OMICRON Magazine

Magazine | Issue 1 2020 TESTRANO 600 supports all common electrical diagnostic tests on power and distribution trans- formers and is known for its simple connection concept and reduced rewiring effort. Although up until now, there has been one exception: For short- circuit impedance and leakage reactance measure- ments, the test leads from the secondary side had to be removed to apply an external short-circuit. In our continuous effort to improve the usability of our equipment and increase the safety for our users, we have implemented a measurement principle which doesn’t require an external short- circuit and, therefore, no change in test setup. The short-circuit is applied inside the device using the test leads already connected to the terminals from the previous test. TESTRANO 600 then determines the short-circuit impedance of the transformer and corrects the results for any additional losses intro- duced by the test leads. Increased speed, accuracy and safety The new feature completes the advantage of Primary Test Manager TM (PTM)’s automatic test procedure. You can now perform a series of measurements such as three-phase ratio, primary and secondary winding resistance, short-circuit impedance, leakage reactance and demagnetiza- tion without changing any test connections with the press of one button. Although there are multiple factors that can influence the accuracy of short-circuit impedance, respectively leakage reactance measurements, by far the most frequent problem is additional losses introduced by an inadequate external short-circuit. The leads used to short-circuit the terminals should be as short as possible, sufficient in diameter and tightly clamped to the terminals. Transformers of different sizes and ratios may require different accessories to apply adequate short-circuits, which can make it difficult for testers in the field to obtain accurate results. This new approach not only speeds up the test and helps to reduce measurement errors, it also increases the safety for testers as it relieves them of an additional ladder trip to change the connections. Get the latest Primary Test Manager TM (PTM) software version 4.60 The latest PTM version 4.60 enables you to take advantage of all these benefits and will be avail- able from May 2020 onwards. Download it free of charge in our Customer Portal. HOW CHANGING CONNECTIONS WILL BECOME A CONCERN OF THE PAST Increase speed, safety and accuracy during transformer testing with TESTRANO 600 GOOD TO KNOW… The leakage reactance represents the reac- tive part of the short-circuit impedance. However, both terms are used synony- mously to refer to the same test method. These sensitive methods are used to assess possible deformation or displacement of transformer windings. 25