Power Cable Fault Locator

The T-907L is a light-weight, portable fault locator for low, medium and high-voltage power

cables, which can be applied for the pre-location of all kinds of faults, including open circuit,

short circuit, low resistance, high-resistance and flashovers.

The T-907L can operate in five modes: Time Domain Reflectometry (TDR), Secondary/Multiple

Impulse Method, (SIM/MIM), Impulse Current Method (ICM), ICM (current) Decay and the

Voltage Decay Method. Most power cable faults exhibit a high resistance, which requires the

application of a high voltage surge to break it down for the purpose of pre-location. Of the

operating modes available, ICM is the most cost-effective method of producing a flashover at

the fault point using a standard surge generator. In the T-907L, the ICM is augmented by an

Automatic Impulse Current (AIC) method, in which waveform recognition techniques are applied

to calculate the fault location automatically, without the need for the operator to manually

interpret the waveforms. For flashover faults requiring a high breakdown voltage, the Decay

Method can be applied in conjunction with a HV DC source. The cable is charged by the DC

source until it breaks down, creating a transient voltage signal which is captured through a

capacitive voltage divider and used for fault location analysis