NDXL-H Transmission Line Fault Distance Tester

Product Introduction

        NDXL-H Transmission Line Fault Locator is used to measure the distance from the fault point to the measurement point (transformer) when a permanent ground (short circuit) or open circuit (open circuit) occurs in an overhead transmission line.

        This instrument is suitable for overhead transmission lines of 35kV and above voltage levels. When a permanent single-phase ground or line break fault occurs, accurate fault distance measurement can be achieved by testing the faulty line at the substation, enabling quick identification of the faulty tower and facilitating rapid repair, thereby reducing downtime.
        This instrument must be used when the line is de-energized. It features a compact size, portability, built-in battery for AC/DC operation, graphical and digital display functions, and ease of operation.

Product Features

        Based on wave transmission theory, when a wave propagates along an overhead line and encounters an open or short circuit point, it reflects, creating a standing wave on the line. The position of the standing wave peaks and troughs varies with the frequency of the wave. By adjusting the wave frequency, the wave trough can be made to occur precisely at the signal injection point. Since the wave velocity in overhead lines is fixed, the line length can be calculated once the wave velocity is known.

Let: f: Injected signal frequency;
       v: Velocity of the injected signal along the line;
       λ: Wavelength of the injected signal;
       L: Line length;
Because: f×λ=v
        From theoretical derivation, it can be concluded:
        For a short-circuited line end, when the injected signal frequency increases from low to high and the first standing wave trough appears at the injection point, the line length is half the wavelength, i.e.:
       L=λ/2=0.5V/F;
        For an open-circuited line end, when the injected signal frequency increases from low to high and the first standing wave trough appears at the injection point, the line length is a quarter of the wavelength, i.e.:
       L=λ/4=0.25V/F.
        Based on this conclusion, the fault distance can be calculated.
        This instrument is equipped with a precise frequency measurement circuit and a module for detecting standing wave troughs. It can detect the frequency at which standing waves occur and, based on the known wave velocities for various voltage levels, calculate the distance L from the fault point to the measurement point.
        With its data memory circuit, the instrument records measurement data at various frequencies, allowing for further precise analysis after testing.

Technical Parameters

☆、Sweep Frequency Range                (100Hz～100kHz) Segmented Selection

☆、Measurement Distance                  2～100kM

☆、Voltage Level of Tested Line     35kV～500kV

☆、LCD Display                  240×128 Dot Matrix (Monochrome)

☆、Display Mode                  Graphics and Text

☆、Output Voltage                 Vp_p≥8V

☆、Internal Battery Usage Time     2～4 Hours per Charge

☆、Charging Current and Time        100～200mA/12 Hours

☆、Dimensions                        260(W)×350(L)×190(H)mm