The M4110 Leakage Reactance Module when used along with the Doble M4100 performs a leakage reactance test, also known as a short-circuit impedance test, which is a reliable indicator of transformer winding deformation. Winding deformation is assessed by the module verifying the geometric integrity of the winding by comparing test results to nameplate providing a quantitative evaluation of the winding deformation. All test results are independent of the transformer’s temperature, deterioration or contamination levels ensuring repeatability. The Doble M4110 is simple to use, the operator enters the nameplate information and the M4100 will recommend a test potential and perform all of the necessary calculations. Data analysis is preformed automatically with changes in impedance and reactance determined based on the benchmark/nameplate values.

Brief Specs:

Impedance

• 0.1 to 700 ohms

Inductance

• 250 uH to 1.8 H(50/60 Hz at less than 10% Power Factor)
• 1% of reading or +/- 10 uH accuracy

Resistance

• 0.1 to 700 ohms (greater than 90% Power Factor)
• 1% of reading or +/- 10 milliohms accuracy

AC Input

• 120 or 240 V at 10 A(50/60 Hz)
• 120 Input
• 0-280 Output Voltage 1.2 kVA Output VA Continuous

Short time overload current

• 25 A rms 4-8 minutes

The Doble M4140 Capacitor Bank Test Kit contains a clamp-on CT probe and cable that allows individual capacitors in a high voltage capacitor bank to be tested without the need to disconnect them from the bank. It is used in combination with the Doble M4100 insulation analyser.

Brief Specs:

Not applicable

The Doble M5400 SFRA Analyser uses sweep frequency response analysis, a proven technique for making accurate and repeatable measurements. The instrument sends an excitation signal into the transformer and measures the returning signals. Comparing this response to baseline and other results from similar units allows for the identification of deviations and confirm internal mechanical problems such as core movement, winding deformation and displacement, faulty core grounds, partial winding collapse, hoop buckling, broken or loosened clamping structures and shorted turns and open windings.

The Doble M5400 can be used to check new transformers to verify condition, improve the quality of a regular inspection program, combat system problems such as short-circuit faults that can damage transformers, inspect for damage if the transformer has experienced mechanical stress and to eliminate unnecessary detanking and costly internal inspections.

Brief Specs:

Wide frequency range

Provides frequency-response measurement from 10 Hz to 25 MHz; the default range (20 Hz to 2 MHz) covers the most important diagnostic areas: core and magnetic properties; winding movement and deformation; and interconnections (leads and tap changers).

High resolution

Measures frequency response at logarithmically spaced intervals of 1.2% with a constant excitation level and can auto-scale each measurement, providing an overall dynamic range of 80 dB with ±1 dB accuracy, for the highest combination of dynamic range and accuracy.

Repeatable tests

Frequency response measurements are highly repeatable; even subtle changes can be used for diagnosis.

Rugged and portable

Rugged construction provides the accuracy of a laboratory instrument with the ability to withstand harsh field conditions and robust test leads to handle the rigors of site testing.

The Doble PDS100 PD Surveyor is ideal to use on a daily basis or during routine substation inspections combined with other methods like infrared scanning. It searches for PD in the radio frequency area with harmful PD revealing itself by the electromagnetic energy emitted from the activity area. The PDS100 captures the electromagnetic energy in the RF spectrum and displays a footprint of the RF interference from partial discharge causing the radiation. The Doble PDS100 is rugged, light-weight, and utilises a large display and soft key button interface. Companion software enables the operator to record and analyze PD signals to make decisions for further actions.

Brief Specs:

Power supply

• External supply External DC adaptor, 12 V @ 2 A
• DC adaptor 85 – 264 V AC (47 – 63 Hz)/ 12 V DC
• Internal battery: Li-Ion, 7.2 V, 6.6 Ah
• Battery life > 4 hours

Detection and Sweep functions

• Detector types: Peak, quasi-peak, RSM and average
• Sweep processing: Continuous, Average, Max Hold and Differential

Frequency

• Measurement range 50 MHz – 1000 MHz

Amplitude Display Units

• Linear (V, mV, μV)
• Logaritmic (dBmV, dBμV)

Data storage/ transfer

• Internal Flash memory
• External USB storage class compliant
• USB Flash Drive/ USB Hard Disk Drive
• Data Transfer Measurements can be downloaded from a PC

The DV Power RMO60TC Winding Ohmmeter can inject current with a voltage 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. It is equipped with thermal and overcurrent protection and has very high ability to cancel electrostatic and electromagnetic interference in HV electric fields. Using the DV-Win software, tests can be performed from a PC with the results sent directly to the PC. Using DV-Win and the RMO60TC it is possible to perform heat run test on distribution and power transformers. The RMO60TC can be used to measure winding resistance of individual taps of a power transformer’s tap changer and can also check whether the on-load tap changer (OLTC) switches without an interruption.

Brief Specs:

The RMO60TD can be used to measure the winding resistance of individual taps on a power transformer’s tap changer without discharging between tests. The unit also checks whether the on-load tap changer (OLTC) performs switching without an interruption as well as analysing measurements of ripple, transition time, and visualizing DRM graphs. The RMO60TD can perform fully automatic demagnetization after a DC current test or when disconnecting a transformer from service. The RMO60TD has a very high ability to cancel electrostatic and electromagnetic interferences that exist in HV electric fields and is equipped with a thermal and overcurrent protection. 

An automatic discharging circuit (independent of power supply) safely discharges the energy stored in the transformer windings at the end of the test in a very short time with an audible and visible indication of the discharging state provided. An automatic connections check is performed at the beginning of each test and the instrument warns the user if an open connection is detected. The companion DV-Win software enables control and observation of the test process, as well as saving and analysing the results on a PC. It provides a test report arranged in a selectable form as an Excel spreadsheet, PDF, Word, or ASCII format. The software provides an OLTC (tap changer) condition assessment through analysis of the graphs representing dynamic resistance values during the tap changer transitions.  

Brief Specs:

Applications:

• Ultrasonic detection of surface PD activity as numerical values and as audible signals
• Measurement of internal PD activity in the form of Transient Earth Voltage(TEV) signals
• Continuous PD measurement mode, incorporating displays of maximum level, pulse count per cycle, severity level etc
• Single shot PD measurement function
• UltraDish waveform concentrator with laser pointer for overhead line equipment 

Features:

• The core functionality of the UltraTEV plus is a combination of the UltraTEV detector and UltraMet plus
• Detects and Measures PD activity as numerical values for both ultrasonic and TEV emissions
• Menu Driven backlit colour screen and keypad
• Locate and listen to ultrasonic PD activity with headphones included
• Switchable modes one-shot PD Detection or continuous measurement
• Lightweight, tough and ergonomically designed

The Megger 550503 measures a wide turns ratio range (10,000:1) while also providing high accuracy (0.1%).  The operator is able to enter the ratio of the transformer and all of its taps which indicates immediately when a tap is outside the acceptable limits. This also allows for a pass/fail limit so problem taps can be easily flagged. For single person testing a remote control switch allows the operator to test transformers with LTCs very quickly. To improve set up times and remove the need for additional test equipment the unit records ratio errors for bushing CTs to an accuracy of ±0.1% nameplate. A Quick Test Mode is also available that provides a fast determination of the turns ratio for single and three-phase transformers.

Phase deviation of the transformer primary versus secondary can be measured to indicate problems such as partial shorted turns and core faults. This measurement is also useful in verifying phase errors in all types of PTs and CTs. The Megger 550503 displays all values for each test including measured and calculated ratio, exciting current, ratio error, and phase angle deviation thus providing comprehensive and conclusive data along with automatically self-calibrating for each test.

Brief Specs:

The Megger TTR100 applies voltage, with voltage ratio being directly proportional to turns ratio, to the high-voltage winding of a transformer and accurately measures the resulting voltage from the low voltage winding. In addition to turns ratio, the unit measures excitation current, phase angle deviation between the high and low voltage windings, percent ratio error, dc winding resistance and polarity. The TTR100 is particularly suited for testing in substations and transformer-manufacturing environments where testing single and three-phase transformers can be performed.

The unique design of the TTR100 allows the user to operate the test set while holding it in one hand and features a high contrast LCD screen which can be seen in bright or ambient light. The Megger TTR100 comes equipped with sufficient onboard memory to store up to 200 test results (including test report header information) in the field for later retrieval, as well as 100 user-defined transformer settings.

Brief Specs:

• Powered by rechargeable battery, provides up to fifteen hours of field operation
• Measures the wide turns ratio range (20,000:1) with the high accuracy (±0.1%, 0.8 to 2000) at a low excitation voltage
• Enables the operator to enter the ratio of the transformer and all of its taps to show when a tap is outside acceptable limits
• Measures the phase deviation (in minutes, degrees or centiradians) of the transformer primary versus secondary
• Can be used for inspection purposes to determine the no-load accuracy of most CTs and PT
• Quick Test mode provides a fast determination of the turns ratio, excitation current, phase angle deviation, and winding resistance in single- and three-phase transformers and CTs
• Automatic self-calibration for each test
• Three user selectable standards: ANSI, IEC, and Australian.