PORTABLE PD TESTER: MODEL 832B                 

For portable PD testing applications the model 832B is supplied with a number of sensors which allow PD activity to be detected in the equipment assets that are vital to the utility.

The lightweight 832B has a laptop PC which displays PD activity in magnitude scale to assist engineers to determine the maintenance requirements needed to prevent deterioration.

As standard, the 832B comes with the ability to monitor three separate PD and noise channels which can be monitored individually or simultaneously. The three noise channel inputs are provided to monitor ambient electrical influences outside the PD spectrum and can be used to gate PD signals during high noise
events.

The 832B unit is expandable to four channels as with the 840U below.

Buffered PD signal outputs are also provided for PD waveform
observation with an oscilloscope.

PD SENSORS: MODEL 834B, 835B, 836B          

These sensors are used to amplify the very low level PD signals and transmit them via coaxial cable to the Model 831 and Model 832B units. The 834B is a split core high frequency CT with 66mm window. For transformer testing a good choice is the 835B ultrasonic sensor which has a strong magnetic base capable of gripping the steel tank of the transformer.

Rejecting spurious signals is important when performing PD tests, and for this purpose we have the 836B noise sensor. This sensor picks up and amplifies ambient electrical noise with its aerial, and the signal is then sent to the 831 or 832 so they can discard any apparent PD which occurs at the same time which may be due to noise.

















 

GIS PD TESTER: MODEL 840U AND 841

To help in maintaining GIS ( gas insulated switchgear ) equipment we developed the Model 840 GIS tester which is designed to take the output signal from a Model 841 GIS sensor. The signal is interpreted by a dedicated microprocessor unit in the 840U which in turn sends digital data to the laptop PC. In the laptop PC the digital data is used to construct graphical representations of the PD activity.

The portable Model 841 is fitted with a high frequency amplifier matched to the typical PD signature of GIS equipment. It has a rechargeable Li-On battery for extended field use, and is connected to the 840U with a coaxial test cable. There is a swivel attachment on the 841 so it can be used on the end of a hot stick when required.