CSX RAILROAD NASHVILLE YARD RAIL WELDING MACHINE POST INSTALL SURGE SUPPRESSION POWER QUALITY STUDY

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1 P. O. Box 1212 Destin, FL Phone Fax Cell June 12, 2007 CSX RAILROAD NASHVILLE YARD RAIL WELDING MACHINE POST INSTALL SURGE SUPPRESSION POWER QUALITY STUDY Thomas W. Butcher, Vice President Technical Services, Surge Suppression Incorporated, conducted the study on June 12, The equipment utilized for the tests was a Dranetz model 658 Power Quality Analyzer. The Surge Suppression Devices (SPDs), ordered from the previous Power Quality (PQ) study conducted on October 31, 2006, had been installed by the facility personnel and supervised by Chuck Battisti from Chemetron. Readings were taken on the DCRW924 Rail Welding Machine DC Supply Power Panel main lugs and at the DCRW924 Rail Welding Machine DC output lugs. AOur Name Says It ALL@

2 The two previous images show the main DC Supply Power Panel with the SPD installed at the top of the main 480 Volt AC buss.

3 The previous two images show the installation of the sine wave tracking SPDs on the 480 Volt breakers for the two DC transformers on the Rail Welding Machine. The SPDs at this point of the system serve two purposes. The first is protecting the switchgear and the DCRW924 Rail Welding machine from catastrophic surge damage from lightning and other externally generated surges. The second purpose is to provide sine wave tracking level secondary protection to the DCRW924 Rail Welding machine from catastrophic surge activity after the first SPD at the main buss has removed the majority of the surge. This second level of SPDs will also provide sine wave tracking protection from surge activity generated by the DCRW924 Rail Welding machine itself from traveling between the two breaker circuits. This type of internally generated surge activity can create cumulative damage over time that significantly shortens the life of the equipment. The first area of study is the 480 Volt, DC Supply Power Panel main lugs. The first set of test results is from the Pre-Heat phase of the operation. The Dranetz was connected to the main lugs. Channel A of the Dranetz measured the Phase A to Phase B voltage, Channel B measured the Phase B to Phase C voltage, channel C measured the Phase C to Phase A voltage and channel D measured the Phase A current. We will first display the four charts from the pre-install testing and then the tests from post-install testing to demonstrate the difference with the SPDs in place.

4 Chart 1 shows 124 Vpk transients on the sine wave of the Phase A to Phase B 480 volt waveform. Chart 1 Chart 2 shows 131 Vpk transients on the sine wave of the Phase B to Phase C 480 volt waveform. Chart 2

5 Chart 3 shows 118 Vpk transients on the sine wave of the Phase C to Phase A 480 volt waveform. Chart 3 As can be seen in the previous three charts, the distortion of the sine wave from the transient activity is affecting the quality of the power on the overall system. Chart 4 shows the current waveform on Phase A with distortions created by the normal functions of the rectifier cabinet. Chart 4

6 Chart 4 shows the current being drawn by the rectifiers. The distortion of the sine wave for the current is a direct effect of the operation of the rectifiers. The rectifiers do not use current in a true sine wave pattern. The rectifiers draw current in such a way as to convert the AC sine wave to DC. This DC is then delivered to the weld point with the positive lead going to the existing rail connection point and the negative lead going to the new rail section connection point. When the weld point is energized, the rails are superheated and the junction between the two rail sections fuses, making the two rail sections into one continuous rail. This is all computer controlled by the rail welder, sensors, PLCs and other computer controls in the system. As the rectifiers within the rail welder gate open and closed, they draw current into the rail welder. This causes the distortions to the current sine wave observed on Chart 4. Notice the number and intensity of the transients, which are constant during the monitoring in the pre-install phase of testing. Chart 5 shows no transients on the sine wave of the Phase A to Phase B 480 Volt waveform. Chart 5 The transients during the pre-heat phase have been removed. This demonstrates the improvements achieved with the installation of the SPDs. Chart 6 shows 136Vpk transients on the sine wave of the Phase B to Phase C 480 Volt waveform. However, notice that the sine wave has been significantly smoothed and the number of transients reduced greatly.

7 Chart 6 Chart 7 shows no transients on the sine wave of the Phase C to Phase A 480 Volt waveform. Chart 7 Once again, the transients have been removed and the sine wave significantly smoothed.

8 Chart 8 shows the current waveform on Phase A. Chart 8 The reduction in the number of transients will have a positive impact on the useful life of the DCRW924 Rail Welding Machine by removing the cumulative damaging transients from the system and by protecting from the periodic catastrophic surges from lightning and other outside sources. Further events show similar results with transients showing up on one or two of the phases, but with substantial reductions in the number and levels of transients from the pre-install tests. Further improvement at this point in the system can be achieved by reinstalling the two SPDs on the breakers by mounting them on brackets on the support struts, thereby shortening the leads by 10 to 12 inches. The next set of tests was conducted during the Final Flash phase of the welding operation. Again, we will first show the charts from the pre-install testing conducted in October 2006 and then the post-install testing results. The Dranetz was connected to the 480 Volt, DC Supply Power Panel main lugs. Channel A of the Dranetz measured the Phase A to Phase B voltage, Channel B measured the Phase B to Phase C voltage, channel C measured the Phase C to Phase A voltage and channel D measured the Phase A current. The next four charts show the results of testing without SPD installed.

9 Chart 9 shows 138 Vpk transients on the sine wave of the Phase A to Phase B 480 volt waveform. Chart 9 This series of tests shows the sine waves at 100 milliseconds per division. This produces a chart with 20 times more sine waves and a more compressed image. Chart 10 shows 139 Vpk transients on the sine wave of the Phase B to Phase C 480 volt waveform. Chart 10

10 Chart 11 shows 121 Vpk transients on the sine wave of the Phase C to Phase A 480 volt waveform. Chart 11 Chart 12 shows the current waveform on Phase A with distortions created by the normal functions of the rectifier cabinet. Chart 12

11 This image shows some of the activity during the Final Flash phase of the process. The next set of charts shows the effect of the installation of the SPDs. Chart 13 shows no transients on the Phase A to Phase B 480 Volt waveform. Chart 13 Chart 14 shows 122Vpk transients on the Phase B to Phase C 480 Volt waveform. Chart 14

12 Chart 15 shows 124Vpk transients on the Phase C to Phase A 480 Volt waveform. Chart 16 shows the current on Phase A. Chart 15 Chart 16 As in the Pre-Heat phase, the Final Flash phase, with the installation of the SPDs, shows a reduction in the number of transients as well as a smoothing of the sine wave. With the pending reinstall of the two SPDs on the breakers, the amplitude of the remaining transients should also be reduced.

13 The Dranetz Power Quality Analyzer was then moved to the 12 Volt DC output buss on the DCRW24 Rail Welding Machine.

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16 The previous six images show the SPDs installed on the 12 Volt DC buss. The initial preinstallation testing was only able to capture the first 10 seconds of the Pre-Heat process before the memory was filled on the Dranetz. The next eight charts show the transients observed on the 12 Volt DC buss during that time. Chart 17 Chart 18

17 Chart 19 Chart 20

18 Chart 21 Chart 22

19 Chart 23 Chart 24 Even though this was only from 10:46:38.37 to 10:46:47.36, a 9.99-second period, there were literally hundreds of transients generated. The reason for the short period is that the amount of transient activity maxed out the Dranetz PQ Analyzer s memory.

20 The next seven charts are from the post-installation testing with the SPDs connected and operating. The time is from 13:11:22.25 to 13:12:29.18, a 1 minute, second period that ran the full weld cycle from Pre-Heat through Final Flash. Chart 25 Chart 26

21 Chart 27 Chart 28

22 Chart 29 Chart 30

23 Chart 31 This represents the entire range of transients captured by the Dranetz Power Quality Analyzer during the entire weld cycle with the SPDs installed. Where the pre-installation testing had only been able to capture a 9.99-second section of the Pre-Heat cycle before it was 100% loaded, the post-install testing ran the complete weld cycle and the memory was only 1% loaded. The number of transients recorded had been reduced from hundreds, or possibly thousands during the full weld cycle, to only seven transients. It is a standard in the surge suppression industry that the shorter the lead length from the SPD to the point of connection, the better the performance of the SPD and the lower the let-through voltage past the SPD to the equipment down line. It was determined that the 12 Volt DC SPDs could be reinstalled with even shorter lead length by repositioning them, thereby providing an even greater improvement in the reduction in the amplitude as well as number of transients. Chuck Battisti is working with the personnel at the Nashville CSX rail yard to accomplish the reinstallation of the SPDs.