Three-phase testing for power transformer diagnostics

Omicron has developed a portable three-phase test system that supports all common electrical tests on power transformers.

Weighing just 20kg, Testrano 600 is suitable for routine and diagnostic testing on site and during factory acceptance tests. Its innovative design significantly reduces wiring efforts, cutting down testing time by two-thirds.

In the past, performing a range of standard electrical tests on a regular basis was both time and cost intensive. Different equipment was needed for each test, each phase had to be measured individually and the connections had to be changed between tests.

With the Testrano 600 test set, operators need just one common set-up to perform multiple tests, such as transformer turns ratio, exciting current, DC winding resistance, dynamic resistance, short-circuit impedance or leakage reactance as well as frequency response of stray losses (FRSL). By combining it with the accessory CP TD1, it can also test power/dissipation factor and capacitance up to 12kV.

In order to work with Testrano 600, just three cables have to be connected: one to the high-voltage side, one to the low-voltage side and one to the tap changer. Three integrated sources ensure measurements with high accuracy and make the device a powerful test system (3 x 33A DC and 400V AC).

In order to fulfil individual customer requirements, the test set offers a flexible operating design. Furthermore, it can be operated via the smart Testrano TouchControl on the integrated touch display or by using the established Primary Test Manager software on the laptop.

The controlled discharging function [patent pending at time of publishing] of Testrano 600 automatically discharges the winding within seconds, such as after resistance tests. This increases efficiency and safety during testing.

Operators can also quickly demagnetise the power transformer’s core before and after testing using the test set. Demagnetisation is recommended after DC has been applied on a power transformer, such as during winding resistance tests. A demagnetised core reduces the risk of high inrush currents and avoids the influence of a magnetised core on subsequent tests, such as excitation current tests or sweep frequency response analysis.

Testrano 600 is equipped with an emergency stop button, as well as safety and warning lights. The connector plugs and the simple wiring concept with labelled connection leads leave a narrow margin for wiring errors.

With all its accessories, the test set comes in a portable case and is easy to transport. Its rugged design makes it suitable for on-site testing even in rough operating conditions.