The testing principle and method of cable fault tester

The cable fault tester can accurately locate the location of cable faults. The classification of cable faults can be divided into short circuit, open circuit, low resistance fault, and high resistance flashover and leakage fault. Next, let’s talk about the testing principle of the cable fault tester and its testing methods.

The testing principle of cable fault tester

In cable fault detection, the cable fault tester uses the principle of radar ranging to test cable faults. The entire testing process is as follows: At the testing end, the tester emits a pulse signal through the testing host of the cable fault on the tested cable. The principle of radar ranging is that during the transmission of this signal in the tested cable, when the characteristic impedance does not match, the signal will generate a reflected wave. At this time, the incident waveform and reflected waveform will appear on the screen of the cable fault tester host, The testing personnel need to place the electronic vernier caliper on the inflection point of the incident and reflected waves. According to the testing principle formula: S=VT/2, S represents the distance between the fault point and the testing end, V represents the propagation speed of the radio wave in the cable, and T represents the time required for the radio wave to propagate back and forth between the cable testing end and the fault point. When V and T are known, S can be calculated. The instrument automatically calculates the distance from the fault point to the testing end through this testing principle.

Testing methods for cable fault testers

There are two main testing methods for cable fault testers: one is the low-voltage pulse method; One is the high-voltage flashover method.

When selecting the detection method for cable faults, testers should choose an appropriate testing method based on the type and severity of the fault, as well as the operating status of the cable line. Low resistance faults generally choose the low-voltage pulse method, while high resistance faults require the high-voltage flashover method and combined with a power frequency withstand voltage test device for detection.

When selecting the “low-voltage pulse method” for testing, the testing host emits a pulse signal on the tested cable,. During this period, the test waveform will be displayed on the screen after signal and data processing. At the same time, in the status display bar, we will also see the specific values of key parameters such as cable type, radio wave propagation speed, sampling frequency, fault distance, and testing date.

By contrast, when selecting the “high-voltage flashover method” for testing, the pulse signal inside the instrument will be disconnected and the instrument will enter an external trigger waiting state. At this point, it is necessary to combine the power frequency withstand voltage test device and apply an impulse high voltage to the tested cable, causing the fault point of the tested cable to flash over and discharge. At this time, the single flashover waveform will be input into the instrument through the current sampler, and the instrument will start sampling and display the test waveform in real time on the screen.

The above is the testing principle and method of the cable fault tester.

The ZC-700A2 cable fault tester consists of three main parts: flash testing, tracking, and positioning. It can be used to detect low resistance, high resistance, short circuit, open circuit, leakage faults, and flashover faults of various cables. It can accurately detect the fault location, cable length, and cable burial path of underground cables. It has the characteristics of accurate testing, high intelligence, wide adaptability, stable performance, and lightweight portability. The instrument adopts a Chinese character system, with high-definition display and a user-friendly interface.

Kvtester Electronics Technology Co.,Ltd. is a high-tech enterprise specializing in power testing, testing, research and development, production, and sales of testing equipment. It has been engaged in the electrical testing industry for many years, and its products are of high quality. We welcome customers to come and purchase. Service hotline: 0086-27-81778799, to learn more, visit the official website: www.kvtester.com