Dynamic resistance measurements is a novel technique developed to determine wear on the primary contacts of circuit breakers. It is probably most valuable for the condition monitoring of SF6 insulated switchgear, where the cost of inspections is great due to gas recovery and management during the inspection. The test set injects a current of up to 200A through the and measures the voltage developed during breaker operation while measures the travel curve through rotary and linear transducers. Megavar engineers are trained in the operation of the ISA CBA 2000 breaker Analyzer.

Contact Resistance Measurement

 

Contact resistance measurement is a simple and effective test that can determine whether high resistance s are present in the primary contact and HV connections that could to heating anf failures.

CB Timing Testing

The time that a circuit breaker takes to operate is of great importance, as it needs to be fast enough that it clears the fault rapidly and fits within the grading allowances for the protection scheme. Another factor that is not as widely known is the importance of the velocity of the contacts at the point that the primary contacts part as this determines how effectively the CB will break the current. To determine the velocity, acceleration and deceleration of the contacts through the stroke, a time/travel test needs to be performed. Megavar utilises the CBA 2000 unit for time travel testing on all timing parameters. For simple open, close and open-close-open timing sequence tests we can also use our Megger TM1600.

Dielectric Loss Angle

The measurement and trending of the dielectric loss angle of circuit breaker bushings is an important tool in the condition monitoring regime. The values and the trend will show degradation of the insulation and can be used in predictive assessment to determine the best time for costly maintenance. Megavar utilises the Omicron CPC+TD1 test system along with the Omicron reactor to perform measurements to the highest accuracy.

AC Hipot Testing

Megavar believes that High Voltage withstand testing is the best way to ensure that new electrical assets are fit for purpose before connection to the grid. The advantage of a hipot test over a soak test is clear and in summary the following key benefits are achieved -

  • The AC Hipot is a controlled energy device that limits the amount of fault current that flows when a dielectric breakdown occurs. This provides immensely improved safety when compared with a soak test, whereby the new asset is connected to the grid and everyone hopes it doesn't flashover.
  • The AC Hipot test will stress the insulation at a voltage significantly higher than the network voltage (in accordance with the relevant standards and NEM requirements) to give a far greater level of certainty that the plant is not on the verge of imminent failure.
  • The cost to perform an AC Hipot is very favourable when compared with the cost of an unscheduled outage and the direct and consequential damages that flow from such an event
PD Measurement
Megavar PD Measurement Service

The Partial Discharge phenomena is a sign of degrading insulation capacity. Partial Discharge detection and monitoring is vitally important, as it often precedes an electrical insulation breakdown in high voltage equipment. Our engineers use the Omicron MPD600 test system and a high voltage source to detect and measure PD in switchgear.

IR and PI

These are a cornerstone test for CB condition monitoring. These tests indicate the insulating quality of a dielectric by applying a DC voltage and measuring the current flow to present the insulation value in ohms and trend this value over a time interval of 10 minutes. Megavar uses high quality Megger units and is able to test to 10kV.

General Enquiries

  • Telephone: 1300 730 499
  • Services: service@megavar.com.au

    All technical enquiries, requests for quotes or questions relating to prospective projects and services.

  • Accounts: accounts@megavar.com.au

    Please direct all account queries, payable & receivable, to this email.

  • Rentals: rentals@megavar.com.au

    All technical enquiries, requests for quotes or questions relating to renting equipment.

  • Employment: recruitment@megavar.com.au

    Please check our employment page for open positions. Due to the number of employment enquiries received we do not reply to emails and we do not deal with agencies.

Offices

  • Head Office

    4/2 Kennedy Drive
    Cambridge TAS 7170
    (03) 62513942

  • Queensland Branch

    23/11 Buchanan Rd
    Banyo QLD 4014
    (07) 31234813

  • Victorian Branch

    12/41 Sabre Drive
    Port Melbourne VIC 3207
    (03) 90880231

  • Tasmanian Branch

    112 Gleadow St
    Invermay Tas 7248
    (03) 63888412

  • Adelaide Branch

    1 Clark Terrace
    Seaton SA 5023
    (08) 72285341

Licences

  • NSW - 284109c
  • Tasmania - 947267
  • Victoria - 21203
  • Queensland - 73595
  • Western Australia - EC010840
  • Northern Territory- C3114
  • South Australia – 267537