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This paper presents a method for voltage stability monitoring based on the maximum power transfer to the load. The only required information is the system topology, the data from PMUs and the operational status of synchronous generators. With this information, the Thevenin impedance seen from a load bus can be estimated and by using the Thevenin theorem for maximum power transfer an impedance based...
This paper analyses the existing protection scheme of a real distribution system with distributed generators, in Greece. Network protection utilizes three successive reclosers at the main trunk and fuses at the laterals. The generating units are protected by overcurrent and voltage/frequency relays. The analysis focuses on the fault-ride-through capability of the generating units and proposes the...
This paper presents a new methodology for allocation of transmission system costs in electricity markets established in one single area or composed by the interconnection of multiple subsystems. Initially, the proposed method allows the decomposition of the total cost of transmission in two installments: the first, referring to the utilized capacity of the network (estimated at a predetermined operating...
Large-scale integration of renewable resources for power generation is a propitious mode to mitigate the impact of human activities in order to reach an environmentally and sustainable way of life. However, uncontrollability and variability of renewable resources is an important barrier that could be overcome by incorporating energy storage systems (ESSs). Among ESSs technologies, Vanadium Redox Battery...
This paper presents some experiences concerning the testing of generating units response to frequency transient. The tests have been performed both for modeling and monitoring the compliance of the settings of the generating units with the operational requirements. A test methodology, based on mathematical modeling, is developed and proposed. The approach is intended to interfere (or disturb) less...
The approach of programmed trajectory motion control (PTMC) is proposed for stabilization of synchronous generators after short-circuit faults followed by islanding and for further synchronization of islanded system with the main grid. This approach is especially useful for small size synchronous machines connected to distribution grid. Integrated solution of both stabilization and synchronization...
This paper describes an unmanned aerial vehicle (UAV) ice tracking framework for use in sea ice management applications. The framework is intended to be used in an ice management scenario where the UAV should detect and track the movement of icebergs and ice floes in an Arctic environment, and seeks to enable the UAV to do so autonomously. This is achieved by using an occupancy grid map algorithm...
Power system restoration continues to be a major challenge for many power systems in sub-Saharan Africa. Hydropower generation also remains as one of the major sources of power in this region. However, many power systems supported by hydropower generation in this region suffer from frequent power system blackouts, which have detrimental implications on the power system and its users. This paper focuses...
Vast increase of renewable energy resources' (RER) share in total electricity production have led to evolving studies regarding different aspects of renewables integration. Other than their effects on network, the electricity markets are also affected by uncertain behavior of RERs in the market place. Hence, new approaches for market clearing are investigated. One of the possible solutions is the...
Photovoltaic (PV) has become the alternative form of clean energy generation world-wide. Many power utilities have embraced this alternative source of power generation and integrating the power to the grid. This research study provides insights on the effects of high levels of Photovoltaic (PV) generation integration on the utility grid with particular emphasis on the South African utility grid. The...
Diesel Engine Generators (DEGs) are used to generate power but in the process produce emissions of toxic air pollutants (taps). These ‘taps’ include Particulate Matter (PM) and Oxides of Nitrogen (NOx) which are harmful to humans and the environment. This paper has investigated the effect of retrofitting a 15kVA DEG using Retrofitted Diesel Fuel (RDF) and Pure Diesel Fuel (PDF). The data obtained...
During static voltage stability analysis, as the load grows, bus voltages tend to drop. This voltage reduction may cause undervoltage trip of distributed generators which, in turn, may diminish the Voltage Stability Margin (VSM) of the bulk power system. The purpose of this paper is to evaluate the effect of Distributed Generation (DG) undervoltage mandatory disconnection in the VSM of transmission...
This paper presents a data analysis of an islanded diesel-PV-battery system, placed in Somalia. Operation of each generator is observed, concerning the most relevant performance indicators. Analysis is carried out during the first 11 months of operation, from November 2015 to September 2016. Investigations are divided into two periods, according to a significant load variation due to the connection...
Electrical weapons and combat systems integrated into ships create challenges for their power systems. The main challenge is operation under high-power ramp rate loads, such as rail-guns and radar systems. When operated, these load devices may exceed the ships generators in terms of power ramp rate, which may drive the system to instability. Thus, electric ships require integration of energy storage...
An ultra low power CMOS voltage reference has been developed in a low-cost CMOS 130 nm technology. The design benefits in particular from using only one standard CMOS process without incorporating any resistors, op-amp, bipolar transistor or other CMOS processes. The circuit draws ultra low current of 230 nA from supply voltage of 1.2 V. The proposed circuit generates output an voltage of 698.5 mV...
The article contains a mathematical description of the asynchronous generator under asymmetric switching loads with non-linearity of magnetization characteristics. Mathematical models allow one to evaluate the actual generator properties without add experiments and to obtain information on such issues as: determination of generator operating characteristics in a wide range of load with symmetric and...
The problem of regulation oscillatory modes with set characteristics in a controlled subsystem by means of the amplitude of oscillations of the control generator is considered. The control generator is connected with the system control object in a nonlinear feedback mode. The structure of control functions, which depends on the variables of the controlled subsystem is studied for the control generator...
The goal of the present paper is connected with spectral quasi-optical ellipsometer (SQOTE) creation, based on the hollow dielectric beamguide and beamguide components as a quasi-optical transmission line. Ultra-broadband quasi-optical transmittance line provides operation of the ellipsometer within 0.17–0.225 THz (1.2–1.8 mm) frequency range. The set of elements of the transmittance line, which require...
Limitations of the existing methods and models for uneven energy consumption forecast are defined. The energy consumption planning method based on informational technologies, the probability theory, the game theory, hour energy prices and volumes relations is offered. All possible variants of prices and volumes relations are identified. Two utility functions for positive and negative correction of...
Nowadays, diesel and turbo-generator sets operated with a constant speed are most widely used as marine power sources. Advantages of standard generator sets include a relatively high efficiency. When generator set is operated as a part of the unified electric power grids with an electric propulsion system and load varying within a wide range, efficiency and reliability of a standard generator set...
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