10 kV distribution transformers, due to their large number, wide distribution, poor operation and maintenance conditions, and difficult field tests, are often prone to test over-period or missed test, misjudgment, etc., thus giving distribution transformers and 10 kV system operation belts Come to unsafe hidden dangers. In order to eliminate these hidden dangers, the following problems should be noted when testing the lightning arrester.
1 Arrange the test time reasonably
In determining the test time of the transformer arrester, the peak period of daily production and maintenance should be avoided as much as possible, and reasonable arrangements should be made at points and sub-areas to avoid the occurrence of misjudgment and missed judgment due to tight working hours and personnel fatigue caused by centralized testing. In the test process, the transformer lightning arrester is easily affected by external factors such as air humidity and surface contamination, which brings difficulties to the analysis and judgment of the test. Therefore, the test should be carried out in sunny weather, and the surface of the arrester should be kept clean and dry, and the leakage current on the surface of the outer porcelain sleeve will be affected to affect the test result, thus causing misjudgment.
2 Select the appropriate current limiting resistor
In the power frequency discharge test circuit of the ordinary valve type arrester (FS-10), a suitable current limiting resistor should be selected to control the discharge current to prevent the lightning arrester from burning out due to the inability to extinguish the arc by itself. The selection of the resistance value is generally controlled by a discharge current of about 0.7 A. The resistance of the current limiting resistor is selected too small, causing the discharge current to be too large, which easily damages the arrester gap. When the resistance value is too large, the arrester gap starts to discharge, but the discharge current is too small, so that the arc cannot be formed stably until the voltage is further increased, and the gap forms a stable breakdown. At this time, the meter will reflect, thereby causing measurement. The phenomenon that the discharge voltage is higher than the true discharge voltage causes the arrester with a low voltage of the work discharge to be mistaken as qualified. In addition, the interval between the two arresters before and after the same arrester should not be too short, so the gap should have sufficient time to free. When using the mechanical meter to measure the voltage of the power amplifier, the boosting speed should not be too fast to prevent the reading error caused by the inertia of the meter.
3 Strengthen the periodic test of zinc oxide arrester
In the transformation of rural power grids, zinc oxide surge arresters have gradually replaced ordinary valve types to avoid lightning devices due to their excellent electrical performance. Due to the large number of manufacturers, the product process and quality are mixed. Therefore, in addition to strictly grasping the two major barriers of the loading and transfer test of the distribution transformer zinc oxide arrester, it is also necessary to pay attention to strengthening the regular test. The newly-launched zinc oxide surge arrester has been tested for a period of time and the meteorological environment has been tested, so the first test is particularly important. The test period should not be too long to prevent the occurrence of defective arresters from continuing to operate, endangering the safety of the grid and distribution transformers.
4 Pay attention to the moisture-proof problem of zinc oxide arrester
10 kV distribution zinc oxide arrester, the general sealing measures are relatively simple, so the moisture resistance is relatively weak. Relevant statistics show that arresters with poor quality and process have a higher probability of being exposed to moisture. By the way, the DC test, especially for the gapless zinc oxide arrester, is carried out by the critical operating voltage of 1 mA DC and the current of 75% of the voltage. It is obvious that the arrester is more effective.
5 Strengthen statistical analysis of the operation of arresters
According to the type of defects of the arrester, the manufacturer, etc., the classification and statistics and analysis work should be done. For the same manufacturer and the arrester with the high failure rate of the same production batch, close attention should be paid to strengthen the regular inspection work to ensure the grid and the distribution transformer. safe operation.
We design, engineer and fabricate mold tooling, both standard and custom. We continuously design custom tooling to satisfy our customer needs. These tools are built for machines such as Newbury, Autojector, Ameriplas, Multiplas, etc. Our Solidworks 3D design capabilities represent the leading edge in the industry.
We provide training and know-how to our customers. We offer this unique advantage to companies interested in On-site training to assist in the development of in-house capabilities. Our company can become your "over -mold engineering department" and can provide quick turn-around, high quality for customers' the complete cable set with wire harness, plastic, silizone o-ring, metal terminal, or plate, etc. Try to give you the whole supporting service.
Molded Plastic Products,Waterproofing Plastic Box,Plastic Connectors,Plastic Cap,Plastic Bushing
ETOP WIREHARNESS LIMITED , https://www.wireharnessetop.com