scholarly journals Reliability Evaluation of Bulk Power Systems Incorporating UPFC

Author(s):  
Mr. B. Madhu

Unified power flow controller (UPFC) is one of the most advanced flexible AC transmission system (FACTS) devices that can simultaneously and independently control both the real and reactive power flow in a transmission line. The utilization of UPFC can result in significant reliability benefits in modern power systems. This paper proposes a novel reliability network model for a UPFC, which incorporates the logical structure and the distinct operating modes of a UPFC. Two-state or three-state models have been used for UPFC by previous researchers. The proposed model divides the UPFC operating modes into four states, namely the UPFC up state, STATCOM state, SSSC state and UPFC down state, in order to improve the accuracy of the model by recognizing the practical operating states of a UPFC. The new model also incorporates an AC flow-based optimal load shedding approach to assess the impact of bus voltages and reactive power flow on UPFC in order to decide appropriate load curtailment in the reliability evaluation process. The performance of the proposed model is verified using a test system, and compared with different reliability models of UPFC. Various operating schemes, such as different placement locations of UPFC, and different capacities of UPFC are used to illustrate the advantages of the developed models, and to examine the impacts of UPFC on the system reliability.

Author(s):  
Himanshu Kumar Singh ◽  
S.C. Srivastava ◽  
Ashwani Kumar Sharma

One of the most important tasks of System Operator (SO) is to manage congestion as it threatens system security and may cause rise in electricity price resulting in market inefficiency. In corrective action congestion management schemes, it is crucial for SO to select the most sensitive generators to re-schedule their real and reactive powers and the loads to curtail in extreme congestion management. This paper proposed the selection of most sensitive generators and loads to re-schedule their generation and load curtailment based on the improved line flow sensitivity indices to manage congestion. The impact of slack bus on power flow sensitivity factors has been determined to encourage fair competition in the electricity markets. Effect of bilateral and multilateral transactions, and impact of multi-line congestion on congestion cost has also been studied. The generators’ reactive power bid has been modeled by a continuous differentiable tangent hyperbolic function. The proposed concept of congestion management has been tested on a practical 75-bus Indian system and IEEE-118-bus test system.


2012 ◽  
Vol 3 (2) ◽  
pp. 147-156 ◽  
Author(s):  
R. A. El-Sehiemy ◽  
A. A. A. El Ela ◽  
A. M. M. Kinawy ◽  
M. T. Mouwafia

Abstract This paper presents optimal preventive control actions using ant colony optimization (ACO) algorithm to mitigate the occurrence of voltage collapse in stressed power systems. The proposed objective functions are: minimizing the transmission line losses as optimal reactive power dispatch (ORPD) problem, maximizing the preventive control actions by minimizing the voltage deviation of load buses with respect to the specified bus voltages and minimizing the reactive power generation at generation buses based on control variables under voltage collapse, control and dependent variable constraints using proposed sensitivity parameters of reactive power that dependent on a modification of Fast Decoupled Power Flow (FDPF) model. The proposed preventive actions are checked for different emergency conditions while all system constraints are kept within their permissible limits. The ACO algorithm has been applied to IEEE standard 30-bus test system. The results show the capability of the proposed ACO algorithm for preparing the maximal preventive control actions to remove different emergency effects.


Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2341
Author(s):  
Benjamin T. Gwynn ◽  
Raymond de Callafon

Load switches in power systems may cause oscillations in active and reactive power flow. Such oscillations can be damped by synthetic inertia provided by smart inverters providing power from DC sources such as photovoltaic or battery storage. However, AC current provided by inverters is inherently non-sinusoidal, making measurements of active and reactive power subject to harmonic distortion. As a result, transient effects due to load switching can be obscured by harmonic distortion. An RLC circuit serves as a reference load. The oscillation caused by switching in the load presents as a dual-sideband suppressed-carrier signal. The carrier frequency is available via voltage data but the phase is not. Given a group of candidate signals formed from phase voltages, an algorithm based on Costas Loop that can quickly quantify the phase difference between each candidate and carrier (thus identifying the best signal for demodulation) is presented. Algorithm functionality is demonstrated in the presence of inverter-induced distortion.


2014 ◽  
Vol 543-547 ◽  
pp. 878-883
Author(s):  
Jun Dong ◽  
Jian Guo Xu ◽  
Hao Zhang ◽  
Yu Jie Pei ◽  
Xian Feng Li

The cause serious deterioration in power quality problems for the growing impact and nonlinear load capacity, introduced SVC device in the role of modern power systems and applications. According to the lack of adequate regional dynamic reactive power regulation means to cause voltage fluctuations, harmonics exceeded the actual situation, through analysis and simulation of the existing 66kV grid power quality conditions, refers to the necessity of application of SVC, the compensation capacity for SVC, filter capacitor system parameters and control strategies were designed, the results show improved 220kV SVC reactive power flow distribution system, reducing the system once or twice a net loss, reducing the impact and harmonic interference voltage caused by nonlinear loads, system security, economic operation of great significance.


2020 ◽  
Vol 9 (5) ◽  
pp. 1755-1765
Author(s):  
Mohammed Y. Suliman ◽  
Mahmood T. Al-Khayyat

The power flow controlled in the electric power network is one of the main factors that affected the modern power systems development. The unified power flow controller (UPFC) is a FACTS powerful device that can control both active and reactive power flow of parallel transmission lines branches. In this paper, modelling and simulation of active and reactive power flow control in parallel transmission lines using UPFC with adaptive neuro-fuzzy logic is proposed. The mathematical model of UPFC in power flow is also proposed. The results show the ability of UPFC to control the flow of powers components "active and reactive power" in the controlled line and thus the overall power regulated between lines.


Author(s):  
Ben Slimane Abdelkader ◽  
Chelleli Benachiba

Interline Power Flow Controller (IPFC) is one of the latest generation Flexible AC Transmission system (FACTS). It is able to control simultaneously the power flow of multiple transmission lines. This paper presents a study of the impact the IPFC on profile of voltage, real and reactive power flow in transmission line in power system. The obtained results are interesting.


Author(s):  
Bih-Yuan Ku ◽  
Yen-Chun Chen ◽  
Guan-Ru Chen ◽  
Ming-Jan Ko

In this paper we present our study on load power quality characteristics of new trains with switch-type converters using field measurement data. We apply these data to perform power flow and harmonic power flow computations to examine the impacts of new train loads to existing ac traction power network with filters designed for old train loads. Our simulation results show that existing filters can result in over-compensation of reactive power and ineffective filtering of load current harmonic components. It is recommended that filter designs be modified to suit the load power characteristics of new-generation trains.


2014 ◽  
Vol 556-562 ◽  
pp. 1643-1646
Author(s):  
Xue Fei Chang ◽  
Xiang Yu Lv ◽  
De Xin Li

In order to improve the calculation efficiency, active power and reactive power are usually optimized separately in optimal power flow considering the decoupling characteristic. However, this would decrease the economy performance of power system. This paper proposed a weighting factor to formulate a multi-objective model, combining the generation cost and system network loss together. The optimization problem is performed using genetic algorithms and quadratic programming respectively. Finally, the feasibility and efficiency of the proposed model are verified with the IEEE 14 Bus test system.


2013 ◽  
Vol 805-806 ◽  
pp. 1136-1139
Author(s):  
Yi Yang

GICs in technological conductor networks are a ground manifestation of space weather. During severe geomagnetic storms, if GICs flow in power systems, real and reactive power flow will swing abnormally, also transformer saturation, over-voltage fluctuation, frequency shift, unnecessary relay trippings and increased harmonic contents, even damage of transformer or a collapse of the whole system may occur. So GIC controlling in power systems is so significant that it can help power systems stand through strong geomagnetic disturbances, as well as ensure safe and stable operation of power systems. In this paper, control methods and techniques on GIC in power systems have been summarized in reference of research achievements and control experience on GIC.


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