PE Elektroprivreda of Bosnia and Herzegovina

Sarajevo, Bosnia and Herzegovina

PE Elektroprivreda of Bosnia and Herzegovina

Sarajevo, Bosnia and Herzegovina
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Idris N.H.,PE Elektroprivreda of Bosnia and Herzegovina | Idris N.H.,University of Sarajevo | Salim N.A.,PE Elektroprivreda of Bosnia and Herzegovina | Salim N.A.,University of Sarajevo | And 6 more authors.
Journal of Electrical Systems | Year: 2017

Transmission line act as a medium of transportation for electrical energy from a power station to the consumer. There are many factors that could cause the cascading collapse such as instability of voltage and frequency, the change of environment and weather, the software and operator error and also the failure in protection system. Protection system plays an important function in maintaining the stability and reliability of the power grid. Hidden failures in relay protection systems are the primary factors for triggering the cascading collapse. This paper presents an Artificial Neural Network (ANN) model for prediction of cascading collapse occurrence due to the effect of hidden failure of protection system. The ANN model has been developed through the normalized training and testing data process with optimum number of hidden layer, the momentum rate and the learning rate. The ANN model employs probability of hidden failure, random number of line limit power flow and exposed line as its input while trip index of cascading collapse occurrence as its output. IEEE 14 bus system is used in this study to illustrate the proposed approach. The performance of the results is analysed in terms of its Mean Square Error (MSE) and Correlation Coefficient (R). The results show the ANN model produce reliable prediction of cascading collapse occurrence. © JES 2017.


Bisanovic S.,PE Elektroprivreda of Bosnia and Herzegovina | Hajro M.,University of Sarajevo | Dlakic M.,PE Elektroprivreda of Bosnia and Herzegovina
International Journal of Power and Energy Systems | Year: 2011

This paper addresses the thermal unit commitment problem for power generation companies that operating in the market environment. The model for this problem is formulated as a deterministic optimization task where the optimal solution obtained using the 0/1 mixed-integer linear programming technique. The main feature of the model is that it provides a comprehensive and accurate representation of operating costs and operating constraints for thermal units. The model have been incorporated a long-term bilateral contracts with defined profiles power and price, and forecasted market for hourly prices for day-ahead auction. Solution is achieved using the homogeneous and self-dual interior point method for linear programming with a branch and bound optimizer for binary programming. The effectiveness of the proposed model is demonstrated through case study with detailed discussion.


Bisanovic S.,PE Elektroprivreda of Bosnia and Herzegovina | Hajro M.,University of Sarajevo | Dlakic M.,PE Elektroprivreda of Bosnia and Herzegovina
International Journal of Electrical Power and Energy Systems | Year: 2012

This paper addresses the self-scheduling problem of generation companies owning thermal power units considering bilateral contracts and day-ahead market. This approach allows precise modelling of variable costs, start-up costs and comprehensive system of constraints. The self-scheduling model is formulated as deterministic optimization problem in which expected profit is maximized by 0/1 mixed-integer linear programming technique. Solution is achieved using the homogeneous and self-dual interior point method for linear programming, with a branch and bound optimizer for integer programming. The effectiveness of the proposed model for optimizing the thermal generation schedule is demonstrated through the case study with detailed discussion. © 2012 Elsevier Ltd. All rights reserved.


Pal Y.,PE Elektroprivreda of Bosnia and Herzegovina | Singh B.,University of Sarajevo | Swarup A.,PE Elektroprivreda of Bosnia and Herzegovina
Journal of Electrical Systems | Year: 2011

In this paper the flexibility of selective compensation is provided in the control scheme of UPQC for different power quality (PQ) problems. The control scheme of shunt APF compensates the source current harmonics, reactive power and unbalance in source currents and their combinations, while the series APF protects a sensitive load from voltage based distortions. The proposed control scheme for the shunt APF decompose the load current into positive and negative sequence fundamental frequency active components, reactive component and harmonic components in synchronous reference frame(SRF). On the other hand, for the mitigation of voltage harmonics, voltage sag, swell and dips, a control scheme based on SRF theory is employed for the series APF of the UPQC. The control scheme of the UPQC performs with priority based schemes, which respects the limited rating of the VSIs. In this proposed control scheme of the UPQC, the current/voltage control is applied oner the fundamental supply currents/voltages instead of fast changing APFs currents/voltages, there by reducing the computational delay and the required sensors. The performances of the proposed control scheme of UPQC are analyzed through simulations using MATLAB software with its Simulink and Power System Block set toolboxes. © JES 2011.


Bisanovic S.,PE Elektroprivreda of Bosnia and Herzegovina | Hajro M.,University of Sarajevo | Dlakic M.,PE Elektroprivreda of Bosnia and Herzegovina
Journal of Electrical Systems | Year: 2010

This paper addresses the self-scheduling problem of determining the unit commitment status for power generation companies before submitting the hourVy bids in a day-ahead market. The thermal unit commitment model is formulated as a deterministic optimization problem where expected profit is maximized using the 0/1 mixed-integer linear programming technique. This approach allows precise modelling of non-convex variable cost, nonlinear start-up cost, ramp rate limits and minimum up and down time constraints for thermal units. Model incorporates long-term bilateral contracts with contracted power and price patterns, as well as forecasted market hourly prices for day-ahead auction. Solution is achieved using the homogeneous and self-dual interior point method for linear programming as state of the art technique, with a branch and bound optimizer for integer programming. The effectineness of the proposed model in optimizing the thermal generation schedule is demonstrated through the case study with detailed discussion. © JES 2010.


Bisanovic S.,PE Elektroprivreda of Bosnia and Herzegovina | Hajro M.,University of Sarajevo | Samardzic M.,University of Sarajevo
International Journal of Electrical Power and Energy Systems | Year: 2014

This paper presents an efficient solution for reactive power control of capacitor bank using changes in reactance of connected reactor. This solution ensures smooth control of reactive power of capacitor banks as important operational characteristic for maintaining the quality of supply. The proposed method works for a wide-range of reactive power variations in the system and is capable of injecting or absorbing reactive power when necessary. This control method can be successfully used in distribution and industrial networks where many loads vary their demand for reactive power. Other applications of this method are voltage regulation, power-factor correction and reactive power compensation. The effectiveness of the proposed method is demonstrated through the case studies in order to prove its feasibility for improvement of voltage profile and reduction of power losses. © 2014 Elsevier Ltd. All rights reserved.

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