Available now from Megger , arc reflection filters marry impulse generators to highvoltage “radars”, providing fault locating crews with integrated systems to meet all cable fault locating needs.
Megger have two models of arc reflection filter available, the Standard and Heavy-Duty arc reflection filter, both detachable. The Standard arc reflection filter is designed to withstand 1,000,000 Joules/hour continuous operation with a standard impulse generator and 50 kV of proof/burn voltage. The Heavy-Duty arc reflection filter is designed to withstand over 3,000,000 Joules/hour continuous operation with a heavy-duty impulse generator and 70 kV of proof/burn voltage.
The choice of arc reflection filter is dependent upon the energy producible by the impulse generator with which it will be used. The Standard arc reflection filter can be used with any non-heavy-duty impulse generator, while the Heavy-Duty arc reflection filter is designed to be used whenever the system includes a heavy-duty style impulse generator.
Megger arc reflection filters, including their sturdy metal cabinets of welded construction and all their components, are designed to withstand the rough handling they will experience in the field.
For operator convenience, a mode selector switch is provided on the top control panel of the arc reflection filter. When the selector switch is set to ARC REFLECTION TEST, the arc reflection filter network is connected to the cable under test. This makes it possible for the operator to make either TDR tests or arc reflection tests, as well as other tests requiring the
use of the filter.
When the selector switch is set to the PROOF/BURN/ IMPULSE mode, the filter is bypassed, allowing stand-alone operation of the impulse generator system on impulse, proof or burn.
A wide-band current transformer is permanently connected electrically and mounted inside the cabinet for use with the surge pulse.
Megger arc reflection filters are able to locate cable faults on power cables rated at up to 35 kV. Relatively small systems, such as most direct buried underground residential distribution (URD) systems, are easily satisfied with the standard filter. Larger systems, including especially long direct buried distribution cable and especially complex circuits using lead-covered cable, require much more energy, made possible using the heavy-duty filter.
Key features and benefits of Megger arc reflection filters include:
- designed to withstand continuous operation
- system is not vulnerable to operator error, such as being left on after fault localisation
- system can be operated for the time required to localise complex faults
- operator can use the full proof-burn capability of the thumper in use
- helps to provide a clear, distinct display on the companion TDR
- helps to eliminate unwanted background reflections on the companion TDR by contributing less than 5% noise
- limits the voltage that reaches the cable under test to the voltage required to break down the fault
- operator cannot overstress a faulted cable while in the arc reflection mode
- more effective in energising large cable/network systems
- improved fault locating capability
- ionises faults immersed in oil or water
- power matches the fault for more effective fault locating.