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Power transformer testing with one-time connection

An innovative design for power transformer testing significantly reduces wiring efforts, cutting down testing time to one-third compared to conventional single-phase testing.

This article first appeared in ESI Africa Edition 4, 2018. You can read the full digital magazine here or subscribe here to receive a print copy. 

OMICRON’s TESTRANO 600 is the world’s first portable, three-phase test system which supports all common electrical tests on power and distribution transformers. Weighing just 20kg (44lbs), it is ideal for routine and diagnostic testing onsite and during factory acceptance tests (FAT).

With this product, operators need just one common setup to perform multiple tests. These tests include transformer turns ratio, exciting current, DC winding resistance, dynamic resistance, shortcircuit impedance and 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.

Powerful features

The controlled discharging function (patent pending at the time of writing) of TESTRANO 600 automatically discharges the winding within seconds; for example, after resistance tests have been performed. This increases efficiency and safety during testing.

Operators can also quickly demagnetise the power transformer’s core before and after testing using this product. Demagnetisation is recommended after DC has been applied on a power transformer; for example, 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.

A vector group check helps operators to double-check on site the vector group of the tested transformer. The quick test submits the definition of individual test procedures and is able to perform special measurements like magnetic balance or zero-sequence impedance tests.

The magic number “3”

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 TESTRANO 600 a powerful test system (3x 33A DC and 400V AC). Compared to conventional singlephase test sets, a true three-phase test system offers several advantages, such as shorter testing times when energising all three phases at once, and a fully automated control of the tap changer during testing.

Flexible, safe, smart and rugged

In order to fulfill individual customer requirements, TESTRANO 600 offers a flexible operating design. 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.

TESTRANO 600 follows the ‘safety first’ principles and is equipped with an emergency stop button as well as safety and warning lights. The unique connector plugs and the simple wiring concept with labelled connection leads leave an extremely narrow margin for wiring errors.

With all its accessories, TESTRANO 600 comes in a portable case and is easy to transport. Its rugged design makes it ideal for on-site testing even in rough operating conditions. All in all, TESTRANO 600 brings on-site and factory acceptance testing of power transformers to a new level – it has never been so quick and easy to test your power transformers. ESI

This article first appeared in ESI Africa Edition 4, 2018. You can read the full digital magazine here or subscribe here to receive a print copy. 



Babalwa Bungane
Babalwa Bungane is the content producer for ESI Africa - Clarion Events Africa. Babalwa has been writing for the publication for over five years. She also contributes to sister publications; Smart Energy International and Power Engineering International. Babalwa is a social media enthusiast.