Partial Discharge Testing
Services in Qatar
PARTIAL DISCHARGE
Partial discharge (PD) refers to the localized electrical discharge or breakdown that occurs within a dielectric material, such as insulating oil or gas, under high voltage conditions. PD can occur in various types of electrical equipment, including power transformers, switchgear, and cables. It is a potential indication of equipment deterioration and can lead to failure if not properly detected and addressed. PD testing is a method used to detect and locate PD activity in order to assess the condition of the equipment and plan for maintenance or replacement.
TYPES OF PARTIAL DISCHARGES
There are several types of partial discharge that can occur, including:
1) Surface discharge: Occurs on the surface of a conductor or insulator and can be caused by defects such as cracks or voids.
2) Internal discharge: Occurs within a material and can be caused by defects such as voids or impurities.
3) External discharge: Occurs outside of a material and can be caused by factors such as high humidity or contamination.
4) Corona discharge: A type of external discharge that occurs at sharp edges or points on a conductor and can be caused by high voltage.
5.Streamer discharge: A type of corona discharge that occurs in gases and is characterized by a faint, visible electrical discharge.
6) Spark discharge: A type of corona discharge that occurs in gases and is characterized by a bright, visible electrical discharge.
PD TESTING APPLICATIONS
1) Quality control testing of new equipment: PD testing can be performed on new equipment before it is put into service to ensure that it meets the manufacturer’s specifications and is free of defects.
2) Condition assessment of in-service equipment: PD testing can be performed on equipment that is already in service to assess its condition and identify any potential issues that may need to be addressed.
3) Cable testing: PD testing is commonly used to test high voltage cables to detect any defects that may be present.
4) Power transformer testing: PD testing is an important method for assessing the condition of power transformers, which are critical assets in power generation and distribution.
5) Switchgear testing: PD testing can be used to detect any defects in switchgear, which is used to control and protect electrical equipment.
6) PD monitoring: PD testing can be used for continuous monitoring of equipment during operation for early detection of potential issues.
TYPES OF PD TESTING
ONLINE PD TESTING
Online PD measurement refers to the process of monitoring PD activity while the equipment is in operation. This method allows for continuous monitoring of equipment and can provide early detection of potential issues. Online PD measurement typically requires specialized equipment that can withstand the harsh operating environment of electrical equipment and can be connected to the equipment without disrupting its operation.
OFFLINE PD TESTING
Offline PD measurement refers to the process of monitoring PD activity when the equipment is not in operation. This method allows for more detailed and accurate PD testing, as the equipment can be disassembled and inspected more thoroughly. However, offline PD measurement requires the equipment to be taken offline and may require specialized equipment and trained personnel to perform.
ONLINE PD MEASUREMENT USING PRYCAM
PRY-CAM (Partial Discharge Camera) is a type of ultraviolet (UV) imaging camera that is used for partial discharge (PD) testing. It captures UV light emitted by PD and displays it as an image on a screen. This allows for the detection and location of PD activity in electrical equipment such as power transformers, switchgear, and cables.
PRY-CAM cameras use a special type of lens that is sensitive to UV light and can capture PD activity in real-time. These cameras are typically used for online PD measurement, as they can be connected to the equipment without disrupting its operation. The image captured by the camera can be analyzed to determine the location and severity of PD activity. This information can then be used to assess the condition of the equipment and plan for maintenance or replacement.
PRY-CAM is a reliable and accurate method for detecting PD in electrical equipment. It is particularly useful for identifying PD in hard-to-reach areas such as inside of power transformers. It also has the advantage of being able to detect PD activity during normal operation of the equipment. However, it may require specialized equipment and trained personnel to perform the test.
