High Voltage Impulse Test

High Voltage Impulse Testing

DEKRA utilizes state of the art high voltage impulse generator and other laboratory facilities and test equipment to perform a wide range of testing services for electrical equipment manufacturers, industrial power users, transmission/distribution utilities and power producers. The ability of insulating materials to withstand transient voltage stresses resulting from causes, such as nearby lightning strokes, is important in establishing the reliability of apparatus/systems insulated with these materials.

Comprehensive Services

DEKRA performs tests according to IEC and ASTM standards including:

  • Dry Lightning Impulse Critical Flashover and Withstand according to ASTM D3426 – 97 “Standard Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials Using Impulse Waves”, and IEC 60060-1 Second edition 1989-11 “High-voltage test techniques – Part 1″
  • Electrical Surface Flashover at Commercial Power Frequencies (60Hz AC) ASTM D149 – 97a (Re-approved 2004) “Standard Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials at Commercial Power Frequencies”
  • Custom test programs for research and new product development.

Technical Articles/Downloads

Complete Test Capabilities

DEKRA maintains following High Voltage testing capabilities:

  • Lightning impulse voltage tests up to 24 kV (peak) for a pressure range from 14.7 psia to 1.5 psia. The variable impulse test voltage is obtained from a programmable impulse generator, which is capable of generating precise impulses of waveform 1.2/50ms. A digital oscilloscope is used to display and record test results.
  • Surface flashover at commercial power frequencies (60Hz AC) up to 16 kV (peak). The variable test voltage is obtained from a step-up 60Hz AC, 120V/10kV RMS/16.2kV Peak Voltage transformer supplied from a variable sinusoidal low-voltage Source, VARIAC 120 /0-120/0-140 VAC. The capacity of the step-up transformer, and its voltage source is sufficient to maintain the test voltage until surface flashover occurs.

Examples of typical tests conducted:

  • Impulse flashover tests on highly insulating materials at various pressure conditions.
  • Surface flashover at commercial power frequencies at various pressure conditions.
  • Contamination testing of external insulation at various pressure conditions.

Specialized Facilities

Testing chamber

Our unique testing chamber is capable of simulating low-pressure conditions continuously, while monitoring the performance of insulation up to test voltages of 24 kV. Tests are performed inside the vacuum chamber, which is placed on an insulating bottom plate equipped with feed-through high voltage insulating bushings, electrode system, and provisions to connect vacuum pump and pressure measuring gauge. The facility accommodates contamination testing of external insulation under standard and non-standard conditions. These tests are of particular interest to utilities looking at the performance characteristics of various insulators. For example, test results can be used to determine the best insulator for a specific utility application.

Direct client benefits

  • Accurate, reliable test results to support informed decision-making.
  • Quality testing by utility industry experts in a world-class facility.
  • Evaluate and confirm product performance before installation.
  • “One-stop-testing-services” – Tests can be combined with other DEKRA Electrostatic testing services. (see Electrostatics for more information).

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