Transformer Tester

Transformer Test Instruments for Electrical, Oil and Insulation Testing

Fifty-two instruments covering the test schedule of a power transformer — the electrical tests on the windings and tap changer, the oil tests on the insulating liquid, and the insulation and gas tests that show what the electrical tests cannot.

What is in this section

• Winding and ratio tests — the HF-TC-601 transformer turns ratio tester and the HF-TC-609 handheld TTR tester for ratio and vector group; winding resistance with the HF-TC-602 transformer DC winding resistance tester, plus single-, three- and dual-channel versions (HF-TC-605, HF-TC-606, HF-TC-607), and the HF-TC-633 DC low resistance tester.
• Dielectric loss and impedance — the HF-TC-603 transformer dielectric loss tester uses the variable-frequency method to reject interference, with 0.5–10 kV of high voltage output in 0.1 kV steps, 0–50 V/40 A self-excitation, tanδ resolution of 0.001 % and Cx resolution of 0.001 pF, accuracy Δtanδ ±(1.0 % of reading + 0.040 %) from AC 220 V ±10 %. Short-circuit impedance with the HF-TC-614 and HF-TC-634 transformer short circuit impedance testers, and no-load and load loss with the HF-TC-648.
• Tap changer, deformation and demagnetisation — the HF-TC-604 load tap changer analyzer records transition resistance and time at 3.0/1.0/0.5/0.1 A over 0–320 ms with a 20 kHz sampling rate, ±(5 % of reading ±0.1 Ω) and ±(0.1 % of reading ±0.2 ms) accuracy on a 24 V open-circuit voltage; the HF-TC-618 and HF-TC-625 sweep frequency response analyzers, the HF-TC-647 winding deformation tester and the HF-TC-646 and HF-TC-651 demagnetisation instruments.
• Transformer oil — breakdown voltage (HF-TC-622, HF-TC-628), moisture (HF-TC-630, HF-TC-638 and a Karl Fischer titrator), tan delta of oil (HF-TC-629), acidity and water-soluble acidity, interfacial tension, open cup flash point, cold filter plugging point, corrosive sulfur and XRF sulfur, oil iron content, particle counter, ferrography and oil spectrometer.
• Insulation, gas and site tests — the HF-TC-619 AC hipot tester, the HF-TC-624 portable transformer PD tester, dissolved gas analysis (HF-TC-621, HF-TC-644, HF-TC-627), the HF-TC-620 SF6 gas analyzer, core ground current with the HF-TC-623 and HF-TC-649 core grounding current testers, the HF-TC-613 automatic integrated test bench and the HF-TC-618 group of site instruments.

How to choose a transformer test set

Match the instrument to the test item and the transformer class. Ratio and winding resistance are routine commissioning checks; dielectric loss, short-circuit impedance and no-load loss separate a healthy unit from a suspect one; oil tests need a defined sampling routine to be worth anything. Confirm the voltage class, the output the test requires, and whether the instrument must work from a generator or its own battery on site.

Every instrument in this section is sourced from qualified partner factories in China, verified and tested against its datasheet before shipment and delivered with its test documentation. Houfeng is a trading company and supplier, not a manufacturer.