CABLE TESTING & FAULT LOCATING EQUIPMENT
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HVI has extensive knowledge and field experience in fault locating and cable testing along with the best tools for the job. Fault locating requires more than just a thumper. Efficient fault locating requires the convergence of knowledge, methodology, and the right hardware. A total approach is needed to get the job done quickly to minimize customer outage time and prevent further damage to the cable system. This includes knowledge of the cable systems design, construction, history, accurate maps, proper fault locating procedures and the right thumper which should include a high resistance fault burn down method, time domain reflectometer/cable radar compatibility, and a top-level acoustic/electromagnetic listening device. HVI can assemble the best system and approach possible to meet all needs from 5kV – 230kV cable.
Q. Why Choose HVI Thumpers?
A. HVI Thumpers Offer All the Features Needed
When fault locating, remember this: do no harm. Don’t harm your insulation and accessories by thumping your 15kV cable at 25kV for hours looking for a fault. Use proper methods and technologies. The goal should be to thump at the lowest possible voltage yet deliver the highest possible energy to find the fault. Locate the fault without making more. To do this you need a thumper with a variable hipot output, multiple full energy discharge outputs, and ample burn current to condition a fault to arc at a lower voltage. HVI thumpers offer all the features and power necessary. Don’t handicap your fault locating efforts by spending the same or more for inferior equipment. HVI thumpers provide all the tools you need.
- Fully Variable Hipot Output On All Three Voltage Settings Needed to identify faulted cable, show breakdown voltage to help choose tap, burn fault and hipot cables after repair.
- Highest Burn Current Burns down high resistance faults to permit thumping at lower, less damaging voltage levels. This standard feature on all HVI thumpers may not even be an option from other manufacturers.
- Three Output Voltage Taps All At Full Energy Allows thumping at lower voltages. Noise of maximum joules @ 5kV = noise of maximum
joules @ 20kV.
- Variable Discharge Rate 6 – 10 second discharge/thump rate. Faster and slower discharge rates are not advisable.
- TDR/Radar Ready Use your old TDR or buy a new one. A separate TDR is advantageous over an integrated TDR. This setup offers greater flexibility allowing use without the thumper in the field, downloading the saved waveforms, or for training purposes. This also allows for plug and play connections when its time to upgrade to the newest technologies.
- Battery Operation HVI thumpers are not battery operated. Thumpers of this class that are battery operated must sacrifice other necessary features like variable hipot outputs and burning capabilities, missing half of what a thumper should be. In addition, some have as long as 15 seconds between discharges, greatly slowing the fault location process. Also, battery life is short, assuming that you remembered to keep it charged between uses. Battery operation is not worth the sacrifice.
A Controlled Energy Thumper With Burn Capability is a Necessity
Due to the known problems associated with DC cable testing, most utilities worldwide have abandoned DC testing of solid dielectric cable (many have switched to VLF AC testing), or greatly reduced their test voltage levels, yet they then thump cables at voltages of 2 – 3 times normal line to-ground voltage. They find the fault but make more in the process. This is avoided by using HVI thumpers with three output voltage taps, and high burn currents used to reduce fault impedances to permit lower voltage thumping. HVI thumpers can thump at voltages below normal line-to-ground voltage yet still deliver maximum joule energy, thereby minimizing damage to the cable system and still supplying the required noise for rapid location.
Energy = Watt Seconds = Joules = 1/2 CV2 = Fault Arc Intensity = Noise = Electro-Magnetic Discharge
PROBLEM: To deliver the full joules of energy possible to a fault, the capacitors within a thumper must be charged to the maximum voltage. With the wrong thumper, this often results in thumping a cable at an excessive voltage, causing significant damage to insulation and accessories. Since the applied voltage is a square function (1/2 CV2), if the thumper is at 2/3 voltage, only 45% of the joules are delivered to the fault. At half voltage only 25% energy is delivered, making the fault hard to hear. Either fault locating takes far longer than necessary or the crew gets impatient and turns the voltage all the way up to get the loudest bang. The fault is found but other benign issues within the cable system are transitioned into growing electrical trees which will be your next in service failure. This practice can and should be avoided.
SOLUTION: Use a multi-tapped, “controlled energy” thumper like those from HVI. With three output voltage taps and ample burn current to condition faults, fault location can be performed at voltages far lower than before. Find your fault quickly while avoiding damage. Wouldn’t you rather thump at 5kV instead of 20kV, as long as the discharge energy, or noise, was equal? The measure of a good thumper is not the maximum voltage it can discharge, but the minimum voltage still capable of delivering the full energy. For instance, our 5/10/20 kV output model is a far better choice than the 12.5/25kV model from others.
The CDS Series (Controlled Energy Capacitor Discharge Systems) includes some of the most powerful and full featured fault locators available, including the industry’s top network systems thumper.
The VT-33 is the world’s only combination VLF hipot and cable fault locator, or thumper. It is a complete tool for AC testing and fault locating cables rated up to 25 kV and is TDR/radar ready. It offers a 33 kV AC peak VLF output, VLF cable burn mode, and a 760 J discharge output up to 13 kV.
The SKD Series is a product line of custom-designed and fabricated skid mounted packages with all of the cable test and fault locating equipment needed to equip a trouble truck or cable test/repair van to your specification.
Radar Engineers Model 1669 is a portable Time Domain Reflectometer (“cable radar”) specially designed for use with thumpers connected to an arc reflection filter for “pre-locating” high resistance (pinhole) faults in buried primary power cables. This product integrates seamlessly with the CDS Series and the VT-33 thumper.
The SDAD from Aquatronics is an acoustic and magnetic/ballistic detector used in conjunction with a cable fault locator/thumper to help quickly isolate faults in underground primary cables.