Group items tagged voltage - Clean Energy Transition

shared by Colin Bennett on 01 Dec 09 - Cached

To date, permanent magnet motors have not been widely used in many industrial applications as they require additional speed or position sensing mechanisms and control by high end drive units, making them relatively costly and complicated to install.  As a result, even though they are less efficient and considerably larger in size, induction motors have generally been the preferred choice for design and production engineers. Now, however, by using innovative algorithm control based on motor voltage and current output, the new AC650S Drive enables standard permanent magnet motors to be used in closed loop applications, without the need for additional sensors.  Engineers can therefore benefit from the energy savings that can be achieved from brushless motor such as Parker’s NX and ATEX EX Series, with savings of up to 12% for a 0.75kW system being possible; similarly, engineers have the opportunity to design more compact control systems, which can be as small as 25% the size of a conventional induction motor assembly.
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shared by Hans De Keulenaer on 10 Jun 08 - Cached

The paper discusses the use of a dual energy storage system based on batteries and supercapacitors in hybrid electric vehicles (HEV). The battery has a large energy density, enabling an all-electric driving range of 100 km, while the supercapacitor has a large power density and provides peak power during acceleration and regenerative breaking. The paper discusses the benefits and drawbacks of both storage systems and the specific requirements imposed by the hybrid drive train. Coupling such a HEV to the grid allows interaction between grid and HEV, providing the grid with a controllable load. Depending on the communication between the hybrid fleet and the grid, this load can be controlled by adjusting the electricity price in order to allow a higher penetration of intermittent renewable energy sources such as wind parks in the grid and if the communication allows the transmission system operator to reduce the load imposed on the grid by the hybrid fleet, the hybrid fleet can become part of the secondary frequency control reserve. In case of sudden demand or supply fluctuations, the hybrid fleet can assist in primary control of the grid. Due to the dual energy storage system the HEVs can also provide fast load tracking to keep the voltage in microgrids at the desired set point. An experimental setup with a battery, grid coupling and induction machine proves the feasibility of the concept.
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shared by Hans De Keulenaer on 02 Dec 09 -

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Many politicians are supportive, not least Barack Obama, the US president, who in October promised $3.4bn in grants to pay for smart grid equipment.However, an investment on that scale does no more than lay the foundations: a full smart grid for the US will require an investment that is orders of magnitude greater. The commercial and regulatory framework to deliver that investment has not yet been developed.
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The epithet “smart” can be applied to a wide range of network technologies. But among industry leaders, there is broad agreement about what a smart grid entails: the use of intelligent devices at all points in the electricity network, from the high-voltage transmission lines to appliances in the home, that can send information and receive instructions.
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shared by Hans De Keulenaer on 20 Oct 09 -

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The European Commission has imposed fines totalling € 67 644 000  on seven companies – ABB, AREVA T&D, ALSTOM, Fuji Electrics, Hitachi and Toshiba - for violating the EC Treaty’s ban on cartels and restrictive business practices (Article 81). Siemens also participated but was not fined because it revealed the existence of the cartel in question to the Commission. Between 1999 and 2003, Japanese and European producers of power transformers operated an oral market sharing agreement, referred to as a "Gentlemen's Agreement", where they agreed that the Japanese members would not sell power transformers in Europe and that the European members would not sell power transformers in Japan. The power transformers in question are used to modify the voltage in electricity transmission networks. The fine for ABB was increased by 50% because it had previously taken part in a similar infringement.
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shared by Sergio Ferreira on 31 Oct 07 - Cached

SDG&E says that nearly 80,000 of its customers lost power, but by October 27th, power had been restored to all but 6,700 customers. Over the weekend, the utility expected to restore power to 97% of those affected, leaving only 2,400 without power
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On Monday, October 22nd, the state's electrical grid operator—the California Independent Systems Operator (ISO)—declared an emergency when the Santiago Fire in Orange County caused two more high-voltage transmission lines to trip off-line. To avoid reduce stress on the power grid, the California ISO asked two utilities—Southern California Edison (SCE)and the San Diego Gas and Electric Company (SDG&E)—to reduce their electrical load by a total of 500 megawatts.
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shared by Hans De Keulenaer on 02 Jul 07 - Cached

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