Emergency Shutdown Research Articles

In-service performance of emergency shutdown valves and dependent operational relationships in the offshore oil and gas industry

Industrial process plants use emergency shutdown valves (ESDVs) as safety barriers to protect against hazardous events, bringing the plant to a safe state when potential danger is detected. These ESDVs are used extensively in offshore oil and gas processing plants and have been mandated in the design of such systems from national and international standards and legislation. This paper has used actual ESDV operating data from four mid/late life oil and gas production platforms in the North Sea to research operational relationships that are of interest to those responsible for the technical management and operation of ESDVs. The first of the two relationships is between the closure time (CT) of the ESDV and the time it remains in the open position, prior to the close command. It has been hypothesised that the CT of the ESDV is affected by the length of time that it has been open prior to being closed (Time since the last stroke). In addition to the general analysis of the data series, two sub-categories were created to further investigate this possible relationship for CT and these are “above mean” and “below mean”. The correlations (Pearson's based) resulting from this analysis are in the “weak” and “very weak” categories. The second relationship investigated was the effect of very frequent closures to assess if this improves the CT. ESDV operational records for six subjects were analysed to find closures that occurred within a 24 h period of each other. However, no discriminating trend was apparent where CT was impacted positively or negatively by the frequent closure group. It was concluded that the variance of ESDV closure time cannot be influenced by the technical management of the ESDV in terms of scheduling the operation of the ESDV.

Power Plant Transients including Hydraulic Short Circuit Operation Mode

Within the XFLEX HYDRO project, the possibility of increasing the flexibility of hydro power plants to support the Electric Power System (EPS) is investigated. The flexibility of the pumped-storage power plant Frades 2, as the target, should increase by extending the operating range for each unit and by using the hydraulic short circuit (HSC) operation mode. Transient investigations of the additional plant conditions are performed to ensure the safety of the plant. With a 1D model of the entire hydro power plant including both pump-turbines, valves, surge tanks, and the water-bearing components, extensive calculations are carried out to verify the safety of the existing plant for extended operation conditions. In particular, the study focuses on the synchronous and asynchronous emergency shutdowns of the plant in the new operating conditions as well as other operation-related power plant transients regarding the HSC mode. With the results presented in this paper, the flexibility of the plant Frades 2 can be increased. Delayed emergency shutdowns are identified as particularly critical during the study and should always be given additional consideration in transient investigations.

Czynniki wpływające na proces piaszczenia w odwiertach kierunkowych

Many wells of offshore fields in Azerbaijan are subject to sanding and plugging. This is especially observed in wells at a late stage of development. The process of plug formation in directional wells is known to be characterized by a variety of factors associated with both natural conditions and the parameters of their development and, most importantly, operation. The degree of influence of the factors varies, in addition to the fact that all of them (directly or indirectly) are interconnected. Sand production is often observed during completion (development) and operation of wells, especially when the productive reservoirs are represented by weakly cemented rocks. It is worth noting that in the case of sand plug formation, the permeability of which is 200 times greater than the per-meability of the productive formation, the oil production rate decreases by 34%. This sand contains up to 5% of oil and poses a problem upon its removal, as it results in environmental contamination. In addition, it deposits in pipelines, surface equipment, causing erosion. This kind of complication is almost universal. Sand removal is one of the main reasons for the formation of cavities and collapse of columns. This problem has acquired particular relevance with the development of thermal methods for the extraction of high-viscous oils: the viscosity of oil decreases, and its fluidity increases. In this case, some reservoirs lose their cementing binder - viscous oil. During planned and emergency shutdowns, when the coolant injection stops, the reverse flow of the coolant enters the injection wells and removes mechanical impurities. This also leads to the formation of sand plugs in the wells and prevents the normal injection of the coolant. The existing methods of operating wells affected by sanding can be divided into two groups: 1) operation of wells with the removal of sand from the reservoir; 2) prevention of sand production from the formation.

Разработка метода исследования режимной надежности электроэнергетических систем

The article considers the urgent choice of a solution to the problem of reliable operation of power plants in the maneuvering modes. The performance reliability of power units is assessed. There are listed actual methods of studying the reliability of power plants, which are used in the practice of operation and design of power plants, in particular the electrical part in a statistical state. There is proposed a structural-functional method of studying the reliability of power plants, which allows to analyze the cause-and-effect relationships of the structural diagram elements in the stationary and transient modes of operation and obtain a synthesizing assessment of the final result of the power plant operation, taking into account the factors affecting the mode change. The scheme of directed graphs is illustrated: serial and parallel connection of elements, with direct and reverse stochastic connections. Formulas are given for calculating the availability factor (operability of an individual element or a functional circuit), as well as the inoperability factor due to the frequency of failures and remedial repairs. A case of practical application of the structural-functional method studying the reliability of power plants is considered. The elements of the block diagram of the power unit, turbine plant, electrical connections are listed. An algorithm for calculating the reliability of operation of a 250-300 MW power unit in the modes of start-up, shutdown, load control, stationary and emergency shutdown is considered. The logical sequence of operations of the technological process of the power unit is given. It is noted that the calculations were made on a personal computer in an interactive mode, labor costs amounted to about eight hours for an engineer of average qualification. According to the calculations performed, the conclusions were drawn for the power plant operating in the shunting mode as a whole: frequent starts/stops have a negative impact on the performance of power units, therefore, there is recommended a load mode within the allowable limits of power change.

Shutdown safety analysis of megawatt-class space gas-cooled reactor system

Among the numerous space nuclear power sources, high temperature gas-cooled reactor with closed Brayton cycle has the advantages of both high power and high energy conversion efficiency. An Open-grid MEgawatt Gas-cooled spAce nuclear reactor (OMEGA) is investigated. Furthermore, a system Transient Analysis code of scheduled Shutdown and emergency Shutdown (TASS) is developed, including core, turbine-generator-compressor, regenerator, condenser, heat pipe radiator and other modules. TASS was verified by comparing prediction value with designed value, and transient performances of system shutdown were simulated. Over the course of shutdown, emissivity of fuel cladding is closely related to cladding peak temperature. Firstly, there is no overlay coating on fuel cladding whose emissivity equals to 0.18, the peak temperature of fuel cladding during scheduled shutdown and emergency shutdown reaches melting point at 7.8 h and 3.6 h respectively. Secondly, there is overlay coating on fuel cladding and emissivity is increased to 0.80. Radiation heat transfer can be greatly enhanced, and peak temperature of fuel pellet and cladding do not exceed the melting point of relevant material, which reflects the importance of fuel cladding surface processing. This paper provides a valuable analysis support for the design of megawatt-class space gas-cooled reactor system.

Розвиток на ДП «КБ «Південне» моделей оцінювання показників польотної безпеки для випадку аварії ракети на етапі польоту

Safety of the up-to-date rocket and space complexes remains a topical problem for the developers of rocket and space technology. The integral component of this problem along with the safety of operations during launch vehicle ground pre-launch processing is organization of flight safety. The basic task of this rocket and space complexes safety component is to prevent or minimize serious consequences in case of launch vehicle failure in the flight leg, after all such accidents can cause damage to the population and facilities (including personnel and facilities of the ground complex), located along the flight paths. It is shown that the flight safety assurance of the launch vehicle is based on the experience of combat missile systems. Flight safety during the launch vehicle launches is provided by laying flight paths through sparsely populated (unpopulated) territories and using special onboard flight safety systems. This system limits the size of impact zones of emergency launch vehicle and its debris by emergency engine shutdown. Recently flight safety process is organized based on the acceptable risk concept. It is based on a risk assessment for the ground-based facilities and people, and it should not exceed the established standards. Such approach requires development and upgrading of the mathematical models of risk assessment in case of launch vehicle failure in the flight phase. Formation of the risk-oriented approach to flight safety in Yuzhnoye SDO is shown. Key moment in this process is to develop the separate structural unit, which started working on rocket and space complexes flight safety assurance and analysis. The basic model for assessing the risks of damage to facilities and people is analyzed, using the maximum impact zone of an emergency launch vehicle, which is realized in case of loss of control and flight safety system activation. The main directions of the basic model improvement are shown, which led to the development of a number of new original models of flight safety assessment in the Yuzhnoye SDO. First of all, the developed models take into account the flight safety system specifics, which are used to equip the launch vehicles, developed by Yuzhnoye SDO: criteria of activation, blocking of the engine emergency shutdown in the initial flight phase and Fe functional. Such models allow to take into account the different nature of emergency situations in the launch vehicle flight phase and ways of their representation, representation of the damage areas of facilities in the form of convex polygons, possible fragmentation of the emergency launch vehicle at the free- fall leg etc. The developed models have found wide application in the practice of assessing flight safety indicators in the Yuzhnoye SDO projects. Key words: launch vehicle; acceptable risk; launch vehicle failure in the flight phase; flight safety system; emergency launch vehicle impact zone; risk of damage to facilities; collection risk.

Elasto-plastic analysis of foundations during emergency shutdown due to blast loading

Behaviour of machine foundations is investigated in this study under harmonic loading with varying frequency and pulse loading. Owing to excessive vibrations from the pulse, the machine encounters an emergency shutdown where the machine’s exciting frequency reduces to zero exponentially. The analysis is performed considering an elastic plastic single degree of freedom system with hardening and softening behaviour. Two cases are analysed depending on the time of application of pulse loading to the foundation system. For both the cases, the governing equations of motion are acquired and solved numerically using the fourth order Runge-Kutta method. Using these solutions, displacement-time graphs are obtained for a variety of parameters such as time constant, hardening/softening index, mass of machine and the foundation block, stiffness, pulse load magnitude, damping ratio and decay coefficient to study their influence on the behaviour of the machine-foundation system. The study helps in predicting the dynamic response of foundations under the emergency shutdown conditions due to pulse loading. Further, these also help in taking the decision if there exists a need for vibration barriers to have the displacements well within the permissible limits.

Development of reduced-order thermal stratification model for upper plenum of a lead–bismuth fast reactor based on CFD

After an emergency shutdown of a lead-bismuth fast reactor, thermal stratification occurs in the upper Plenum, which negatively impacts the integrity of the reactor structure and the residual heat removal capacity of natural circulation flow. The research on thermal stratification of reactors has mainly been conducted using an experimental method, a system program, and computational fluid dynamics (CFD). However, the equipment required for the experimental method is expensive, accuracy of the system program is unpredictable, and resources and time required for the CFD approach are extensive. To overcome the defects of thermal stratification analysis, a high-precision full-order thermal stratification model based on CFD technology is prepared in this study. Furthermore, a reduced-order model has been developed by combining proper orthogonal decomposition (POD) with Galerkin projection. A comparative analysis of thermal stratification with the proposed full-order model reveals that the reduced-order thermal stratification model can well simulate the temperature distribution in the upper plenum and rapidly elucidate the thermal stratification interface characteristics during the lead-bismuth fast reactor accident. Overall, this study provides an analytical tool for determining the thermal stratification mechanism and reducing thermal stratification.

Design and Implementation of an Oil and Gas Surface Processing Plant using Digital SCADA

Abstract: The oil and gas surface processing plant or station is the gathering station where the crude oil is separated into its constituent units of oil, water, and gas. This paper reports the sensor data capturing, the process operation, and the SCADA design of the processing unit using Wonder-ware InTouch Software. The system monitors/controls various process variables including pressure, temperature level, flowrates, and the emergency shutdown system based on the Cause & Effect Chart.

Transient torque reversals in indirect drive wind turbines

AbstractThe adverse effect of transient torque reversals (TTRs) on wind turbine gearboxes can be severe due to their magnitude and rapid occurrence compared with other equipment. The primary damage is caused to the bearings as the bearing loaded zone rapidly changes its direction. Other components are also affected by TTRs (such as gear tooth); however, its impact on bearings is the largest. While the occurrence and severity of TTRs are acknowledged in the industry, there is a lack of academic literature on their initiation, propagation and the associated risk of damage. Furthermore, in the wide range of operation modes of a wind turbine, it is not known which modes can lead to TTRs. Further, the interdependence of TTRs on environmental loading like the wind is also not reported. This paper aims to address these unknowns by expanding on the understanding of TTRs using a high‐fidelity numerical model of an indirect drive wind turbine with a doubly fed induction generator (DFIG). To this end, a multibody model of the drivetrain is developed in SIMPACK. The model of the drivetrain is explicitly coupled to state‐of‐the‐art wind turbine simulator OpenFAST and a grid‐connected DFIG developed in MATLAB®'s Simulink® allowing a coupled analysis of the electromechanical system. A metric termed slip risk duration is proposed in this paper to quantify the risk associated with the TTRs. The paper first investigates a wide range of IEC design load cases to uncover which load cases can lead to TTRs. It was found that emergency stops and symmetric grid voltage drops can lead to TTRs. Next, the dependence of the TTRs on inflow wind parameters is investigated using a sensitivity analysis. It was found that the instantaneous wind speed at the onset of the grid fault or emergency shutdown was the most influential factor in the slip risk duration. The investigation enables the designer to predict the occurrence of TTRs and quantify the associated risk of damage. The paper concludes with recommendations for utility‐scale wind turbines and directions for future research.

Integrating condition-based monitoring with process sensors information for operation and maintenance in a functional modeling framework

Safe operations and adequate maintenance are two main means to achieve reliable production and reduce downtime of a plant. While the tasks of operations and maintenance are carried out by two different groups of staff, as a result, the close relationship between the two tasks is split. In this paper, this challenge is handled by a proposed integrated functional modeling framework. In this framework, the Multilevel Flow Modeling (MFM) method with its cause-consequence reasoning rules is used. Condition-based monitoring is a well-accepted strategy for predictive maintenance and fault detection based on measurements is a well-developed technology for operation support. Information fusion including monitoring conditions of assets and process sensors information for both operation and maintenance in the same modeling framework is desired. The qualitative relationship distribution between operations and maintenance can be established based on the function states of the system. In addition, these relationships are visible for both groups of staff. As a result, the detected information in the early stage of the development of the unpleasant scenarios is used to improve their situation awareness, so that the undesired emergency shutdown from both perspectives of operation and maintenance is prevented. Consequently, it can reduce production loss. A case study of operations and maintenance of a seawater injection system is carried out and shows the industrial applicability of the proposed framework. The case study strongly reveals that there is a highly close relation between operation and maintenance for ensuring the system working properly. It demonstrates that the proposed integrated framework is not only able to support operational tasks but also for the maintenance tasks by including relevant maintenance information of the system. The results show that it can potentially help with decreasing downtime of the system.

Reliability Study of Electrical Distribution Network in Kampala East

This research focuses on the reliability study of the electrical distribution network in Kampala East, which is connected to Lugogo, Nakawa, Kireka and Ntinda substations. The network is unable to supply its customers with reliable power at all times. Methods used in this research involve data identification, collection, cleaning, analyzing and interpretation. Also conducted are determination of reliability indices, identification of causes of supply interruptions and improvement of reliability. Depending on the reliability study outcome, the electrical distribution network in Kampala East has customer hours lost (System Average Interruption Duration Index) of 8.34 per month per customer, number of outages per month per customer (System Average Interruption Frequency Index) is 5.65 hours, Energy not served to customers of 2.14 GWh per month and Faults resolution time (Customer Average Interruption Duration Index) of 1.58 hours. The major cause of interruptions are system faults and emergency shutdowns. In this study, Reconfiguring network through use of appropriate combinations of opening of sectionalizing (normally Closed) switches and closing of tie-line (normally- Open) switches on feeders, the reliability is improved to 4.18 customers hours lost per month per customer and the number of outages per month per customer is 5.35, the energy not served of 0.18 GWh and faults resolution time of 0.84 Hours. This gives percentage improvements of 49.88%, 5.31%, 54.2%, and 88.61% in SAIDI, SAIFI, ENS and CAIDI respectively. The current level of reliability of electrical distribution network in Kampala East exceeds the target set by the regulator for 2022.

Renewable energy sources for backup energy supply of small wastewater plants and individual households

These researches concern the use of renewable sources of electricity during emergency shutdowns for uninterrupted operation of water management systems. The ability to purify drinking water during a power outage requires a backup power source. A mobile power plant, which is usually used as a backup power source during blackouts and emergencies, is known to cause environmental pollution and greenhouse gas emissions. The use of wind energy for these purposes requires the location of wind stations next to small treatment plants and households in order to quickly switch to autonomous mode, which does not always meet the territorial requirements and wind resources of the region. Open areas for the location of solar panels make the use of this type of renewable sources as a reserve in the conditions of military operations in Ukraine not quite suitable. On the basis of foreign experience in the use of small hydroelectric power plants (MHPs) and with different layouts of their location when working at sewage treatment plants, four possible options for providing electricity to sewage treatment plants and households during a blackout are proposed for the conditions of Ukraine. The option of the location of the MHP, which uses the energy of water transported through pipelines and which has successfully proven itself at operating treatment plants, is considered. Variants of using the pressure of an artesian well are proposed: MHP located in a vertical well that supplies artesian water under pressure; when an active artesian well supplies water under natural pressure at a constant flow rate to an above-ground (or underground) tank that simultaneously supplies normal household needs and a connected turbine-powered alternator. In addition, an option for the location of the MHPS was considered for the treatment and further use of rainwater sewage, including for the use of rainwater collected from "green roofs" in a tank-reservoir. The peculiarities of using this scheme are that it is easy to combine it with the case of using energy obtained from artesian wells. The proposed technological solutions allow for significant energy savings, including in places where high-quality water supply from artesian wells is possible, depending on the hydrogeological conditions of the area.

Mechanisms of Hydride Nucleation, Growth, Reorientation, and Embrittlement in Zirconium: A Review.

Zirconium (Zr) hydrides threaten the reliability of fuel assembly and have repeatedly induced failures in cladding tubes and pressure vessels. Thus, they attract a broad range of research interests. For example, delayed hydride cracking induced a severe fracture and failure in a Zircaloy-2 pressure tube in 1983, causing the emergency shutdown of the Pickering nuclear reactor. Hydride has high hardness and very low toughness, and it tends to aggregate toward cooler or tensile regions, which initiates localized hydride precipitation and results in delayed hydride cracking. Notably, hydride reorientation under tensile stress substantially decreases the fracture toughness and increases the ductile-to-brittle transition temperature of Zr alloys, which reduces the safety of the long-term storage of spent nuclear fuel. Therefore, improving our knowledge of Zr hydrides is useful for effectively controlling hydride embrittlement in fuel assembly. The aim of this review is to reorganize the mechanisms of hydride nucleation and growth behaviors, hydride reorientation under external stress, and hydride-induced embrittlement. We revisit important examples of progress of research in this field and emphasize the key future aspects of research on Zr hydrides.

Simulation of decay heat removal by active means following emergency shutdown in SFRs

Decay heat removal (DHR) is an important safety function in sodium-cooled fast reactors (SFRs). Dedicated systems are provided in the plant for performing DHR functionalities. Transients following reactor shutdown need to be studied to understand the dynamics of DHR systems, design the systems, and establish reactor safety. DHR systems can operate by active as well as passive means, thanks to the phenomenon of natural circulation. In the present work, a DHR system riding on the Balance of Plant (BoP) of a typical medium-sized SFR has been modeled and incorporated into the in-house developed plant dynamics code DYANA-P. DYANA-P already has models of primary and secondary circuits of SFR. With this code enhancement, the simulation of DHR in an integrated manner became possible. In particular, thermal models of the Moisture Separator Tank (MST), Decay Heat Removal Condenser (DHRC), and hydraulic model of the DHRC flow circuit were developed. Two-phase one-dimensional mass, momentum, and energy conservation equations with homogeneous flow assumptions were used to create the models. Simulation of SCRAM in a typical SFR has been carried out to demonstrate the applications of the modified code. Two different DHR deployment schemes were studied and compared – 1. Using DHR systems designed for high pressure of ∼170 bar, 2. Using DHR systems designed for low pressure of ∼15 bar. In the first scheme, reactor cooling was achieved at the desired rate of ∼20 K/h. In the second scheme, the reactor cooling rate will be higher at ∼60 K/h.

Preliminary Design of Insulation System for Superconducting Conductor Testing Facility

The Superconducting Conductor Testing Facility, which is developed to evaluate the reliability of engineering technology and safe operation in fusion reactor operation environment, is under engineering design by ASIPP. In case of an emergency shut-down like in succession of a quench, the voltage across the coil may rise to about 2.5 kV. The facility has to be reliably insulated. In this study, we present the preliminary design of the insulation system of the Superconducting Conductor Testing Facility, which includes turn and ground insulation. Since the magnet of the facility adopts the manufacturing process of “Wind&React”, the turn insulation material should withstand a heat treatment with temperature up to 650 °C. The insulation system is composed of S-glass fiber reinforced tape and vacuum-pressure impregnated in a DGEBF epoxy system. The mechanical properties are being subjected to investigations with respect to the design requirements and operating conditions. The test results are analyzed to verify the feasibility of the insulation system design.

A mathematical modeling in applying hydraulic element method for a hydraulic buffer and its performance analysis

The hydraulic buffer is the key to decreasing the impact force between the control rod drive system and the fuel assembly in the case of an emergency shutdown of a pressurized water reactor (PWR). This paper proposes a new theoretical modeling method for studying a multi-hole hydraulic buffer featured by the variable number and location of flow holes. Four typical hydraulic elements are proposed, given the relative position of the buffer’s spider and cup. The equations of each hydraulic element are firstly derived independently. Then the complete equations of the buffer are completed by assembling the equations of each hydraulic element. The numerical results obtained by this method show good agreement with the experiment results. In addition, the influence of several system parameters on the buffer’s dynamical characteristics is explored by using energy dissipation rate efficiency and energy dissipation rate power.

Development and Practical Implementation of Digital Observer for Elastic Torque of Rolling Mill Electromechanical System

The strategic initiative aimed at building “digital metallurgy” implies the introduction of diagnostic monitoring systems to trace the technical condition of critical production units. This problem is relevant for rolling mills, which provide the output and determine the quality of products of metallurgical companies. Making up monitoring systems requires the development of digital shadows and coordinate observers, the direct measurement of which is either impossible or associated with numerous difficulties. These coordinates include the spindle torque applied by the spring-transmitting torque from the motor to the rolling stand rolls. The development and research are conducted by the example of the electromechanical systems of the horizontal stand at the plate mill 5000. The stand electric drive characteristics are given, and the emergency modes that cause mechanical equipment breakdowns are analyzed that. The relevance of analyzing transient torque processes in emergency modes has been accentuated. The paper points to the shortcomings of the system for elastic torque direct measurement, including low durability due to the harsh operating conditions of precision sensors. It also highlights the need to install the measuring equipment after each spindle. The disadvantage of the previously developed observer is the function of calculating the electric drive speed derivative. This causes a decrease in noise immunity and signal recovery accuracy. The contribution of this paper is building a digital elastic torque observer that has advantages over conventional technical solutions, based on the theoretical and experimental studies. The technique for virtual observer adjustment was developed and tested in the Matlab-Simulink software package. For the first time, a comprehensive analysis was conducted for spindle elastic torques in emergency modes that caused equipment damage. An algorithm was developed for an emergency shutdown of a stand electric drive in the worst-case mode of strip retraction between work and backup rolls, due to the overlap of the strip on the roll. Further, the algorithm was tested experimentally. The criteria for diagnosing pre-emergencies was then justified. An adaptive motor-braking rate controller was developed. The developed observer and emergency braking system are in operation at the mill 5000. Long experimental research proved the efficiency of dynamic load monitoring and the reduction in the number of equipment breakdowns.

Modular maintenance instructions architecture (MMIA)

PurposeThe study consists of a literature study and a case study. The need for a method via which to handle instruction complexity was identified in both studies. The proposed method was developed based on methods from the literature and experience from the case company.Design/methodology/approachThe purpose of the study presented in this paper is to investigate how linking different maintenance domains in a modular maintenance instruction architecture can help reduce the complexity of maintenance instructions.FindingsThe proposed method combines knowledge from the operational and physical domains to reduce the number of instruction task variants. In a case study, the number of instruction task modules was reduced from 224 to 20, covering 83% of the maintenance performed on emergency shutdown valves.Originality/valueThe study showed that the other methods proposed within the body of maintenance literature mainly focus on the development of modular instructions, without the reduction of complexity and non-value-adding variation observed in the product architecture literature.

Wear-optimized partial stroke test for all-electric actuation systems

Offshore production industry is continuously growing. Access to unexplored resources at the seabed represents a challenge for current technologies to fulfill the demanding standards to guarantee safe and pollution-free solutions. All-electric actuation systems arise as an alternative for the actuation of Emergency Shutdown valves in subsea x-mas trees. Partial Stroke Test (PST) corresponds to a diagnosis test that actuates all-electric actuation systems by partially opening/closing the valve. The novelty of this paper lies in a wear-optimized PST approach to diagnose all-electric actuation systems, evaluated through experimental tests. The PST software is designed and implemented in the actuators controller, keeping the system complexity level unaltered. Torque vs position graphs are live generated while varying parameters such as valve travel, operation modes, and process fluid. As conclusion, the PST approach implemented on all-electric actuation systems has a higher diagnostic coverage over the state of the art for a Normally Closed operation mode by detecting valve leakage through pressure estimation. For a Normally Open operation mode, the diagnostic coverage reaches the state of the art without additional hardware. The results are obtained with a PST that does not unseal the valve, avoiding the most critical moments that add wear to it.