Flooding of alarms is a very crucial problem in process industries. An alarm flood makes an operator ineffective taking necessary actions, and often risking emergency shutdown or major upset. In this work, the flooding discussed based on standards presented ISA 18.2. A new analysis method proposed to investigate similar floods from historic data group them basis patterns occurrences. case study real industrial also demonstrate utility analysis.

The performance of a univariate alarm system can be assessed in many cases by three indices, namely, the false rate (FAR), missed (MAR), and averaged delay (AAD). First, this paper studies definition computation FAR, MAR, AAD for basic mechanism generation solely based on trip point, advanced exploiting on/off delays. Second, systematic design systems is investigated indices tradeoffs among them. require probability density functions (PDFs) process variable normal abnormal conditions. Thus,...

Accuracy and efficiency of alarm systems are paramount importance in safe operations industrial processes. is measured by false missed rates (probabilities); while relates to the detection delay complexity technique used. Moving average filters often employed industry for improved accuracy. Can one do better than moving filters? The following two problems studied this paper: First, given both normal abnormal statistic distributions, how design an optimal filter (of fixed complexity) best...

In islanded microgrids, sharing load power and retaining voltage-frequency stability are two main tasks that should be guaranteed through grid-forming units. Accurate active reactive can assure optimal reliable operation of the microgrid. practice, however, uncertain feeder line impedances nonlinear loads could lead to harmonic voltages consequently poor sharing. this paper, a robust voltage-current (V-I) droop controller is proposed address these issues. The idea utilize impedance shaping...

Using alarm deadbands is a common method for reducing the number of false and missed alarms amount chattering. Existing methods designing are quite general or need online computations. This paper studies relation between optimal thresholds deadbands. Two equations proposed to estimate threshold with respect deadband history process variable.

This brief considers sliding mode control of hysteresis in piezoelectric actuators. For modeling hysteresis, the Bouc-Wen model that is based on differential equations utilized. One states this unmeasurable. Therefore, a state observer proposed, and proper selection parameters discussed. Based observed state, rule asymptotic stability observer-based closed-loop system proven using Lyapunov theory. also presents design method, i.e., sufficient conditions for are derived explicitly....

In industrial plants, operators constantly receive a large number of alarms that are mostly false or nuisance. A majority these generated by small process variables known as bad actors. These actors either poorly controlled which result in lot fluctuations; their configured. There products on the market and many methods literature can identify give recommendations to resolve Nonetheless, although rectifying will significantly drop alarm count, it is not nearly enough. To bring performance an...

Alarm systems are an important complement to good control design. However alarm have not received the attention that they deserve and as a result do necessarily operate in most reliable efficient manner. Delay timers latches often used process industry reduce chatter minimize nuisance alarms. Effect of varying size on-delay, off-delay on accuracy detection is discussed from theoretical view point by modeling them using Markov chains. The performance delay compared latches. A design procedure...

Piezoelectric actuators are widely used in micro and nano-positioning systems for accurate movement.However, they exhibit some nonlinearities, particularly hysteresis, which makes precise control rather challenging.Many methods available the literature to compensate hysteresis effect piezoelectric actuators, but often a model of actuator is required this purpose.Identification such challenging too.In paper, we propose using robust observer-based controller motion tracking without need...