This paper presents a new method for achieving transient stability control to solve the optimal load distribution problem by considering the transient stability constraint (TSCOPF). The novelty of this research includes the use of the equivalent single machine (SIME) me More
This paper presents a new method for achieving transient stability control to solve the optimal load distribution problem by considering the transient stability constraint (TSCOPF). The novelty of this research includes the use of the equivalent single machine (SIME) method to implement and improve the two important and main parts of the TSCOPF problem. Part 1: SIME is used to analyze the transient stability of the power system. Part 2: SIME equates a multi-machine system to a single machine connected to an infinite bus (OMIB). The instability angle obtained from the equivalent OMIB angular path is used to construct the transient stability constraint. In this method, the transient stability constraint is included by SIME in each iteration of the TSCOPF method to accurately determine the dynamic behavior of the power system. Differential equations representing the dynamic behavior of system machines are decomposed into algebraic equations according to the trapezoidal rule. The proposed load distribution model is tested and analyzed on the IEEE 9-bus system (WECC).
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Considering environmental issues and the use of green energy resources has led to the increase of Distributed Generations (DGs) connection to electric power grid. Beside many benefits, these generations impose challenges to the electric system. Two main challenges inves More
Considering environmental issues and the use of green energy resources has led to the increase of Distributed Generations (DGs) connection to electric power grid. Beside many benefits, these generations impose challenges to the electric system. Two main challenges investigated in this article are related to the impact of DGs on the Protective Devices (PDs) coordination and the transient stability of these resources at the fault time incidence. As for Synchronous-based Distributed Generations (SBDGs), the challenge of protection coordination arises from the injection current rate of these generations under fault circumstances and the transient stability challenge is due to the low inertia constant. In proposed method, by shifting the relay characteristic curve downwards and repositioning the curve below the Critical Clearing Time (CCT), not only the coordination of the PDs will be improved, but also the instability of SBDGs will be eliminated. This paper presents a modified time-current-voltage characteristic curve for the overcurrent relays. The simulation results done by ETAP software confirm the effective performance of the proposed method.
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With the rapid progress of semiconductors in the level of voltage and power of the power system as well as the progress of control systems, compensators with high flexibility and performance range have been designed and built to increase the flexibility of energy transm More
With the rapid progress of semiconductors in the level of voltage and power of the power system as well as the progress of control systems, compensators with high flexibility and performance range have been designed and built to increase the flexibility of energy transmission systems. to be These compensators installed in power systems are called flexible ac transmission systems (FACTS). One of the most important advantages of FACTS devices in the transmission system is to increase the transient stability margin of the power system by controlling the active and reactive power of the line during the occurrence of a fault in the system. In this article, the effect of one FACTS device with parallel connection, i.e. static compensator, on transient stability is investigated. The studied system is a two-machine power system including a hydropower plant and a local power plant. The simulation results show the effect of the compensator on the damping of electric power angle fluctuations. Also, the simulation results show the lack of influence of the compensator on the transmission active power in the transmission line. The simulation results have been obtained using Simulink MATLAB software.
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In general, the basis of operation of most fault current limiters is to reduce the short-circuit current by adding a large impedance to the system at the time of the fault. However, fault current limiters differ in the type of impedance and how the impedance adds and re More
In general, the basis of operation of most fault current limiters is to reduce the short-circuit current by adding a large impedance to the system at the time of the fault. However, fault current limiters differ in the type of impedance and how the impedance adds and removes the system. In this paper, taking into account three different locations for installing fault current limiter in a sample power network, as well as changing the type (inductance or resistance) and its impedance value in an extensive range, the effects of these parameters on the stability of the power system have been investigated and analyzed. The criterion used for the first time in this article by the authors to examine and evaluate the transient stability of the power system is the method of the difference between the accelerating and decelerating area. The basis of this method is based on the equal area criterion. Other issues addressed in this paper are presenting a method for locating and determining the optimal value of fault current limiter impedance to improve the stability of the power system. Also, the effect of fault clearing time on transient stability has been studied when the fault current limiter is present in the power grid.
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One of the benefit of FACTS devices is increase of stability in power systems with control active and reactive power at during the fault in power system. Although, the power system stabilizers (PSSs) have been one of the most common controls used to damp out oscillation More
One of the benefit of FACTS devices is increase of stability in power systems with control active and reactive power at during the fault in power system. Although, the power system stabilizers (PSSs) have been one of the most common controls used to damp out oscillations, this device may not produce enough damping especially to inter-area mode and therefore, there is an increasing interest in using FACTS devices to aid in damping of these oscillations. In This paper, UPFC is used for damping oscillations and to enhance the transient stability performance of power systems. The controller parameters are designed using an efficient version of the Takagi-Sugeno fuzzy control scheme. The function based Takagi-Sugeno-Kang (TSK) fuzzy controller uses. For optimization parameters of fuzzy PI controller, the GA, PSO and HGAPSO algorithms are used. The computer simulation results, the effect of UPFC with conventional PI controller, fuzzy PI controller and intelligent controllers (GA, PSO and HGAPSO) for damping the local-mode and inter-area mode of under large and small disturbances in the four-machine two-area power system evaluated and compared.
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In order to improve transient stability and increase the system damping, this paper introduces a specific way of coordination between FACTS devices (TCSC and SVC). In order to improve the performance and use all the features of TCSC and SVC (presented in this article), More
In order to improve transient stability and increase the system damping, this paper introduces a specific way of coordination between FACTS devices (TCSC and SVC). In order to improve the performance and use all the features of TCSC and SVC (presented in this article), it is necessary a controller be used in which does not have the limitations of other controllers and simply be also able to quickly respond and adapt to the power system model. Hence, these features can be found in the intelligent controllers in which the ADALINE network is one of them. To better understand the performance of the ADALINE network controller; this controller will be compared with a controller which is designed by the optimal control parameters (LQR). The instruments used for FACTS are from the injection type and therefore, it is possible to use a fixed factorization ybus matrix in the calculations. Simulation results using non-linear network show that the ADALINE neural network controller has better performance than the LQR controller and can cause significant improvement on damping and transmission ability in the power system.
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