On-Load Tap Changer Tester|XHYZ1668 Precision Transition Resistance & Waveform Analysis for YN, Y, and Delta Transformer Diagnostics
Product Overview
The XHYZ1668 On-Load Tap Changer (OLTC) Tester is a high-precision diagnostic instrument designed for comprehensive evaluation of transformer on-load tap changers—the only moving component in the transformer circuit connection. Per the requirements of the Power Equipment Commissioning and Preventive Test Regulations, this instrument measures critical OLTC parameters including transition waveform, transition time, instantaneous transition resistance values, and three-phase synchronicity.
Built around an intelligent microcontroller platform with a 7-inch high-brightness LCD and full Chinese/English menu navigation, the XHYZ1668 delivers laboratory-grade analysis in a portable 6.15kg package. It supports both with-winding and without-winding test modes for YN, Y, and Delta transformer configurations, with direct resistance display that eliminates the need for manual conversion. The 20kHz sampling rate captures fine waveform details, while the built-in high-speed thermal printer, 500-group storage, and RS232/USB interfaces enable complete on-site documentation and data export.
Key Features
- Three-Mode Current Output: Selectable 1.0A, 0.5A, and 0.2A test currents to optimize measurement accuracy across different resistance ranges
- Wide Resistance Range: Covers 0.3Ω~100Ω across three current ranges with direct readout—no manual calculation required for YN, Y, or Delta configurations
- Dual Test Modes: Supports both with-winding testing (on installed transformers) and without-winding testing (bench-top switch evaluation) for maximum flexibility
- High-Speed 20kHz Sampling: Captures fine waveform details with transition time measurement accuracy of ±(0.1%+0.2ms)
- Auto-Scaling Waveform Display: Automatically adjusts resistance and time axis scaling based on sampled values for optimal waveform visualization
- 7-Inch High-Brightness LCD: Large, clear display for comfortable field operation with intuitive touch-panel parameter configuration
- 500-Group Data Storage: Internal memory with waveform storage for comprehensive test documentation and trend analysis
- RS232 & USB Connectivity: Dual data interfaces for computer communication, firmware updates, and digital report generation
- Built-in High-Speed Printer: Immediate on-site waveform and data printing for complete test documentation
- Comprehensive Protection: Refined protection circuits, 2-minute automatic current output timer, and robust anti-interference design for reliable field performance
Technical Specifications
| Measurement Performance |
| Output Current |
1.0A, 0.5A, 0.2A (Selectable) |
| Transition Resistance (1.0A) |
0.3Ω ~ 20Ω |
| Transition Resistance (0.5A) |
5Ω ~ 40Ω |
| Transition Resistance (0.2A) |
20Ω ~ 100Ω |
| Transition Time |
0 ~ 320ms |
| Open Circuit Voltage |
24V |
| Resistance Accuracy |
±(5% Reading ±0.1Ω) |
| Time Accuracy |
±(0.1% Reading ±0.2ms) |
| Sampling Rate |
20kHz |
| Testing Configuration |
| Transformer Types |
YN, Y, Delta (Δ) with/without winding |
| Tap Positions |
00-95 Configurable |
| Tap-Changing Direction |
Up / Down Selectable |
| Measurement Phases |
Single-Phase / Three-Phase |
| Trigger Sensitivity |
Adjustable Trigger Resistance Threshold |
| Waveform Filter |
0-60 Level Adjustable Digital Filter |
| Interface & Data |
| Display |
7-inch High-Brightness LCD |
| Storage |
500 Groups Internal Memory |
| Data Interfaces |
RS232 Serial + USB |
| Printer |
Built-in High-Speed Thermal Printer |
| Operating Specifications |
| Power Supply |
AC 220V±10%, 50±1Hz |
| Operating Temperature |
-10℃ ~ 50℃ |
| Operating Humidity |
≤85%RH |
| Physical Specifications |
| Dimensions (Main Unit) |
360 × 290 × 170mm |
| Dimensions (Cable Case) |
360 × 290 × 170mm |
| Weight (Main Unit) |
6.15kg |
| Weight (Cable Case) |
4.55kg |
Frequently Asked Questions
Q1: What parameters does the XHYZ1668 measure and why are they critical for transformer maintenance?
The XHYZ1668 measures transition resistance, transition time, three-phase synchronicity, and generates complete switching waveforms for on-load tap changers. These parameters are critical because the OLTC is the only moving component in a transformer's circuit connection. Degraded transition resistors, worn contacts, sluggish mechanism timing, or poor phase synchronicity can lead to arcing, coking, and catastrophic transformer failure. Regular OLTC testing per preventive maintenance schedules identifies degradation before it causes unplanned outages.
Q2: What is the difference between with-winding and without-winding test modes?
With-winding testing is performed on installed transformers with the windings connected, measuring the OLTC in its actual operating configuration. The non-test windings (typically medium and low voltage sides) must be three-phase short-circuited and grounded. Without-winding testing disconnects the windings and tests the tap changer mechanism directly—this mode produces faster transition times (by approximately 3-7ms) and is ideal for bench-top switch evaluation during manufacturing or refurbishment. The XHYZ1668 supports both modes with automatic parameter adjustment.
Q3: How does the XHYZ1668 handle different transformer winding configurations?
The XHYZ1668 directly supports YN (star with neutral), Y (star without neutral), and Delta configurations without requiring manual resistance value conversion. For YN configurations, all three phases and neutral are connected for simultaneous measurement. For Y configurations where the neutral is not accessible, the instrument supports two-phase sequential measurement with automatic conversion (R=1/3R'). For Delta configurations, the instrument similarly handles two-phase measurement with conversion (R=R' for two-phase, R=2/3R' for single-phase). Real-time wiring diagrams are displayed on the 7-inch screen for setup guidance.
Q4: How does the waveform analysis help identify specific OLTC fault types?
The XHYZ1668 captures waveforms at 20kHz, enabling fine-detail analysis of switching behavior. Common fault signatures include: extended bridging time (indicating mechanism spring fatigue or sluggish operation), asymmetrical zero-crossing segments (broken transition resistors—resistance reads >50Ω), oscillation patterns (excessive trigger sensitivity in decreasing inductance direction), and irregular or noisy waveforms (loose/broken flexible connections or partial short-circuits). The auto-scaling display and manual cursor-based measurement mode allow operators to precisely identify fault types and quantify severity directly on-site.
Q5: What are the MOQ, warranty terms, and included accessories for the XHYZ1668?
The minimum order quantity is 1 unit, with payment via T/T or L/C. Standard delivery is 5-10 working days in two protective aluminum alloy carrying cases (main unit: 6.15kg, cable case: 4.55kg). Each unit includes the main instrument, one complete test cable set (A/B/C/N), power cord, ground cable, 2 spare fuses, 1 roll of thermal printer paper, and a comprehensive user manual. Annual supply capacity reaches 500 units. Each instrument includes a 12-month comprehensive warranty with lifetime technical support. OEM/ODM configurations are available upon request. For volume pricing or technical consultation, please contact our sales team.
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