The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The increasing demand for the use of electricity results in a necessary expansion of the energy matrix through alternative sources, including the participation of small power generators in low or medium voltage. In this scenario, one of the challenges is the automation of network communication process between different devices, such as generator controllers, smart meters etc., in order to facilitate...
Low carbon emission is one of the main targets for smart grid planning. To achieve this goal, intermittent energies such as wind and solar are integrated to the power systems increasingly. However, this may create huge challenges to the power system operators for balancing the generation and demand at all times and guaranteeing the system reliability at the same time. With high penetration of renewable...
Permanent magnet synchronous generator (PMSG) is attractive as a power source for mobility due to its high power density and low maintenance needed. However, increase of the generator current results in the voltage drop due to the synchronous reactance. That means the generator capability including rated voltage cannot be sufficiently used in whole operating range without reactive power control. This...
For the integration of more renewable energy in a micro-grid greenhouse we have conducted a research for geothermal energy conversion into electricity. Thermal energy conversion uses a steam turbine providing mechanical torque on the shaft of a permanent magnet synchronous motor. Electronic conversion of alternating current to continuous current is performed with conventional modules. Finally, an...
In this paper, an agent-based distributed control scheme is presented to control single-phase parallel inverters in solar photovoltaic (PV) systems connected to microgrids. A communication assisted multi-agent framework is developed within microgrids where agents perform their tasks in a distributed manner with an aim of stabilizing load voltage and current under normal and faulted conditions through...
We proposed a novel power converter system with lithium-ion capacitors (LiCs) or lithium-ion batteries (LiBs) as the energy buffer for photovoltaics (PVs). This system can improve converter efficiency in partial load and increase total power output by charging the energy buffer without a power converter when solar irradiance is low, such as in the morning/evening or on cloudy/rainy days. However,...
A 2 MV lightning surge generator is a powerful source of interference, in particular when the voltage waveform is chopped by a shorting spark gap. We not only do need to protect the sensitive diagnostic electronic equipment that operates on small signals, but we also should guarantee its flawless operation during the discharge. The paper discusses the setup, the EMC measures taken, and the results...
This paper presents a new approach to voltage estimation for N−1 contingency analysis. The voltage magnitude after a single line or generator outage is estimated using a voltage sensitivity matrix. The sensitivity matrix is derived using phasor measurements during normal operation. This technique is compared to the traditional voltage sensitivity calculation using the Jacobian of the system, which...
The increase of Distributed Generators (DG) has encouraged the operation of these generators in islanded mode or intentional islanding. Such operation mode can increase the system reliability, once in the event of network failure the supply of critical consumers will be maintained by the DGs. However, it is necessary to consider that the fault current is considerably reduced when the system is in...
This paper introduces a method to generalize the Active Impedance Estimation (AIE) fault location method for Shipboard Power Systems (SPS.) In the proposed method short-duration high-frequency voltage sources are employed at selected buses and voltage/current measurements are taken at specific shipboard power system busses and the effect of the applied sources are observed for the purpose of fault...
To assess static voltage stability in power networks, critical load values were examined at each load bus as a voltage instability predictor. However, the information that is required to evaluate loadability conditions is usually not available at load buses. To predict impending voltage collapse in a droop-controlled power distribution network, this paper introduces a static voltage stability detector...
Generation connected to electrical distribution systems requires reliable and timely detection of loss of-mains (islanding). Passive loss of mains detection relays typically use measurements of parameters such as frequency, phase, and the magnitudes of voltage and current. If a part of the power network becomes islanded and there is a very close match between generation and demand of both active and...
The high levels of energy produced by Distributed Generation (DG) may create some problems to the voltage control of transmission systems if a great amount of active power crosses transformers and autotransformers from lower to higher voltage level (reverse power flow). In addition DG is usually intermittent and often does not participate to the voltage regulation process. This situation may be accepted...
During the charging process of impulse voltage generator, the ununiformity phenomenon of charging voltage of different stage capacitors inevitably occur which can influence the accuracy of output forecast and control settings, especially for most multi-stage generators. In the paper, the mathematical analysis of the charging process is discussed using the artificial transmission line model. The simulation...
To solve generator problem of the sensor nodes for floating bridge monitoring system, design a kind of self-sustaining circular sheet piezoelectric generator. Its most important feature is the use of a self-sustaining circular sheet piezoelectric structure, it converts the mechanical energy into vibration excitation source, so as to extend the load's continuous effect and correspondingly extend the...
Most utilities use a standard small generator interconnection procedure (SGIP) process that includes a screen for placing potential PV interconnection requests on a fast track that do not require more detailed study. One common screening threshold is the 15% of peak load screen that fast tracks PV below a certain size. This paper performs a technical evaluation of the screen compared to a large number...
In high altitude wind power (HAWP) generating system, medium voltage AC (MV-AC) permanent magnet synchronous generator (PMSG) is used. The generated electrical power is transmitted to ground without any power conditioning in the air-borne unit. The ground based power conversion system (PCS) interfaces variable voltage and variable frequency medium voltage power into distribution level grid voltage...
The classical equal area criterion in the power-angle domain, which is typically used for power systems planning/stability studies, is modified to the time domain for out-of-step protection. Wide-area measurements are necessary to obtain the power-angle information if the traditional equal area criterion is applied for out-of-step detection. However, its time-domain modification requires only the...
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...
This paper discusses the relationship of line overload cascading and loss of synchronism in interconnected power systems. The mechanisms of recent blackouts ending in loss of synchronism are reviewed and assessed. Further, theoretical considerations about the phenomenom of loss of synchronism ending in Out of Step (OOS) are discussed. Moreover, loss of synchronism scenarios are simulated in a multi-area...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.