Ceps (Czechia)

The paper presents the use STATCOM for damping of power system oscillations. Interarea oscillations are simulated on the simplified twenty areas dynamic models of the Continental Europe and their damping using the additional stabilization circuit of the STATCOM control is presented.

The increasing pressure to decarbonise energy production leads to the need to use low or zero carbon fuels or energy carriers. One of the promising fuels of the future is hydrogen, which is carbon-free if renewable energy sources are used for its production. However, the capacity for hydrogen production is currently insufficient to make it applicable on a large scale. Adding hydrogen to natural gas allows for a reduced carbon footprint without costly modifications to pipeline distribution network. However, changing the composition of gas in transport and distribution facilities requires a thorough assessment of the impact on operational safety. Fire safety of flammable mixtures is commonly assessed on the basis of explosive limits and other parameters. Although methods are available to calculate these parameters based on the composition of the mixtures being evaluated, the final safety assessment should rely on actual measured values. The scope of this work is to determine the explosion limits of natural gas from the transit system and changes in the limits caused by the addition of hydrogen at the concentration levels of 10% and 20% (v/v). Obtained experimental results were further compared with theoretically calculated values. Attention was also paid to the change in maximum explosion pressure, maximum pressure rise rate and oxygen concentration limits (LOC). As a result, valuable data on the expansion of the explosion limits of natural gas after the addition of hydrogen are presented.

The planned phase-out of coal power plants connected to transmission and distribution networks 110 kV is associated with the task of substitution of current active and reactive sources with new ones, based on an innovative technology. The new connected sources are mainly decentralized, renewable and are based on the non-synchronous power modules connected particularly to distribution networks (MV and LV). This influences their capability for reactive power operation. Improvement recommendations for the reactive management in distribution and interface transmission/distribution systems are presented based on wider technical studies in cooperation with TSO and DSOs in the Czech Republic.

En 1999, le Traité d’Amsterdam a établi les fondations de l’Espace européen de liberté, de sécurité et de justice (ELSJ). Celui-ci prévoit l’harmonisation des lois dans les domaines de l’immigration, de l’asile, du contrôle des frontières et des visas, à l’appui du principe de la libre circulation des personnes. Le programme de Stockholm, adopté en décembre 2009, définit les orientations stratégiques des politiques européennes correspondantes pour les cinq prochaines années. Il entend placer ...

L’expulsion de Roms bulgares et roumains d’Italie en 2009 et de France en 2010 a provoqué de nombreuses discussions, contestations et préoccupations. En ce qui concerne la France, les expulsions de Roms de juillet et août 2010 (des expulsions seraient encore en cours selon de nombreuses sources) ont eu de multiples conséquences : elles ont généré de la discorde au sein des institutions de l’Union Européenne ; elles ont amené le commissaire européen chargé des droits des citoyens à s’opposer a...

Behavior of grids with different types of sources should be investigated during variable conditions like daily demand change, sunshine and wind fluctuations. Dynamic model is used for simulation of parallel operation of different types of dispersed sources - wind farms, photovoltaic plants, small hydro and gas turbines. The first two sources are modeled according up to data knowledge. Paper pays attention to appropriate load/frequency and reactive power/voltage regulation of all source, not only bulk power plant, but embedded small and renewable sources as well.

Installing new power generation unit always effects operation and performance of a power system including balance between load and generation. Consequently, demand for power reserves the power balancing authority has to acquire for keeping the power system in the equilibrium is changing. Restructuring power system in terms of shutting down old generation units, installing new ones or changing operational characteristics of the existing units will result in different needs for the amount and dynamics of power reserves in the respective categories. The paper studies the situation when the portfolio of power generation units is planned to be changed, new units are going to be installed and some old ones shut down. The effect on power system reliability and change in demand for ancillary services (AS) which are needed to meet the reliability standards is analyzed. Power system reliability is expressed in terms of reliability indices as used by the Czech TSO. Two scenarios of future development of power unit portfolio differ in number and capacity of new units. Finally the impact of new units on AS reservation cost is shown and discussed.

The demand for capacity reservations at the transmission interconnections between control areas in Central Europe is usually much higher than the capacity available for electricity trading. It is expected, that as a consequence of market opening according to the market liberalisation in Europe, the demand will further increase over time. In the beginning of 90 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sup> , before liberalisation of electricity market, there were vertically integrated utilities - monopolies in each of Central European countries. Cross border exchange was mainly between two utilities, and only as an addition to the overall national balance. Utilisation of interconnectors was planned together with system balance planning and there was under normal operation no congestions. Since 2002, demand for cross border capacity exceeded permanently offered capacities. Congestion management methods was gradually developed on different interconnectors depend on the level of electricity market opening in different states. The vast majority of electricity trading in control areas of concerned TSOs is thus based on OTC bilateral contracts. For that reason, explicit auctions was established as the most appropriate market mechanism for cross border capacity allocation. First auctions was organized independently on both sides of the interconnection i.e. two auctions for one interconnection. Soon after, under the pressure from traders side, concerned TSOs established on most of the interconnectors common bilateral auction. Due to the technical constrains in the regional network there are two possible technical limits, which must be taken into account. Either the internal network in one control area is congested as a consequence of the past development. Concerned TSO's in the region agreed to start a common regional auctioning procedure for transmission capacities reservation on all borders between them in the same time and to allocate available capacities on the congested profiles in the way which gives to market players a requested transmission capacity reservation on the indicated border . Auctions for yearly, monthly and daily capacities for the year 2005 was organized followed by monthly auctions. Daily auctions and capacity transfers among market participants are administrated by Internet based system through auction e-portal