FRAX 150 Sweep Frequency Response Analyzer
Contents
1. the curve Operation Buttons All essential functions at your fingertips select with mouse function keys or touch screen 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 EJ H2 H0 open O ax open Ss Bexi open O Boxeo O Elmo lopen O x e E Einm fope O xixa open 0 O Bax opna Box open 1 Q Built in decision support is provided by using a built in analysis tool based on the international standard DL T 911 2004 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 gro2. 2 Simultaneously 500 100 MS s Windows based 1000 records in internal memory External storage on USB stick Megger FRAX 150 Sweep Frequency Response Analyzer Included accessories 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 Optional accessories Ordering information Item FRAX 150 With 18 m 60 ft Leads FRAX Generator cable 18 m 60 ft FRAX Measure cable 18 m 60 ft AC 39090 FRAX 150 With 9 m 30 ft Leads FRAX Generator cable 9 m 30 ft FRAX Measure cable 9 m 30 ft AC 39092 Included Accessories AC Power cord IEC60320 C13 to US standard AC Power cord IEC60320 C13 to Schuko CEE 7 7 Canvas carrying bag for leadset Ground cable 5 m 16 ft FRAX software for PC Earth Ground braid lead 2 x 3 m 9 ft Earth Ground braid lead insulated 2 x 3 m 9 ft Cclamp Bushing clamps 2 pcs Cclamp Ground braid clamps 2 pcs The FRAX Demo box FDB101 is a transformer kit that can be Field Test Box FTB101 used for in house training and demonstrations The small Earth Ground braid with clamp 2 x 0 3 m 1 ft transformer is a single phase unit with capability to simulate Nylon accessory bag normal as well as fault conditions Open as well as shorted User s man
3. Megger FRAX 150 FRAX 150 Sweep Frequency Response Analyzer Sweep Frequency Response Analyzer 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 transformer FRAX 150 detects problems such as Winding deformations and displacements Shorted turns and open windings Loosened clamping structures Broken clamping structures Core connection problems Partial winding collapse Faulty core grounds Core movements Highest dynamic range and accuracy in the industry Built in PC with powerful backlit screen for use in direct sunlight Highest possible repeatability by using reliable cab
4. 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 20 Hz and 200 Hz as between 200 KHz and 2 MHz and a relatively long measurement 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 FTB101 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 FTB 101 as a standard accessory and allows the user to perform this
5. e the shape of the curve The SERA method is based on comparisons between measured T OQ L S oO z Ses L D S H 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 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 occurr
6. ed or if the transformer can safely be energized 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 Medium High 10k 1M Hz 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 compare 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 m v gt v D a c a z The figure above shows a single phase transformer after a service overhaul where by mistake the core ground never got co
7. important validation in the field at any time and secure measurement quality fiel FTB101 Field Test Box 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 Itis rugged able to filter induced interference and has the highest dynamic range and accuracy in the industry FRAX 150 dynamic range or noise floor is shown in red below with a normal transformer measurement in black A wide dynamic range low noise floor allows for accurate measurements in every transformer A margin of about 20 dB from the lowest response to the instruments noise floor must be maintained to obtain 1 dB accuracy Minimum 20dB An example of FRAX 150 s dynamic limit red and transformer measurement black Close up of FRAX 150 control panel Test button Built in mouse with left and right click buttons sealed to protect from dust and other contaminants Navigation arrows Enter key FRAX 150 Sweep Frequency Response Analyzer Specifications FRAX 150 Specifications are valid at nominal input voltage and an ambient temperature of 25 C 77 F Specifications are subject to change without notice Environmental Application field Ambient temperature Operating Storage Humidity CE marking EMC LVD General Mains voltage Dimensions Weight The in
8. le 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 Magnitude dB a Ve A M i E arma rery 10M 10 k Frequency Hz 4 ibe Collecting fingerprint data using Frequency Response Analysis FRA is an easy way to detect electro mechanical problems in power transformers and an investment that will save time and money Megger Application Power transformers are specified to withstand mechanical forces from both transportation and in service events such as faults and lightning However mechanical forces may exceed specified limits during severe incidents or when 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 Method basics A transformer consists of multiple capacitances inductances and resistors a very complex circuit Ng 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 chang
9. nnected 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 Features and benefits Built in PC with powerful backlit screen for use in direct sunlight Guaranteed repeatability by using superior cabling technology thus avoiding the introduction of error due to cable connection and positioning which is common in other FRA manufacturers equipment Fulfills all international standards for Sweep Frequency Response Analysis SFRA measurements Highest dynamic range and accuracy in the industry allowing even the most subtle electro mechanical changes within the transformer to be detected Advanced analysis and support software tools allows for sound decision making with regard to further diagnostics analysis and or transformer disposition FRAX 150 Sweep Frequency Response Analyzer Test Object Browser Unlimited number of tests and sweeps Full user control Quick Select Tabs Quickly change presentation view for dif ferent perspectives and analysis tools Quick Graph Buttons Programmable graph setting lets you change views quickly and easily Sweep Curve Settings Every sweep can be individually turned on or off change color thickness and position Dynamic Zoom Zoom in and move your focus to any part of
10. strument is intended for use in medium and high voltage substations and industrial environments 20 C to 50 C 4 F to 122 F 20 C to 70 C 4 F to 158 F lt 90 RH non condensing 2004 108 EC 2006 95 EC 90 264 V AC 47 63 Hz 305 x 194 x 360 mm 12 x 7 6 x 14 2 6 kg 13 Ibs Measurement section FRA Method Frequency range Number of points Measurement time Points spacing Dynamic range Noise floor Inaccuracy IF bandwidth Integration time Software PC Communication Calibration interval Standards guides Analog Output Channels Compliance voltage Measurement volt age at 500 Output impedance Protection Analog Input Channels Sampling Input impedance Sampling rate PC Operating system 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 2000 XP Vista 7 USB galvanically isolated Max 3 years Fulfill requirements in Cigr Brochure 342 2008 Mechanical condition assessment of trans former windings using FRA and Chinese Standard DL T 911 2004 FRA on winding deformation of power transformers as well as other international standards and recom mendations 1 0 2 24 V p p 0 1 12 V p p 500 Short circuit protected
11. ual measurements can be performed The unit also contains two Optional Accessories a impedances one of them the same as used in the FTB101 A TE AC 90020 ield test box ZA eee FRAX Demo Box FDB101 AC 90050 SWEDEN UK Other Technical Sales Offices Registered to ISO 9001 and 14001 Megger Sweden AB Archcliffe Road Dover Dallas USA Norristown USA Subject to change without notice Eldarvagen 4 Box 2970 CT17 9EN England Toronto CANADA Trappes FRANCE ATENO AALOE FDOG ACODE E ANT SE 187 29 T BY T 44 0 1304 502101 Oberursel GERMANY Johannesburg FRAX 150_DS_en_V07 T 46 8510 195 00 F 44 0 1304 207342 SOUTH AFRICA Kingdom of BAHRAIN www megger com F 46 8510 195 95 Mumbai INDIA Chonburi THAILAND Megger is a registered trademark E seinfo megger com Sydney AUSTRALIA
12. und 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 the 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 Hook up practice Main flat braid connected to coupling hanging next to bushing A a daas s Short braid connected between main braid and bushing flange C g 9g ga 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 the measurement 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 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
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