Transformer Demagnetization Tester with DC Frequency Attenuation Technology for 35kV-330kV Power Systems| XHXC105

Q1: Why is transformer demagnetization necessary before commissioning?

After DC resistance testing or voltage ratio measurements, residual magnetism remains in the transformer core due to ferromagnetic hysteresis. When the transformer is energized, this residual flux can cause half-cycle core saturation, generating high-amplitude harmonic-rich inrush currents that may trip protective relays, damage circuit breakers, reduce CT measurement accuracy, and even trigger sympathetic inrush events causing cascading blackouts across interconnected substations. Complete demagnetization ensures safe and reliable transformer energization.

Q2: How does the XHXC105 achieve demagnetization in under 4 minutes when traditional methods take 30 minutes?

The XHXC105 employs patented DC frequency attenuation technology, which progressively reduces the applied DC current amplitude while periodically reversing current polarity. This dual-action approach simultaneously shrinks the magnetic hysteresis loop and enables magnetic pole mutual cancellation, achieving deep demagnetization far more efficiently than conventional single-direction attenuation methods used by older instruments.

Q3: Can the XHXC105 handle three-phase transformers, and what is the connection method?

Yes. For three-phase transformers, the XHXC105 requires connection only to the B-phase to achieve complete demagnetization of all three phases. For single-phase transformers, connect to terminals A and X. The degaussing output is polarity-independent—positive and negative connections are interchangeable. If the specific phase with higher residual magnetism is unknown, you can perform two to three passes across different phase combinations (AB, BC, CA).

Q4: What is the difference between Automatic and Manual modes?

In Automatic mode, the instrument performs an initial measurement phase (tens of seconds), then automatically sweeps through all four current levels—5A, 1A, 200mA, and 5mA—in sequence until the degaussing progress reaches 100%, after which it automatically discharges. This provides the highest effectiveness (≥90% per cycle) and is recommended for most applications. In Manual mode, the operator selects a single current level for targeted degaussing, which completes in approximately 3 minutes per cycle with ≥80% effectiveness—useful for specific scenarios where a particular current level is preferred.

Q5: What safety precautions should be observed when operating the XHXC105?

Key safety guidelines include: (1) Read the complete user manual before operation and follow all connection procedures. (2) Never connect or disconnect test leads while the instrument is powered on. (3) Ensure the grounding terminal is securely connected to a reliable earth ground before powering on. (4) Do not remove test clamps during the degaussing process. (5) If any abnormality occurs, immediately press the red Reset button or turn off the main power switch. (6) The instrument contains high-precision electronic components—avoid violent impact, and only qualified personnel should perform internal servicing. (7) When powered by a generator, verify the output is a clean 50Hz sine wave with proper grounding.