Presenting a New Method Based on Branch Placement for Optimal Placement of Phasor Measurement Units

In this paper, a new method based on branch placement for the optimal positioning of Phasor Measurement Units (PMUs) in power systems is proposed. In this method, the PMUs are in type of single-channel and are installed at the beginning of the branches. Therefore, they are able to measure the bus voltages. Also, the installation of the PMUs on the branches increases the security of observability in comparison to the bus placement method at the time of line or PMU outages. In this paper, the Genetic Algorithm (GA) method is used to solve the optimization problem. The proposed method is applied to IEEE 30-bus and 24-bus case study networks. In addition, the method is tested on a real 400 kV network in Iran

DC Microgrid Protection in the Presence of the Photovoltaic and Energy Storage Systems

In recent years, most of the loads and distributed generations are connected to the AC grid through the power electronic converters. Using the DC grid beside the AC grid can reduce the conversion stages and power losses. Protection of the DC grids is a challenging issue because of the new structures of DC grids and fast transients of the DC faults. This paper studies the protection of the low voltage DC (LVDC) system in the presence of the photovoltaic (PV) and energy storage systems (ESS). An LVDC system consisting of a DC microgrid is considered and Different operating modes are analyzed. DC faults behavior and protection challenges are discussed for each mode through simulations employing MATLAB software. Finally, some methods are presented to solve the protection challenges. The results show that changing the protection arrangement of the system and choosing suitable control logics for the ESS and the PV prevent the unwanted outage of the loads and provide the possibility of the microgrid operation in islanded mode

An Enhanced Adaptive Algorithm to Mitigate Mis-coordination Problem of the Third Zone of Distance Relays

ABSTRACT Cascaded tripping of power lines due to mal-operation of zone 3 distance relays is one of the main causes of many blackouts worldwide. The improved protection technique for zone 3 can help to prevent such mal-operation and, thus, more reliable power systems can be envisaged. This paper presents a novel zone-3 setting scheme based on impedance seen by distance relays in order to calculate zone-3 setting of the relays when faults are simulated on the reach of zone-2 of primary distance relays. The new technique is also enhanced to be used in an adaptive protection system. Since three phase fault rarely occurs in the system and in order to have better demonstration of effectiveness of the proposed scheme, it is tested for various type of faults such as, two phase (AB), single phase to ground (AG) and two phase to ground (ABG) as well as three-phase (ABC) using data simulated through DIgSILENT in the IEEE 30-bus test system during different topologies. The simulation results show that the novel zone 3 distance relay elements using the proposed method operate correctly for various events

Adaptive Fuzzy Synergetic PSS Design to Damp Power System Oscillations

This paper presents a novel indirect adaptive Power System Stabilizer (PSS) via a developed synergetic control methodology and fuzzy systems. Fuzzy system is utilized in an adaptive scheme to estimate the system using a nonlinear model. The synergetic control guarantees robustness of the controller and makes the controller easy to implement because of using a chatter free continuous control law. Additionally, the parameters of the controller are optimized by Imperialist Competitive Algorithm (ICA). The effectiveness of the proposed scheme is confirmed on a single machine power system while the stability is guaranteed through Lyapunov synthesis

OVERCURRENT RELAY COORDINATION EFFECTS ON RELIABILITY INDICES

<p>ENGLISH ABSTRACT: Mechanical equipment used on process plants can be categorised into two main types, namely static and rotating equipment. A brief survey at a number of chemical process plants indicated that a number of maintenance strategies exist and are used for rotating equipment. However, some of these strategies are not directly applicable to static equipment, although the risk-based inspection (RBI) methodology has been developed for pressure vessels. A generalised risk-based maintenance strategy for all types of static equipment does not currently exist. This paper describes the development of an optimised model of inspection methodologies, maintenance strategies, and risk management principles that are generically applicable for static equipment. It enables maintenance managers and engineers to select an applicable maintenance strategy and inspection methodology, based on the operational and business risks posed by the individual pieces of equipment.</p><p>AFRIKAANSE OPSOMMING: Mislukkings van beveiligingstelsels is hoofsaaklik verantwoordelik vir kaskadeonderbrekings van elektriese netwerke. Derhalwe is dit noodsaaklik dat betroubaarheidsindekse geevaleer moet word teen die agtergrond dat min aandag gegee word aan relêkoördinasie. Monte-Carlo simulasie word voorgehou as oplossing van die koördinasievraagstuk. Die voorgestelde algoritme word toegepas op die afsonderlike koördinasiemetodes van ‘n denkbeeldige network. Die resultate van die ondersoek toon dat die berekende betroubaarheidsindeks afhang van hoe koördinasiemetodes toegepas word.</p&gt

Adaptive Fuzzy Synergetic PSS Design to Damp Power System Oscillations

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