partial discharge testing

Partial Discharge Testing: Online And Offline Partial Discharge

Partial discharges are small discharges that take place between two electrodes. These minor discharges primarily occur in a few select areas around the insulation. Unbalanced electrical stress may be the root cause of these partial discharges. Catastrophic failures could result from these undetected partial discharges. 

There are techniques to detect these partial discharges before failure occurs. Ultrasonic PD testing is one of the most reliable techniques for assessing insulation.

Read more about:

  1. Cloud-based Vibration Monitoring: A Defence Against Unplanned Downtime in Machines
  2. Understanding the Concept of Wireless Condition Monitoring
  3. Guidelines For Condition Based Maintenance

What Are the Different Types of Partial Discharge(PD) Testing?

Thankfully, there are various testing techniques to find these partial discharges. The various partial discharge tests can be broadly categorized as follows:

1. Online Partial Discharge Testing

Online PD testing is usually carried out while the equipment is powered up at the recommended operating voltages. Therefore, the real operational conditions are necessary for this test: Typical temperature ,Vibration levels  & Voltage stress

It is a nondestructive test that does not use excessive voltages, which could adversely affect the equipment. Another advantage is that online PD testing is relatively inexpensive compared to offline partial discharge testing.

2. Offline Partial Discharge Testing

As the name implies, offline partial discharge testing involves the disconnection of the circuit. The test is then carried out once the circuit is powered by the low-frequency test set. Since there is far less noise when compared offline than online, testing done offline helps to find future flaws. Due to the difficulties of taking equipment offline, offline testing might be more expensive than online testing.

Online PD Testing vs. Offline PD Testing 

Online partial discharge testing and offline partial discharge testing have both been shown to be effective ways to find partial discharges in equipment. Each offers unique benefits and drawbacks as a result of the conditions needed for each sort of testing.

  • Online partial discharge testing can be far less expensive than offline partial discharge testing. This is due to the condition of switching off the circuit and conducting the test at a lower frequency range. 
  • Online PD Testing finds certain defects that might go undetected in offline testing as well as defects that happen under normal operating settings.
  • Offline PD Testing, on the other hand, mostly picks up partial discharges that could happen in the future rather than ones that happen often.

To Summarize

Online and offline PD testing has been shown to be the most efficient way of detecting partial discharges. The testing procedures make it simple to understand the equipment’s status. As a consequence, you can guarantee that the equipment is in top shape and lower the likelihood of equipment breakdowns and other power outages.

Being the leading engineering company in Oman, Ocean Technical and Mechanical Services have a team of engineers with more than 15 years of expertise who analyze and deliver the best electrical and mechanical equipment throughout the world. Ocean Technical and Mechanical Services would therefore be one of your best options if you’re looking for top-notch PD testing tools for both online and offline partial discharge testing.

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