Designing and operation experience of real-time monitoring systems

Transcription

1 Abstract Designing and operation experience of real-time monitoring systems Vladimir N. Kostyukov, Alexandr P. Naumenko SPC Dynamics Omsk, , Russia Tel: +7 (3812) The fundamental causes of operational problems of potentially dangerous and critical objects are low objectivity of the technical condition evaluation and low observability of hidden degradation processes of technical state of these objects, flowing due to wear and inadequate actions of technological, servicing and repair personnel. These problems can be solved on the basis of results of technical condition monitoring of the objects in real-time. On the basis of the existing normative and scientific-methodical documents the goals and objectives of monitoring are formulated and their solutions are pointed. The complex real time condition monitoring system is presented. Key words: monitoring, system, potentially dangerous object, critical object. 1. Introduction Low objectivity of a technical condition evaluation and insufficient observability of latent processes of a technical condition degradation of potentially dangerous and crucial objects, proceeding owing to deterioration and inadequate actions of the technological, serving and repair personnel, are the fundamental reasons of the objects operational problems. Operating losses can be minimized through timely and targeted maintenance, based on the results of the real-time technical condition monitoring of the objects, using fully its resource, excluding its emergency stop and groundless repair, ensuring a high level of safety and technical readiness. The existing normative base in the form of international standards defines only the general approaches of monitoring problems solutions [1, 2, 3, 4] by measuring various parameters of processes [5, 6, 7] including measurements of vibration [8, 9]. A joint use of manifold methods of technical diagnostics and non-destructive testing for technical condition inspection of potentially dangerous and critical facilities, on the one hand, is a very complicated and relevant issue because of the need to develop a set of diagnostic parameters based on different characteristics of various physical processes. On the other hand, diverse kinds of facilities demand special solutions concerning a choice of diagnostics methods and operated diagnostic parameters. The given problem solution can be received on the basis of carrying out the fundamental research operations, adequate approbation of proposed solutions and practice of the developed systems maintenance in real conditions of potentially dangerous and crucial facilities functioning. First of all it is necessary to define the terminology, strategy and tactics under addressing the challenges of hazardous industries monitoring. Technical condition monitoring as a conception has been for the first time introduced in scientific literature in [16], and in the normative documents in [21, 22]. The complete 1

2 definition which does not have an ambiguous interpretation, reads as follows: technical condition monitoring is the observation under technical condition of an assembly or set of assemblies (construction, machine, unit, mechanism) in order to determine and predict the moment of their transition in limiting condition. The result of monitoring represents a set of the objects diagnoses which have been received during indissolubly adjoining to each other time intervals when the condition of the objects does not significantly change. The notion of parameters monitoring implies the observation upon any parameters (vibration, temperature, deformation, acoustic emission etc.). The fundamental difference between condition monitoring and parameters monitoring lies in the presence of an interpreter in the first one. It transfers the measured parameters in the technical condition terms an expert system of decision-making support regarding object condition and further control. Quite important is the notion of real time condition monitoring (RTCM) concerning the system (machine), which product is a current information about equipment technical condition and its danger with necessary comments (residual life forecast, instructions for personnel urgent actions) and given risk [13, 21]. Complex RTCM system is to provide receiving of information about condition of equipment (monitoring object) in quantity and quality sufficient for observability maintenance of technical condition. As a consequence of observation, systems should produce beforehand operating influences which provide a necessary stock of technological system stability, quality of its functioning, create an indispensable margin of its technogenic, ecological and economic safety. Standards [13, 21] have for the first time presented the classification of systems and define the requirements to systems which are carrying out equipment monitoring of various categories of danger. In [13, 21] there were also for the first time determined the requirements to monitoring systems with respect to risk of an unexpected failure admission which implies a set of risks with regard to an admission of timely recognition of equipment dangerous condition, caused by the fact that the system perceives (diagnoses) a defective equipment condition as correct and by the fact that a monitoring (diagnosing) period exceeds an interval of development of malfunction from the moment of its detection to the limiting equipment condition and with respect to the human factor caused by late implementation of monitoring system requirements to elimination of detected dangerous condition of equipment. Depending on the equipment hazard category and the risk of failure admission, a monitoring system class is chosen. Thus, possessing a normative [13, 21] and scientific-and-methodological base [15, 16, 17, 18, 19] we can formulate monitoring objectives and tasks and the ways of their solutions. The objective of equipping with RTCM system is assurance of safe resource-saving operation by means of advance development of control actions, which should provide a necessary stock of technological system stability, quality of its functioning, create an indispensable margin of its technogenic, ecological and economic safety [12]. Complex RTCM systems intended for safe resource-saving operation of industrial enterprises equipment by means of real-time receiving of information about past, current and projected technical equipment state, should solve the following tasks [13, 14, 20, 21]: - supervision and assessment of equipment technical condition during acceptance tests and operation by various types (methods) of non-destructive testing and technical diagnostics (vibroacoustic, acoustic emission, thermal, of stress-strain state etc.); - identification of defective equipment units and reasons of occurrence of defects and malfunctions; - ensuring of the technological mode of monitoring objects based on their technical condition; 2

3 - identification of the necessity to control technological process parameters to minimize overloads affecting the monitoring object to ensure maximum resource of safe operation of equipment; - informing about the necessity to change the periodicity of maintenance work (for equipment in service); - actual condition-based operation of industrial enterprises equipment which implies that volume and content of regular periodic inspections and examinations of objects, equipped with CMS, can be changed; - informing about the conditions of further equipment maintenance above the normative lifetime. Complex monitoring of technical condition of monitoring objects equipment is based upon the system of software and hardware, arrangements and technical measures, providing with continuous receipt of real-time information about equipment technical condition in quantity and quality, sufficient for observability maintenance of its technical condition [12]. Equipment category while choosing monitoring objects is based on the analysis of risk matrix [8]. Quantitative evaluation of risk requires an analysis of frequency (probability) of equipment failures and caused by them consequences (losses). For failures frequency evaluation they use, as a rule, operating statistics which is listed in the handbooks, regulations, operating logs or equipment reliability reports of the particular enterprise or company in which they plan to install the CMS. Analysis of consequences (losses) due to equipment failure includes losses, connected with full or partial object deprivation economic, significant or insignificant harm to the environment ecological, damage to life and/or health - vital functions safety violation. In the Standards [12, 24] the recommended levels of losses evaluation in the monitoring arrangement are presented. One of the most common methods of technical diagnostics of industrial enterprises equipment is a vibroacoustic method [16, 17, 19, 25]. An existing industry and global normative base does not comply with the current level of vibroacoustic diagnostic method development. Developed and enacted standards of vibration levels evaluation [14, 20] meet the most contemporary achievements of scientific thought in this area. A distinctive feature of these documents is a co-regulation of such parameters as acceleration, velocity and displacement. The Standards [14, 20] apply to the centrifugal pump and compressor units driven by electric motors and/or steam turbines with gearboxes and other equipment, and establish standards of vibration assessment of technical state during maintenance and acceptance tests after installation and repair. The document reflects the general requirements for machine units monitoring systems, sensors installation conditions, standardized options, criteria for unit condition assessment, operating rate of vibration of centrifugal and screw pumps, electrical machines and fans, centrifugal and screw compressors, multipliers and steam drives; a list of machines and units, which vibration parameters are used to develop these standards, is presented. The Standard [20] enumerates the automatically separated failures of machine units such as alignment damage, imbalance including motor wheel wearing and half-coupling, weakening of a unit s fastening to the foundation or mounted structures, electric motors failures. According to [14, 20, 24], four grades of technical condition are applied: «GOOD», «TOLERABLE», «ACTION REQUIRED», «INTOLERABLE». Each evaluation of the technical state of machinery determines the appropriate set of the personnel actions aimed at condition management. Each evaluation must meet a certain set of operations to maintain the equipment in the state «REQUIRES ACTION» at least. The general requirements to procedures of the RTCM system application, their implementation, acceptance and commissioning are set in [23]. The Standard applies 3

4 to the RTCM system which is designed to enable operation and/or repair of industrial enterprises equipment on the actual technical state. In order to avoid ambiguous interpretations and erroneous decisions, it is necessary to use the common terminology concerning industrial facilities monitoring. For this purpose the Standard CTO [22] has been prepared and issued; according to the scope it describes abbreviations, terms and definitions relating to the technical condition monitoring of hazardous industrial facilities with regard to regulatory and reference documents. The Standard is recommended for use by specialists, expert and design organizations and industrial enterprises when elaborating standards, methodical and other technical documentation regarding the choice and justification of technology of safe, resource-saving equipment operation on the actual state, as well as writing articles, books and other materials [22]. Analysis of architecture and operation principles of known and available systems, which are called monitoring systems, points out the following: - in well-known systems the diagnostic signals are received by dint of stationary systems which are frequently called as on-line monitoring systems. Equipment condition evaluation in on-line monitoring systems is carried out at the time of signal receipt by measuring a value of a parameter and without defining a cause of its changing; - as a rule, on-line monitoring systems do not take into account a duration of failures development, a measuring period is set by a user or the system designer from his own experience. A diagnosis making is carried out by specialists of an appropriate scope as needed; that does not allow to evaluate timely a failure or defect emergence, their reasons and danger; - absence of automatic expert systems and a significant period of diagnosis making, which exceeds a time of failures development [13, 21], testify that the reviewed on-line monitoring systems are the systems of parameters monitoring but not of technical condition diagnostics and monitoring (see the notion of «monitoring» in [22]). At the same time in real-time condition monitoring systems: - monitoring and diagnosis methodology is based on measuring of indirect processes parameters (particularly vibroacoustic wavering, acoustic emission signals), measuring of direct structural and thermodynamic parameters is also provided; - algorithms of the expert system of real-time decision support are implemented with automatic determination (diagnosis making in rate of diagnostic signals measuring) of equipment units failures, degree of their danger and distribution to the personnel of purposeful prescriptions concerning compensatory measures. - science-based period of diagnosis making allows to gain a less than 5% significance of statistical and dynamic errors recognition of equipment condition, which permits to carry out a condition monitoring of all categories of crucial equipment and industrial facility on the whole. ACS SRSM COMPACS - the automatic control systems for safe maintenance and repair of equipment (fig. 1) realize safe and resource-saving SM -technology (Safe Maintenance) of equipment condition control and represent a system which provides observability after manufactured, operated and repairable equipment, ensures equipment quality control at all stages of life cycle and stability, security and efficiency. ACS SRSM -technology is based on three components: 1. Real-time condition monitoring systems; 2. Systems of quality diagnostics of manufactured and repairable equipment; 3. Diagnostic net of enterprise and industry. 4

5 Diagnostic network server Remote users of COMPACS-Net Local users of COMPACS -Net COMPACS-Asset Management RF patents , , Stationary systems COMPACS RF patents , , , Personal automated vibrodiagnostic systems Compacs -micro RF patent Benchtop systems COMPACS RF patents , , Fig. 1 ACS SRSM - the automatic control systems of safe operation and maintenance of equipment The core of ACS SRSM are stationary systems of equipment RTCM systems, which have a built-in automated expert system, invariant to design of the unit, which provides a strategy for diagnosis of minimal cost SDMS, i.e. makes it possible to continuously automatically receive and use of objective information about monitoring objects condition of units for maintenance and repair of equipment, to identify and eliminate the fundamental causes of equipment failures (technology LIFPO ), to increase production discipline by objective monitoring and timely correction of personnel actions. The basis of the RTCM systems is a long-term practical experience in development, implementation and operation of more than 400 monitoring systems in 10 industries, as well as achievements of scientists and researchers in various scientific-research directions, which results are reflected not only in the above mentioned Standards but also in the series of dissertations, monographs, articles, reports in the international and other conferences, symposiums, meetings, devoted to systems of diagnostics and monitoring of industrial enterprises equipment [15, 16, 17, 18, 19]. The RTCM system includes: - a distributed system of sensors which control the principal equipment parameters; 5

6 - a distributed system of remote modules which provide the initial signals conversion from the sensors and their transmission to the diagnostic controller, they also provide control over the integrity of sensors and communication lines; - a diagnostic station which provides collection, storage, processing and displaying the results of monitoring. The field network contains measuring modules with a function of analog-digital processing of the measured signals, and probes of various physical quantities. Remote modules of the RTCM system are installed in close proximity to the measuring object on which sensors are placed. The modules are put in protective boxes or metal enclosures. The system remote modules are connected with the diagnostic station by means of two communication lines in order to reduce the length of cable runs. Modules and sensors are made of explosion-proof materials of 0ExiallCT5 class and can be operated in areas of any class. The diagnostic station with a set of equipment provides such functions as measurement of parameters of any physical quantities, transmission of the measured and processed data to the diagnostic station through a modem or a network equipment, voice information output as a result of operating activity of the expert system of decision support and further control, information safekeeping as a result of operating activity of the system, functioning explosion safety, preservation and display of diagnostic features trends, explosion safety of the field network [16]. The information from the portable diagnostic system and the alarm control system can be transmitted to the diagnostic system. For equipment condition monitoring depending on solvable diagnostic problems, the following parameters are used: vibroacceleration; velocity; vibrodisplacement; temperature; pressure; radial clearance; current consumption; shaft rotation speed; level of liquids (condensate); signal of acoustic emission sensor; AC/DC parameters (e.g ma); voltage parameters from sensors of various physical quantities. The RTCM system, receiving signals from sensors, forms a vector of orthogonal diagnostic features, invariant to the type of the diagnosed equipment; the vector includes about 10 of non-destructive testing types: vibratory, acoustic emission, thermal, electric and others. As far as the RTCM system has a distributed parallel-sequential structure it requires far less sensors and cable, and consequently less installation and maintenance costs, it provides a low cost of ownership compared to many other systems, and also provides an opportunity to transfer the equipment to operate on the actual technical state and, accordingly, has highly cost-effective implementation [18]. Prospects of monitoring systems development are in the full implementation of regulatory requirements to condition control and monitoring facilities diagnostics, as well as in the use of modern methods and means of facilities parameters measuring which define their technical condition, such as the use of fiber-optic transducers and sensors built with nanotechnology, achievements in various methods of non-destructive testing and technical diagnostics, and in particular, the acoustic emission. References 1. ISO , Condition monitoring and diagnostics of machines. Data processing, communication and presentation. Part 1: General guidelines, London, British Standards Institution, ISBN: p. 2. ISO , Condition monitoring and diagnostics of machines. Data processing, communication and presentation. Part 2: Data processing, London, British Standards Institution, ISBN: p. 3. ISO , Condition monitoring and diagnostics of machines. Data processing, communication and presentation. Part 3: Communication, London, British Standards Institution, ISBN: p. 6

7 4. ISO , Condition monitoring and diagnostics of machines. Data processing, communication and presentation. Part 4: Presentation, London, British Standards Institution. 5. ISO 13379, Condition monitoring and diagnostics of machines. General guidelines on data interpretation and diagnostics techniques, London, British Standards Institution, ISBN: p. 6. ISO 13380, Condition monitoring and diagnostics of machines. General guidelines on using performance parameters, London, British Standards Institution, ISBN: p. 7. ISO , Condition monitoring and diagnostics of machines. Prognostics. Part 1: General guidelines, London, British Standards Institution, ISBN: p. 8. ISO , Condition monitoring and diagnostics of machines. Vibration condition monitoring. Part 1: General procedures, London, British Standards Institution, ISBN: X p. 9. ISO , Condition monitoring and diagnostics of machines. Vibration condition monitoring. Part 2: Processing, analysis and presentation of vibro data, London, British St GOST R , Risk management. Risk analysis of technological systems, Moscow, STANDARTINFORM p. 11. GOST R , Risk management. Reliability management systems, Moscow, STANDARTINFORM. 12. GOST R , Condition monitoring and diagnostics of machines. Condition monitoring of hazardous production facilities. Order of organization, Moscow, STANDARTINFORM, ISBN: p. 13. GOST R , Condition monitoring and diagnostics of machines. Condition monitoring of hazardous production facilities. Requirements to monitoring systems, Moscow, STANDARTINFORM p. 14. GOST R , Condition monitoring and diagnostics of machines. Condition monitoring of hazardous production facilities. Vibration of centrifugal pump and compressor units, Moscow, STANDARTINFORM p. 15. Kostyukov V.N., Boichenko S.N., Kostyukov A.V., Automated control systems for safe resource-saving operation of the refinery and petrochemical equipment (ACS SRSM) [edited by Kostyukov V.N.], Moscow, Mashinostroenie, ISBN: p. 16.LKostyukov V.N., Monitoring of production safety, Moscow, Mashinostroenie, ISBN: p. 17. Kostyukov V.N., A P Naumenko A.P., Practical fundamental of vibroacoustic analysis of machine equipment: tutorial [edited by V N Kostyukov], Omsk, Publishing house of Omsk State Technical University, ISBN: p. 18.IKostyukov A.V., Kostyukov V.N., Increase of operational efficiency of enterprises based on real-time monitoring, Moscow, Mashinostroenie, ISBN: p. 19. V N Kostyukov, A P Naumenko, Fundamental of vibroacoustic analysis of machine equipment, tutorial, Omsk, Publishing house of Omsk State Technical University, ISBN: p. 20. CA , Centrifugal pump and compressor units in hazardous industrial facilities. Operating standards for vibration: the standard of the association of Russian Technical Expertise, the association of petrochemical and refiners and the ITU RISKOM (Approved by the Federal Service of Ecological, Technical and Nuclear Supervision of the Russian Federation, the letter 11-16/219 from ), Moscow, Compressor and Chemical Equipment, ISBN: p. 7

8 21. CA , Systems for monitoring of units on hazardous production sites. The general technical requirements: the standard of the association of Russian Technical Expertise, the association of petrochemical and refiners and the ITU RISKOM (Approved by the Federal Service of Ecological, Technical and Nuclear Supervision of the Russian Federation, the letter 11-16/219 from ), Moscow, Compressor and Chemical Equipment p. 22. CTO , Monitoring of hazardous industries. Terms and definitions: collection of standards of the ITU RISKOM, Monitoring of hazardous industries equipment. The standard of organization, Auth.coll., Moscow pp CTO , Monitoring of hazardous industries, Application procedures: collection of standards of the ITU RISKOM, Monitoring of hazardous industries equipment, The standard of organization, Auth.coll., Moscow pp CTO , Monitoring of hazardous industries, Order of organization: collection of standards of the ITU RISKOM, Monitoring of hazardous industries equipment, The standard of organization, Auth.coll., Moscow pp GOST R ISO, Vibration. Evaluation of machinery condition by vibration measurements on non-rotating parts, Moscow, STANDARTINFORM p. 8