XHYZ1668T On-Load Tap Changer Tester 20kHz Sampling OLTC Analyzer for Plant Transformer Preventive Testing

The on-load tap changer is the only moving part connected to the transformer circuit, and OLTC faults are a leading cause of transformer unplanned outages. The XHYZ1668T lets plant electrical teams measure the transition waveform, transition time, instantaneous transition resistance and three-phase synchronization of transformer on-load tap changers during routine preventive maintenance, without sending the transformer to a workshop. The instrument is intelligent, compact and light (6.15kg main unit), with a 7-inch screen, 20kHz sampling and storage for 500 groups of data so that maintenance history can be compared over time.

• High output current (1.0A) with a lightweight main unit of only 6.15kg
• Tests YN, Y and Delta connected transformers with resistance values displayed directly without conversion
• Supports both with-winding and without-winding measurement methods
• Waveform display automatically adjusts resistance and time amplitude according to sampled values
• Complete protection circuit for high reliability in field use
• 7-inch high-brightness LCD with clear menu-driven operation for on-site work
• Built-in storage for 500 groups of test data with query and print functions
• High-speed built-in printer plus USB and RS232 interfaces for data export
• 20kHz high-speed sampling captures every detail of the OLTC switching waveform
• With-winding test method avoids lifting the transformer cover, so most checks are done with the unit in service position
• Strong anti-interference design for reliable measurement in substation and plant environments

The XHYZ1668T adapts to the connection of the regulating winding under test, so plant teams can follow the correct wiring and conversion rules:

When testing with the winding connected, the non-tested side of the transformer must be three-phase short-circuited and grounded, and the instrument ground terminal must be reliably earthed before any voltage is applied. Note that with-winding action time is approximately 3-7ms longer than without-winding action time — a normal difference, not a fault.