Insulating Oil Dielectric Loss & Volume Resistivity Tester

Dielectric Loss & Volume Resistivity Tester

MT-DR303

The Dielectric Loss & Volume Resistivity Tester is a fully automatic portable instrument designed for measuring the dielectric dissipation factor (tan δ), relative permittivity, and volume resistivity of insulating oils and other liquid dielectric materials.

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Introduction

The Dielectric Loss and Resistivity Tester is developed according to GB/T 5654 – Measurement of Relative Permittivity, Dielectric Dissipation Factor and DC Resistivity of Liquid Insulating Materials. It allows simultaneous determination of dielectric loss and volume resistivity, providing an effective method for evaluating the electrical insulation performance of transformer oils.

In high-voltage equipment such as power transformers, reactors, and oil-filled electrical systems, the dielectric properties of insulating oil directly affect insulation reliability and operational safety. Increased dielectric loss or reduced resistivity often indicates oil contamination, moisture ingress, or insulation aging.

This Instrument integrates oil cup, heating system, temperature control, and voltage regulation into a compact system. With an intelligent touchscreen interface, automatic calibration, and built-in protection functions, the instrument delivers accurate, reliable, and efficient testing for transformer oil laboratories and power industry applications.

Typical Applications

The Transformer Oil Dielectric Loss Tester is used for evaluating the electrical insulation properties of liquid insulating materials.

  • Transformer insulating oil
  • Mineral insulating oil
  • Synthetic insulating liquids
  • Capacitor oils
  • High-voltage insulating liquids

Typical application environments include:

  • Power generation plants
  • Electrical utility maintenance departments
  • Transformer manufacturing facilities
  • High-voltage equipment laboratories
  • Petroleum and insulating oil testing laboratories
  • Electrical insulation research institutes

Key Features

1. Intuitive Touchscreen Operation

The instrument features a color touchscreen interface with Chinese menu operation and printing capability, allowing convenient parameter input and easy test control.

2. Integrated Testing Structure

The analyzer integrates oil cup, heating unit, temperature control system, and voltage regulation module into a single instrument, simplifying operation and improving laboratory efficiency.

3. Automatic Empty Cup Calibration

An automatic empty electrode cup calibration function measures the capacitance and dielectric loss of the empty test cell, ensuring correct assembly and cleanliness of the electrode cup.

4. Automatic Calibration Data Storage

Calibration parameters are automatically stored, enabling accurate calculation of relative permittivity and DC resistivity during subsequent measurements.

5. Comprehensive Safety Protection

The system includes overvoltage, overcurrent, and temperature protection mechanisms, automatically disconnecting the high-voltage circuit and issuing warning messages when abnormal conditions occur.

6. Temperature Sensor Monitoring

If the temperature sensor fails or becomes disconnected, the instrument automatically generates an alarm to ensure safe operation.

7. High-Frequency Induction Heating

The electrode cup is heated using high-frequency induction heating, providing rapid and uniform heating for stable testing conditions.

8. Stable 50 Hz Test Voltage Source

The instrument includes a digital voltage regulation system and sine wave generator, producing a stable 50 Hz high-power test voltage required for dielectric loss testing.

Technical Specifications

Name

MT-DR303 Insulating Oil Dielectric Loss & Volume Resistivity Tester

Test Voltage Range

D500 – 2000 V AC (50 Hz); 0 – 500 V DC

Temperature Range

Room Temperature – 125°C

Dielectric Loss Range

0.00001 – 1

Measurement Accuracy

± (Reading × 0.5% + 0.0001)

Relative Permittivity

(1.0 – 10.0) ±1%

Resistivity Resolution

0.01 MΩ·m

Resistivity Measurement Range

2.5 MΩ·m – 20 TΩ·m

Power Supply

AC 220 V ±10%, 50 Hz ±1 Hz

Power Consumption

500 W

Dimensions

470 × 430 × 380 mm

Operating Environment

Ambient Temperature: 0°C – 40°C

Relative Humidity: <75% RH

Standards Compliance

This Transformer Oil Dielectric Loss and Resistivity Analyzer is designed in accordance with:

  • GB/T 5654 – Measurement of Relative Permittivity, Dielectric Dissipation Factor and DC Resistivity of Liquid Insulating Materials
  • ASTM D924 – Standard Test Method for Dissipation Factor (or Power Factor) and Relative Permittivity of Electrical Insulating Liquids
  • ASTM D1169 – Standard Test Method for Specific Resistance (Resistivity) of Electrical Insulating Liquids

These standards are widely applied in transformer oil testing and electrical insulation analysis laboratories.

Why Choose Our Dielectric Loss & Resistivity Tester

Accurate Transformer Oil Dielectric Analysis

Provides reliable measurement of dielectric dissipation factor (tan δ), relative permittivity, and volume resistivity.

Integrated Laboratory Testing System

Combines oil cup, heating system, temperature control, and voltage regulation into one compact device.

Automatic Calibration and Data Storage

Automatic empty cell calibration ensures high measurement accuracy and repeatability.

Enhanced Safety Protection

Multiple safety mechanisms protect the instrument against overvoltage, overcurrent, and overheating.

Ideal for Power Industry Oil Testing

Widely used in power plants, transformer maintenance laboratories, electrical utilities, and research institutions.

FAQ – Dielectric Loss & Volume Resistivity Tester