Three-Phase Transformer Demagnetizer DEM60

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Marlene Williamson
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Three-Phase Transformer Demagnetizer DEM60 Fully automatic demagnetization Demagnetization currents 5 ma 60 A DC Automatic discharging circuit Lightweight 13,1 kg High DC Current Source for Automatic

magnetism). Also, when disconnecting a transformer from service, some amount of magnetic flux trapped in the core could be present.

1 Three-Phase Transformer Demagnetizer DEM60 Fully automatic demagnetization Demagnetization currents 5 ma 60 A DC Automatic discharging circuit Lightweight 13,1 kg High DC Current Source for Automatic Transformers and CT Demagnetization Description After a DC current test, such as a winding resistance measurement, the magnetic core of a power or instrument transformer may be magnetized (remanent magnetism). Also, when disconnecting a transformer from service, some amount of magnetic flux trapped in the core could be present. The remanent magnetism can cause various problems such as erroneous diagnostic electrical measurements on a transformer, or an inrush current at start-up of power transformer, or incorrect operation of protective relays due to magnetized CT cores. To eliminate this source of potential problems, demagnetization should be performed. When suspecting remanent magnetism, or when various test results, like FRA or magnetization/excitation current, show possible remanency use the DEM60 to perform fully automatic demagnetization. Demagnetizing magnetic core of a transformer requires alternating current applied with decreasing magnitude down to zero. The DEM60 provides this alternating current by internally changing the polarity of a controlled DC current. During the demagnetization process the instrument supplies current at decreasing magnitude for each step, following a proprietary developed program. DV-Win Using DV-Win software, instrument can be operated and controlled from a PC. The standard interface is USB and optional RS232.

2 Discharging Circuit Injection of current and discharging energy from the inductance are both automatically regulated. During and after the operation, an intrinsically safe discharge circuit with an indicator rapidly dissipates the stored magnetic energy. The discharging circuit is independent of power supply. Accessories Included DV-Win PC software, USB cable Mains power cable Ground (PE) cable Recommended Current cables 4 x 10 m 10 mm 2 with TTA clamps Cable plastic case Optional Current cables 4 x 15 m 10 mm 2 with TTA clamps Cable bag Current cables Technical data 1 Mains Power Supply - Connection according to IEC/EN ; C320 - Voltage 90 V 264 V AC, 50 / 60 Hz, single-phase - Power consumption 2250 VA - Fuse 15 A / 250 V, type F 2 Output data - Test current 5 ma DC 60 A DC - Test voltage 60 V DC 3 Environmental conditions - Operating temperature -10 o C o C / 14 F F - Storage and transportation -25 o C o C / -13 F F - Humidity 5 % - 95 % relative humidity, non condensing 4 Dimensions and Weight - Dimensions 480 x 190 x 385 mm (W x H x D) 18,90 x 7,48 x 15,16 in - Weight 13,1 kg / 28,8 lb 5 Warranty three years 6 Applicable Standards - Installation/overvoltage: category II - Pollution: degree 2 - Safety LVD 2006/95/EC, (CE Conform) Standard EN EMC Directive 2004/108/EC (CE Conform) Standard EN 61326:2006 *Specifications are subject to change without notice.

Tap Changer Analyzer & Winding Ohmmeter RMO60TT Test current 5 ma 60 A DC Three resistance measurement channels Three temperature measurement channels Automatic resistance/temperature measurement for

3 Tap Changer Analyzer & Winding Ohmmeter RMO60TT Test current 5 ma 60 A DC Three resistance measurement channels Three temperature measurement channels Automatic resistance/temperature measurement for the Heat Run test On-load tap changer dynamic resistance measurement Rapid automatic demagnetization AC Current monitoring channel Measuring range 0,1-2 k Automatic discharge circuit Built-in Tap Changer Control Unit USB flash drive feature High DC Current Tap Changer Analyzer & Resistance Meter for Transformers Description The Tap Changer Analyzer & Winding Ohmmeter RMO60TT is designed for tap changer analysis and for resistance measurement of inductive test objects. RMO60TT generates true DC ripple-free current. The injection of current and discharge of energy from the inductance are both automatically regulated. RMO60TT injects the current at the voltage level as high as 60 V. This ensures that the duration of test is as short as possible, and that the desired test current is reached faster. Three independent channels enable testing of three series windings - primary, secondary and tertiary windings. There is enough memory within RMO60TT instrument to store 500 measurements. All measurements are time- and date-stamped. The set is equipped with thermal and overcurrent protection. The RMO60TT has very high ability to cancel electrostatic and electromagnetic interference in HV electric fields. It is achieved by very efficient filtration based on a proprietary solution method. On-Load Tap Changer Analysis The RMO60TT can be used to measure winding resistance of individual taps on a power transformer s tap changer. It can also check whether the on-load tap changer (OLTC) performs switching operation steps properly. The moment a tap position is changed from one tap position to the next, the device detects a sudden, very short current drop. A properly working tap changer results differ from a malfunctioning one. This is obvious if an interruption during the change occurs, by the magnitude of the current ripple, the value of measured resistances, and also by different transition times. The instrument displays resistance value and ripple in percents. The Tap Changer Control Unit allows the operator to control the Tap Changer

4 operation from the RMO60TT instrument. For additional diagnostic functions, our DV Win software should be used. Demagnetization Feature After a DC current test, e.g. a winding resistance measurement, the magnetic core of a power or instrument transformer may remain magnetized (remanent magnetism). Also, when disconnecting a transformer from service, some amount of magnetic flux stays trapped in the core. The remanent magnetism can cause various problems such as erroneous diagnostic electrical measurements on a transformer, or an inrush current at start-up of power transformer, or incorrect operation of protective relays due to magnetized CT cores. To eliminate this source of potential problems, demagnetization should be performed. When a discharging process has terminated, the RMO60TT can perform fully automatic demagnetization. Demagnetizing magnetic core of a transformer requires alternating current applied with decreasing magnitude down to zero. The RMO60TT provides this alternating current by internally changing the polarity of a controlled DC current. During the demagnetization process the RMO60TT supplies current at decreasing magnitude for each step. DV Win Using DV Win software, instrument can be operated and controlled from a PC, and results are obtained directly at a PC. The DV Win software allows results to be arranged in an Excel spreadsheet, which can be shown later as a diagram and printed as a report, or exported in ASCII format. This software provides more detailed condition assessment of an OLTC (tap changer) by recording the graph which represents dynamic resistance during the tap change and motor current. The DV Win measures OLTC transition time, an important characteristic for condition assessment. The standard interface is USB and optional RS232. Heat Run Test Application The DV Win software has an additional Heat Run temperature/resistance interpolation feature. After the transformer heating is switched off, the device is immediately connected to all three transformer windings and the timer is started. The winding resistance and temperature are measured at regular time intervals. This information is used to automatically interpolate these values at the moment when the transformer was switched off. AC Current Monitoring Channel AC current monitoring channel is intended for monitoring and recording the OLTC mechanicaldrive motor-current during tap changer operation. The motor current waveform is also printed on the DV Win generated graph, and can help in detecting OLTC mechanical problems. An AC current clamp is provided.

Typical application Typical application of RMO60TT is

Changers Generators and electrical motors High-current

software Built-in Tap Changer Control Unit Tap Changer

Recommended Current cables 2 x 10 m 10 mm 2 and Sense cables

mm 2 with TTA clamps Sense cables 2 x 2 x 10 m with TTA

thermal printer 80 mm Test shunt 150 A / 150 mv Current

m with TTA clamps Cable plastic case Current cables with TTA

5 Typical application Typical application of RMO60TT is measuring the resistance of: Power transformers On-Load Tap Changers Generators and electrical motors High-current busbar joints Cable splices Accessories Included DV Win PC software Built-in Tap Changer Control Unit Tap Changer Control cable set 5m Mains power cable Ground (PE) cable Recommended Current cables 2 x 10 m 10 mm 2 and Sense cables 2 x 10 m with TTA clamps Current connection cable 2 x 5 m 10 mm 2 with TTA clamps Sense cables 2 x 2 x 10 m with TTA clamps Current clamp 30/300 A Cable bag Optional Built-in thermal printer 80 mm Test shunt 150 A / 150 mv Current cables 2 x 15 m 10 mm 2 with TTA clamps Sense cables 2 x 15 m with TTA clamps Cable plastic case Current cables with TTA clamps Voltage sense cables with TTA clamps Current connection cable Current clamp Shunt Cable bag

6 Technical data 1 Mains Power Supply - Connection according to IEC/EN ; C320 - Voltage 90 V 264 V AC, 50 / 60 Hz, single-phase - Power consumption 2250 VA - Fuse 15 A / 250 V, type F 2 Output data - Test current 5 ma DC 60 A DC - Test voltage 60 V DC - Measuring range / Resolution 0,1-999,9 0,1 1,000 m - 9,999 m 1 10,00 m - 99,99 m ,0 m - 999,9 m 0,1 m 1,000-99,99 10 m 100,0-999,9 0, Typical accuracy ± (0,1 % rdg + 0,1 % FS) 3 AC Current monitoring channel - Current monitoring resolution: 0,1 ms - Amplitude resolution: 16 bit 4 Environmental conditions - Operating temperature -10 o C o C / 14 F F - Storage and transportation -25 o C o C / -13 F F - Humidity 5 % - 95 % relative humidity, non condensing 5 Dimensions and Weight - Dimensions 450 mm x 175 mm x 320 mm 17,72 in x 6,89 in x 12,6 in (W x H x D) - Weight 13 kg / 28,6 lb 6 Warranty three years 7 Applicable Standards - Installation/overvoltage category II - Pollution degree 2 - Safety LVD 2006/95/EC, (CE Confirm) Standard EN EMC Directive 2004/108/EC (CE Confirm) Standard EN 61326:2006 *All specifications herein are valid at ambient temperature of + 25 C and standard accessories. *Specifications are subject to change without notice.

Tap-Changer & Winding Analyzer TWA30D Three-phase On-Load Tap Changer dynamic resistance measurement 30 A total current, 10 A per phase Total test current 10 ma 30 A DC Winding Ohmmeter range 0,1-2 k

7 Tap-Changer & Winding Analyzer TWA30D Three-phase On-Load Tap Changer dynamic resistance measurement 30 A total current, 10 A per phase Total test current 10 ma 30 A DC Winding Ohmmeter range 0,1-2 k Extremely quick measurement, one cable setup Automatic discharge and demagnetization circuit Rapid automatic demagnetization Tap changer motor current recording Built-in tap changer control unit Three-phase extra-high DC-current tap changer analyzer and six-winding resistance meter for power transformers The Tap Changer Analyzer & Winding Ohmmeter TWA30D is designed for simultaneous threephase tap changer analysis and six-winding resistance measurement of both the primary and the secondary transformer side. This is done on a transformer with only one single-cable setup, with test current up to 30A. Once all 6-8 bushings are connected and the transformer configuration selected, the instrument adjusts the test automatically. The TWA30D generates true DC ripple-free current. Both the injection of current and the discharge of energy from the magnetic circuit are automatically regulated. Winding resistance of all six windings The TWA30D injects current with a voltage as high as 60 V to all three phases simultaneously. This ensures that the magnetic core is saturated quickly and duration of test is as short as possible. The instrument enables testing of all transformer windings, both primary and secondary. There is enough memory within the TWA30D instrument to store 500 measurements. All measurements are time and date stamped. The set is equipped with thermal and overcurrent protection. The TWA30D has very high ability to cancel electrostatic and electromagnetic interference in HV electric fields. It is achieved by very efficient filtration. The filtration is made utilizing proprietary hardware and software. On Load Tap Changers all three phases simultaneously The TWA30D can be used to measure the winding resistance of individual taps of a power transformer without discharging between tests. All three phases are recorded simultaneously with currents of up to 10 A per phase. The unit also checks whether the on-load tap changer (OLTC) switches without an interruption. The moment a tap position is changed from one tap to another, the device detects a sudden, very short drop of the current. A properly working tap changer differs from a malfunctioning one. This is obvious from an interruption during the change, by the magnitude of the current ripple and also by the transition time. Malfunctioning behavior of Tap Changer will result in much higher current ripple

TWA30D value and by transition time that differs from a properly functioning Tap Changer. Incorrect make before break tap changer performance results in 100% ripple value, which is easy to observe.

8 TWA30D value and by transition time that differs from a properly functioning Tap Changer. Incorrect make before break tap changer performance results in 100% ripple value, which is easy to observe. Dynamic resistance graphs are recorded for all three phases simultaneously, so the synchronization is verified, and all three phase traces are plotted on the same graph. The tap changer motor current is recorded, and displayed on the graph, while the UP-DOWN operation is controlled from the instrument keypad. DV-Win software The DV-Win software enables PC-controlled testing and obtaining results directly at the PC. The DV-Win software enables presenting of results in a standard report, arranged in an Excel spreadsheet, PDF, Word, or ASCII format. The software can control the TWA30D instrument, allowing a condition assessment of OLTC (tap changer) analyzing graphs which represent dynamic resistance during the tap change. The DV-Win measures and calculates OLTC transition time, ripple and resistance for each tap changing operation. Connecting a Transformer to TWA30D Using two sets of four-wire cables, all bushings of primary and secondary side are connected one time only. The connection is with two-contact clamps providing for the four-wire Kelvin test method. Using the Tap Changer menu, the power transformer winding resistance of individual tap positions can be measured. Also, you can check whether the on-load tap changer switches without an interruption and record a dynamic graph of this operation with overlaying motor current trace. The TWA30D current output injects a controlled current into a power transformer. This current and voltage values are measured, and the winding resistance is calculated. The figure above shows simultaneous testing of both windings (high side and low side) on a threephase transformer. That way, the setup time is minimized and the test is performed very quickly. The speed is increased by saturating all three legs of the magnetic core at the same time, so the total test time is extremely short. Accessories Included: Recommended: Optional: DV-Win PC software Mains power cable Ground (PE) cable Test cables 2 x 5 m with clamps Extension cables 5 m Cable bag Current clamps 30/300A Test shunt 150 A / 150 mv Test cables 2 x 10 m with clamps Extension cables 10 m Cable plastic case

9 TWA30D Technical data 1 Mains Power Supply - Connection according to IEC/EN ; C320 - Voltage 90 V 264 V AC, 50 / 60 Hz, single-phase - Input power 1200 VA - Fuse 12 A / 250 V, type F 2 Output data - Test current 10 ma DC 30 A DC - Measuring range / Resolution 0,1-999,9 0,1 1,000 m - 9,999 m 1 10,00 m - 99,99 m ,0 m - 999,9 m 0,1 m 1,000-99,99 10 m 100,0-999,9 0, Typical accuracy ± (0,1 % rdg + 0,1 % FS) 3 Environmental conditions - Operating temperature -10 o C o C / 14 F F - Storage and transportation -25 o C o C / -13 F F - Humidity 5 % - 95 % relative humidity, non condensing 4 Dimensions and Weight - Dimensions 410 mm x 180 mm x 320 mm 16,14 in x 7,08 in x 12,59 in (W x H x D) without handle - Weight 12,8 kg / 28,3 lbs 5 Warranty three years 6 Applicable Standards - Installation/overvoltage: category II - Pollution: degree 2 - Safety LVD 2006/95/EC, (CE Conform) Standard EN EMC Directive 2004/108/EC (CE Conform) Standard EN 61326:2006 *All specifications herein are valid at ambient temperature of + 25 C and standard accessories. *Specifications are subject to change without notice.

Tap Changer Analyzer & Winding Ohmmeter RMO60TD

Tap Changer Analyzer & Winding Ohmmeter RMO60TD Test current 5 ma 60 A DC Rapid automatic demagnetization AC Current monitoring channel Lightweight 13 kg Measuring range 0,1-2 k Two voltage sense channels