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Hojjat M.,Islamic Azad University at Shahrood | Javidi M.H.,Ferdowsi University of Mashhad | Yazdanpanah D.,Khorasan Regional Electrical Company
Turkish Journal of Electrical Engineering and Computer Sciences | Year: 2016

Considering system uncertainties in developing power systems, algorithms such as congestion management (CM) are vital in power system analysis and studies. This paper proposes a new model for power system CM by considering power system uncertainties based on chance-constrained programming (CCP). In the proposed approach, transmission constraints are taken into account by stochastic, instead of deterministic, models. The proposed approach considers network uncertainties with a specific level of probability in the optimization process, and then an analytical approach is used to solve the new model of stochastic congestion management. In this approach, the stochastic optimization problem is transformed into an equivalent deterministic problem. Moreover, an efficient numerical approach based on a real-coded genetic algorithm and Monte Carlo technique is proposed to solve the CCP-based congestion management problem in order to make a comparison to the analytical approach. The effectiveness of the proposed approach is evaluated by applying the method to the IEEE 30-bus test system. The results show that the proposed CCP model and the analytical solving approach outperform the existing models. © Tubitak. Source


Bashir M.,Ferdowsi University of Mashhad | Sadeh J.,Ferdowsi University of Mashhad | Kamyab E.,Khorasan Regional Electrical Company | Yaghobi H.,Semnan University
2012 11th International Conference on Environment and Electrical Engineering, EEEIC 2012 - Conference Proceedings | Year: 2012

In substations, protective equipments such as arresters and neutral transformer are being connected to substation ground grid to protect them against transient overvoltage, firing and other damages. But unfortunately, lack of grounding connection of electrical equipments or high resistance of grounding grid is one of the main reasons which cause risk for staffs and electrical equipments. In this paper, effect of increasing in grounding grid resistance on transient overvoltage which is caused by short circuit, switching and lightning on the interior equipments and safety in a grounding grid at substation is investigated. Effect of transient overvoltage with different short circuits is another subject that is considered. In this paper, indices for ground grid safety are expressed and grounding grid analysis will be done with CYMGrd software. Transient analysis simulations are carried out using DigSilent software and the results of investigation on a real system are presented © 2012 IEEE. Source


Niazy I.,Ferdowsi University of Mashhad | Mortazavi H.,Khorasan Regional Electrical Company | Ebadi J.,Ferdowsi University of Mashhad | Sabzevari S.,Ferdowsi University of Mashhad | Niazy A.,Ferdowsi University of Mashhad
International Review of Electrical Engineering | Year: 2010

As one of the most important ancillary services, reactive power production plays a crucial rule in power system operation, reliability and security. Because of the opportunity costs in providing reactive power, producers are under great pressure to provide VAr support. This paper presents a new challenge on the reactive capability curves (RCC) of the synchronous generator taking in account the normal limits of operation without exceeding thermal limitations. The importance of re-evaluation of RCC in the real world is because of the RCC is changed over time and aging of the generators. In this paper it is discusses about some reasons, which lead to the variations, and the importance of re-evaluation of RCC. © 2010 Praise Worthy Prize S.r.l. - All rights reserved. Source


Mashhadi M.R.,Ferdowsi University of Mashhad | Mashhadi M.R.,Khorasan Regional Electrical Company | Ghazizadeh M.S.,Power and Water University of Technology, Tehran | Javidi M.H.,Ferdowsi University of Mashhad
Iranian Journal of Science and Technology, Transaction B: Engineering | Year: 2011

Primary frequency regulation, as an ancillary service, is usually supported by generation reserves. Modern generating units have special technical features; e.g. their governor operation mode can be selected, their ramp rate can be selected to be either normal or fast, etc. On the other hand, there are some technical constraints; e.g. some generating units cannot participate in primary frequency control at their capacity limits. In this paper, operational technical features and constraints of generating units are incorporated in a"simultaneous scheduling of energy and primary reserve" problem. To obtain the optimal scheduling, a heuristic iterative method based on genetic algorithm is proposed. The role of fast ramp rate and other capabilities and constraints on scheduling are investigated through simulation studies. Simulation results show that taking fast ramp rate of generating units into account not only reduces the total operation cost, but will also end up with a feasible solution, even in cases where previously proposed methods fail. Also, simulation results indicate that using fast ramp rate, results in the reduction of both the price of electricity and its volatility. © Shiraz University. Source


Rajabi Mashhadi M.,Ferdowsi University of Mashhad | Rajabi Mashhadi M.,Khorasan Regional Electrical Company | Javidi D. B. M.H.,Ferdowsi University of Mashhad | Ghazizadeh M.S.,Power and Water University of Technology, Tehran
Electrical Engineering | Year: 2011

Frequency control, as an ancillary service, is usually provided by generation reserves. Modern generating units have special technical capabilities; e.g., their governor operation mode can be selected to be either active or passive, their ramp rate can be selected to be either normal or fast, etc. On the other hand, generating units have some technical constraints; e.g. some generating units cannot participate in primary frequency control at their capacity limits. In this paper, operational capabilities and constraints of generating units are incorporated in a "simultaneous scheduling of energy and primary reserve" problem. Furthermore, a heuristic iterative method (based on genetic algorithm) is proposed to obtain the optimal scheduling. The impacts of capabilities and constraints on scheduling are investigated through simulation studies. Simulation results depicts that taking these capabilities and constraints of generating units into account, not only reduces the total operational cost of generating units, but also will end up with a feasible solution for the system, even in cases where the previously proposed methods fail. © 2011 Springer-Verlag. Source

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