Different Methodologies to check Partial Discharges in Engineering System

There are several methodologies to check partial discharges in engineering systems. Here are some commonly used ones:

1. Capacitive Coupling Method

This method uses capacitive probes to detect partial discharges. The probes are placed on the surface of the equipment being tested, and the signals are captured by an oscilloscope or other monitoring device. This method is non-invasive and can be used for online or offline testing.

The capacitive coupling method is a non-invasive and relatively simple technique for detecting PD activity, making it a popular choice for both offline and online PD testing. It can be used to test a wide range of equipment, including transformers, cables, motors, and generators. However, it is important to note that this method is most effective for detecting surface discharge activity and may not be as sensitive to PD activity within the insulation system.

A capacitive coupling method is a valuable tool for detecting PD activity and ensuring the safety and reliability of high-voltage electrical equipment. By detecting insulation problems early on, this method can help prevent equipment failure and reduce the risk of accidents or downtime.

2.Inductive Coupling Method

The inductive coupling method is another commonly used technique for detecting partial discharge (PD) activity in high-voltage electrical equipment. This method involves using an inductive sensor to detect PD activity in the cables or windings of the equipment.

The inductive sensor consists of a coil of wire that is wrapped around the cable or winding being tested. A high-frequency voltage is applied to the coil, which generates an electromagnetic field that induces a voltage in the cable or winding. As PD activity occurs within the insulation system, it generates high-frequency electromagnetic waves, which can be detected by the inductive sensor.

The PD signals are then captured by a measuring instrument, such as an oscilloscope or a spectrum analyser, which analyses the signals to determine the location and severity of the PD activity. The results of the analysis can be used to identify insulation problems and take corrective action to prevent equipment failure.

3.UHF Method

The Ultra High Frequency (UHF) method is a commonly used technique for detecting partial discharge (PD) activity in high-voltage electrical equipment. This method involves using a UHF antenna to detect PD activity in the insulation system of the equipment.

The UHF antenna consists of a metal rod or cone that is connected to a measuring instrument, such as an oscilloscope or a spectrum analyzer. The antenna is placed in close proximity to the equipment being tested, and a high-frequency voltage is applied to the insulation system. As PD activity occurs within the insulation system, it generates high-frequency electromagnetic waves that can be detected by the UHF antenna.

The PD signals are then captured by the measuring instrument, which analyzes the signals to determine the location and severity of the PD activity. The results of the analysis can be used to identify insulation problems and take corrective action to prevent equipment failure.

4.Acoustic Method

The acoustic method is a commonly used technique for detecting partial discharge (PD) activity in high-voltage electrical equipment. This method involves using a microphone to detect the acoustic emissions generated by PD activity in the insulation system of the equipment.

The microphone is placed in close proximity to the equipment being tested, and a high-frequency voltage is applied to the insulation system. As PD activity occurs within the insulation system, it generates acoustic emissions in the form of air-borne sound waves, which can be detected by the microphone.

However, it is important to note that the acoustic method may be affected by external noise, which can reduce the accuracy of the results. To minimize this interference, it is recommended to perform acoustic testing in a controlled environment, such as a shielded room or an area with low noise levels.

5.High-Frequency Current Transformer Method

The High-Frequency Current Transformer (HFCT) method is a commonly used technique for detecting partial discharge (PD) activity in high-voltage electrical equipment. This method involves using a current transformer to detect the high-frequency currents generated by PD activity in the insulation system of the equipment.

The HFCT is placed around the high-voltage conductor being tested, and a high-frequency voltage is applied to the insulation system. As PD activity occurs within the insulation system, it generates high-frequency currents that can be detected by the HFCT.

Each of these methodologies has its own advantages and disadvantages, and the choice of methodology depends on factors such as the type of equipment, the level of risk associated with the equipment, and the availability of testing resources.