Fiber optic temperature sensor, Intelligent monitoring system, Distributed fiber optic manufacturer in China
Why do substations need temperature measurement
There are a large number of connection points in various links of the power system, including generation, transformation, transmission, distribution, and use. These connection points have high or low contact resistance due to various reasons, which causes the temperature of the contact points to rise. During operation, these connection points further increase the contact resistance due to mechanical vibration, overheating oxidation, expansion and relaxation, surface corrosion, and other reasons, resulting in local heating and even arc discharge at the connection points, ultimately leading to electrical equipment damage, power outage, fire or explosion accidents, seriously threatening the economic and safe operation of the power grid.
There are many lead points for electrical equipment in the station, ranging from tens to thousands. Temperature detection of indoor and outdoor lead points is the most time-consuming and laborious task for the operation management department. When using color changing temperature measuring patches or infrared thermometers for detection, the effectiveness is greatly affected by the surface shape and degree of contamination of the tested object. This reliance on a large amount of manpower for detection has certain limitations, low automation level, and more importantly, the heating situation of electrical equipment inside the cabinet and unmanned substations cannot be detected in a timely manner, which poses great accident hazards.
In production, accidents caused by overheating of electrical equipment connection points account for a large proportion of overall electrical accidents. If not detected in a timely manner, such hidden dangers will pose a great threat to safe power supply. In order to timely detect hidden dangers and avoid accidents, it is necessary to implement online real-time temperature monitoring and intelligent alarm for each connection point of electrical equipment.
During the operation of the substation, the temperature of electrical equipment fluctuates accordingly with changes in its load, and on the other hand, it may exhibit abnormal changes due to equipment aging or defects. At present, the methods for managing the operation of substations in the power system mostly rely on monitoring the temperature of electrical equipment such as joints, transformers, and reactors to control the operation of substations. When the temperature of the electrical equipment reaches the set control upper limit, the load should be reduced or the operation should be stopped. After the temperature of the electrical equipment slowly drops, the operation should be restarted, which will lead to a large-scale and prolonged shutdown of power transmission and supply. For the condition of electrical equipment itself, regular inspections and maintenance are often carried out to ensure its adaptability to the operation of the substation. The drawback of this operation and management mode is that it cannot analyze the causes of temperature rise in electrical equipment, leading to misjudgment of non load temperature rise factors, failure to timely eliminate aging or defect factors in electrical equipment, resulting in long-term low-level operation of equipment and an increase in substation operation failure rate. This not only seriously affects operational efficiency, but also leads to the expansion of fault range and economic losses, and is prone to serious accidents; Secondly, electrical equipment is in a passive management state, often only discovered and repaired after major equipment failures occur, and maintenance needs to be carried out in the overall or partial shutdown state of the substation, which will also cause losses to the power department and users; The third is that the monitoring of temperature changes in electrical equipment is often achieved through manual inspections, which makes it difficult to detect and deal with equipment temperature rise in a timely manner, and also endangers the reliable operation of substations.
Disadvantages of infrared temperature measurement in substations
The infrared thermal image detector for substations generally consists of an optical system, photodetectors, signal amplification and processing systems, display and output units, etc. It is usually handheld for detection. During use, the infrared thermometer needs to be handheld. For outdoor open equipment, there are no obstructions on the detection path, and the effect is good. However, for indoor equipment (such as indoor station transformers, grounding transformers, capacitor banks), due to the presence of fences and equipment arranged against walls on the detection route, it is not possible to effectively detect various parts of the equipment, and some defects cannot be detected in a timely manner, often resulting in a “gray” area.
Advantages of fluorescence temperature sensors in substations
The fiber optic temperature measurement system in the substation can monitor the easily heated parts inside the switchgear in real-time, and when used in conjunction with the cooling and ventilation system of the switchgear, it can keep the temperature inside the cabinet within the allowable range at all times; Installing the fiber optic probe on the cable joint inside the cabinet, the arc shield of the primary plug of the circuit breaker car, or the heat shrink sleeve of the static contact can monitor its temperature in real time, and detect and take measures early before it evolves into an accident.