PD detector

21 years professional manufacturer and supplier in china, standardized factory, best product quality, and cheap wholesale prices！！！

What Is PD detector?

The PD detector is an on-line partial discharge (PD) spot tester for HV assets. The instrument detects TEV signals generated by internal discharge in Air Insulated Switchgear (AIS), acoustic discharge generated by surface tracking or corona, high-frequency signal generated by cable partial discharge, and ultra-high frequency signal generated by internal discharge in Gas Insulated Switchgear (GIS). A mobile device receives data directly from the instrument for display and synchronisation with a central server.

Advantages of PD detector

Early Detection Of Electrical Faults

PD detection, when compared with the conventional method, helps identify minor changes in the electrical switchgear at the earliest. This helps in implementing mitigation strategies to avert catastrophic failures, which lead to occupation hazards, downtime, and financial losses.

Cost-effectiveness

Inspection of electrical equipment using PD detectors helps save money in two ways. To begin with, by using pd detectors, more equipment can be inspected efficiently and precisely on time. Secondly, this assessment helps in addressing the issues promptly, which helps reduce the overall expenses associated with them.

Enhanced Safety

PD detector helps electrical engineers and inspectors examine high-voltage electrical equipment without close contact. Unlike the conventional approach, this greatly reduces the risk of accidents and shocks.

Precision And Efficiency

PD detection is done with the help of sensors and software, which offer a high degree of precision in detecting and locating dim-outs/outages/discharges or failures, eliminating ambiguity associated with the conventional approach, which enables maintenance personnel to effectively address the identified problems.

Versatility And Broad Range Of Applications

The application of PD detection comes in handy to diverse fields such as power-generation industries, manufacturing, and transportation & utilities industries etc. Furthermore, PD detector can be implemented on a wide range of electrical equipment, including motors, switchgear, cables, and transformers. All these make pd detection an indispensable part of electrical maintenance and asset longevity.

Why Choose Us

Our factory

We are a professional OEM manufacturer engaged in the R&D, sales and service of high voltage test equipment.We have the right to import and export by ourselves.

Customized services

We listen to our clients objectives and aspirations and therefore provide customize solutions.

Quality control

Our experienced staff is committed to strict quality control and thoughtful customer service and is always available to discuss your requirements and ensure full customer satisfaction.

Wide application of products

We have production lines of more than 108 different products in the field of high-voltage testing, and they are widely used in power energy, transportation, metallurgy, chemical industry, mining and water conservancy projects.

Types of PD detector

The 3 main types of Partial Discharge

Internal Partial Discharge - The silent killer

Internal PD occurs within the insulation material itself, often without any external warning signs like sound, smell, or visual cues. This makes it particularly dangerous, as it can be the root cause of unexpected equipment failures. Regular asset condition assessment is essential to detect internal PD before it leads to severe consequences.

Surface Partial Discharge - A more visible concern

Surface PD occurs on the surface of insulation and can often be seen with the naked eye, especially under certain environmental conditions like high humidity. While it is easier to detect through visual inspection, early detection is still crucial to prevent further deterioration. Regular testing helps in identifying surface PD before it causes significant damage.

Corona Partial Discharge - A Precursor to Surface PD

Corona PD is typically heard as a buzzing sound in outdoor switchyards. While it is generally less harmful in outdoor environments, if left unchecked, it can initiate surface PD in enclosed spaces. Continuous testing for partial discharge is key to monitoring and mitigating corona PD risks.

Application of PD detector

Analyzing Switchgear
PD detectors can be used to analyze high-voltage (HV) and medium-voltage (MV) switchgear.

Detecting Insulation Issues
PD detectors can help identify insulation problems in transformers, cables, and substations before they lead to catastrophic failures.

Preventing Forest Fires
PD detectors can be used to detect partial discharges from covered conductors on high-voltage power lines in forested areas. This can help prevent forest fires and other disasters caused by contact between the conductors and vegetation.

Optimizing Maintenance
PD detectors can provide information about the condition of insulation systems, which can help optimize maintenance activities.

Extending Transformer Lifespan
PD detectors can help extend the lifespan of transformers by detecting and addressing insulation issues early.

Detection methods of partial discharges

Acoustic Detection
The DP can be accompanied by sound generation. The acoustic wave is due to the expansion of gases near the discharge. This acoustic signal can be detected by piezoelectric transducers. The main frequency used for acoustic detection ranges from 20 kHz to 100 kHz.

Electrical Detection
If a partial discharge occurs in the phase-to-ground isolation of an element of the high-voltage plant, such as a metal-clad cabinet, a small amount of electrical charge is transferred from the high-voltage conductor to the grounded metal cladding. .
Because this cabinet is grounded with a wire, it is possible to measure the current that passes through that wire with a high frequency current transformer (HFCT) which is an inductive coupling sensor.
Transient earth voltages (TEV) are voltage spikes induced on the surface of the surrounding metal work. The TEV occurs because the partial discharge creates current peaks in the conductor and a small amount of this energy is transferred to the metallic liner connected to the ground.

Detection of the EMI Method
The partial discharge will emit electromagnetic waves. EMI can be captured by antenna and converted, in function of its power, in dB.

Chemical Detection
This method is used in transformers through the analysis of dissolved gases (DGA). The method is also applicable in the Isolated Gas Substation (GIS) where the analysis and detection of SF6 gas components can be used.

How to ensure the safety of PD detector?

The voltage at the test site of the PD detector is as high as tens of thousands of volts, so the relevant testers must strictly abide by various safety precautions. Make sure there are clear warning signs in the test area so anyone on site knows where the high voltage area is. No one is allowed to enter the high voltage area during the test.

Whether it is the operation or regular maintenance of the PD detector, it must be a competent professional, and other people who do not understand the PD detector must never touch the instrument. This is not only for the service life of the instrument, but also to ensure the personal safety of everyone.

Before using the PD detector to test, the user should master the test method, test procedure and test purpose and keep it in mind, which is very important for the test.

The place where the PD detector is tested must be kept clean and tidy, and no other items unrelated to the test shall be stored. In particular, there must be no metal fragments on the ground in high pressure areas.

The surface of the test object, step-up transformer and coupling capacitor should be kept dry and clean. If there is moisture or dirt on the surface, it is easy to cause partial discharge, resulting in abnormal measurement. The most important thing is to make the PD detector detector play a greater role in the test and make the whole measurement process smoother.

Safety Precautions When Using the PD detector

The test site voltage of the PD detector is as high as tens of thousands of volts, and the test personnel should strictly abide by all safety precautions. There should be obvious and clear warning signs in the test area, and everyone on site should be aware of the high-voltage area. Direct test personnel should understand all live components and high-voltage components in the measurement circuit, and those who do not directly test should be isolated outside the test area. During the test and after power-on, no one is allowed to enter the high-voltage area.

The test site should be tidy and clean, and other irrelevant items should not be stored. There should be no messy small metal pieces (such as bare copper wire segments, screws, nuts and other small metal pieces) on the ground in the high-voltage range. The tested product, step-up transformer, coupling capacitor, etc. should be kept at a proper distance from the surroundings.

The surface of the test product, step-up transformer, coupling capacitor, etc. should be kept dry and clean, because moisture and dirt on the surface will cause partial discharge on the surface and cause abnormal measurement.

The test operator should master the test circuit, test method, test procedure and test purpose. Before starting the test, connect the lines according to the regulations. Various metal objects in the test area should be firmly grounded, and then check and improve all possible discharge parts in the test area (if there are no sharp or acute angles), pay special attention to the grounding line , Whether the wires of high-voltage lines and strong current circuits are firmly connected.

Avoid exposing the connecting wires to prevent corona discharge, especially for partial discharge tests with higher voltage levels. If necessary, thicken the high-voltage connecting wires and install an anti-corona cover to reduce the excessive field strength. Caused by corona discharge. The shielding cover should not be in contact with the porcelain skirt of the test product.

Under normal circumstances, during the test, the partial discharge of the test product during the withstand voltage and pre-boost is much larger than the normal value. At this time, the instrument will inevitably exceed the full scale. In order to prevent damage to the instrument, the coarse gain adjustment knob of the instrument should be turned counterclockwise by one or more steps, and the standard is not to exceed the full scale. When the voltage drops to the measured voltage, turn the coarse gain adjustment switch clockwise by one or more gears to record the measured value.

When the test is abnormal, the power supply should be cut off before further processing.

Our Factory

21 years professional manufacturer and supplier in china, standardized factory, best product quality, and cheap wholesale prices！！！

Wuhan UHV Power Technology Co.,Ltd. established in 2021, located in Wuhan East Lake New Technology Development Zone and have convenient transportation access. We are professional OEM Manufacturer which is engaged in the research, development, sale and service of High Voltage Testing Equipment including: Resonant Test System, High Voltage Tester,Transformer Tester,Circuit Beaker Tester, Relay Protection Tester, Cable Tester, Oil Tester, DC Battery Tester, Generator Tester, Insulation Resistance Tester, Power Metering Products etc.They are widely applied in power engineering project, transportation,petrochemical industry,mining and water conservancy project. In addition, We have obtained CE, ISO9001 & other certificates. Our products are not only selling well in mainland China, but also exported to the countries around the world including Malaysia, Indonesia, Vietnam, Philippines, Saudi Arabia, The United Arab Emirates,America, Australia, Argentina,Chile, Brazil etc. We are highly trusted and praised by clients in competitive products and strong technique support.

If you have any requirements, pls feel free to contact us, and we will always right be here ready to serve for you. Our slogan: Smart Electric Testing Equipment Manufacturer, making your testing work more easy.

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Our Certificates

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FAQ

Q: What is the purpose of a PD test?

A: Detect insulation defects and prevent failure in your electrical assets. Insulation faults are a major cause leading to the eventual breakdown and failure of electrical equipment. Therefore, it is crucial that the insulation condition is verified throughout equipment lifecycles.

Q: What is PD in electrical terms?

A: “Partial discharge (PD) is a localized electrical discharge that only partially bridges the insulation between conductors and which may or may not occur adjacent to a conductor.” PD occurs whenever there is a stressed region due to some impurity/cavity inside the insulation or when there is a protrusion outside it.

Q: How does PD testing work?

A: The partial discharge measurement made by PD testers, using the surge test as the driver, is the voltage of the PD spikes. This voltage is proportional to the amount of discharge and measured in mV. The range measured is typically from a few mV to a few volts. A charge or discharge is measured in coulombs.

Q: What is PD in testing?

A: Partial discharge testing, also known as PD testing, is performed to assess electrical insulation health. PD is best described as a failure of part of an insulation system to withstand the electrical field applied to it.

Q: What is a PD sensor?

A: Its main function is to detect Partial Discharge through contact with these assets. The contact sensor uses capacitive coupling technology and is used oil filled cabinets. When installed the sensor detects high frequency signals caused by partial discharge inside the switchgear.

Q: What is PD testing?

A: Partial discharge testing is a leading indicator of machine failure. If left undetected, it can eventually lead to complete deterioration of the electrical insulation which is one of the principal causes for forced outages of generators and motors.

Q: What is PD monitoring system?

A: On-line partial discharge (PD) monitoring provides you with continuous insulation condition status while electrical equipment is in operation and under the influence of deteriorating forces.

Q: What are the methods of detecting partial discharge?

A: 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.

Q: What equipment is used to detect partial discharge?

A: Partial discharge emits sound in the ultrasonic frequency range. With a high-sensitivity acoustic imaging camera, such as the Fluke ii910 Precision Acoustic Imager, you can detect and precisely locate partial discharge.

Q: Which is the acoustic method for PD detection?

A: External acoustic detection systems, currently more utilized in power systems, employ sensors mounted to the outside of power equipment to detect the PD acoustic signal. Internal systems on the other hand use sensors placed inside of power equipment to directly measure the pressure wave.

Q: How many types of partial discharge are there?

A: Partial discharge occurs in a variety of locations and mediums in high voltage electrical equipment. Although the terms vary, there are generally four types of partial discharge, each occurring for different reasons and each with the propensity to cause varying levels of damage.

Q: What is the IEC standard for partial discharge test?

A: When speaking of partial discharge, the most important standard that every expert will refer to is IEC 60270: High-voltage test techniques – Partial discharge measurements. This standard applies to the measurement of PD in electrical apparatus or systems when testing with AC voltage up to 400 Hz or with DC voltage.

Q: What is the difference between acoustic and ultrasonic testing?

A: It does not require any use of external energy (unlike ultrasonic testing), because the test material or structure itself releases the acoustic emission. In ultrasonic testing, on the other hand, inspectors send ultrasonic waves through a structure of material from an external source.

Q: How to detect partial discharge?

A: Acoustic detection.The DP can be accompanied by sound generation. The acoustic wave is due to the expansion of gases near the discharge. This acoustic signal can be detected by piezoelectric transducers.

Q: What is optical detection of partial discharge?

A: The optical partial discharge detection is based on the detection of light produced as a result of various ionization, excitation and recombination processes during the discharge. However, the optical spectrum of different types of discharge is not the same.

Q: What are the major equipment required for measurement of partial discharges?

A: Partial discharges produce sound waves. Therefore, acoustic sensors can be used to detect PD activity. The available equipment is usually a hand-held device that acts as an antenna in the ultrasound frequency range. Piezo sensors are also available and are usually attached to the equipment enclosure.

Q: What are the two types of ultrasonic testing?

A: Ultrasonic testing can be performed using two basic methods – Pulse-echo and through-transmission.

Q: What defects lead to partial discharge?

A: Impurities in the insulation material: Impurities such as moisture, dust, and other contaminants can cause partial discharges in the insulation. Mechanical damage: Physical damage to the insulation system can create voids or cracks that can lead to partial discharges.

Q: What sensor detects partial discharge?

A: The Contact Acoustic Sensor is mainly used for oil filled transformers, circuit breakers and other plant. Its main function is to detect Partial Discharge through contact with these assets. The contact sensor uses capacitive coupling technology and is used oil filled cabinets.

Q: What is the difference between corona discharge and partial discharge?

A: While a corona discharge (CD) is usually revealed by a relatively steady glow or brush discharge (BD) in air, partial discharges within solid insulation system are not visible. PD can occur in a gaseous, liquid, or solid insulating medium.

As one of the leading pd detector manufacturers and suppliers in China, we warmly welcome you to buy high-grade pd detector made in China here from our factory. For price consultation, contact us.

tev partial discharge tester