KEP Power Testing Blog: Cable Test Vans from KEP for Fast and Accurate Cable Testing and Fault Location

The progress in the power cable testing sector has equipped technicians with a range of high performance cable testing tools. Yet, despite the tendency for combining various testing techniques in one instrument, it is frequently the case that a complex of tools is required to tackle the job at hand. In these circumstances it is best to opt for a cable test van, like KEP’s ELT-Series test systems, which will ultimately help to save time and money, while facilitating effective fault location.

The ETL-Series cable test vans allow the user to carry out non-destructive diagnostics, testing and fault location on low and medium voltage power cables. These modular test systems comprise a thumper, a time domain reflectometer, and an audio frequency system, which gives the necessary flexibility in terms of choosing the most appropriate cable testing method. The fault location instruments integrated in the ETL test vans are from KEP’s product line and can be customized to the customer’s requirements.

The ETL-series test systems offer the most effective methods of power cable testing such as the acoustic thumping and TDR-based approaches. The latter include pulse echo (TDR), arc reflection (ARC), impulse current (ICE) and voltage decay (DCY).
Fault conditioning is achieved with the systems’ burning and arc reflection modes.

Fault pinpointing

One of the components of a KEP’s test van is the thumper, or a surge wave generator. In conjunction with the receiver P-900, it allows to effectively conduct acoustic cable fault pinpointing. Sheath faults can be pinpointed with either pulsed DC step-voltage or burning.

To facilitate cable route tracing and fault location, the test systems are equipped with an audio frequency generator.

ETL-8V Cable Test Van

Time domain reflectometry

Cable fault prelocation is achieved with the RIF-9 Time Domain Reflectometer, which can be operated either with the high contrast, high resolution touch-screen, or with the handy control knob. The RIF-9 can be used in the TDR mode; coupled with the system’s surge wave generator, it enables running tests in the modes of arc reflection, impulse current and decay.

The onboard memory stores test results and allows sending reports to a PC for further processing.

ETL-40V Cable Fault Location Test System

Audio frequency system

Utilizing the incorporated audio frequency generator (a 50 W LFG-50 or 200 W LFG-200), the ETL-Series test systems help solve the tasks of cable route tracing, fault location, depth measurement and cable identification. The LFG offers a choice of three frequency levels, 491 Hz, 982 Hz and 8440 Hz, and can be operated in a single or two-frequency modes. The load is adjusted automatically, with the overload trip interlock ensuring an even higher safety of operation.

In addition, the audio frequency system makes it possible to test a cable’s shield integrity and identify splices.

Safe operation

The ETL test systems comply with safety standards and integrate a system of interlocks, emergency stop, and key lock switch.

A vital component of the ETL safety is the earthing system delivered through operational, protective and auxiliary earth. To ensure proper operation, the ETL control unit monitors the voltage between protective and auxiliary earth as well as the resistance between operational and protective earth. The safety level is raised even further with the isolating transformer.

Also, the ETL systems incorporate overcurrent protection to make sure the object under test will not be damaged in case of the current exceeding the threshold value.