Partial Discharge Detector
1. The operation and maintenance of the partial discharge tester should be carried out by qualified professional personnel.
2. The test site voltage of the partial discharge tester can be as high as tens of thousands of volts. Test personnel should strictly comply with all safety precautions. The test area should have clear and visible warning signs, and everyone on site should be aware of the high-voltage area. Personnel directly involved in measurements should understand all live and high-voltage components in the measurement circuit, while those not directly involved should be isolated from the test area. During the test and after power is applied, no one is allowed to enter the high-voltage area.
3. Before the test, operators should master the test circuit, test method, test procedure, and test purpose.
4. The test site should be clean and tidy, without any unrelated items. There should be no scattered small metal pieces (such as bare copper wire segments, screws, nuts, and other small metal objects) on the ground in the high-voltage area. The test object, step-up transformer, coupling capacitor, etc., should be kept at an appropriate distance from the surroundings.
5. The surfaces of the test object, step-up transformer, coupling capacitor, etc., should be kept dry and clean, as surface moisture and dirt can cause surface partial discharge, leading to abnormal measurements.
6. Test operators should connect the circuit according to the regulations. All metal objects in the test area should be firmly grounded. Check and improve any parts in the test area that may cause discharge (e.g., no sharp or acute angles), and pay special attention to whether all ground wires are properly grounded.
7. Before applying voltage, test personnel must thoroughly and comprehensively check the circuit to avoid incorrect connections. Special attention should be paid to whether the grounding wires, high-voltage wires, and power circuit connections are firmly connected.
8. If an abnormality occurs during the test, first cut off the power supply, then proceed with further handling.
(IV) Precautions
1. Before applying voltage, test personnel must thoroughly and comprehensively check the circuit to avoid incorrect connections. Check whether the grounding wire at the test instrument is firmly connected to the grounding body. If the connection is not secure or the wire is accidentally kicked off during preparation, it may cause personal injury or equipment damage.
2. For connecting wires, avoid exposing sharp tips to prevent corona discharge at the tips. Especially for partial discharge tests at higher voltage levels, it may be necessary to thicken the high-voltage connecting wire and add anti-corona shields to reduce corona discharge caused by excessive field strength. The shielding cover should not come into contact with the porcelain skirt of the test object.
3. Generally, during the test, the partial discharge level of the test object during withstand voltage and pre-voltage rise is much higher than the normal value, and the instrument's meter will inevitably exceed full scale. To prevent instrument damage, turn the coarse gain adjustment knob counterclockwise by one or more steps to keep the reading within full scale. When the voltage drops to the measurement voltage, turn the coarse gain switch clockwise by one or more steps to record the measured value.
[Including mechanical fault detection in electrical equipment and gas/liquid leak detection]
I. Fault finding in GIS switch operating mechanisms to prevent switch refusal or maloperation accidents
GIS is the most important switchgear in today's power systems. Whether the switches inside GIS operate correctly is a key factor in the safe operation of the power grid. High-voltage GIS switch operations are mostly driven by hydraulic or compressed air systems. To ensure the normal operation of hydraulic and pneumatic drive systems, the motor must be started periodically to pressurize and verify the system's performance reliability. However, due to manufacturing defects, installation issues, or improper maintenance by equipment manufacturers, there are increasing incidents of drive speed reduction or failure, even air compressor damage, which seriously threaten the stable operation of the power grid and directly affect people's lives and production, with severe social consequences. The SDT electrical equipment partial discharge patrol instrument uses advanced ultrasonic principles and sophisticated sensing technology to vividly detect internal leaks in hydraulic and pneumatic systems, identify drive faults in advance, and notify maintenance personnel digitally and audibly to eliminate defects, ensuring the safe operation of GIS.
II. Detection of insulator pollution flashover and internal cracks, and partial discharge detection at cable joints
Various types of insulator internal crack faults and external pollution faults also urgently require effective detection methods. When the air around insulators is ionized, chemical reactions occur, corroding metal parts and weakening the insulation capability. The high energy from corona discharge can cause severe damage to mechanical components, leading to unplanned outages and affecting thousands of customers, and in severe cases, fire and explosion. Particularly in factories, fires and explosions caused by electrical partial discharge can have serious chain reactions due to the presence of hazardous and toxic chemicals. Traditional infrared imaging technology can detect hot spots invisible to the naked eye. However, partial discharge, corona, arcing, and tracking phenomena do not necessarily accompany significant temperature rises, and ambient high temperatures can mask these phenomena. Nevertheless, these phenomena generate ultrasonic noise, which can be accurately detected using ultrasonic detection equipment.
III. Internal partial discharge fault detection in GIS/GCB, switchgear cabinets, power supply cabinets, and communication cabinets
There are increasing internal partial discharge faults in GIS/GCB and switchgear cabinets in power plants and substations, urgently requiring appropriate detection methods for predictive maintenance and alarm. The SDT electrical equipment partial discharge patrol instrument is timely. The insulation medium of GIS/GCB varies, and the propagation speed of internal and external partial discharge also differs. Detection methods using chromatography or electrical measurement are not only cumbersome, dangerous, and expensive but also cannot provide real-time detection. Electrical maintenance personnel urgently need a detection method that is simple to operate, reasonably priced, and safe for spring inspections, autumn inspections, and routine predictive maintenance. The SDT electrical equipment partial discharge patrol instrument fully meets these requirements.
IV. Partial discharge detection for transformers, bushing bushings, CT/PT, capacitors, and reactors
