| Popis: |
Electrical arc phenomenon is being studied for a long time. It is an inevitable process that occurs during interruption of high electrical currents (e.g. during a short circuit current interruption). In addition, effects of the electrical arc on the breaker contacts are known and great attention has been paid to methods of analyzing the arc behavior and minimizing damage of the breaker contacts. One of very good mitigation solutions in this direction is the separation of main and arcing contacts. It is clear the arcing contacts are the ones responsible for carrying the arc inside of the breaker chamber during the breaker operation and those contacts have to be designed to withstand high currents and high temperatures with minimal deformation and erosion. The real challenge in this case is to learn about the state of these contacts during regular maintenance procedures. In doing so, one of the main restrictions is time spent on testing in order to bring down maintenance costs and keeping equipment out of operation as short as possible. The arcing contacts are active (carrying current) only a few milliseconds. Thus, the test and the collection of the useful data set must be adjusted to this very limited time frame. Dynamic Resistance Measurement (DRM) method, already adopted and approved as standard testing procedure by many maintenance companies, is usually based on recording a resistance and a motion curve during opening operation of HV CB. On the other hand, also by recording a dynamic resistance curve during closing operation of the breaker, the useful data set can be extended and consequently a diagnostic process can be made more reliable. The main goal of this paper is to investigate possibilities of performing Dynamic Resistance Measurement during closing operation of the high voltage circuit breaker and to present specifics of this approach. |
