PT Accuracy Test Systems: Complete Guide to Components & Functionality

PT (Potential Transformer) Accuracy Test Systems are specialized setups for verifying the precision of voltage transformers under load conditions. These integrated systems combine multiple instruments to automate testing per IEC 61869-1 and IEEE C57.13 standards.

Core Components of PT Accuracy Test Systems

1. Control Desk

The central operation unit featuring:

• Integrated voltage regulator (manual/auto)

• Touchscreen HMI for parameter setting

• Test sequence programming

2. Standard Voltage Transformer

Reference-grade device with:

• 0.05% or better accuracy class

• Multiple ratio taps (100V-500kV)

• Temperature-controlled enclosure

3. Transformer Tester (Calibrator)

Dual-function unit capable of:

• PT ratio/phase angle measurement

• CT excitation curve testing

• Auto-calibration against NIST standards

4. Induced Voltage Divider

Precision instrument for:

• Step-down voltage conversion

• Harmonic analysis up to 3kHz

• ±0.01% linearity

Integrated CT/PT Testing Capability

Modern systems combine both functions:

Unified Test Platform

• Single control desk manages CT & PT tests

• Shared calibrator reduces equipment footprint

• Switchable current/voltage burden circuits

Configuration Options

Systems offer flexible setups:

• Centralized control: All burdens set via control desk

• Distributed testing: Remote burden units in test area

• Software-selectable test modes (routine/type tests)

Key Technical Specifications

Operation Workflow

1. Connect PT secondary terminals to calibrator

2. Set voltage burden via control interface

3. Apply test voltage through regulator

4. System auto-compares PT output vs. reference

5. Generate error report (ratio/phase angle)

Advanced systems include auto-demagnetization functions between tests to eliminate residual flux effects on measurement accuracy.