DV Power TWA Series 3-Phase Winding Ohmmeters, Tap Changer & Winding Analyzers



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DV Power TWA
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TWA Datasheet
DV Power TWA Series 3-Phase Winding Ohmmeters, Tap Changer & Winding Analyzers are designed for six-winding resistance measurement of power and distribution transformers, as well as resistance measurement of inductive test objects. In addition, they provide powerful tap changer analysis options by using proprietary, non-intrusive DV test features. These devices generate true DC ripple free current with automatically regulated measurement and discharging circuit. Transformer measurements performed with the DV Power TWA instruments require only one single-step cable setup. Each transformer configuration has a special measurement algorithm which is optimized for the fast stabilization of test results. The test current can be automatically passed through the HV and LV winding simultaneously in order to achieve shorter stabilization times. Additional testing mode, Quick YN, is enabled by the DV-Win software. In this mode, it is possible to measure the resistances of three transformer windings in the YN configuration simultaneously. It is also possible to test the resistances of all tap changer positions of all three phases in a single pass through the tap changer positions. Auto-Demagnetize function once testing complete.

The DV Power TWA40D model is a true three-phase instrument capable of simultaneously measuring winding resistances of three phases of YN configuration, as well as three-phase tap changer analysis. All TWA instrument models are capable of both single-phase and three-phase demagnetization. The DV-Win software, which provides full control of all TWA functions from a PC, as well as additional test and analysis modes and features, is included with The DV Power TWA instruments.

The DV Power Three-Phase Winding Ohmmeter TWA25A is designed for six-winding resistance measurement of both the primary and the secondary transformer windings. This is performed with a one single-step cable setup, with test currents of up to 25 A. Each transformer configuration has a special measurement algorithm which is optimized for the fast stabilization of test results.

The DV Power Tap Changer & Winding Analyzer TWA40D is designed for six-winding resistance measurement and simultaneous three-phase on-load tap changer dynamic graphic analysis of both the primary and the secondary transformer windings. This is performed with a one single-step cable setup, with test currents of up to 40 A. Each transformer configuration has a special measurement algorithm which is optimized for the fast stabilization of test results.
 
DV Power TWA Features
  • Resistance measurement of all tap positions in all six windings performed in a single test
  • True three-phase on-load tap changer dynamic resistance measurement
  • Extremely quick measurement, single-step cable setup
  • Automatic discharge process
  • Rapid automatic demagnetization
  • Built-in tap changer control unit
  TWA25A TWA40D
Six-winding resistance measurement yes yes
DC test current 5 mA – 25 A 5 mA – 25 A; up to 25 A for winding resistance measurement and up to 40 A for the 3-phase synchronization test
Measurement accuracy ± (0,1 % rdg + 0,1 % FS) ± (0,1 % rdg + 0,1 % FS)
Simultaneous 3-phase winding resistance measurement no yes
DVtest sampling resolution 4 ms 0.1 ms
Simultaneous 3-phase DVtest no yes
Tap changer motor current measurement no yes
3-phase demagnetization yes yes
Interchangeable test leads with TRT turns ratio testers yes yes
USB flash drive feature yes yes
Built-in tap changer control unit yes yes
YES-YES, NO-NO