supply reliability (rate) directly reflects the capability of a network in supplying power to its customers. Through reliability analysis, it is possible to locate major factors in links of power generation, transmission and distribution that affect the reliability of power supply and to put forward measures for improvement. This paper makes an analysis of the reliability of the urban power supply of the Shandong power network, China, in 1995. (5 pages)

With the increasing frequency of large-scale events, the demand for the reliability of power supply is more stringent. In order to ensure the reliability of the power supply system during the event, this paper proposes a method of reliability evaluation and weak link identification for stadium power supply system. Firstly, fault tree model was constructed with any load power supply failure as the top event, and the corresponding minimum cut set was quickly obtained by Binary decision diagram algorithm. Secondly, the two-state model of the system was established based on Monte Carlo simulation, and the operating states of the system and components were obtained by random sampling simulation. System reliability evaluation and component importance evaluation are conducted to assess system power supply capacity and quantify the contribution of each component to system failure. Finally, the proposed method is applied to a typical stadium power supply system to verify the effectiveness.

Hippopotamus algorithm for optimal sizing of hybrid renewable energy system

The rapid growth of consumers, industrial development and global economic expansion inspired a lot of improvement in reliable power supplies. The integration of distributed generations (DGs) in unbalanced radial distribution systems (RDS) is one of the solutions to handle all above issues. This paper proposes an optimal planning for unbalanced RDS integrated with DGs. The objective function is designed as a non-linear function, which is framed as the combination of active power losses, voltage deviation and load balancing index of RDS. The Crow Search Optimization Algorithm (CSOA) is used for identifying the optimal size, location, power factor for DG and distribution system phase in order to reduce the proposed objective function by satisfying all system constraints. The proposed model is tested on 33-bus unbalanced RDS. There is reduction of annual cost of energy loss (ACEL) due to proper integration of DG. The obtained results prove that the proposed CSOA can effectively solve the non-linear objective function and can help to obtain optimized results for unbalanced RDS.

The reliability of power supply for users is an actual reflection of power supply enterprises in sustained power supply for users. The current statistical methods of power supply reliability for users adopted currently are mainly based on medium-voltage distribution transformer statistics, which is hard to truly reflect the genuine reliability level for users. This paper has put forward reliability statistical evaluation methods, carried out statistical analysis and calculation to the power supply reliability of medium-voltage users and low-voltage users, and analyzed the impact of different statistical methods for the power supply reliability index. Finally, the feasibility of the calculating modes has been verified by choosing some areas of Shanghai as an example of application, and suggestions on improvement of power supply reliability statistical evaluation for low-voltage users implemented by power supply enterprise have been expounded.

When grid-connected micro grid operates in island mode, the energy output of micro sources and the capacity of energy storages cannot ensure the power supply for all micro grid loads, it is necessary to remove part of micro grid loads in order to maximally guarantee the power supply for the important loads and extend the power supply time of all loads as far as possible. In this paper, an optimal load shedding strategy of micro grid based on improving the reliability of load power supply is presented, according to the power prediction of micro sources and loads during the operation of the island, charging and discharging power and surplus energy of energy storages are predicted, and the switching time of loads at different level are determined by optimization. The application of this strategy improves the power supply reliability of all the loads in the micro grid while ensuring the continuous and reliable power supply of important loads. A micro grid simulation system based on the load shedding strategy is established, and the simulation results show the correctness and practicability of the strategy.

A low voltage, high current, modular 50 V, 700 A dc power supply has been developed to bias 35 number of 500 W, 505.8 MHz solid state RF amplifiers. This power supply incorporates 7 number of 50 V, 100 A ac-dc power modules, operating in parallel to share the load current. This power supply has two unique attributes namely modular hot swappability and active redundancy. Hot swappable feature incorporated in power modules enables isolation of faulty power modules and facilitates their online replacement without affecting the operation of RF amplifiers and remaining power modules. Active redundancy increases reliability of the power supply significantly. Both these features reduce the down time and increase the availability of the overall system significantly. This paper presents comparison of system reliability of this modular dc power supply with other modular dc power supplies of same output voltage and current rating and having different number of power modules. Suitable mathematical expressions for system reliability of these modular dc power supplies have been evaluated. This power supply also has a digital controller for monitoring the status of 35 number of RF amplifiers and 7 number of power modules as well as controls load current sharing among the power modules. This power supply achieves current THD ≤ 6.2%, input power factor ≥ 0.98, output voltage stability ≤ 0.4% and peak to peak output ripple ≤ 0.2% with overall system reliability and availability approaching near 100%.