Measuring electrical equipment, non-contact infrared thermal imager can measure the surface temperature of objects within a safe distance, which is an indispensable tool for the maintenance of electrical equipment.
Infrared thermal imager can effectively prevent equipment failures and unplanned power outages.
The following are some facilities that need to be inspected by infrared thermal imager:
Answer: Electrical equipment: Hidden dangers such as loose joints or poor contact, unbalanced load, overload and overheating can be found. The potential effects of these hidden dangers are arc, short circuit, combustion and fire.
B: Transformer: The hidden dangers that can be found are loose joint, overheated bushing, poor contact (tap changer), overload, unbalanced three-phase load and blocked cooling pipe. The air cooler winding can be directly measured by infrared thermal imager to check whether the temperature exceeds the standard, and any hot spot indicates that the transformer winding is damaged. Its effects are arc, short circuit, combustion and fire.
C: Motor and generator: The hidden dangers that can be found include high bearing temperature, unbalanced load, short circuit or open circuit of winding, heating of carbon brush, slip ring, overload and overheating, and blockage of cooling pipes. Its influence is that the faulty bearing will damage the iron core or winding coil; Defective carbon brushes can damage slip rings and slip rings, and then damage winding coils. Check the hot spots, and repair or replace the equipment regularly before the problem leads to equipment failure.
Motor coil insulation-By measuring the temperature of motor coil insulation, its life can be extended. It may also cause harm to the driving target. In order to maintain the service life of the motor, check whether the temperature of the power supply connecting wire and the circuit breaker (or fuse) are consistent.
D: Connector: The electrical connection part will gradually loosen the connector, and repeated heating (expansion) and cooling (contraction) will generate heat or surface dirt, carbon deposition and corrosion. Non-contact infrared thermal imager can quickly determine the temperature rise indicating serious problems.
Motor bearing:
E: Phase-to-phase measurement: Check whether the phase-to-phase temperatures of wires and connectors of induction motors, large computers and other equipment are the same.
F: uninterruptible power supply: determine the heating point of the connecting wire on the UPS output filter. The low temperature point indicates that the DC filter line may be open.
Spare battery: Check the low-voltage battery to make sure it is connected correctly. Poor contact with the battery connector may be heated enough to burn the battery core rod.
G: Ballast: Before the ballast starts to smoke, check whether the ballast is overheated.
H: Utilities: Identify hot spots of connectors, wire connectors, transformers and other equipment. The measuring range of some types of optical instruments is 60: 1 or even larger, so that almost all the measuring targets are within the measuring range. 1: various electrical equipment: hidden dangers such as loose joints or poor contact, unbalanced load, overload and overheating can be found. The potential effects of these hidden dangers are arc, short circuit, combustion and fire. Their average repair cost is 6,543,800+0,000 to 50,000 dollars; Replacement costs 50,000-80,000 dollars, and the construction period is several weeks to several months.
2. Transformer: The hidden dangers that can be found are loose joint, overheated bushing, poor contact (tap changer), overload, unbalanced three-phase load and blocked cooling pipe. Its effects are arc, short circuit, combustion and fire. The rewinding cost is 6,543.8+0,000 to 50,000 USD, the replacement cost is 80,000-6,543.8+0.4 million USD, and the construction period is several weeks or months.
3. Motors and generators: The hidden dangers that can be found include excessive bearing temperature, unbalanced load, short circuit or open circuit of windings, heating of carbon brushes and slip rings, overload and overheating, and blockage of cooling pipes. Its influence is that the faulty bearing will damage the iron core or winding coil, and the faulty carbon brush will damage the slip ring and slip ring, thus damaging the winding coil. It may also cause harm to the driving target. Motor rewinding (5000 horsepower) needs 50,000 ~ 90,000 dollars, replacement needs 90,000 ~ 654.38+0.5 million dollars, and the construction period is several weeks to several months.
Application of infrared thermal imager in electric power
There are all kinds of faults in power equipment, but most of them are accompanied by fever. From the point of view of infrared diagnosis, it is usually divided into external faults and internal faults. As we all know, in the operation of power system, the current-carrying conductor will produce resistance loss due to the action of current, and there are a large number of connectors, joints or contacts in the whole transmission line. In an ideal situation, the contact resistance of various joints, joints or contacts in the transmission circuit is lower than that of the connected conductor, so the loss and heat generation of the connecting part will not be higher than that of the adjacent current-carrying conductor. However, once the contact resistance of some connectors, joints or contacts increases due to poor contact, more resistance loss and higher temperature rise will occur in this part, leading to local overheating. This kind of fault is usually an external fault.
External faults are characterized by local temperature rise, which is easy to be found by infrared thermal imager. If not handled in time, the situation will deteriorate rapidly, which will easily lead to accidents and losses. External faults account for a large proportion of faults.
The so-called internal faults of high-voltage electrical equipment mainly refer to the faults of electrical lines enclosed in solid insulation and equipment shells and various faults caused by the deterioration of insulation media. Because this kind of fault occurs inside the electrical equipment, the temperature rise on the surface of the equipment is very small, usually only a few K, and the detection of this kind of fault requires the high sensitivity of the detection equipment.
Internal faults are characterized by low failure rate, low temperature rise, great harm and high requirements for infrared detection equipment.
According to the long-term measured data provided by relevant units and the comprehensive statistics of a large number of cases, the external thermal defects of power equipment generally account for 90% ~ 93% of the total index of equipment defects, and the internal thermal defects only account for about 7% ~ 10%.
In the power industry, thermal imager has been used in equipment safety maintenance for a long time. It can detect thermal defects of electrical equipment and lines, such as transformers, bushings, circuit breakers, knife switches, transformers, power capacitors, lightning arresters, power cables, buses, wires, combined appliances, insulator strings, low-voltage appliances and secondary circuits of equipment with thermal effects of current and voltage or other thermal effects, which is very important for timely discovery, treatment and disposal.
The so-called thermal defect of electrical equipment usually refers to the heating phenomenon caused by internal or external reasons, which is detected by certain means.
According to the different causes of defects, we can usually divide them into three types: one is the heating caused by the reduction of the conductive cross-sectional area of parts exposed to air for a long time due to the influence of temperature and humidity, or the poor contact caused by surface scaling, or the damage of parts caused by external force. Such as poor joint connection, bolts and washers are not tightly pressed; Long-term operation corrosion oxidation; Corrosion caused by active gases and dust in the atmosphere; The conductor is damaged due to poor component material and poor processing and installation technology; Due to various reasons, such as mechanical vibration, the actual cross section of the conductor decreases; The load current is unstable or exceeds the standard.
The other is due to the internal failure of the electrical appliance itself, such as poor contact of internal connecting parts, which leads to excessive resistance; Aging, cracking and shedding of insulating materials; The internal components are affected by moisture, and the loss of gas components increases; The cooling medium pipeline is blocked and so on.
For those devices and components that can be directly observed, infrared thermal imager can find the thermal hazards of all connection points. For those parts that can't be seen directly because of being blocked, we can analyze and draw conclusions according to the heat transfer to the external parts. Because the actual situation is ever-changing, even if a hot picture is obtained through a thermal imager, it may be influenced by many factors if you want to make an accurate judgment. Such as the current temperature, air volume, load and so on. We can make relevant analysis and make corresponding judgments according to different characteristics, such as:
In order to ensure the safe and efficient operation of power production, higher requirements are put forward for condition-based maintenance of power equipment. Because condition-based maintenance mainly depends on the condition detection and online monitoring means of operating equipment, the operation condition detection and online monitoring of power equipment has always played an important role in power safety production. As a new technology, infrared imaging technology has incomparable advantages in the detection of power equipment operation state. Infrared imaging is to diagnose whether the equipment runs well according to the thermal state distribution of the equipment. It can quickly and intuitively image the thermal state of the equipment without stopping or touching. Because the thermal image of equipment is a true description of the thermal state and temperature distribution of equipment in operation, and whether the thermal distribution of power equipment in operation is normal or not is an important feature to judge whether the equipment is in good condition. Infrared imaging technology can diagnose the state of equipment and its hidden dangers and defects by analyzing the thermal image of equipment.
Infrared imaging technology can be used for subsequent state detection and fault diagnosis of power equipment.
● High-voltage electrical equipment operation state detection and internal and external center fault diagnosis;
● Various conductive joints, clamps and wiring pile heads are oxidized and corroded, resulting in poor connection;
● Contact defects of various high-voltage switch centers;
● Isolate the defects of poor combination between the switch blade of the knife and the contact piece, and between the rotating cap and the ball head;
● Various CT primary defects such as poor connection between the inner center and the outer center, poor insulation between the body and the oil, abnormal overheating of the inner center core and coil;
● Various PT insulation defects, oil shortage, abnormal overheating of inner core and coil;
● Overheating of various capacitors, poor insulation of coupling capacitor oil and oil shortage (low oil level) defects;
● The internal center of various lightning arresters is affected with damp, and the internal central components are aging or have abnormal nonlinear characteristics;
● Surface contamination defects of various insulating porcelain bottles, detection of zero-value insulators, and detection of deteriorated porcelain bottles;
● Generator running state detection, brush and slip ring contact state detection, internal center overheating detection;
● Abnormal overheating of power transformer box, eddy current overheating, poor connection between upper and lower ends of high and low voltage bushings, and oil shortage of oil-filled bushings (low oil level);
● Poor contact of bearing pads of various motors, abnormal overheating of internal and external centers of motors.