SOURCES SOUGHT
A -- Power Line Protection Filter
- Notice Date
- 8/18/2005
- Notice Type
- Sources Sought
- NAICS
- 335999
— All Other Miscellaneous Electrical Equipment and Component Manufacturing
- Contracting Office
- Department of the Air Force, Air Force Space Command, 90CONS, 7505 Marne Loop, F.E.Warren AFB, WY, 82005-2860
- ZIP Code
- 82005-2860
- Solicitation Number
- FA4613-05-Q-0012
- Response Due
- 8/19/2005
- Archive Date
- 9/3/2005
- Description
- AC Power Service Entrance Surge Shunt Panels The following document presents the scope of the AC Surge Shunt Panel Development Project for the Air Force Space Command Launch Support Building upgrade as outlined in related request for information/quotation documents. The AC Surge Shunt Panel Development consists of a series of AC panels rated for use on service applications per schedule A. Each panel shall consist of a two-stage surge suppressor array designed to meet the AC service requirements as well as the desired surge handling capabilities. Schedule A Unit Service Voltage Series Load Current 1 120VAC WYE 250A 2 480VAC Delta 250A Figure 1: Electrical Service Applications The products shall be designed to provide continuous low voltage power distribution with suitable connector and conductor fittings. The surge suppression shall protect down stream loads from both high exposure lightning events and 20 second duration over-voltage/over-current fault conditions. The contractor will conduct all required 8/20?s Lightning Qualification testing at agreed upon levels in-house. All SREMP Driver testing, however, will be conducted by qualified third party test facilities at no expense to Transtector. SREMP testing will be performed by Boeing under prior direct agreements with Air Force Space Command. The Surge Shunt Panel shall consist of a surge array designed to handle all nominal lightning conditions without degradation. The surge arrays shall be housed in a robust enclosure to preclude external damage. Upon catastrophic surge events (such as an SREMP driver or an AC power fault), the SASD array portion shall fail open and the robust MOV array portion shall fail short. The MOV array shall be designed to withstand any available fault current without catastrophically failing and still exhibit a fail short condition. Any subsequent surge events shall be shunted directly to ground. The surge arrays shall be housed in a NEMA4 type enclosure, approximately 44? tall, x 24? wide x 12? deep. All surge elements must remain in ?same as new? operational status upon the application of 25 pulses, each polarity, each phase L-N modes, 50kA ASC, 7.5kVOCV surge levels, as described by test standard IEC 61643-1. The unit shall exhibit a fail short electrical path upon the application of Over-voltage test with available fault current up to 65kAIC. Prototype Development Quotation: SREMP Protected Cabinet Qty. UnitCost Total Cost Delivery Dates Details Minimum Order Figure 2: Per Unit Costs Powerline SREMP Current (U) (U) Introduction (U) This section documents the powerline SREMP current calculation for the near neighbor ECS trade study. Figure 1 is a drawing showing the problem of interest. A 1-megaton nuclear blast detonates about 6 kilometers from an LF. The blast is located directly over the powerline that services an LF. The Compton current generated in the around the fireball drives current on the powerline and into the LF support building. Figure 1. SREMP Coupling to a Powerline (arrows show electron flow which is opposite from positive current flow) (U) The powerline close to the fireball sees the E field in the highly dosed region around the fireball (600m ? 800m). This E field contact drives current down the power line and into the LF support building. The majority of the current drive occurs during the quasi-static phase of the SERMP drive when secondary gammas, produced from ground capture and air capture neutrons, drive a Compton current that lasts for several milliseconds. (U) Fireball Voltage (U) By integrating the E field outward from the fireball, we get a ground voltage profile as shown in Figure 2. Figure 2. Ground voltage due to neutron captures Compton current. (U) The fireball is highly conductive and therefore has one constant voltage. The ground voltage outside the fireball extends out to about 600 meters. Since this distance is small compared to the distance between LFs (about 6000m), we can lump the ground voltage drive onto a powerline as a voltage driver as shown in Figure 3: Figure 3. Fireball voltage driver. (U) We choose fireball voltage driver parameters to reflect a 1 MT bomb and a soil conductivity of 0.001 1/ohm-m. From previous calculations we know that the chosen soil conductivity maximizes the powerline current. (U) The fireball resistance is dominated by the air channel return current and has a value of (Reference 1): RS ? 1 ohm (U) The fireball inductance is computed in Reference 1 as: LS ? 0.0001 henrys (U) The formula for the fireball voltage, V(t), as a function of time, is obtained from scaling data in Reference 2 and can be expressed as a sum of two exponentials: (1) (U) The fireball voltage is plotted in Figure 4 using a log-log scale to clearly show the both exponential components: Figure 4. Fireball voltage as a function of time. (U) The first exponential component with decay time of 1.1 milliseconds comes from gamma radiation produced by ground capture neutrons. The second exponential component with decay time of 25 milliseconds comes from gamma radiation produced by air-captured neutrons. (U) Powerline Model (U) We now construct a lumped circuit model of a powerline. A typical rural electric powerline is composed of wires mounted on top of a 40 ft (12m) wooden pole. The poles are placed 225 ft (65m) apart. The powerline uses three 4/0 aluminum clad steel reinforced (ACSR) wire. For lightning protection, lighting arrestors are typically place every 1700 ft (500m) along a powerline run. The lighting arrestor uses an 8 ft ground rod driven into the ground at the base of the power pole. There is always a lighting arrestor at the LF service pole, before the step-down transformer. (U) The lumped circuit model of the powerline is shown in Figure 5. Because we are dealing with the millisecond timeframe (Equation 1), we chose to divide the 6000m powerline into two 3000m segments. Each 3000m segment is modeled as a resistor and inductor in series. At the 3000 meter mark we construct one resistor to ground at is the parallel combination of all the lighting arrestors along a 6000-meter run of powerline. Finally we model the site resistance as a 2.5 ohm resistor (Reference 3) for a soil conductivity of 0.001 1/ohm-m. Figure 5. Lumped circuit for SREMP current on Powerline (U) The equation and numerical values of the parameters in Figure 5 are: (U) The line inductance includes the internal inductance of each line, the line inductance of each line assuming magnetic skin depth cutoff in 0.001 1/ohm-m soil at 1 millisecond (Reference 3), and the mutual inductance between all three lines using the methods in Reference 4. (U) The circuit model response was computed using the SPICE code that uses an implicit differential equation solver. We then divided the site current by 3 to compute the SREMP current per wire into the LSB. The result of this calculation is shown in Figure 6. Figure 6 SREMP current per powerline wire into the LF site. (U) The same current per wire is plotted on a log-log scale in Figure 7 to ephasize the fact there is a significant SREMP current tail due to air captured neutrons. Figure 7 SREMP current of Figure 6, plotted on a log-log scale. References 1. M. Leonard, ?SREMP Induced Rail Curent? TRW IOC# F543-MWL-87-006, Dec 22, 1987. 2. M. Rose, T. Rynne, ?SALTE and APECS, Two Phenomologically Based Codes for Calculating SREMP Environments?, (Secret, CNWDI), TRW Doc# 46441-8101-SN-00, Oct. 1986. 3. M. Stieglitz, H. Lurch, ?SREMP Coupling Analysis of Overhead Power Lines and the Power Distribution System of the Wing V Minuteman Launch Control Facility?, (Secret), TRW Doc# 46743-6242-SX-00, Oct. 1986 4. W. Stevenson, Jr., ?Elements of Power System Analysis?, McGraw-Hill, 1975.
- Place of Performance
- Address: F.E. Warren AFB, Cheyenne, WY 82005
- Zip Code: 82005
- Country: USA
- Zip Code: 82005
- Record
- SN00873796-W 20050820/050818212607 (fbodaily.com)
- Source
-
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