Damped Oscillatory Wave Testing

Electronic measurement and control equipment in energy distribution networks can be susceptible to environmental disturbances called damped oscillatory waves (DOW). Repetitive damped oscillatory waves are phenomena associated with the opening and closing of high voltage busbars in high voltage and medium voltage power transmission stations. The physical environment influences the fundamental oscillation frequency and repetition of the impulses. The most common type of switch used in power distribution is an air insulated type which has been measured as generating damped oscillatory impulses up to 1 MHz with a repetition rate up to 400 Hz. Damped oscillatory impulses up to 1 MHz are termed “Slow Waves”. Damped oscillatory impulses up to 30 MHz are termed “Fast Waves”. 

Slow DOW Fast DOW
tr = 75 ns ± 20% tr= 5 ns ± 30%
fosc. = 1 / Tosc. fosc. = 1 / Tosc.
fosc. = 100 kHz, 1 MHz ± 10% fosc. = 3 MHz, 10 MHz, 30 MHz ±10 %
Pk5 > 50% · Pk1| Pk10 < 50% · Pk1 Pk5 > 50% · Pk1| Pk10 < 50% · Pk1
Repetition: 40/s @ 100 kHz, 400/s @ 1 MHz Repetition: 5000 / s
Burst duration: ≥ 2 s Burst duration: 50 ms @ 3 MHz, 15 ms @ 10 MHz, 5 ms @ 30 MHz
Zout = 200 Ω (Voc / Isc) Zout = 50 Ω (Voc /Isc )

Often times there is confusion between IEC 61000-4-18 DOW and IEC 61000-4-12 ring wave. DOW and ring wave refer to different phenomena that occur in different environments. Generally, equipment that requires DOW testing does not require ring wave testing!

The DOW-CG1 test generator from EMC Partner is designed for full compliance DOW testing. It is a configurable test system that can be extended for Slow Wave, Fast Wave, Impulse voltage test or any combination of all three. This provides optimum and cost-efficient capabilities to a wide spectrum of users. This unique system includes an integrated 32 A three phase coupler which enables both Slow and Fast DOW signals to be directly injected into the EUT. Additionally, DOW3000 is the first tester with integrated 0.5 J impulse, required together with the DOW, for product standard testing. A modern user interface provides an easy to follow menu structure. Graphic and contextual help functions make operation simple and efficient.

The DOW-CG1 system meets and exceeds the requirements of the basic standards:

  • IEC 61000-4-18
  • IEC 61000-4-10

Additionally, many product standards can also be met:

  • IEC 60255-27 Measuring Relays and Protection Equipment
  • IEC 62052-11 Electricity Metering Equipment (AC) General Conditions
  • ANSI C37.90.1 IEEE Standard for Surge Withstand Capability for Relays and Relay System


Features at a glance

  • Proven state of the art technology from EMC Partner
  • Sophisticated touch screen control
  • Modular, configurable generator: SLOW and FAST DOW modules selectable
  • Possibility to add 1.2/50 μs pulse generator up to 8 kV with 500 Ω output and energy 0.5 J / pulse in accordance with IEC 60255-27
  • Built-in 3 phase CDN 3 x 690 V / 32 A per phase
  • Maximum voltage L-N, L-PE: 400 V
  • Advanced EUT automatic protection, supply control
  • Slow DOW output up to 5 kV. Fast DOW output up to 4.4 kV
  • I/O line CDNs available for Slow DOW and Fast DOW
  • Complete test automation with TEMA3000 software