MEGGER

DC overvoltage or withstand testing

Overvoltage protection is critical to the long-term health of any cable. DC overvoltage testing (also known as withstand testing) is the most popular method of general condition and integrity assessment in the power, industrial and domestic markets. This method of testing is distinguished a number of key advantages:

Transient overvoltage on the supply, which is typically a very brief voltage spike, can be easily simulated and tested by DC withstand test equipment. DC withstand testing equipment is generally smaller and lighter than an equivalent AC test set. Because overvoltage tests are typically field based, being able to easily transport your tester is critical. Another significant advantage is that DC overvoltage testing has been a popular method for a long time, so there is plenty of historical data available from different technical bodies. Reference to these records allows operators to monitor condition quality through trend analysis. By regularly updating this data, insulation quality and integrity can be monitored indefinitely. 

However, DC overvoltage testing is not always a perfect simulation of the stresses that power systems contend with on a day-to-day basis. For example, many power systems are subjected to frequencies of 50/60 hertz in their operational state, which are not always accurately represented. For conditions such as these, an AC test set is recommended.

220000 series - 70/120/160 K V DC DIELECTRIC TEST SETS

  • Lightest weight available in air-insulated high-voltage model
  • Advanced performance with long-term reliability provided by filtered half-wave rectification
  • Designed for maximum operator safety
High Voltage DC dielectric test sets provide the most dependable, portable DC highvoltage sources for checking the quality of electrical power cables, motors, switchgear, insulators, transformers and capacitors.

*Please note the analog models are no longer available.

EST - HIGH VOLTAGE DISCHARGE ROD

  • Choice of 6 versions of discharge rod
  • Complies with EN 50191, EN 61230 and EN 61219
  • Versions for 35 kV to 150 kV working.
  • Discharge resistors ensure damped discharge
For damped discharge and direct, visible earthing.

In its tip with which the live conductor is touched the SebaKMT discharge rod features a discharge resistor which limits the discharge current and ensures a damped discharge.

Within a split second, most of the charge of the cable has flown off a post charging effect is thus eliminated.

The discharge rods are made of GFK (fibre glass strengthened plastic). They are equipped with a handle and conservatively rated clearance against physical contact with high voltage.

HPG70-K - 70 KV DC PORTABLE HV TEST SYSTEM

  • Highest safety thanks to fully insulated design
  • Separate control and HV-unit
  • Voltage continuously adjustable
  • Expandable with a VLF CR attachment for VLF testing on MV cables
The high voltage test set HPG 70-K from SebaKMT is a fully insulated test set for DC testing up to 70 kV. Thanks to its fully insulated design this system is ideal for stand-alone applications. The DC voltage is obtained through a bridge rectifier which ensures a very low ripple of the test voltage. Moreover the DC voltage is measured on the secondary side and therefore ensures a precise output voltage.

HV test set 50 kV, HV test set 80 kV and HV test set 110 kV - PORTABLE HIGH VOLTAGE TEST SET FOR D.C. TESTING OF CABLE

  • Highest safety by monitoring functions and easy operation
  • Quick and easy mounting with compact and simple setup
  • Meeting individual needs by modular design
The HV Test Set is a cable tester for DC voltage testing of cables and cable installations in accordance with the international standards. It consists of an operation unit and HV unit. Due to its small size and low weight the test sets can easily be transported and used on-site. The HV Test Set is available in three versions (50/80/110 kV DC).

HV Tester 25 - HIGH VOLTAGE GENERATOR

  • DC and insulation testing of cables, joints, electrical fixtures, etc.
  • High flexibility with built-in battery
  • Internal discharge facility
The HV Tester 25 kV is a high-voltage generator with a variable negative DC output voltage of 0 - 25 kV. The condition of the test object with regard to electrical strength and insulation quality can be determined on the basis of the unit's readings for output voltage and current. Due to its small size and internal battery this test-system is ideal for test-conditions where no external power supply is available.

T 99/1 - HIGH POTENTIAL TESTER (HIPOT)

  • Ideal for field application because of its low weight and compact design
  • High safety due to internal discharge facility
  • High flexibility with the external battery
  • Over-current tripping
The high voltage test unit T99/1 is a portable and powerful test device able to generate a DC voltage of up to 40 kV. The T 99/1 is used for testing of cables, cable accessories, plant and installations. Because of the short-circuit proof design and high output current of the T 99/1, this is device is also suitable for cable fault location (in conjunction with a TDR unit).

T26/1A 200 kV, T26/1B 400 kV and T26/1C 800 kV - HIGH VOLTAGE TEST SETS

  • Great mobility
  • Simple, safe operation
  • Thermal overload shutdown
  • Discharge switch
The T 26/1A and T 26/1B high-voltage test sets are efficient, mobile systems for high-voltage testing of cables, cable systems and installations as required by current regulations (VDE) with DC voltages of up to 400 kV and 650 kV respectively. The sets are suitable for both installation in measuring trailers and onsite testing as stationary test set. The spatial separation of the operating and high-voltage units makes it possible to operate the sets from outside the immediate danger area. Their modular structure makes them easy to set up on site and allows adaptation to measuring tasks.

The sets are primarily designed for power supply companies, cable laying firms and cable manufacturers for the DC voltage testing of high-voltage systems and cables. Their short-circuit-proof output circuit and high power make them suitable for use in fault location as a burn-down unit for burning high-impedance and intermittent cable fault.