No abstract

Resource Planning (or Long Term Transmission Planning) and System Adequacy assessment at the RTO/ISO level in an electricity market environment had added more requirements for new computing tools. The decoupled approach of forecasting the performance of a generation portfolio (LOLE-based) given its historical outage information combined with a deterministic approach to transmission planning based on N-1 criteria present major weaknesses in that the consequences of multiple component failures and the probabilities of single components failure are excluded from consideration. Other considerations that are excluded are a number of uncertainty factors such as load forecasts, location of future generation and fuel price forecasts in addition to social, political and environmental issues and their impact on electricity price volatility. As a result system adequacy is understated which at best leave system operators, at times, with not enough available resources for secure and reliable operation, which in turn lead to high system congestion and inefficient use of resources, and at worst leads to an underestimated forecast of future system reliability needs (transmission, generation or demand response resources).This paper presents a resource adequacy approach that evaluates system reliability taking into consideration the combined unavailability of both transmission and generation resources. Using the ABB GridView application, a production cost based market simulation software, which is capable of conducting chronological Monte-Carlo simulations; the overall system resource adequacy was assessed. Effects of including transmission unavailability are illustrated through a market simulation analysis of the NYCA system based on publicly available transmission, generation, and demand data. This approach is not meant to replace the N-1 based criteria; it will only provide an added dimension to the transmission planning process.

No abstract

CCD cameras have gained wide acceptance in electron microscopy due to their ease of use, high resolution and excellent linearity. It has been demonstrated that at 120 KeV the DQE and SNR of the latest fiber-optically coupled CCD cameras equals or exceeds that of film over most spatial frequencies [1,2]. At higher accelerating voltages that are often necessary to penetrate thick tomography specimens, the resolution of fiber-coupled cameras is reduced by electron back-scatter in the fiber optic [3] (Figure 1). We have developed a new lens-coupled camera that utilizes a transmission scintillator and 90 degree fold mirror to reduce the effect of electron back-scatter and thus improve DQE at high spatial frequencies. Figure 2 illustrates the basic geometry of the CCD imaging system. The beam, after passing through a Gatan Imaging Filter (GIF) forms a zero-loss energy-filtered image on the far side of a transmission scintillator 90 mm in diameter. The image is reflected by a Beryllium mirror oriented at 45 degrees and transferred to a 4K x 4K back-illuminated CCD with 15 µm square pixels by a 0.25 NA image transfer lens of unit magnification. The entire assembly is coupled rigidly to the TEM column and supported by an additional air spring tied into the TEM air suspension system. DQE was measured at 100, 200, and 300 KeV, 10 primary electrons per pixel (pe/pixel), with a Gatan US4000U fiber-coupled 4K x 4K camera with 15 µm square pixels ( Figure 3) and at 200 KeV with the lens-coupled camera equipped with a front-illuminated 4K x 4K CCD (Figure 4). The backilluminated CCD for the lens-coupled system is currently under development so the effect of its greater quantum efficiency on DQE was estimated. In the fiber-coupled system, there is a 4-fold reduction in DQE at half Nyquist at both 200 and 300 KeV compared with 100KeV. The DQE of the lens-coupled camera at half Nyquist, when corrected to include the enhanced performance of the back-illuminated CCD, is improved by a factor of 2.75 at 200 KeV compared with the US4000U. At 300 KeV, it is expected that the DQE of the lens-coupled system will increase further due to less electron scatter.We will present new DQE data obtained from the back-illuminated CCD at 300 KeV demonstrating the ultimate performance of the system.

No abstract