FRAX 150 Sweep Frequency Response Analyzer
Contents
1. is an easy way to detect electro mechanical problems in power transformers transformer and an investment that will save time and money 3 J Lis T E E y 1k FieQuetecy Hz FRAX 150 detects problems such as Winding deformations and displacements APPLICATION Power transformers are specified to withstand mechanical Shorted turns and open windings P 8 forces from both transportation and in service events such Loosened clamping structures as faults and lightning However mechanical forces may Broken clamping structures exceed specified limits during severe incidents or when Core connection problems the insulation s mechanical strength has weakened due to aging A relatively quick test where the fingerprint response is compared to a post event response allows for a reliable decision on whether the transformer safely can be put back into service or if further diagnostics is required Partial winding collapse Faulty core grounds Core movements Megger Method Basics A transformer consists of multiple capacitances inductances and resistors a very complex circuit that generates a unique fingerprint or signature when test signals are injected at discrete frequencies and responses are plotted as a curve Capacitance is affected by the distance between conductors Movements in the winding will consequently affect capacitances and change the shape of the curve The SFRA m2. time The frequency response from the transformer contains a few resonances in the low frequency range but a lot of resonances at higher frequencies FRAX allows the user to specify less measurement points at lower frequencies and high measurement point density at higher frequencies The result is a much faster sweep with greater detail where it is needed Variable Voltage The applied test voltage may affect the response at lower frequencies Some FRA instruments do not use the 10 V peak to peak used by major manufacturers and this may complicate comparisons between tests FRAX standard voltage is 10 V peak to peak but FRAX also allows the user to adjust the applied voltage to match the voltage used in a different test FTB 101 Several international FRA guides recommends to verify the integrity of cables and instrument before and after a test using a test circuit with a known FRA response supplied by the equipment manufacturer FRAX comes with a field test box FTB101 as a standard accessory and allows the user to perform this important validation in the field at any time and secure measurement quality FTB 101 Field Test Box FRAX 150 has a built in computer with high contrast and powerful backlit screen suitable for use in direct sunlight Solid connections using the C clamps and the shortest braid method to connect the shield to ground makes it possible to eliminate connection problems and cable loops that otherwise affect th
3. 0036 I a aa 2 x C clamp Bushing Clamps GC 80010 2 x G clamp Ground Braid Clamps GC 80020 FRAX Generator Cable 2xBNC 9 m 30 ft GC 30040 for use with AC 39092 only Optional Accessories Calibration Set AC 90020 FRAX Demo Box FDB 101 AC 90050 UK UNITED STATES OTHER TECHNICAL SALES OFFICES Registered to ISO 9001 2000 Cert no 10006 01 Archcliffe Road Dover 4271 Bronze Way Valley Forge USA College Station FRAX150_DS_en_V04 CT17 9EN England Dallas TX 75237 1019 USA USA Sydney AUSTRALIA Taby www megger com T 44 0 1 304 502101 T 1 800 723 2861 USA only SWEDEN Ontario CANADA Trappes Megger is a registered trademark F 44 0 1 304 207342 T 1 214 333 3201 FRANCE Oberursel GERMANY Aargau UKsales megger com F 1 214 331 7399 SWITZERLAND Kingdom of BAHRAIN Specifications are subject to change USsales megger com Mumbai INDIA Johannesburg SOUTH without notice AFRICA and Chonburi THAILAND
4. Interval Standards guides Input Power 90 264 V ac 47 63 Hz Analog Output Channels Compliance Voltage Measurement Voltage at 50 Q Output Impedance Protection Analog Input Channels Sampling Input Impedance Sampling Rate Operating System Windows based Memory Sweep frequency SFRA 0 1 Hz 25 MHz user selectable Default 1046 User selectable up to 32 000 Default 64 s fast setting 37 s 20 Hz 2 MHz Log linear or both gt 130dB 0 5 dB down to 100 dB 10 Hz 10 MHz User selectable 10 default FRAX for Windows Max 3 years Fulfill requirements in Cigr Brochure 342 2008 Mechanical condition assessment of transformer windings using FRA and Chinese standard DL T 911 2004 FRA on winding deformation of power transformers as well as other international standards and recommendations 1 Output voltage 0 2 24 V p p open circuit 10 V adjustable 0 1 12 V 50 Q Short circuit protected 2 Simultaneously 50 Q 100 MS s 1000 records in internal memory External storage on USB stick Physical Dimensions Weight Environmental Operating Ambient Temp Operating Relative Humidity Storage Ambient Temp Storage Relative Humidity CE Standards 305 mm x 194 mm x 360 mm 12 in x 7 6 in x 14 2 in 6 kg 13 Ib 0 Cio 450 G 7 432 Pte 122 F lt 90 non condensing 20 C to 70 C 4 F to 158 F lt 90 non condensing IEC61010 LVD E
5. Megger FRAX 150 Sweep Frequency Response Analyzer FRAX 150 Sweep Frequency Response Analyzer Highest dynamic range and accuracy in the industry E Built in PC with powerful backlit screen for use in direct sunlight Highest possible repeatability by using reliable cable practice and high performance instrumentation Fulfills all international standards for SFRA measurements Advanced analysis and decision support built into the software Imports data from other FRA test sets DESCRIPTION Power transformers are some of the most vital components in today s transmission and distribution infrastructure Transformer failures cost enormous amounts of money in unexpected outages and unscheduled maintenance It is important to avoid these failures and make testing and diagnostics reliable and efficient The FRAX 150 Sweep Frequency Response Analyzer SFRA detects potential mechanical and electrical problems that other methods are unable to detect Major utilities and service companies have used the FRA method for more than a decade The measurement is easy to perform and will capture a unique fingerprint of the transformer The measurement is compared to a reference fingerprint and gives a direct answer if the mechanical parts of the transformer are unchanged or not Deviations indicate geometrical and or electrical changes within the Collecting fingerprint data using Frequency Response Analysis FRA
6. N61326 EMC Megger FRAX 150 Sweep Frequency Response Analyzer CLOSE UP OF FRAX 150 CONTROL PANEL INCLUDED ACCESSORIES Test button Built in mouse with Left and Right click buttons sealed to protect from dust and other contaminants Navigation arrows g Included accessories shown above Mains cable ground cable 2 ground braid sets 2 earth ground braid leads insulated 2 C clamps generator cable measure cable field test box nylon accessory pouch 2 earth ground braids with clamp and canvas carrying bag for test leads Enter key ORDERING INFORMATION Item Qty Cat No Item Qty Cat No FRAX 150 with 18 m 60 ft Leads AC 39090 FRAX Measure Cable 1xBNC 9 m 30 ft GC 30050 FRAX 150 with 9 m 30 ft Leads AC 39092 for use with AC 39092 only FRAX Generator Cable 2xBNC 18 m 60 ft GC 30042 Included Accessories thts for use with AC 39090 only AC Power Cord IEC60320 C13 to US standard 17032 a ae 0 dd hod tC ss ___ FRAX Measure Cable 1xBNC 18 m 60 ft GC 30052 AC Power Cord IEC60320 C13 to Schuko CEE 7 7 17032 13 for use with AC 39090 only Canvas Carrying Bag for leadset 30915 211 Field Test Box FTB 101 AC 90060 Ground Cable 5m 16 ft 1001428 2x305 mm 1 ft Earth Ground Braid with Clamp GC 30035 FRAX software for PC 1001427 ln Accessory Bag GD 31040 2 x3 m 9 ft Earth Ground Braid Lead GC 30033 User s Manual AVTMFRAX150 2 x 3 m 9 ft Earth Ground Braid Lead insulated GC 3
7. e The response can be viewed in traditional Magnitude vs Frequency and or Phase vs Frequency view The user can also choose to present the data in an Impedance or Admittance vs Frequency view for powerful analysis on certain transformer types The figure above shows a single phase transformer after a service overhaul where by mistake the core ground never got connected red and after the core ground was properly connected green This potential problem clearly showed up at frequencies between 1 kHz and 10 kHz and a noticeable change is also visible in the 10 kHz 200 kHz range Megger FRAX 150 Sweep Frequency Response Analyzer Test Object Browser Unlimited number Quick Select Tabs Quickly change Quick Graph Buttons Programmable of tests and sweeps Full user control presentation view for different graph setting lets you change views quickly perspectives and analysis tools and easily Help _ E 5 O to oO i iti gt Nameplate Aken Magnitude ARON Phin ASE Magnate Paen LARIE OUT 8112004 Anatom ie o axra open Q pox oven E Mid 2007 08 29 12 28 15 l Triho fope x X x ory eee Se re a Sweep Curve Settings Every sweep Dynamic Zoom Zoom in and Operation Buttons All essential functions can be individually turned on or off move your focus to any part of at your fingertips select appropriate change color thickness and pos
8. e measurement Megger DYNAMIC RANGE Making accurate measurements in a wide frequency range with high dynamics puts great demands on test equipment test leads and test set up FRAX 150 is designed with these requirements in mind It is rugged able to filter induced interference and has the highest dynamic range and accuracy in the industry FRAX 150 internal noise level is shown in red below with a normal transformer measurement in black A wide dynamic range i e low internal noise level allows for accurate measurements in every transformer A margin of about 20 dB from the lowest response to the internal noise level of the instrument must be maintained to obtain 1 dB accuracy Minimum 20dB An example of FRAX 150 s dynamic limit red and transformer measurement black OPTIONAL ACCESSORIES The FRAX Demo box FDB 101 is a transformer kit that can be used for in house training and demonstrations The small transformer is a single phase unit with capability to simulate normal as well as fault conditions Open as well as shorted measurements can be performed The unit also contains two test impedances one of them the same as used in the FTB101 field test box FRAX 150 Sweep Frequency Response Analyzer SPECIFICATIONS General FRA Method Frequency Range Number of Points Measurement time Points Spacing Dynamic Range Noise Floor Accuracy IF Bandwidth Integration Time Software Calibration
9. ethod is based on comparisons between measured curves where variations are detected One SFRA test consists of multiple sweeps and reveals if the transformer s mechanical or electrical integrity has been jeopardized Practical Application In its standard application a finger print reference curve for each winding is captured when the transformer is new or when it is in a known good condition These curves can later be used as reference during maintenance tests or when there is reason to suspect a problem Transformer Housing R R R R R R R The most reliable method is the time based comparison where curves are compared over time on measurements from the same transformer Another method utilizes type based comparisons between sister transformers with the same design Lastly a construction based comparison can under certain conditions be used when comparing measurements between windings in the same transformer These comparative tests can be performed 1 before and after transportation 2 after severe through faults 3 before and after overhaul and 4 as diagnostic test if you suspect potential problems One SFRA test can detect winding problems that requires multiple tests with different kinds of test equipment or problems that cannot be detected with other techniques at all The SFRA test presents a quick and cost effective way to assess if damages have occurred or if the transformer can safely be energi
10. he connection clamp next to the insulating discs to the ground connection at the base of the bushing This creates near identical conditions every time you connect to a bushing whether it is tall or short FRAX 150 with Built in PC FRAX 150 has a built in PC with a high contrast powerful backlit screen suitable for work in direct sunlight The cursor is controlled via the built in joystick or using an external USB mouse and the built in keyboard makes data entry easy All data is stored on the built in hard drive The data can be moved to any other computer using a USB memory stick Hook up practice a Main flat braid z f connected t F coupling hanging maxi to bushing z se y S i 2S ZB as SS a e nr FRAX 150 Sweep Frequency Response Analyzer Import and Export The FRAX software can import data files from other FRA instruments making it possible to compare data obtained using another FRA unit FRAX can import and export data according to the international XFRA standard format as well as standard CSV and TXT formats Optimized Sweep Setting The software offers the user an unmatched feature that allows for fast and efficient testing Traditional SFRA systems use a logarithmic spacing of measurement points This results in as many test points between 20Hz and 200Hz as between 200KHz and 2MHz and a relatively long measurement
11. ition the curve function keys on screen with mouse Built in decision support is provided by using a built in analysis tool based on the international standard DL T 911 2004 Automated analysis compares two curves using an algorithm that compare amplitude as well as frequency shift and lets you know if the difference is severe obvious or light Megger Considerations When Performing SFRA Measurements SFRA measurements are compared over time or between different test objects This accentuates the need to perform the test with the highest repeatability and eliminates the influence from external parameters such as cables connections and instrument performance FRAX offers all the necessary tools to ensure that the measured curve represents the internal condition of the transformer Good Connections Bad connections can compromise the test results which is why FRAX offers a rugged test clamp that ensures good connection to the bushings and solid connections to the instrument Contacts made with the C clamp guarantee good connections Shortest Braid Concept The connection from the cable shield to ground has to be the same for every measurement on a given transformer Traditional ground connections techniques have issues when it comes to providing repeatable conditions This causes unwanted variations in the measured response for the highest frequencies that makes analysis difficult The FRAX braid drops down from t
12. zed again If there is a problem the test result provides valuable information that can be used as decision support when determining further action Having a reference measurement on a mission critical transformer when an incident has occurred is therefore a valuable investment as it will allow for an easier and more reliable analysis FRAX 150 Sweep Frequency Response Analyzer Analysis and Software As a general guideline shorted turns magnetization and other problems related to the core alter the shape of the curve in the lowest frequencies Medium frequencies represent axial or radial movements in the windings and high frequencies indicate problems involving the cables from the windings to bushings and tap changers havo a a bho eee 4 Pr L F ran boda baae t a i t ae oa bane t a 1 i E 8 2 eoee b a 1 p ap aoe a 1 piao D t F Par b ae ar Li L 4 E aee a 7 Hom o i PE i ndith Ci b b a etieen t a i b i C Be E E P a 3 oo toee 1 a a io 24 ETT a a E we ake a a F Ji d tae k pane 4 a boa npg F 2 bof E Bae i B FoR eta i TEREE oe CE biere deete te t me i eE EE a tof fa fone Ei Ak n a H r a ry a at a 2 Pee Ce ee Pe An example of low medium and high frequencies The FRAX Software provides numerous features to allow for efficient data analysis Unlimited tests can be open at the same time and the user has full control on which sweeps to compar
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