Portion Of Overhead Research Articles

Single-Pole Autoreclosure in uncompensated EHV AC mixed overhead-cable lines: A parametric time-domain analysis

The successful application of the Single-Pole Autoreclosure (SPAR) to Extra-High Voltage (EHV) overhead lines (OHLs), as well as to the overhead portion of EHV mixed cable-overhead lines (MLs), significantly improves system stability. SPAR success requires that the secondary arc self-extinguishes during the dead time: according to the literature, self-extinction times increase with the increase of both secondary arc current and recovery voltage. Steady-state analyses of EHV MLs not equipped with inductive shunt compensation showed larger secondary arc currents and smaller recovery voltages compared to OHLs. Since steady-state analyses cannot give indications on arc self-extinction times, transient studies are required to assess which of the above effects has a prevailing influence, i.e., whether SPAR in uncompensated MLs results hindered or facilitated. This paper presents a time-domain study of the SPAR cycle in an uncompensated 400 kV-50 Hz ML, making use of detailed ATP-EMTP line and fault arc models. A parametric study has been carried out, evaluating secondary arc current, extinction time and recovery voltage for different single-phase fault locations along the overhead section of the line. Transient simulation results point out to extinction times being shorter in MLs than in OHLs of the same total length.

2008 AACP Treasury Report

Good Morning, my name is Keith Herist and I am your Academy's Treasurer. This meeting completes my first year as Treasurer, and I am pleased to report our Academy is financially strong with growing revenues and a solid balance sheet. 2008 was a pivotal year in the Academy's advancement and one of infrastructure investment. The most significant change was the acquisition, build out, furnishing and relocation to a new, more expansive headquarters office within Alexandria, VA - actually only a few blocks away from the former office building. Staff took occupancy of the new office occurred on March 17- St. Patrick's Day – always a lucky charm! Staff also initiated projects during the year for developing a new web site and upgrading the membership and financial databases and both projects are expected to be implemented this fall. AACP hired a seasoned Director of Finance, Sibu Ramamurthy. Working with Dan Cassidy, our COO, and I, Sibu brings many years of financial experience to the table and would be the third CPA on ‘staff’ in addition to Dan and myself once he completes his exam. Last fall, staff worked with the Academy's auditor and completed the annual financial audit in record time- and plans are in place to complete the audit even earlier this year as well as making sure we have the requisite financial policies in place to operate our complex organization more effectively. And now, what would a Treasurer's report be without at least a few numbers … While we have not ‘closed’ out FY 2008 yet, we are expecting total revenues of $9.2M and net revenue of 3% or about $275,000, before investment gains and losses. These results are below the 6% net in 2007 and reflect expansion of many program areas such as publications, communications, meetings and outreach efforts. AACP's $5M balance sheet is highly liquid and we maintain about two-thirds of our assets in cash and investments. Speaking of investments, our portfolio of nearly $2.0M returned 11% over the past 5 years but is down 7% since January 1. The Board approved a change in our investment policy, which we redeveloped with our money manager, to a balanced allocation of assets with targets of 65% - 35% stocks to bonds. This change will help regulate asset declines in difficult markets and is expected to yield a more modest 8%, based on modeling the accounts under these new allocations. With the former office building on the market for sale, we are expecting a large capital gain and well over $1.0M of cash to be added to investments upon its sale. Sales traffic has been lighter than expected because of a slowing economy since the property went up for sale at the end of 2007. Looking ahead to the Budget for FY 2009, we are expecting higher total revenues of $9.8M but with a very small net revenue of roughly 1% or slightly more than $100,000. AACP continues to derive most of its revenues from three main areas- PharmCAS, meetings and membership dues (both individual and institutional). While all three areas are growing, only PharmCAS and meetings are contributing to the bottom line (with PharmCAS having the largest net). Dues, on the other hand, now comprises a smaller % of total revenues because they have not been raised in almost 10 years. In addition and as an internal benchmark, dues no longer covers staff costs and a portion of overhead as it has in the past. Expense changes include new or expanding programs along with costs for a full year of the new office lease and a fully staffed office - with several positions reflecting our strategy to gain more control and in-source certain functions such as Technology, Meetings, and Communications now that AACP has reached its current size. As you may have already heard, some of the new programs include our plans for building a new portfolio of assessment tools incorporating an electronic Assessment system called PEAS along with efforts to address faculty shortages, among others. Overall, we have a solid financial foundation from which to expand as AACP continues to shape a growing and dynamic profession with your leadership and support. The coming year will be driven by economic factors and our collective vision to improve the delivery of healthcare here and help influence its development around the world.

Five-Wire Distribution System Demonstration Project

During this demonstration project, an overhead portion of a four-wire power distribution circuit was converted to a five-wire system. The fifth wire is an isolated neutral that carries all of the unbalanced return current. The measurements suggested that a ground relay could be set much lower on a five-wire system than a comparable four-wire system for improved high-impedance fault detection. Stray voltage was also much lower when the circuit was operated as a five-wire configuration. Magnetic fields were generally lower on the five-wire circuit than at the same locations during four-wire operation. Conversion of an existing four-wire system to a five-wire system presented several unique concems including fifth-wire placement, crew safety and operations, and how to interface the five-wire system with the existing four-wire distribution system.