Three-Phase Transformer Turns Ratio Tester (TTR)
A Three-Phase Transformer Turns Ratio Tester (TTR) measures the voltage ratio between transformer windings and verifies performance against nameplate specifications.
Key Testing Functions
Ratio & Deviation Measurement
Applies a controlled AC test signal to calculate individual phase ratios and automatically display percentage deviation against expected values.
Vector Group & Polarity Verification
Confirms winding connection configurations (e.g., Dyn11, Ynd11) and phase displacement prior to site energization.
Tap Changer Progression Testing
Evaluates ratio progression across all tap positions (OLTC / DETC) to detect contact wear or mechanical misalignment.
Excitation Current Measurement
Monitors no-load excitation current during ratio testing to provide deeper diagnostic insights into magnetic core and winding integrity.
Model Selection Guide
|
Feature / Parameter |
Standard Field Model |
Advanced Diagnostic Model |
|
Primary Application |
Substation Maintenance / Field Service |
Factory Acceptance Testing (FAT) / R&D |
|
Ratio Range |
0.8 to 5,000 |
0.8 to 10,000 |
|
Ratio Accuracy |
0.1% |
0.05% |
|
Three-Phase Testing |
Automatic |
Automatic (High-Speed Signal) |
|
Vector Group Detection |
Supported |
Auto-Identification & Display |
|
Excitation Current |
Optional |
Integrated |
|
Power Supply |
AC Mains / Built-in Battery |
AC Mains |
|
Data Export |
USB Flash Drive / Built-in Printer |
USB, Ethernet, PC Software, Bluetooth |
Applications & Target Audience
Transformer Manufacturers
Factory acceptance testing (FAT) and quality control documentation.
Utilities & Grid Operators
Routine preventive maintenance, commissioning, and safety audits.
Service Contractors
Fast on-site diagnostics with automated report generation.
Repair & Rewinding Centers
Winding ratio verification post-overhaul.
Step-by-Step Testing Workflow
Information Verification: Confirm nameplate ratings, vector group, and tap positions.
Isolation & Safety: Safely isolate, discharge, and ground the transformer under test.
Lead Connection: Connect high-voltage (H) and low-voltage (X) test leads per diagram.
Parameter Entry: Select test voltage, vector group, and tap configuration.
Automated Test: Execute the test sequence and review real-time phase data.
Report Generation: Save or export data via USB or PC software for documentation.
Built-in Safety & Protection
Reverse-connection detection (prevents HV injection into LV terminals)
Automatic short-circuit and over-voltage protection
Emergency auto-interruption and grounding control
Rugged, weather-resistant IP67 enclosure
Request a Custom Quote (RFQ)
Transformer Rating & Type: Power, Distribution, or Auto-transformer
Voltage Ratings: Primary (HV) and Secondary (LV) Nominal Voltages
Vector Group & Tap Changer Details: e.g., Dyn11, On-Load vs. De-Energized Taps
Operating Environment: Field (Battery Required) vs. Factory Laboratory
FAQ
Q: What is a Three-Phase Transformer Turns Ratio Tester?
A: It is an electrical test instrument used to measure the ratio between transformer windings. Depending on the model, it can also test polarity, vector group, phase relationship, tap positions, and excitation current.
Q: Why should all three phases be tested?
A: Testing all three phases allows engineers to compare the individual phase ratios and identify differences that may not be visible from a single-phase measurement.
Q: Can a TTR tester detect transformer winding problems?
A: TTR testing can identify abnormal ratio results that may be associated with winding, connection, tap, or manufacturing problems. An abnormal TTR result should be followed by appropriate diagnostic testing rather than being treated as proof of a specific fault.
Q: Can the tester verify transformer vector group?
A: Models equipped with vector group testing can verify supported transformer winding connection groups and phase relationships.
Q: Can TTR testing be performed on transformers with tap changers?
A: Yes. Ratio measurements can be performed at applicable tap positions when the transformer configuration and tester support the required test procedure.
Q: What ratio range should I choose?
A: The required range depends on the transformers that will be tested. The tester's specified ratio range should cover the lowest and highest ratios in the intended testing program.
Q: Can TTR test results be saved and exported?
A: This depends on the model. Available options may include internal storage, USB export, printing, or software-based reporting.
Q: What information is needed to select a TTR tester?
A: Important information includes transformer type, rated voltage, ratio range, phase configuration, vector group, tap changer arrangement, required accuracy, test functions, and whether the equipment will be used in the field or laboratory.
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