Utility evaluates circuit-breaker operating mechanisms: TXU electric uses portable equipment to determine circuit-breaker signature analysis

摘要

Data management is an important part of analyzing breaker characteristics, as it provides a means for collecting historical information for later comparison. A bar code in the breaker analyzers can help maintain consistent data. As experience has shown, the first test shot is important, because a problem breaker that has not been operated from time-to-time will display slow and sluggish characteristics. Once the breaker has operated, it will free itself to a point of getting off the latch, and the stored energy will mask potential bearing problems. To eliminate potential problems related to making proper connections from the analyzer to the breaker, use tape to color code the placement of the four leads. While most breaker operators will show a difference in speed between the first and second shots if the lubrication is faulty, a particular type of operator will be consistent on successive shots, even if the lubrication has already begun to deteriorate. Despite its ability to store information for ultimate downloading, the analyzer has a finite memory capacity, which requires downloading after completing tests on about 20 breakers. In addressing breaker lubrication problems, it is good practice to completely disassemble the breaker-operating mechanism, clean it, apply new lubrication and make final adjustments. It may be worthwhile to have a spare operator available as a direct replacement, allowing the removed operator to be overhauled in the shop. In general, the consequences of faulty lubrication are more serious in vacuum breakers than in oil ones, because oil breakers have more energy to overcome bearing problems. In addition, it is important to recognize the potential value of synthetic grease, which has better long-time characteristics than petroleum-based grease. Finally, a disadvantage of the breaker analyzer is its inability to easily accommodate the testing of independent pole breakers.