Grid Applications

This paper presents an optimized digital implementation of phase locked loops (PLLs) for grid applications suitable for implementation in low-cost industrial devices. A robust PLL is crucial in most of power converter applications, particularly in distorted environments. That is, the phase estimation should not be affected by power quality phenomena, given by Standard EN 50160, such as harmonics, imbalance, line notching, and voltage sags. The PLL dynamics is optimized as follows. A notch filter inside the loop is implemented to enhance the steady-state filtering.

During the past years it has become evident to the technical community that computational resources cannot keep up with the demands generated by some applications. As an example, particle physics experiments produce more data than can be realistically processed and stored in one location (i.e. several Petabytes/year). In such situations where intensive computation analysis of shared large scale data is needed, one can try to use accessible computing resources distributed in different locations (combined data and computing Grid).

Distributed computing & the concept of a computational Grid is not a new paradigm but until a few years ago networks were too slow to allow efficient use of remote resources. As the bandwidth and the speed of networks have increased significantly, the interest in distributed computing has taken to a new level. Recent advances in optical networking have created a radical mismatch between the optical transmission world and the electrical forwarding/routing world. Currently, a single strand of optical fiber can transmit more bandwidth than the entire Internet core. What's more, only 10% of potential wavelengths on 10% of available fiber pairs are actually lit. This represents 1-2% of potential bandwidth that is actually available in the fiber system. The result of this imbalance between supply and demand has led to severe price erosion of bandwidth product. Annual STM-1 (155 Mbit/sec) prices on major European routes have fallen by 85-90% from 1990-2002. Therefore it now becomes technically and economically viable to think of a set of computing, storage or combined computing storage nodes coupled through a high speed network as one large computational and storage device.

The use of the available fiber and DWDM infrastructure for the global Grid network is an attractive proposition ensuring global reach and huge amounts of cheap bandwidth. Fiber and DWDM networks have been great enablers of the World Wide

Web fulfilling the capacity demand generated by Internet traffic and providing global connectivity. In a similar way optical technologies are expected to play an important role in creating an efficient infrastructure for supporting Grid applications.

The need for high throughput networks is evident in e-Science applications. The USA National Science Foundation (NSF) and European Commission have acknowledged this. These applications need very high bandwidth between a limited number of destinations. With the drop of prices for raw bandwidth, a substantial cost is going to be in the router infrastructure in which the circuits are terminated. "The current L3-based architectures can't effectively transmit Petabytes or even hundreds of Terabytes, and they impede service provided to high-end data-intensive applications. Current HEP projects at CERN and SLAC already generate Petabytes of data. This will reach Exabytes (10^18) by 2012, while the Internet-2 cannot effectively meet today's transfer needs."

The present document aims to discuss solutions towards an efficient and intelligent network infrastructure for the Grid taking advantage of recent developments in optical networking technologies.

SUMMARY Low power wind turbines (WTs) are less widely applied compared to medium and high power systems. These WTs are suitable for decentralized applications and can provide electricity to residential buildings, hotels, greenhouses, etc. These WTs can be of horizontal or vertical rotor axis, must be of low cut-in wind speed and flexible in installation and operation, considering their limits

There is a growing need to explore path dependence of aging processes in batteries developed for longterm usage, such as lithium-ion cells used in hybrid electric vehicle (HEV) or plug-in hybrid vehicle (PHEV) applications that may then be "retired" to be utilized in grid applications. To better understand the foremost influences on path dependence in the PHEV context, this work aims to bridge the gap between ideal laboratory test conditions and PHEV field conditions by isolating the predominant aging factors in PHEV service, which would include, for example, the nature and frequency of duty cycles, as well as the frequency and severity of thermal cycles. These factors are studied in controlled and repeatable laboratory conditions to facilitate mechanistic evaluation of aging processes. This work is a collaboration between Idaho National Laboratory (INL) and the Hawaii Natural Energy Institute (HNEI). Commercial lithium-ion cells of the Sanyo Y type (18650 configuration) are used in this work covering two initial independent studies of path dependence issues. The first study considers how the magnitude of power pulses and charging rates affect the aging rate, while the second seeks to answer whether thermal cycling has an accelerating effect on cell aging. While this work is in early stages of testing, initial data trends show that cell aging is indeed accelerated under conditions of high discharge pulse power, higher charge rates, and thermal cycling. Such information is useful in developing accurate predictive models for estimating end-of-life conditions.