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Previous papers proposed a method to find the maximum possible dried area of soil expected due to heating by underground cables. A method was also proposed to include this dried soil area in cable ampacity calculations. This assumed cables would be loaded 100% of the time. To dry soil to the maximum possible extent may take very long time periods, and in many installations the cables actually carry...
This paper develops and experimentally tests the performance of a digital interconnection protection for grid-connected wind energy conversion systems (WECSs). The developed protection is constructed by two frequency frames to process voltages and currents measured at the point-of-common-coupling (PCC). The first frequency frame is set to process the d - q-axis components of the instantaneous 3Φ apparent...
Most refineries, drilling platforms, and chemical plants are equipped with receptacles used for powering equipment. This can present a shock hazard; therefore, NFPA and OSHA require ground-fault circuit interrupter (GFCI) on all receptacles powering equipment used by personnel and are not part of the building permanent wiring. Due to the lack of GFCI at voltages above 240 V, both NFPA and OSHA require...
Current-differential principles are well known and commonly used for protection of medium and large size transformers, large motors, medium voltage (MV) generators, medium and high voltage buses, and any type of important power equipment with measurable input and output currents. However, is it practical to protect low voltage distribution buses using differential protection? This paper will describe...
Transformation of energy supply towards fully renewable generation presupposes readily available distributed energy storage systems to compensate the variability of renewable sources. Battery energy storage systems (BESS) connected to the grid via power electronics are well suited to be deployed in large numbers in Smart Grid applications to provide system services like load balancing, grid stabilizing...
This paper presents a computational intelligence technique for optimal coordinated reactive power control between a wind turbine (WT) equipped with doubly fed induction generator (DFIG) and a static synchronous compensator (STATCOM), during faults. The proposed control model is formulated as a multi-objective optimization problem (MOP) in order to simultaneously minimize two conflicting objectives:...
Power electronics-based electrolyzer systems are prevalently in current use. This paper proposes the more recently employed directly coupled photovoltaic (PV) electrolyzer systems. Equipped with accurate electrical models of the advanced alkaline electrolyzer, PV system and Hydrogen storage tank simulated using MATLAB, the system's performance for a full week is analyzed using Miami, Florida's meteorological...
This paper presents the analyzed results on small-signal stability of a grid-connected tidal power-generation system (GCTPGS) as affected by system-parameter variations. The studied GCTPGS containing a permanent-magnet synchronous generator driven by a tidal turbine through a gearbox is connected to a power grid through power-electronics converters, a submarine cable, and a step-up transformer. A...
This paper presents a coordinated anti-islanding protection for collector systems with multiple distributed generation units (DGUs). The presented anti-islanding protection is established based on processing the d-q-axis components of the instantaneous three phase apparent powers (sd and sq), determined at the point-of-common-coupling, using the wavelet packet transform (WPT). Processing sd and sq...
This paper analyzes the average efficiency gap in a building final electrical distribution system when loads and multiple sources are either linked by an AC distribution bus or a DC distribution bus. This paper shows that the gap is rather small to be a good enough reason for adopting AC or DC for low voltage electrical power distribution.
Electric motors or power drive systems convert nearly half of the worldwide electric energy into mechanical energy, ultimately used in the final application or process. Overall motor driven system optimization is the key approach to effectively achieve the highest system efficiency levels for a given investment. Looking individually to each component may not lead to the most cost-effective option...
Electric motors or power drive systems convert nearly half of the worldwide electric energy into mechanical energy, ultimately used in the final application or process. Overall motor driven system optimization is the key approach to effectively achieve the highest system efficiency levels for a given investment. Looking individually to each component may not lead to the most cost-effective option...
In order to reduce the influence of the grid harmonic currents and voltages, harmonic compensation is regularly implemented for a grid-tied inverter. In this paper a new topology of higher order power filter for single-phase grid-tied voltage-source inverters (VSI), named L(LCL)2, is introduced. The subscript is added to the name to avoid confusion with LLCL filter. In the proposed design the inverter...
In this paper, a new generic composite load model structure for industrial facilities is proposed, which consists of four main loads, an induction motor, a synchronous motor, a motor drive system, and a static load. This structure can be applied to existing or future industry facilities. Major factors to be considered when developing this new composite load model are demonstrated. To achieve the final...
A portion of generated electrical power is lost in transmission and distribution systems while serviced to endusers. These losses are called technical and non-technical losses in electricity distributions systems. With privatization processes taken place over the world, huge debate arose regarding non-technical losses. In this study, information about types of losses in distribution systems, privatization...
This research provides detailed calculations of Equal Energy Lines, EELs, of Arc-flash categories defined by IEEE Std. 1584 for the application of Protection Device Coordination. The Personal Protective Equipment, PPE categories are illustrated as curves in Time-Current Coordination, TCC, plots in order to set and coordinate over-current devices such as fuses, breakers and relays. This would help...
Efficiency of the transformer is in the range of 95–99%, which means that up to 5% of the energy is wasted in the losses of the power transformer. The efficiency of power transformers is defined as the ratio between output and input power. Input power is the sum of the output power and transformer losses.
This paper develops a new approach for formulating and the power flow for power systems. The developed approach is based on expressing the active and reactive power injections at each bus, in a power system, using the d - q-axis components of bus voltages and admittance matrix. The new power flow formulation produces a scaled Jacobian matrix, which can offer a fast convergence to the solution. The...
The use of underground cables as power lines, either alone or in combination with overhead lines, is steadily increasing. After a cable is isolated from the system, its trapped charge starts to slowly discharge. We may need to determine the discharge time for multiple reasons such as safety, and limitations on circuit breaker capabilities to withstand capacitive inrush currents. This paper will modify...
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