By HDK / Published on Tue, 2009-09-15 14:55
In cooperation with PSERC, we are pleased to offer access to this archived webinar. To watch the recording (56 minutes), click the link in the further reading block.
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By HDK / Published on Tue, 2009-06-09 12:58
All users of an electrical power system expect that the frequency and voltages are maintained within acceptable boundaries at all times. Some participants, mainly generating units, provide the necessary frequency and voltage control services, called ancillary services. Since these participants are entitled to receive a payment for the services provided, markets for ancillary services have been developed along with the liberalisation of electricity markets. However, current arrangements vary widely from a power system to another.
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By Hans De Keulenaer / Published on Sat, 2009-01-17 12:06
The Department of Energy's (DOE) Electricity Advisory Committee (EAC) has released three reports prepared for the Secretary of Energy's consideration. These reports review challenges facing DOE and the Nation in many important electricity areas, and include recommendations for policy and program initiatives. They address issues surrounding generation and transmission adequacy, energy efficiency and demand response, deployment of energy storage technologies, and deployment of smart grid technologies. The EAC was chartered by Secretary Samuel W.
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By Fernando Nuno / Published on Fri, 2008-04-04 14:16
Up to 40.8% of the overall electricity demand is supplied by wind power at some moments of the day in the Spanish electricity system. This record constitutes a real challenge for transmission system operators (TSOs).
In more general terms, renewable energy penetration strongly depends on the ability of TSO to evolve towards a new way of operating the system: dedicated predictability for renewable generation, voltage dip management and managing the power balance.
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By Hans De Keulenaer / Published on Wed, 2007-11-28 13:09
As the fifth in a series of tutorials on the power system, Leonardo ENERGY introduces its minute lecture on voltage and frequency control, using the analogy of a metal/rubber plate to demonstrate the centralised nature of frequency control, whereas voltage control is more a local matter.
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By Hans De Keulenaer / Published on Fri, 2007-09-21 09:45
The amount of power a power plant can be reliably called upon to provide, usually defined by its statistically reliable output during times of peak load. In these guidelines, it is assumed to indicate the amount of a power plant’s capacity that may be considered firm.
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By Isabelle Heriakian / Published on Mon, 2007-09-03 00:00
In this paper the possibility of errors in the measurement of average values (in particular rms values or active powers) in power systems under nonsinusoidal conditions are discussed. The errors considered are either due to the fact that the measurement time interval is not an exact multiple of the fundamental period of the voltage and current signals, or due to the presence of interharmonics or subharmonics. The errors are calculated and the results are illustrated by means of simple examples.
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By Isabelle Heriakian / Published on Sun, 2007-09-02 00:00
The paper presents an implementation of a virtual instrument to perform wavelet analysis on the Park Power components. The main purpose of the analysis is an automatic detection of load in a power system applying load signature analysis. A justification for the approach is presented, followed by the details about the specific implementation performed in the laboratory. Finally a preliminary testing activity based on the use of Hardware in the Loop approach is also presented.
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By David Hirst / Published on Mon, 2006-03-20 10:39
Date: April 25, 2006 at 14h00 GMT+1
Duration: 1 hour
Speaker: David Hirst
Ambient generation is available when nature decides, not us. Therefore, its use requires actions to balance the electricity system. Up to now, ambient generation has been considered largely as negative load, simply adding to the variability of the daily load profile. The unbuffered use of ambient generation will be limited to a certain extent. Beyond this, more active approaches are needed, such as smart distribution grids and demand response schemes. This web event, part of Leonardo ENERGY's campaign on the 'electricity system of the future' present a promising scheme using system frequency to use the inherent storage capacity of domestic appliances.
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By Hans De Keulenaer / Published on Thu, 2006-02-16 18:07
During the last decades, wind power has known an immense growth over the world, and particularly in Europe. The traditionally mentioned advantages are the infinite availability of the ‘fuel’ (wind), and the fact that wind turbines produce electricity without emitting carbon dioxide or other toxic gases.But can wind power be installed without limits, in a country like Belgium? Except for the lack of space, there is the difficulty that wind power is never as reliable as conventional power plants, because wind can never be predicted with unlimited accuracy, let alone controlled.
However, accurate prediction and control is necessary. The European electricity grid is divided in a number of control areas. The grid operator in each control area (e.g. Elia in the control area Belgium – Luxembourg) makes sure that the instantaneous power production in its area is always equalto the total consumption. Otherwise, the grid becomes instable, with severe disturbances resulting from it. Because the grid operator can never know in advance the exact amount of total power consumption in its control area, an amount of ‘regulatingpower’ is needed: this consists of power plants that can control their output power or that can be put into service within a very short timeframe, to immediately respond to load fluctuations.
With an increasing number of wind turbines connected to the grid, more regulating power is required. While the variation of power consumption in a control area is well predictable, because it shows the same pattern every day, the power production by wind turbines is much less predictable. When the wind speed is high and all wind turbines are operating at full power, the risk that the wind speed suddenly drops must always be taken into account. In that case, the system depends on the regulating power. Regulating power consists of e.g. turbojets, well controllable but consuming a lot of fossil fuel. With high penetration of wind power in a control area, the uncertainty of power production becomes an order of magnitude higher than was previously the case. The turbojets will operate more, as a consequence the total fuel consumption and carbon dioxide emissions of all power plants together will possibly be higher than for a scenario with less wind power.
What if the wind turbines are geographically well spread over the control area, rather than all turbines installed close to each other in large wind farms? Is there then a high probability that always somewhere in the control area there will be much wind, and somewhere else not, making sure that the fluctuations of total power production by the aggregated wind park are limited? The answer is no. The correlation between wind speeds in Belgium is very high, or, when the wind speed changes in the coastal region, the probability is high that de wind speed changes to the same extent at the same hour in Brussels or elsewhere. The advantage of spatially distributing wind turbines over the control area is only relevant when large areas can be considered, e.g. Western Europe. Unfortunately, it is at this moment technically not feasible for a large region such as Western Europe to operate permanently as a single control area. This would result in large and unpredictable power flows between the actual control areas, requiring high investment costs for reinforcement of the many congested high voltage lines connecting the different control areas.
Then how far can you go with wind power in Belgium? The conclusion of the thesis is that in Belgium there is space – from the electrotechnical point of view – for 500 to 700 MW of wind power, or 250 to 350 medium-sized turbines. From then on, the negative effect of the extra required regulating power becomes relevant. Considering that nearly 200 MW is installed in Belgium by now, and 216 MW will possibly be constructed offshore in a near future, this limit is already relatively near. Meanwhile, it is worth the effort to look for alternatives for responding to the increased demands of regulating power. ‘Demand side management’ (actively controlling the power consumption, as a function of the available power) is a very promising option for this.
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By Hans De Keulenaer / Published on Mon, 2006-01-23 18:29
Date: February 16, 2006 - 14h00 Europe Standard time
Duration: 1 hour
Speaker: Joris Soens, KULeuven
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