Sajad Samadinasab
Lorestan University

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Journal : Indonesian Journal of Electrical Engineering and Computer Science

A New Method for Optimal Coordination of Overcurrent Relays Considering the Communication Channels Constraints Farhad Namdari; Sajad Samadinasab
Indonesian Journal of Electrical Engineering and Computer Science Vol 1, No 1: January 2016
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v1.i1.pp17-30

Abstract

The most of the new protective schemes are based on a communication channel, which cannot be guaranteed in practice. However, during blackouts or cascading failures in the power grid, as system conditions change significantly and rapidly, more information exchanges may be required by the control centers and substations. In other words, the communication channels are operating with high load and therefore become more vulnerable when the power grid is in contingent conditions. Thus, relying on the communication channel for decision making may not be the optimal solution for protective relays, although it might be beneficial to have information exchange. In this article, a novel protective logic is proposed based on phasor measurement units (PMUs) data for optimal coordination of overcurrent relays. PMUs measure the positive sequence voltage at two substations separated by hundreds of miles which are synchronized precisely with the aid of a GPS satellite system. The precise time-tags are attached with samples, and this information is exchanged over communication channels and collected by control centers and/or substations. By extracting the relevant information from these measurements, phasor information can be obtained at any node where PMUs are installed in the power grid. This can be used to do more accurate state estimation, control, and protection. In these relays, besides current and voltage, phasor information has become an important measurement in decision making. The proposed method is tested on IEEE 8-bus standard network.
The Influence of Moisture and Temperature on the Behavior of Soil Resistivity in Earthing Design Using Finite Element Method Sajad Samadinasab; Farhad Namdari; Mohammad Bakhshipor
Indonesian Journal of Electrical Engineering and Computer Science Vol 2, No 1: April 2016
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v2.i1.pp11-22

Abstract

Protection of equipment, safety of persons and continuity of power supply are the main objectives of the grounding system. For its accurate design, it is essential to determine the potential distribution on the earth surface and the equivalent resistance of the system. The knowledge of such parameters allows checking the security offered by the grounding system when there is a failure in the power systems.A new method to design an earthing systems using Finite Element Method (FEM) is presented in this article.In this approach, the influence of the moisture and temperature on the behavior of soil resistivity are considered in EARTHING system DESIGN. The earthing system is considered to be a rod electrode and a plate type electrode buried vertically in the ground.The resistance of the system which is a very important factor in the design process is calculated using Finite Element Method. Finite Element Method is used to estimate the solution of the partial differential equation that governs the system behavior. COMSOL Multiphysics 4.4 which is one of the packages that work with the FEM is used as a tool in this design.Finally the values of the resistance obtained by COMSOL Multiphysics are compared with the proven analytical formula values for the ground resistance, in order to prove the work done with COMSOL Multiphysics.
Optimal Coordination of Overcurrent and Distance Relays Using Cuckoo Optimization Algorithm Farhad Namdari; Sajad Samadinasab; Nader Shojaei; Mohammad Bakhshipour
Indonesian Journal of Electrical Engineering and Computer Science Vol 16, No 3: December 2015
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v16.i3.pp389-400

Abstract

The duty of protective systems is the timely detection of fault and removing it from the power network. The accuracy of the results and reducing the execution time of the optimizing algorithm are two crucial elements in selecting optimizing algorithms in protective functions. The most important protective elements that are used in power networks are distance and overcurrent relays. In this article, a new algorithm is presented to solve the optimization problem of coordination of overcurrent and distance relays by using Cuckoo Optimization Algorithm which considers the non-linear model overcurrent relays at all stages of setting. The proposed method is tested on a standard 8-bus power system network. Also the results obtained have been compared with other evolutionary algorithms. The results show that the proposed approach can be provide more effective and practical solutions to minimize the time function of the relays and achieving optimal coordination in comparison with previous studies on optimal coordination of overcurrent and distance relays in power system networks.
A Novel Protective Logic for Optimal Coordination of Overcurrent Relays Sajad Samadinasab; Farhad Namdari; Nader Shojaei
Indonesian Journal of Electrical Engineering and Computer Science Vol 16, No 3: December 2015
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v16.i3.pp439-453

Abstract

Usually coordination of overcurrent relays is done by taking into account the specific structure of the system which does not show the real state of the system. On the other hand, dynamic changes in network can occur due to short circuit conditions, the malfunctioning relays, development, operation and repairs on any part of the power system. Also the most of the new protective schemes are based on a communication channel, which cannot be guaranteed in practice. Therefore, solving the problem of relay coordination is extremely difficult in case of dynamic changes in the network structure and the absence of communication links between some relays. In this article, a novel protective logic based on phasor measurement units (PMUs) data is proposed for optimal coordination of overcurrent relays. In this method, by using the PMU measurements, phasor information can be obtained continuously at any node where PMUs are installed in the power grid. For this purpose, in the first the Optimal PMU placement is determined for full network observability. Then, the dynamic changes of network will be observe by using wide area measurements based on PMUs data. Finally this information is sent via communication links PMUs for the optimal coordination of overcurrent relays. The use of PMU for the coordination of overcurrent relays improve the decision making capability and performance of protective relays and help them to form a reliable and robust protection system. The proposed method is tested on IEEE 8-bus and 14-bus standard networks.