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The objective of this paper is to provide a method for steady-state short-circuit analysis in power networks with distributed energy resources (DERs). For this purpose, we suggest an approach that takes into account the impact of current controlled DERs in the fault analysis. The current controlled DER has some characteristics that we should consider–1) DER's large filter inductance and 2) the limit...
Protection security assessment of power grids is getting an important task in the course of a decarbonized power generation and a competitive energy business. The analysis of past blackouts studied by the North American Electric Reliability Council (NERC) shows that protection relays are involved in about 75% of all major disturbances. Protection security assessment can be investigated under two different...
Photovoltaic (PV) cells have non-linear electrical characteristics with only one operating point at which the maximum available power can be extracted. This is called the maximum power point (MPP). In order to maximally utilize the energy of solar radiation by using PV generators, they must be forced to operate at their MPP. This is done by using interfacing devices, which are capable of changing...
This paper investigates the settings of the generator out of step protection relays (ANSI device 78) for all six gas and steam turbine generators used in a grid connected CHP power plant. Detailed model of the CHP power system is developed in PSCAD/EMTDC tool which includes a representation of the synchronous generator, turbine governor, Automatic Voltage Regulator (AVR), Power System Stabilizer (PSS),...
With the development of wind power on a large scale, more and more wind sources will be integrated into power grid. However, due to intermittent nature, power grid dispatch will face new difficulties. It is necessary for us to analyze wind power systems and locate the specific points of power loss. This is of great significance to timely adjust the output of the remaining units to keep the balance...
Low voltage ride-through (LVRT) requirements, listed in modern grid codes, have proven to be a significant technical issue for many wind turbine manufacturers. The LVRT requirements are usually defined by the transmission system operators at the point of common coupling (PCC) of wind farm to the power network. However, depending on the transformers configuration, the voltage sag conditions experienced...
The deficiencies of existing load models and their implementations in power system simulation programs are addressed in this paper. To improve the load model for power system simulation, a Synthesis Load Model (SLM) with distribution network, which is consistent with the structure of power loads and distribution networks, is presented. The SLM is reasonable in structure and convenient to use. The...
With the continued expansion of the scale of wind power generation, the power quality problems due to grid connected wind farms are concerned widely. The voltage fluctuation and flicker and harmonics are main aspects of power quality problems. The fluctuation of wind farm output and grid voltage due to the random fluctuation of wind speed and inherent characteristics of wind turbines may cause flicker...
The aim of this article is to describe how closely PV grid-connected inverters operate at the actual maximum power point. To carry this study out six 50 Hz single-phase inverters were selected from European market. Each one of them was put into an outdoor grid-connected system installed in Leganes (Madrid) Spain (by using flat and concentrating PV modules). Different electrical signals with respect...
The author worked on distributed generation (DG) connected to the transmission and distribution GRIDS of Ontario Hydro, from 1985 to 1999. During that period, he has experienced lots of technical problems in connecting to the GRID. In this paper, he would discuss his experiences with the following topics: 1) Types of DG's, including sources of prime power (e.g. water, gas, wind, solar, etc.) in brief...
Distributed generators (DG), while working in conjunction with the main electricity grid, must have antiislanding protection. This paper presents a local detection scheme for distributed generators by using an SCR based device to draw a current pulse around the zero- crossing of the voltage waveform and analyzing the pulse to determine whether islanding has occurred. This method is based on the fact...
A Z-source inverter based grid-interface for a variable-speed wind turbine connected to a permanent magnet synchronous generator is proposed. A control system is designed to harvest maximum wind energy under varied wind conditions with the use of the permanent magnet synchronous generator, diode-rectifier and Z-source inverter. Control systems for speed regulation of the generator and for DC- and...
This paper presents the application of a suitable control strategy for multibus microgrid applications. The control strategy, used with each distributed generation system in the microgrid is developed so as to combine the advantages of the current control and the voltage control strategies. The performance of the proposed application in terms of power management has been verified in simulation on...
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