scholarly journals An Efficient Testing Scheme for Power-Balanceability of Power System Including Controllable and Fluctuating Power Devices

Designs ◽  
2020 ◽  
Vol 4 (4) ◽  
pp. 48
Author(s):  
Saher Javaid ◽  
Mineo Kaneko ◽  
Yasuo Tan

Renewable power sources are environmentally friendly power generation systems, such as wind turbines or photovoltaics; however, the output power fluctuations due to the intermittence and variability of these power systems can greatly affect the quality and stability of the power system network. Furthermore, the power fluctuations that are triggered by power load devices also have similar results on the power system. Therefore, it is essential to introduce power level control for controllable power devices and connection in order to lessen the effects of dynamic power fluctuations that are caused by fluctuating power source devices and load devices. The issue of power balancing as a part of power level control presented in this paper assigns power levels to controllable power devices and connections between power source devices and load devices to absorb dynamic power fluctuations. In this paper, we focus on power conservation law instead of detailed voltage or current-based network characterization and present a new power balanceability test for a power flow system that comprises of both fluctuating and controllable power devices. Our proposed power balanceability test can assure the existence of a power flow assignment of power devices and connections for any value of power generation and/or the consumption of fluctuating power devices. Our proposed power balanceability test method can be expressed as a linear programming problem, and it can be resolved in polynomial time complexity.

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1627 ◽  
Author(s):  
Saher Javaid ◽  
Mineo Kaneko ◽  
Yasuo Tan

This paper discusses a structural property for a power system to continue a safe operation under power fluctuation caused by fluctuating power sources and loads. Concerns over global climate change and gas emissions have motivated development and integration of renewable energy sources such as wind and solar to fulfill power demand. The energy generated from these sources exhibits fluctuations and uncertainty which is uncontrollable. In addition, the power fluctuations caused by power loads also have the same consequences on power system. To mitigate the effects of uncontrollable power fluctuations, a power flow control is presented which allocates power levels for controllable power sources and loads and connections between power devices. One basic function for the power flow control is to balance the generated power with the power demand. However, due to the structural limitations, i.e., the power level limitations of controllable sources and loads and the limitation of power flow channels, the power balance may not be achieved. This paper proposes two theorems about the structural conditions for a power system to have a feasible solution which achieves the power balance between power sources and power loads. The discussions in this paper will provide a solid theoretical background for designing a power flow system which proves robustness against fluctuations caused by fluctuating power devices.


2021 ◽  
Vol 14 (1) ◽  
pp. 52-60
Author(s):  
V. A. Shakirov ◽  
V. G. Kurbatsky ◽  
N. V. Tomin ◽  
G. B. Guliev

The problem of the influence of power fluctuations of wind farms due to the variability of the wind speed on the electric power system is considered. With high wind energy penetration, an increase in the operating reserve in electric power systems is required to cover possible sudden power fluctuations. One of the ways to reduce the stochastic nature of the wind farms power generation is their geographically distributed location. A method is proposed for the selection of capacity and distributed placement of wind farms, taking into account the factor of the variability of the total generated power. In each of the prospective areas for wind farm placement, the simulation of electricity generation by a single wind turbine with hour-by-hour breakdown is carried out using the developed WindMCA software based on long-term ground-based weather stations data. Optimization of wind farms capacity and their distributed placement in areas is carried out using a genetic algorithm in the MATLAB environment. The target function is the coefficient of variation of the power generated by all wind farms in the areas under consideration, depending on the number of wind turbines therein. Power duration curves are used in the final comparison of wind farms siting options. The application of the method is carried out on the example of the wind farms placement in the Zabaykalsky Krai. A solution has been obtained that provides a minimum coefficient of variation of the wind farms generated power and a relatively high capacity utilization factor. With a distributed location of wind farms, the duration of the period with the maximum output is reduced, however, the duration of low power generation is significantly increased. With an increase in the number of wind farms connected to various nodes of the electric power system, a certain guaranteed level of power generation can be obtained, which, ultimately, will reduce the required amount of the reserve of generating capacities.


Author(s):  
Sana Khalid Abdul Hassan ◽  
Firas Mohammed Tuaimah

<p>Now-a-days the Flexible AC Transmission Systems (FACTS) technology is very effective in improving the power flow along the transmission lines and makes the power system more flexible and controllable. This paper deals with overload transmission system problems such as (increase the total losses, raise the rate of power generation, and the transmission line may be exposed to shut down when the load demand increase from the thermal limit of transmission line) and how can solve this problem by choosing the optimal location and parameters of Unified Power Flow Controllers (UPFCs). which was specified based on Genetic Algorithm (GA) optimization method, it was utilized to search for optimum FACT parameters setting and location based to achieve the following objectives: improve voltages profile, reduce power losses, treatment of power flow in overloaded transmission lines and reduce power generation. MATLAB was used for running both the GA program and Newton Raphson method for solving the load flow of the system The proposed approach is examined and tested on IEEE 30-bus system. The practical part has been solved through Power System Simulation for Engineers (PSS\E) software Version 32.0 (The Power System Simulator for Engineering (PSS/E) software created from Siemens PTI to provide a system of computer programs and structured data files designed to handle the basic functions of power system performance simulation work, such as power flow, optimal power flow, fault analysis, dynamic simulations...etc.). The Comparative results between the experimental and practical parts obtained from adopting the UPFC where too close and almost the same under different loading conditions, which are (5%, 10%, 15% and 20%) of the total load. can show that the total active power losses for the system reduce at 69.594% at normal case after add the UPFC device to the system. also the reactive power losses reduce by 75.483% at the same case as well as for the rest of the cases. in the other hand can noted the system will not have any overload lines after add UPFC to the system with suitable parameters.</p>


Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5785
Author(s):  
Sunoh Kim ◽  
Jin Hur

As the importance of renewable generating resources has grown around the world, South Korea is also trying to expand the proportion of renewable generating resources in the power generation sector. Among the various renewable energy sources, wind generating resources are emerging as a key alternative to conventional power generations in the electricity sector in Korea accounted for 17.7 GW of total capacity by 2030. As wind generating resources are gradually replacing traditional generating resources, the system security and reliability are negatively affected because of the variability, due to intermittent outputs. Therefore, existing power grids will need to be correctly re-measured to cover the large scale of renewable energy, including wind generation. To expand the grid, we must understand the characteristics of renewable energy and the impact of its adoption in the grid. In this paper, we analyze various characteristics of wind power generation, and then we propose a probabilistic power output modeling method to consider the uncertainty of wind power generation. For the probabilistic approach, Monte-Carlo simulation is used in the modeling method. The modeled wind power outputs can help planning for the reinforcement and expansion of power systems to expand the capacity for large-scale renewable energy in the future. To verify the proposed method, some case studies were performed using empirical data, and probabilistic power flow calculation was performed by integrating large-scale wind power generation to the Jeju Island power system. The probabilistic method proposed in this paper can efficiently plan power system expansion and play a key strategy of evaluating the security of the power system through the results of stochastic power flow calculation.


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