A traveling wave ranging solution based on RS485 transceiver GX33055 and clock chip GX04828, replacing XR33055/LMK04828

Traveling wave distance measurement is a fault location method for power lines based on traveling wave theory, which determines the fault location by detecting the propagation time difference of voltage or current traveling waves between the fault point and the measurement point. The main method is to use the high-frequency transient current/voltage traveling wave signals generated at the moment of line faults (such as short circuits and grounding) and propagated along the line to both ends. By accurately measuring the time difference between these traveling wave signals reaching the two ends of the line, the precise location of the fault point can be calculated.

When transmitting data remotely, the RS485 transceiver chip GX33055 has strong anti-interference ability and supports long-distance reliable transmission of sampled data to the monitoring center, which can improve equipment performance in noisy industrial environments and increase fault tolerance for system failures. The input impedance of GX33055 receiver should be at least 120k (1/10 unit load), allowing for more than 320 devices on the bus.

The GX33055 receiver includes a complete fail safe circuit to ensure a logically high receiver output when the receiver input is open, short, or not driven. The analog bus pins can protect against ESD events up to ± 10kV HBM. The common mode operating range can reach -7V~12V, making it more reliable in noisy environments, and the ESD protection is more suitable for field environments with traveling wave ranging. This driver maintains high impedance during shutdown or power failure through short circuit detection and thermal shutdown protection. The DE and RE pins include hot swappable circuits to prevent erroneous switching on the bus during power on or live insertion, and can enter a 1nA low current shutdown mode, which can greatly save power.

In the clock synchronization stage of traveling wave ranging, the GX04828 chip can provide ultra-low jitter clock for analog-to-digital converters and processors, reduce timestamp errors, and improve the accuracy of traveling wave arrival time measurement. GX04828 features high performance, low power consumption, dual VCO, dynamic digital delay, and signal loss preservation. Therefore, GX04828 is an ideal choice for providing flexible and high-performance clock trees.

GX04828 supports JEDEC JESD204B. When using the device and SYSREF clock, PLL2‘s 14 clock outputs can be configured to drive 7 JESD204B converters or other logic devices. SYSREF can be provided using DC and AC coupling. Not limited to JESD204B applications, all 14 outputs can be individually configured as traditional high-performance clock system outputs.