Currently, asynchronous electric drives are the most common for machinery at petrochemical facilities. To ensure their safe and steady operation it is required to perform monitoring and diagnostics of their condition, and condition of their insulation. In this case, it is advisable to monitor the condition of the power supply circuits as a whole, since the failure of the cable line (CL) or the supply cell will also entail a shutdown of the machinery unit. The authors consider it obvious that such issues are highly important.Currently, asynchronous electric drives are the most common for machinery at petrochemical facilities. To ensure their safe and steady operation it is required to perform monitoring and diagnostics of their condition, and condition of their insulation. In this case, it is advisable to monitor the condition of the power supply circuits as a whole, since the failure of the cable line (CL) or the supply cell will also entail a shutdown of the machinery unit. The authors consider it obvious that such issues are highly important.
Kostyukov Al.V., Boychenko S.N., Burda E.A. Condition Monitoring of Drive Insulation in Machinery at Petrochemical Facilities Based on Partial Discharge Method // Technique and technology of petrochemical and oil and gas production: proceedings of the 8th international scientific and technical conference (Omsk, February 26 - March 2, 2018). - Omsk: Publishing house of OmSTU, 2018 . p. 198
Operation of a turbine unit causes mechano-caloric processes deteriorating state of shafting parts which increases the risk of accidents and emergencies. Common types of accidents in the power industry in Russia and abroad are the ones related to the deterioration of rotors of a generator and exciter, including the one happening twice in 2013–2014 when there were partial and full deteriorations of half-coupling bolts of the exciter’s armature of a 1000 MW turbine unit. In 2014–2015 several 250 MW turbines bolt connecting high and medium pressure rotors deteriorated soon after the assembly. It should be noted, that some parts can work in similar operating conditions 5-10 years or more, while others degrade in a few months. This is also true for half-coupling bolts. Such a wide range in the wear-off is due to two crucial factors: a)variations of material properties may be caused by a 100% variation of operational characteristics; b) variations of technical deviations due to human factors during assembly may decrease operation life substantially.
Kumenko A.I., Timin A.V. Improved engineering methods of a rotor’s bolt connection state evaluation using multiple-factor analysis // Proceedings of the IX International Scientific and Technical Conference. - Moscow: OAO "VTI", 2017. - p.136-146
The paper analyses ISO standards and Russian Standards serving the same purpose, including:
• ISO 13373-3:2015 (GOST ISO 13373-3–2016). Condition monitoring and diagnostics of machines. Vibration condition monitoring. Part 3. Guidelines for vibration diagnosis;
• ISO 13373-4:2016. Condition monitoring and diagnostics of machines – Vibration condition monitoring – Part 4: Diagnostic techniques for gas and steam turbines with fluid-film bearings (In that case, there is no Russian analog, since the ISO is not approved yet).
Kumenko A.I., Kuzminykh N.Yu ISO Standards and phenomena of “oil whip” and “oil whirl” in rotary system operation // Proceedings of the IX International Scientific and Technical Conference. - Moscow: OAO "VTI", 2017. - p.73-82
The paper gives preliminary results of experimental research aimed at two tasks:
check-up of methods for diagnostics of supports misalignment by data on pivot journal floating-up measured by shaft sensors;
determining generalized sensitivities measured on the shaft in the frequency range from 0 to the operational frequency and necessary for improving the methodology of monitoring and diagnostics of residual imbalances in shafting.
Kumenko A.I., Timin A.V., Kuzminykh N.Yu. Experimental check-up of methods for diagnostics of misalignment and imbalance of rotary bench // Proceedings of the IX International Scientific and Technical Conference. - Moscow: OAO "VTI", 2017. - p.43-52
Today vibration diagnostics is one of the basic methods used in the manufacturing and maintenance of electric motors in order to diagnose their condition by vibration parameters of bearing units. At the same time, such motors may have specific defects of the electromagnetic systems, such as defects of laminations and stator windings, rotor squirrel cage, and others. Those defects can be found by vibration diagnostic methods, but it’s usually more difficult to localize and classify them, since the vibration signals may reflect processes occurring in windings of different stages of the stator, its laminations, and rotor’s conducting system. Method of partial discharges can increase the accuracy of the diagnostics, since various defects of the electro-magnetic system have their own special parametric numbers of partial discharges, and that allows determining the stage of the stator winding in which the defect is developing and its type. The combined usage of vibration diagnostic and partial discharge methods improves the quality of asynchronous motor monitoring and provides a better assessment of changes in their condition in operation.
Kostyukov A.V., Shchelkanov A.V., Burda E.A. Quality control of electric motor maintenance by vibration diagnostics and partial discharge methods // Omsk State Transport University. Omsk, 2017.217 - p. 169-175
The paper considers prerequisites for creating and rationalizing the usage of vibration status estimation criteria for electric motor-driven rolling stock, providing efficient operation, maintenance and repair of the rolling stock due to higher reliability of diagnostics and lower cost for its utilization.
Kostyukov A.V., Zaitsev A.V. Developing assessment criteria for vibration status of wheel-motor units of electric motor-driven rolling stock // Proceedings of the second all-Russian scientific and technical conference / Omsk State Transport University. Omsk, 2017 .-- P.104-111
Improvement of distinguishing criteria, determining defects of machinery and mechanisms, by vibroacoustic signals is a recent problem for technical diagnostics. The work objective is the assessment of instantaneous values by methods of statistical decision-making theory and risk of regulatory values of characteristic function modulus. The modulus of the characteristic function is determined given a fixed parameter of the characteristic function. It is possible to determine the limits of the modulus, which correspond to different machine’s condition. The data of the modulus values are used as diagnostic features in the vibration diagnostics and monitoring systems. Using such static decision-making methods as the minimum number of wrong decisions, maximum likelihood, minimax, Neumann-Pearson characteristic function modulus limits are determined, separating conditions of a diagnosed object.
V. N. Kostyukov, A. P. Naumenko, I. S. Kudryavtseva Assessment of Characteristic Function Modulus of Vibroacoustic Signal Given a Limit State Parameter of Diagnosed Equipment // Procedia Engineering, Volume 152, 2017, p. 239-244
Condition monitoring of critical components is essential in ensuring the reliability of rolling stock. The condition of wheel-motor units is monitored using systems of vibroacoustic diagnostics. The effectiveness of diagnostic systems is determined by a combination of reliability, duration, and price. This study aims to develop engineering solutions for improving the efficiency of operation, repair, and maintenance of electric rolling stock. The studies were based on the methods of technical diagnosis, fuzzy logic decision-making techniques, reliability, and probability theories. Experimental studies were conducted on the basis of the experimental design theory. The in-site testing data were obtained during the diagnosis of the wheel-motor units in the railcar depots of the Moscow and October Railways. The use of fuzzy logic in the decision-making model on the technical condition of the wheel- motor units have been substantiated. The lognormal distribution law, which the vibration parameters of wheel-motor units of the electric rolling stock are subject to, has been established. An analytical model that provides the possibility to preset the values of the false alarm probability and the defect missing probability in the diagnosis of wheel motor units has been proposed. The paper offers a scientifically grounded engineering solution for improving the efficiency of operation, repair, and maintenance of electric rolling stock by increasing the diagnostic reliability to 99% and reducing the test duration by 20%.
V. N. Kostyukov, Al. V. Kostyukov, D. V. Kazarin, A.V. Zaytsev Vibration Monitoring of Wheel-Motor Units of Electric Rolling Stock // NDT World. - #3-2017, p.63-68
Equipment reliability is of high importance for companies of the processing and transport industries aimed at increasing their output and reducing unproductive downtime. Decrease in the equipment reliability is associated with progressive wear and negative impact of personnel who blindly, without knowing the real condition, control various production processes. This causes accidents, downtime, high repair costs, and significant loss of profit. The absence of critical progressive defects in equipment and conditions that accelerate their development or increase in the level of danger is called the equipment health. To make the health observed and predictable, the automatic defect and operation risk monitoring, so-called health monitoring, is used,
The purpose in view - improving the safety and efficiency of companies in the processing and transport industries by health monitoring of their equipment - is still a relevant problem to be addressed.
Technically the purpose is achieved by simultaneous monitoring of all equipment that makes up a processing complex using the COMPACS® machine monitoring systems. The monitoring result is a set of diagnoses made for all pieces of equipment at adjacent time intervals, when the health had not significantly changed. The diagnosis is formed based on the algorithms of the expert system, which provide an automatic detection of the type and danger level of equipment malfunctions, as well as the factors that cause destructive loads on it and accelerate the development of malfunctions. The expert system conclusions clearly indicate to the personnel the actions to be taken to eliminate the malfunction, and to overcome the disturbing factors.
The single platform COMPACS® systems monitor health of various equipment during its life milestones. Within one plant ali systems can be combined into a single automated control system providing safe resource-saving operation.
The paper has solved the following issues:
- the authors have developed the methodical backgrounds, and created hardware and software that ensure automatic monitoring of the plant health through the health of its equipment:
- a large number of health monitoring tools have been implemented and tested;
- the authors have created the technology of equipment operation according to its maximum running time with a minimum operational risk.
V. N. Kostyukov, Al. V. Kostyukov, E.V. Tarasov, D. V. Kazarin Automatic Health Monitoring of the Equipment for the Production and Transport Complex // NDT World. - #3-2017, p.19-22
At present time, widely used methods of vibration diagnostics cannot entirely provide required volume of diagnostics of machinery drivers. Specifically, such methods cannot determine condition of the machinery isolation. In order to solve the problem, it is suggested to use a partial discharge method during repair and maintenance of the machinery.
The up-to-date industry mainly uses the asynchronous motors as drivers of the machinery. One of the most common causes of failures is isolation damages. To prevent such failures, it is required to conquer and apply new diagnostics methods.
The purpose of the research is developing a technical solution. The solution, paired with vibration diagnostics, should provide more complete diagnostics of drivers' isolation systems. The partial discharge method was applied for solution of the problem. The method determines and traces the defects of isolation online without use of increased test voltage.
The undertaken study confirms applicability of the partial discharge method at the different stages of machinery operation. The method, as a part of the bench system tooling, controls condition of drivers' isolation of the equipment during its repair and acceptance testing of new equipment. As a part of the system, this method monitors condition of the isolation system of critical tags in real-time. This contributes machinery maintenance according to its actual condition instead of scheduled one. Due to the increase of completeness and profound diagnostics, and elimination of additional time and efforts, combining such methods as vibration diagnostics and partial discharge increases reliability and effectiveness of diagnostics of machinery.
А. V. Kostyukov, S. N. Boychenko, А V, Schelkanov, Е. A Burda Complex Application of Vibration Diagnostics and Partial Discharges Methods at Various Stages of Dynamic Equipment Operation // NDT World. - #3-2017, p.15-18