13,731 research outputs found
Tests of the 30-MJ Superconducting Magnetic-Energy Storage Unit
No full textA 30-MJ (8.4 kWh) superconducting magnetic energy storage (SMES) unit with a 10-MW converter was installed during the later months of 1982 at the Bonneville Power Administration (BPA) Tacoma substation in Tacoma, Washington. The unit, which is capable of absorbing and releasing up to 10 MJ of energy at a frequency of 0.35 Hz, was designed to damp the dominant power swing mode of the Pacific AC Intertie. Extensive tests were performed with the unit during the first half of 1983. This paper will review the major components of the storage unit and describe the startup and steady state operating experience with the coil, dewar, refrigerator and converter. The unit has absorbed power up to a level of 11.8 Mw. Real power was modulated following a sinusoidal power demand with frequencies from 0.1 to 1.2 Hz and a power level up to +- 8.3 MW. The unit has performed in accordance with design expectations and no major problems have developed
Power System Frequency Control: Modeling and Advances
No full textPower System Frequency Control: Modeling and Advances evaluates the control schemata, secondary controllers, stability improvement methods, optimization considerations, microgrids, multi-microgrids, and real-time validation required to model and analyze the dynamic behavior of frequency in power systems. Chapters review a range of advanced modeling and analytical considerations for single to multi-area networks using traditional and hybrid sources, including renewable sources, FACT devices and storage. The work also considers broad aspects of upstream and downstream control mechanisms which enable novel solutions in the area of automatic generation control in power system networks. Highly recommended for power system engineers, researchers and practitioners with interests in load frequency control, automatic generation control, linearized models of isolated microgrid, and multi-microgrid, and hybrid LFC scheme, this book is an ideal resource on the topics discussed.No Full Tex
Increasing output power of electromagnetic vibration energy harvesters using improved Halbach arrays
No full textThis paper extends previously published studies into the performance of Halbach arrays for electromagnetic vibration energy harvesting. A Halbach array is a specific arrangement of permanent magnets that concentrates the magnetic field on one side of the array while cancelling the field to almost zero on the other side. This arrangement can improve electromagnetic coupling in a limited space. Previous research showed that although the Halbach array has higher magnetic field density compared to normal magnet layouts, its magnetic flux change rate is not necessarily high. Thus, output powers of energy harvesters with standard Halbach arrays are not always greater than those with normal magnet layouts. Two improvements to the Halbach arrays that lead to increased output power of electromagnetic vibration energy harvesters are presented in this paper. Test results showed that the proposed improved Halbach arrays can increase the output power of energy harvesters by a factor of seven compared to the standard Halbach array
Actively pulse-shaped 2 mJ, 200 W fiber MOPA at 2048 nm for mid-IR generation in OPOs
No full textWe report on a high-power, nanosecond-pulsed, linearly polarized fiber MOPA system operating at 2048 nm, based on a flexible Tm3+-doped photonic crystal fiber (PCF), developed for pumping an optical parametric oscillator (OPO) for mid-infrared (mid-IR) generation. The system delivers pulses with 2.07 mJ pulse energy, 49 ns pulse duration, and 52 kW peak power at 100 kHz, resulting in 207W average output power. Active temporal shaping yields nearly rectangular pulses with a narrow 10-dB linewidth of 390 pm. We apply the developed laser to pump a linear, doubly resonant OPO targeting mid-IR generation across 3 μm to 5 μm via type-I phase matching in ZnGeP2 (ZGP) and CdSiP2 (CSP). For a 2 cm long ZGP crystal, we obtain 25.8W at 37.6W pump power, hence a 69% conversion efficiency and a mid-IR pulse energy of 1.03 mJ at a beam quality of Ms2=4.1 (signal) and Mi2=4.8 (idler). For a 1 cm long CSP crystal, we achieve 13.3W at 27.9W pump power and a 48% conversion efficiency with 0.53 mJ mid-IR pulse energy at a beam quality of Ms2=2.5 (signal) and Mi2=2.4 (idler)
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Design considerations for 100 MJ class flux compression pulse power systems
No full textWith the cost of high performance, capacitor-discharge, pulse power systems continuing around 0.01J per shot. While less economical than laboratory pulsed power systems, if system life exceeds a few hundred full-energy shots, explosive pulse power techniques allow initial experiments to be performed quickly and economically at energies that are prohibitively costly, and hence unavailable, using conventional techniques. A variety of configurations for flux compressors suitable for 100-MJ operation can be considered. Among these, the disk configuration, pioneered by researchers at the All Russian Institute of Experimental Physics has demonstrated both high current and high energy capabilities
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30-MJ Superconducting Magnetic-Energy-Storage Stabilizing System: An Overview
No full textThe 30-MJ superconducting magnetic-energy-storage (SMES) system was devised as an alternate means to modulate the Bonneville Power Administration (BPA) Pacific AC Intertie, a part of the Western US Power System, to prevent undamped power oscillations at 0.35 Hz that were observed to be associated with high power transmission. The SMES system was installed at the BPA Tacoma Substation and successfully operated as an experimental device to initiate tests to determine power system dynamics, to investigate their variability, to assess system response to SMES modulation with a major variable load, and to use SMES to develop stability-control techniques. The system has been operated at frequencies of 0.1 to 1.0 Hz at power levels of +- 8.3 MW with a parallel modulation of the converter bridges and up to 9.5 MW reactive power together with +- 4.5 MW real power in constant VAR mode with buck-boost modulation of the bridges. The coil has been charged at a maximum rate of 11.8 MW. Operation of the SMES system is now under BPA jurisdiction, and all hardware has been transferred to BPA
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Plant and operational features of the BPA 30 MJ superconducting magnetic energy storage system
No full textA 30 MJ superconducting magnetic energy storage (SMES) system was designed and developed for application in the Western US Power System to damp power oscillations that limit high voltage ac transmission. The system is in place at the Bonneville Power Administration (BPA) Tacoma Substation and has been in an experimental use for over a year. Extended operations of the unit have been undertaken with success. The physical, electrical, and operational features of the SMES system are given
100W fully-fiberised ytterbium doped master oscillator power amplifier incorporating adaptive pulse shaping
No full textWe report a pulsed, fully-fiberised, Yb-doped MOPA with a maximum average output power of 100W. Adaptive pulse shaping was incorporated to reduce the impact of nonlinearities, delivering 2mJ flat-topped pulses with 20kW peak power
Characteristics of Q-switched cladding-pumped ytterbium-doped fiber lasers with different high-energy fiber designs
No full textWe theoretically and experimentally analyze Q-switched cladding pumped ytterbium-doped fiber lasers designed for high pulse energies. We compare the extractable energy from two high-energy fiber designs: (1) single- or few-moded low-NA large mode area (LMA) fibers and (2) large-core multimode fibers, which may incorporate a fiber taper for brightness enhancement. Our results show that the pulse energy is proportional to the effective core area and, therefore, LMA fibers and multimode fibers of comparable core size give comparable results. However, the energy storage in multimode fibers is mostly limited by strong losses due to amplified spontaneous emission (ASE) or even spurious lasing between pulses. The ASE power increases with the number of modes in a fiber. Furthermore, spurious feedback is more difficult to suppress with a higher NA, and Rayleigh back-scattering increases with higher NA, too. These effects are smaller in low-NA LMA fibers, allowing for somewhat higher energy storage. For the LMA fibers, we found that facet damage was a more severe restriction than ASE losses or spurious lasing. With a modified laser cavity, we could avoid facet damage in the LMA fiber, and reached output pulse energies as high as 2.3 mJ, limited by ASE. Theoretical estimates suggest that output pulse energies around 10 mJ are feasible with a larger core fiber, while maintaining a good beam qualit
Power-scalable Ho:YAG slab laser intracavity side-pumped by a Tm:YLF slab laser
No full textWe report the first demonstration of an intracavity side-pumped Ho:YAG slab laser, delivering 13W at 2.09µm and discuss the advantages of this scheme as an approach for power scaling
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