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The hybrid offshore renewable energy conversion system (HORECS) consists of offshore wind, wave and tidal power generations. Its output power fluctuates, which may cause power quality problems. A coordinated control method is presented in this paper to smooth the short-term power fluctuations. The tidal generation system is used to compensate the wind and wave power fluctuations. According to the...
This paper presents a new control strategy called induction converter for integration of voltage source converters (VSCs) in smart power grids such that grid senses VSC as a virtual induction machine by proper adjustment. In this sense, related filter and line impedance is modeled as virtual stator of an induction machine and the VSC and the VSC and associated dc-link mimic mechanical and electrical...
In order to identify the dynamic signature of power systems, it is important to monitor the generator rotor angles. The rotor angles can be obtained either by direct measurements of the rotor position or by indirect calculation of rotor angle from voltage and current measurements. Considering limited availability of direct measurements of rotor angles the indirect method is used in this paper taking...
The impact of several technologies of dispersed generation on the fault current flow in regular distribution networks is discussed. The short-circuit current behavior of conventional generators (for instance those used in heat and power plants), of generators equipped with full convertors and of double fed induction generators (DFIG) are described from the perspective of a distribution system operator...
This paper presents a two-step approach for defining coherent generators in disturbed power systems based on the similarity among their inter-area oscillations and swing curves. In the first step, an online visualization of the generator swing curves is performed by extracting time domain solutions of the swing equation using PMU measurements. In the second step, the similarity between each pair of...
This paper presents a new methodology to improve the frequency stability of power system with the large integration of distributed energy resources. Distributed energy resources don't contribute to the inertial response of the system as they are decoupled from the grid by the converters. The capability of the distributed energy resources especially (PV and Wind) to provide active power support in...
Modeling of distributed generation and associated controllers have a considerable influence on the results of transient stability analysis. Synchronous generators and induction generators are two common types of generators which are used for distributed generation, for example in micro-turbines and wind turbines. In this paper, the effect of detail of modeling of synchronous generators on the transient...
This paper presents a controlled islanding algorithm based on k-means clustering. It considers Voltage Source Converter-based HVDC (VSC-HVDC) links within a synchronous system and places one VSC-HVDC terminal in each island so that power can be exchanged between the islands. This limits load shedding and/or generator tripping and reduces the overall restoration costs. The controlled islanding algorithm...
This paper describes the process of performing site tests and model development of brushless exciters. Brushless exciters are often a source for model inaccuracy when studying synchronous machines and excitation system, which may lead to incorrect stabiliser design and poor performance. The process described here involves on site testing of the excitation system both with the generating unit operating...
Nowadays, grid code requirements demand that wind energy converters (WEC) remain connected to the grid during grid faults and contribute to the voltage support, in the same way as conventional power plants. WEC which are capable of ridding through grid faults providing voltage and reactive power support are connected to the grid via electronic power converters, increasing the failure risk and reducing...
Transient stability of doubly-fed induction machine (DFIM) in hydro pumped storage plant (PSP) is analyzed and compared with synchronous machine in this paper. Model of turbine governor and model of converter control of DFIM are presented as they are applied in computer software for dynamic analyses of electric-power system. The principle of frequency control—i.e., permanent droop—and control of network...
Due to the integration of Distributed Energy Resources (DERs), both non-synchronous generators and energy storage technologies, the dynamic behavior of power systems is changing. The extent of the impact is yet to be fully investigated and quantified. Proper models, suitable for large scale studies but also representing all the DER control and protection mechanisms that affect the dynamic behavior...
One of the most important aspects in power systems concerns their capability of maintaining their stability under large disturbances. System stability is a crucial aspect to consider when expanding a network, e.g. increasing the wind power penetration. Wind turbine generators differ from the Coal, Hydroelectric or any Conventional Power Plants in their amount of inertial contribution to the grid....
The main subject of this paper is the classification and identification of observables for present and future grids. In order to make an inventory of present and potentially new observables, a systematic classification and identification of observables for future grids is conducted. After first introducing some fundamental definitions for observables, observables are further classified by the characteristic...
The paper presents a methodology to estimate the rotor angle of a synchronous generator by using measurements from phasor measurement units (PMUs). Based on the available measurements, an observer for the damper currents is designed. Using the observed damper currents, known machine parameters, and PMU measurements, stator reactances of the machine are estimated during transients following a disturbance...
This paper deals with the application of a practically oriented methodology for the phase shaping of all the PSSs in a multimachine power system. The phase shaping is carried out independently for each generating plant, but the PSS gains are determined by a coordinated tuning process considering the entire multimachine system. Results are presented for the implementation of this methodology to a 110-machine...
This paper proposes a method for assessing the damping torque contribution of generators equipped with power system stabilizers (PSSs) using synchrophasor measurements from disturbance events exhibiting lightly damping oscillations. The method is based on an extension to the Heffron-Phillips and deMello-Concordia synchronizing and damping torque analysis method to include the sensitivities for the...
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