Press Release

Why do you need an independent specific testing tool for Travelling Waveform Fault Locating Equipment?

Why do you need an independent specific testing tool for Travelling Waveform Fault Locating Equipment/Relay, other than an existing relay test set?


In the actual Power System, Transmission line fault traveling wave signal normally is an unstable and complex signal and the travelling wave signal from Travelling Waveform Locating equipment/ relay includes broadband traveling wave signal which is upto hundreds thousand Hz, and the rising speed of traveling wave signal is less than 3us.

So far in the market, all the protection relay test set, including PONOVO and others, the test set frequency amplitude range is normally within DC~1kHz and the transient value is lower than 3kHz. The step response time can not be less than 3us which is not compliance with the required range upto hundreds thousand Hz, and the rising speed of traveling wave signal is less than 3us to test the TWFL((Traveling waveform fault locating) equipment/relay.

 As we know, when you use a test set to test other equipment, the test set need to be with wider range and higher accuracy capability, otherwise the test result maybe not so provable.

 So due to the hardware limitation of the existing relay test set in the market,we don’t recommend users to use the current relay test set for testing the Traveling Waveform Fault Locating Equipment/Relay.

But some manufacturers may also try to use relay test sets with different signal methods to check the indicators and functions of the traveling wave distance measuring device, for example, using relay test set to send the pulse signal or to superimpose the pulse signal with the current / voltage signal to simulate the traveling waveform signal to the measured  equipment/relay to do the test.

Although the pulse signal or the superimposed signal can be sent to the long-distance traveling waveform fault locating device/relay, but the simulated signal is not the real Traveling waveform fault signal. It is only the basic simple signal which TWFL device/relay can receive.

Due to the variety of the real traveling waves at the fault site, there are many other kinds of traveling waveform fault signal which is different from the simulated pulse signal or the superimposed signal, but the relay test set can not simulate other real traveling wave signals.

So even using relay test set to do the basic simple testing of the TWFL device/relay, it does not prove enough that the TWFL(Traveling waveform fault locating) equipment can work correctly 100% as a complete test result.

The importance of testing for TWFL(Traveling waveform fault locating)equipment/relay is to test if it can work functionally to recognize all kinds of complicated fault waveform, not only one simple signal.


The real complex traveling waveform fault signals can not be replaced by the simple pulse signals or superimposed signals, cause they cannot feed back the true traveling waveform conditions at the fault site and can not verify the true performance situation of the travelling waveform fault locating equipment/relay.



So as to test the traveling waveform fault locating equipment/relay, it shall need a specific test set which can output reliable and undistorted fault traveling wave signal to verify the TWFL equipment/relay. The hardware capability should be much higher than the range requirement of traveling waveform fault locating equipment/relay.


Based on the features of traveling waveform fault signal, PONOVO has designed and  launched PH series specific TWFL(Traveling waveform fault locating) test set, whose hardware has the special design on the fast response power amplifier,broader bandwidth, high-speed DA conversion,etc.



Main Features:

(1) Wide frequency domain, 0 ~ 500KHz (3dB bandwidth)

(2) Excellent transient characteristics, the rise and fall time is less than 3μS

(3) The output waveform is smooth and true, with no glitches

(4) The amplitude is accurate and can be accurate to 0.5%

(5) Remote synchronization, GPS trigger synchronization error of remote device≤0.5μs

(6) High-speed playback, maximum data sampling rate of 10MHz


The current and voltage power amplifier adopts fast drive design and high power MOSFET designs, so that it has excellent transient response characteristics, which the bandwidth is >500kHz and step response is <3us, amplitude accuracy is within 0.5%.

PH series specific TWFL test set can generate the high-accuracy signal,with sampling rate at 10MHz, 200k points a cycle and undistorted playback the real fault traveling current by its 6 channels, 16bits, high-speed DA.

PH series specific TWFL test set can be time synchronized with GPS to do the testings of double-ended long-distance TWFL equipment/relay. And the double-ended error time can be controlled within 500ns, which is with high accuracy for the testing.

Based on its good advantage of hardware capability, PH series specific TWFL test set can do single or double-ended TWFL equipment/relay verification.

It can playback the real recorded traveling waveform fault signal from the site to TWFL device/relay to verify and test.


Also, it supports of importing pre-set waveform or the complex waveform file modeled by simulator software, such as RTDS, PSCAD, simulate many kinds of traveling waveform fault types, grounding types, any fault distance, any fault moment, etc, for testing and verifying the double-ended TWFL device/relay.

Besides the field site testings, PH series specific TWFL test set can also be used by TWFL equipment/relay manufacturer in the factory cause it can output a reliable and undistorted fault traveling wave signal, so as to detect the potential design defects of the device or to be used for factory test in production line.

PH series specific TWFL test set supports reading Comtrade format data files and can play back the waveform files through the software of the calibrator, which can reproduce the current wave fault signal completely with high quality, which is convenient for laboratory verification testing.

PH series specific TWFL test set has 6 channels low-level analog input design so that it could support external control from simulator, for example, RTDS to do the real-time simulation experiment.






If you may need further information about PH series specific TWFL test set, please feel free to contact [email protected]