Tap Changer Analysis

On-load tap changers (OLTC) play a vital role in regulating the voltage level in the electrical grid. Depending on the load, the transformer turns ratio has to be adapted during operation by the OLTC. These mechanical switching operations can lead to wear and tear of the tap changer contacts over time. Therefore, tap changer analysis focuses on static contact problems of the tap selector and of the diverter switch. In addition, a dynamic resistance and motor current measurement can be performed to analyse the transient switching operation for each tap position.

Benefits of this solution

One system – multiple tests

With TESTRANO 600 you can measure transformer turns ratio, DC winding resistance, dynamic resistance, leakage reactance / short-circuit impedance and frequency response of stray losses as well as demagnetize your transformer.

Easy and fast testing setup

All these tests can be performed with one common setup and on all three phases simultaneously. Thus, TESTRANO 600 cuts down testing time to one third.

Flexible operation

TESTRANO 600 can be flexibly operated using TESTRANO TouchControl on the integrated display, or by using a laptop with the Primary Test Manager software.

Powerful and compact

The three integrated sources ensure measurements with high accuracy and make it a powerful system (3 x 33 A DC and 400 V AC). With a weight of just 20 kg / 44 lbs, it is ideal for on-site and FAT testing.

CPC 100 + CP SB1 + PTM

By combining the CPC 100 with the CP SB1 you can test all three phases and the tap changer automatically. Thus, power transformer testing becomes faster and safer as the rewiring effort and the likelihood of measurement errors are minimized.

The transformer ratio and winding resistance are automatically measured in all three phases (in sequence) in all tap changer positions. The measurement results are recorded by the CPC 100 and can be analysed with the accompanying Primary Test Manager™ (PTM) software.