Embed Size (px)
Citation preview
LT113393
TEST REPORT:LIGHTNING DIRECT EFFECTS TESTSON SHIELDED SHELTER ENCLOSURESReport by: Approved by:
K. E. Crouch M. M Dargi
For
PEPRO, LLC 671 Colbert Ave. Oil City, PA 16301
Purchase Order No. 4097
Tests by: Witnessed by:
K. Crouch Victor Garmong D. Deblois Kelly Lander P. Saldo Terry Ausel
Adam Felmlee Gerardo Ruiz Tom O’Neil (PEPRO)
Test dates: References:
31 January 2011 DB: 361, pp. 58 13 February 2011
3 March 2011
Lightning Technologies, Inc. 10 Downing Industrial Parkway Pittsfield, MA 012013890U.S.A.
Lightning Technologies, Inc. Test Report LT113393, Rev. () 10 Downing Industrial Parkway 3 March 2011
Pittsfield, MA 012013890 Page ii of iv
TABLE OF CONTENTS
SECTION NO. PAGE NO.
1.0 INTRODUCTION .................................................................................................. 1
2.0 BACKGROUND .................................................................................................... 1
3.0 SUMMARY ........................................................................................................... 1
4.0 TEST ARTICLES .................................................................................................. 2
5.0 TEST EQUIPMENT .............................................................................................. 5
6.0 TEST REQUIREMENTS ...................................................................................... 6
6.1 Lightning Test Levels ................................................................................. 6 6.2 Shielded Shelter Enclosure Grounding Means .......................................... 6 6.3 Isolated Test Generator Current Returns ................................................... 6
7.0 TEST SETUP AND PROCEDURES ..................................................................... 6
8.0 TEST RESULTS ................................................................................................... 8
8.1 High Voltage Tests .................................................................................... 8 8.2 HighCurrent Tests ..................................................................................... 9
9.0 DISCUSSION OF RESULTS ................................................................................ 8
9.1 Walkin Shelter .......................................................................................... 8 9.1.1 High Voltage Tests ....................................................................... 8 9.1.2 High Current Tests ....................................................................... 9
9.2 Mobile Shelter ............................................................................................ 9 9.2.1 High Voltage Tests ....................................................................... 9 9.2.2 High Current Tests ....................................................................... 9
9.3 Micro Shelter .............................................................................................. 9 9.3.1 High Voltage Tests ....................................................................... 9 9.3.2 High Current Tests ..................................................................... 10
Appendix A – Raw Data Oscillograms .............................................................. A1 – A21
Lightning Technologies, Inc. Test Report LT113393, Rev. () 10 Downing Industrial Parkway 3 March 2011
Pittsfield, MA 012013890 Page iii of iv
LIST OF TABLES
TABLE NO. PAGE NO.
Table 1 – Radio and Antenna Cable Equipment ............................................................. 4
Table 2 – Calibrated Equipment ...................................................................................... 5
Table 3 – High Voltage Test Results ............................................................................. 10
Table 4 – High Current Test Results ............................................................................. 11
LIST OF FIGURES
FIGURE NO. PAGE NO.
Figure 1 – SMRS 650 Voltage and Current Configuration ............................................... 2
Figure 2 – FDRS 6 x 6 Voltage and Current Configuration ............................................. 3
Figure 3 – CLP1Mini Site Voltage and Current Configuration ........................................ 4
Figure 4 – Typical Applied High Voltage Test Oscillogram, Vpk
=1,300 kV, Chop Time = 8 μs........................................................................................ 12
Figure 5 – Typical Flat Line and Oscillatory Measurement Response, Test No. 3 ........ 12
Figure 6 – Typical High Current Test Oscillogram, Ipk
= 89 kA, Test No. 11 .................. 17
Figure 7 – Walkin Shelter Positioned in High Voltage Test Area ................................. 13
Figure 8 – Walkin Shelter Setup Showing Gap between Electrode and Antenna ........ 13
Figure 9 – High Voltage Strike Attachment to Walkin Shelter ...................................... 14
Figure 10 – Typical High Current Measurement Response, Test No. 11, 88 kA ........... 17
Figure 11 – Typical High Current Measurement Response, Test No. 18, 76 kA ........... 18
Figure 12 – High Current Injection Test Setup for Walkin Shelter ................................ 18
Figure 13 – Antenna High Current Injection Point (Similar for all Shelter Tests) ........... 19
Figure 14 – Mobile Shelter Positioned in High Voltage Test Area ................................. 14
Lightning Technologies, Inc. Test Report LT113393, Rev. () 10 Downing Industrial Parkway 3 March 2011
Pittsfield, MA 012013890 Page iv of iv
LIST OF FIGURES
FIGURE NO. PAGE NO.
Figure 15 – High Voltage Strike Attachment to Mobile Shelter ...................................... 15
Figure 16 – High Voltage Strike Attachment to Isolated Mobile Shelter ........................ 15
Figure 17 – High Current Injection Test Setup for Mobile Shelter ................................. 19
Figure 18 – High Current Injection Test on Mobile Shelter ............................................ 20
Figure 19 – Micro Shelter Positioned in High Voltage Test Area ................................... 16
Figure 20 – High Voltage Strike Attachment to Micro Shelter ....................................... 16
Figure 21 – High Current Injection Test on Micro Shelter, Test No. 14, 70.5 kA ........... 20
Lightning Technologies, Inc. Test Report LT113393, Rev. () 10 Downing Industrial Parkway 3 March 2011
Pittsfield, MA 012013890 Page 1 of 20
1.0 INTRODUCTION
Lightning direct effects tests were performed on shelter enclosures (Faraday cage design) to demonstrate their ability to tolerate lightning strikes to the shelter without damage to the radio equipment. The shelter enclosures tested represented the range of enclosure sizes presently deployed. The test results contained in this report relate only to the test items/part numbers tested.
Tests were performed by K. Crouch, D. DeBlois and P. Saldo of Lightning Technologies, Inc. (LTI) in Pittsfield, MA during the period of 31 January to 3 February 2011. Testing was conducted in accordance with LTI Test Procedure LTTP11437 (Ref. 1). Changes were made during the tests and are outlined in this document. The systems were operated, monitored and witnessed by Victor Garmong, Adam Felmlee, Gerardo Ruiz, Terry Ausel, Kelly Lander and Tom O’Neil of PEPRO, LLC.
2.0 Background
When radio equipment shelters are installed in field locations, lightning strikes attach to the radio antennas injecting high voltages and currents into the radio antenna tower and the antenna cables.
During a natural lightning strike event, the high voltage attachment portion of the strike connects the lightning channel to the shelter. After attachment, the high current portion of the strike is injected into the shelter. During the simulated lightning tests, a high voltage test generator was used to make the attachment. A high current generator was then connected to the attachment point and discharged to deliver a high current discharge.
For those installations where the shelters can be powered from electric utility transmission lines, lightning strikes can also attach to the utility lines injecting high voltages and/or currents into the radio power supply. The power surge suppressors used in the shelters have been designed and certified to the requirements of IEEE C62.421991, Table 4, Category C3. No tests were applied to the power line suppressors
3.0 SUMMARY
High voltage lightning strike attachment tests were applied to the shelters using a 1.2 x 50 μs waveform at a 1,300 kV peak level. High current conducted entry tests were applied to the shelter using a 25 x 60 μs waveform with levels from 75 to 90 kA.
Portable radios transmitted and received a signal (tone) to and from the shelterduring the tests. The radios operated between and after all tests. The continued operationof the radios met the survivability requirements of this test program. ________Ref. 1 Lightning Technologies, Inc. Test Procedure LTTP11437, Lightning Direct Strike Tests on
Shielded Shelter Enclosures, Rev. , K. E. Crouch, 31 January 2011
Lightning Technologies, Inc. Test Report LT113393, Rev. () 10 Downing Industrial Parkway 3 March 2011
Pittsfield, MA 012013890 Page 2 of 20
Energy delivered to a 50 Ω resistor at the location where the antenna cable entered the radio did not exceed 10 μJ. Antenna cable shield currents monitored at the radio entrance did not exceed 40 A peak and 25 μs durations. Voltage measurements made between an internal equipment rack and the shelter wall ground point did not exceed 50 V and 25 μs durations during high voltage tests. Measurements made during the high current tests did not exceed 5 volts and 80 μs durations. Measurements made on the ac power line exhibited voltage clamp levels typical of suppressors installed on 240 volt power lines. These measurements were all very similar and did not yield any unexpected levels.
4.0 TEST ARTICLES
The test items supplied by and operated by PEPRO, LLC personnel included a Mobile Shelter (SMRS 650), a Walkin Shelter (FDRS 6 x 6) and a Micro Shelter (CLP1 Mini Site). Pictures and descriptions of the test items are given in Figures 1 through 3 and Table 1. Limits on the size of the high voltage and high current test areas prevented testing the enclosures with the antenna towers fully raised. The following pictures show the test articles as configured for both high voltage and high current tests.
Figure 1 – Mobile Shelter (SMRS 650)
Lightning Technologies, Inc. Test Report LT113393, Rev. () 10 Downing Industrial Parkway 3 March 2011
Pittsfield, MA 012013890 Page 3 of 20
Top View
Figure 2 – Walkin Shelter (FDRS 6 x 6)
Side View
Lightning Technologies, Inc. Test Report LT113393, Rev. () 10 Downing Industrial Parkway 3 March 2011
Pittsfield, MA 012013890 Page 4 of 20
Top View
Figure 3 – Micro Shelter (CLP1Mini Site)
Table 1 – Radio and Antenna Cable EquipmentManufacturer Equipment Model No. Serial No. Shelter Channel
Motorola Quantar
680CYB0021 SMRS 650 8TAC92 T5365A
301CZF0007 CLP1Mini Site 8TAC93
T5367A 360CCM0033 FDRS 6x6 8TAC94
Side View
Lightning Technologies, Inc. Test Report LT113393, Rev. () 10 Downing Industrial Parkway 3 March 2011
Pittsfield, MA 012013890 Page 5 of 20
5.0 Test Equipment
Table 2 provides a list of calibrated equipment used during these tests. All measurement equipment furnished by Lightning Technologies, Inc. is calibrated by a commercial calibration agency in accordance with the requirements of the second edition of ISO/IEC 17025:2005, General Requirements for the Competence of Testing and Calibration Laboratories, and/or ANSI/NCSL Z54011994, Calibration Laboratories and Measuring and Test EquipmentGeneral Requirements, using standards traceable to the National Institute of Standards and Technology.
Table 2 – Calibrated EquipmentManufacturer Equipment Model No. Serial No.
Calibration
Date Due Date
High Voltage Tests
Tektronix Oscilloscope
DP04034 C021222 26 Mar 10 26 Mar 11
TDS3034B
C010791 22 Dec 10 22 Dec 11
B027504 21 Jan 11 21 Jan 12
Haefely Voltage Divider CR2400350
05101161.12.1 12.2 05101161.20.1
22 June 06 22 June 11
Pearson Current Probe 4160
080861 13 Jul 10 13 Jul 11
080862 4 Aug 10 4 Aug 11
80134 20 May 10 20 May 11
High Current Tests
Tektronix Oscilloscope
B033378 20 Oct 10 20 Oct 11 TDS3032B
B015906 6 Aug 10 6 Aug 11
TDS3034B
B027504 21 Jan 11 21 Jan 12
C010791 22 Dec 10 22 Dec 11
Pearson
Attenuator A10 099671 15 Jul 10 15 Jul 11
Current Probe
1423 099639 18 Nov 10 18 Nov 11
4160
80134 20 May 10 20 May 11
80861 13 Jul 10 13 Jul 11
T&M Research
Current Viewing
F10004 041028 14 Oct 10 14 Oct 11
Resistor
W2014S 830310 14 Oct 10 14 Oct 11
Lightning Technologies, Inc. Test Report LT113393, Rev. () 10 Downing Industrial Parkway 3 March 2011
Pittsfield, MA 012013890 Page 6 of 20
6.0 TEST REQUIREMENTS
6.1 Lightning Test Levels
The high voltage transients were applied with a 1.2 x 50 μs waveform in the positivepolarity at 1,300 kV. This was sufficient to arc across a nominal 3 meter gap.
The high current test waveform and current level was applied with a nominal 25 x 60 μs waveform, in the positive polarity at current levels of 68 kA to 89 kA. Current waveforms and amplitudes varied as a function of test article impedance (inductance and resistance). These current levels were the maximum currents that the generator could supply to the test article impedances.
6.2 Shielded Shelter Enclosure Grounding Means
Encasement of rebar in concrete is used as a grounding electrode when fabricated in accordance with the NFPA 70: NEC2005, Article 250, Paragraph 250.52, Grounding Electrodes (A) Electrodes Permitted for Grounding, (3) ConcreteEncased Electrode.
Concrete pads were installed on the SSE units for all tests. The concrete pads were included for informational purposes. Failure of the pads did not constitute a failure of the shelter.
6.3 Isolated Test Generator Current Returns
The voltage between a shelter and the earth depends on the resistivity of the soil and the grounding materials buried in the soil. On mountaintops where the shelter may be installed, the soil may be very rocky which results in a very high soil resistivity. In some of these sites, the lightning surge arcs through the soil as it exits from the shelter. To verify that Faraday Cage designs can protect the radio equipment in these situations, tests were conducted with the shelter isolated which allowed the strikes to arc to the ground plane.
There are many considerations that must be taken into account in designing grounding for a facility. The tests described herein used isolation as a worstcase situation but that does not mean that ungrounded structures are advocated.
7.0 TEST SETUP AND PROCEDURES
The shelters were subjected to simulated lightning tests to determine the ability of the shelter to prevent damage to electrical and/or electronic radio equipment contained in the shelter. High voltage attachment tests were applied to the shelters and high current tests were injected into the antenna attachment point of the shelter.
