Using semantic knowledge of distributed objects to increase reliability and availability
Proceedings Sixth International Workshop on Object-Oriented Real-Time Dependable Systems
The article presents ways to improve reliability of agricultural semiconductor frequency converters. It is shown that an increase in reliability of semiconductor converters can be achieved increasing the power reserve. At the same time, if the economic indicator is chosen as an optimization criterion, the coefficient of failure-free operation reaches no more than 0.8. In the event that resulting coefficient of failure-free operation is allowed according to operating conditions, selected
... s, selected criterion can be successfully applied at design stage of semiconductor converters. 2 Analysis of requirements to reliable indicators of semiconductor converters The probability of system failure-free operation Rsys is the multiplication of failure-free operation probabilities all elements, included in the Pi. The motor and сonverter are the main elements of electric drive system, reliability determining of the all complex. Exactly for them will consider the probability of failure makes sense  . The calculated working capacity of induction motors is less than 15 years with produce 40000 hours or 4.5 years continuous operation (power induction motors 4A series from 0.37 kW to 400kW). Produce is less 20000 hours of stator armature and calculated produce is less than 14000 hours of bearing. The probability of failure Paem asynchronous electric motor for industrial performance is less than 0.9 for 10 thousand hours of produce. In other words, this means that asynchronous motor will never fail with probability of 0.9 during produce of 10 000 hours  . The satisfactory value of the probability failurefree operation Pp is 0.9 during 10 000 hours for converter. On the reliability of all electrical installations are divided into three categories: the first category, from which emit a special group, the second and third categories of electrical consumers, this is known from classification rules for electrical appliances  . As a rule blowers, pumps, compressors, fans, are the first category of reliability, but on some industries (metallurgical, chemical) to a "special" group from the same category. Exhausters BOF production is categorized as special consumers, as their uninterrupted operation is required for troublefree shutdown of production with preventing aim threats to lives of people, explosions and fires. An example of electrical equipment from the "special" group on electrical safety can be the electric drive of pipeline valves for nuclear power plants. In table I the quantitative values are given of probability of failure-free operation mechanisms of pipe fittings nuclear power plant  .