Energy Recovery Optimization by Means of a Turbine in a Pressure Regulation Node of a Real Water Network Through a Data-Driven Digital Twin

In recent years, various devices have been proposed for pressure regulation and energy recovery in water distribution and transport networks. To provide a real net benefit, they require a dedicated long-distance management system in order to carry on both hydrau- lic regulation and electricity production without direct human manual operations. This work presents a new proposal for the management of a pressure regulation system based on the PRS turbine. The proposal is applied to a real water distribution network, named Montescuro Ovest pipeline, at the San Giovannello station. The Real Time Control (RTC) logic currently applied at San Giovannello station is first presented and discussed. A new Advanced Real Time Control (ARTC) logic is then proposed, based on direct configura - tion of the turbine and the surrounding valves as computed by the solution of an optimiza- tion problem. In ARTC a digital twin, including the hydraulic model of the surrounding network, provides a one-to-one relationship between the configuration parameters and the state variables, i.e. flow rates and pressures. The digital twin model equations are continu - ously updated on the basis of the recorded measures. Besides providing almost identical performance to the current RTC logic in the current operational scenario, the improved ARTC is more robust, in that it guarantees better hydropower generation in modified oper- ational scenarios, as shown in specific tests. The proposed methodology constitutes a new approach to regulating the valves in hydroelectric plants which are currently regulated with traditional automation algorithms

Computationalcost Reduction of Robust Controllers Foractive Magnetic Bearing Systems

This work developed strategies for reducing the computational complexity of implementing robust controllers for active magnetic bearing (AMB) systems and investigated the use of a novel add-on controller for gyroscopic effect compensation to improve achievable performance with robust controllers. AMB systems are multi-input multi-output (MIMO) systems with many interacting mechanisms that needs to fulfill conflicting performance criteria. That is why robust control techniques are a perfect application for AMB systems as they provide systematic methods to address both robustness and performance objectives. However, robust control techniques generally result in high order controllers that require high-end control hardware for implementation. Such controllers are not desirable by industrial AMB vendors since their hardware is based on embedded systems with limited bandwidths. That is why the computational cost is a major obstacle towards industry adaptation of robust controllers. Two novel strategies are developed to reduce the computational complexity of singlerate robust controllers while preserving robust performance. The first strategy identifies a dual-rate configuration of the controller for implementation. The selection of the dualrate configuration uses the worst-case plant analysis and a novel approach that identifies the largest tolerable perturbations to the controller. The second strategy aims to redesign iv the controller by identifying and removing negligible channels in the context of robust performance via the largest tolerable perturbations to the controller. The developed methods are demonstrated both in simulation and experiment using three different AMB systems, where significant computational savings are achieved without degrading the performance. To improve the achievable performance with robust controllers, a novel add-on controller is developed to compensate the gyroscopic effects in flexible rotor-AMB systems via modal feedback control. The compensation allows for relaxing the robustness requirements in the control problem formulation, potentially enabling better performance. The effectiveness of the developed add-on controller is demonstrated experimentally on two AMB systems with different rotor configurations. The effects of the presence of the add-on controller on the performance controller design is investigated for one of the AMB systems. Slight performance improvements are observed at the cost of increased power consumption and increased computational complexity

Frit-based controller tuning of a dc-dc boost converter

This report presents a Fictitious Reference Iterative Tuning design for a DC-DC boost converter based on a Model-Free approach. A Fictitious Reference Iterative Tuning is a data-driven controller tuning technique that uses one-shot experimental data to construct the input controller of an undefined plant model. Fictitious Reference Iterative Tuning ensures that the plant output fits the reference model output by optimizing the performance index, which comprises a fictional reference output calculated from oneshot experimental input-output results. A DC-DC boost converter is a step-up converter with an output voltage higher than the input voltage. This converter system has a nonlinear dynamic behaviour, as it works in switch mode. The modelling of a Boost converted system is first provided to form data collection and fictitious reference signal derivation. The configuration of a nonlinear system discussed here is assumed to be known, but the parameters remain unknown. Design and simulation analyses using MATLAB software have been conducted for results validation and verification. Furthermore, we formulate the algorithm for determining the optimal controller parameters based on the Model-Free approach. Lastly, we verify and compare the proposed tuning technique’s output with any controller design techniques

Studies on Data-Driven Controller Tuning for Cascade Control Systems

13301甲第4623号博士（工学）金沢大学博士論文本文Full 以下に掲載：Journal of Robotics and Mechatronics 28(5) pp.739-744 2016. FUJI TECHNOLOGY PRESS LTD. 共著者：Huy Quang Nguyen, Osamu Kaneko, Yoshihiko Kitazak

Coordinated Voltage Control in Modern Distribution Systems

Modern distribution systems, especially with the presence of distributed generation (DG) and distribution automation are evolving as smart distribution systems. Distribution management systems (DMSs) with communication infrastructure and associated software and hardware developments are integral parts of the smart distribution systems. With such advancement in distribution systems, distribution system voltage and reactive power control are dominant by Volt/VAr (voltage and reactive power) optimisation and utilisation of DG for system Volt/VAr support. It is to be noted that the respective controls and optimisation formulations are typically adopted from primary, secondary and tertiary voltage and reactive power controls at upstream system level. However, the characteristics of modern distribution systems embedded with high penetration of DG are different from transmission systems and the former distribution systems with uni-directional power flow. Also, coordinated control of multiple Volt/VAr support DG units with other voltage control devices such as on-load tap changer (OLTC), line voltage regulators (VRs) and capacitor banks (CBs) is one of the challenging tasks. It is mainly because reverse power flow, caused predominantly by DG units, can influence the operation of conventional voltage control devices. Some of the adverse effects include control interactions, operational conflicts, voltage drop and rise cases at different buses in a network, and oscillatory transients. This research project aimed to carry out in-depth study on coordinated voltage control in modern MV distribution systems utilising DG for system Volt/VAr support. In the initial phase of the research project, an in-depth literature review is conducted and the specific research gaps are identified. The design considerations of the proposed coordinated voltage control, which also uses the concept of virtual time delay, are identified through comprehensive investigations. It emphasises on examining and analysing both steady-state and dynamic phenomena associated with the control interactions among multiple Volt/VAr support DG units and voltage control devices. It would be essential for ensuring effective coordinated voltage control in modern distribution systems. In this thesis, the interactions among multiple DG units and voltage control devices are identified using their simultaneous and non-simultaneous responses for voltage control through time domain simulations. For this task, an analytical technique is proposed and small signal modelling studies have also been conducted. The proposed methodology could be beneficial to distribution network planners and operators to ensure seamless network operation from voltage control perspective with increasing penetration of DG units. Notably, it has been found that the significant interactions among multiple DG units and voltage control devices are possible under conventional standalone, rule-based, and analytics based control strategies as well as with real-time optimal control under certain system conditions. In the second phase of the research project, the proposed coordinated voltage control strategy is elaborated. The control design considerations are fundamentally based on eliminating the adverse effects, which can distinctly be caused by the simultaneous and non-simultaneous responses of multiple Volt/VAr support DG units and voltage control devices. First, the concept of virtual time delay is applied for dynamically managing the control variables of Volt/VAr support DG units and voltage control devices through the proposed control parameter tuning algorithm. Because it has been found that the conventional time-graded operation cannot eliminate the adverse effects of DG-voltage control device interactions under certain system conditions. Secondly, the distinct control strategies are designed and tested for effectively and efficiently coordinating the operation of multiple Volt/VAr support DG units and voltage control devices in real-time. The test results have demonstrated that the proposed coordinated voltage control strategy for modern MV distribution systems can effectively be implemented in real-time using advanced substation centred DMS. The proposed coordinated voltage control strategy presented in this thesis may trigger paradigm shift in the context of voltage control in smart distribution systems. In the final phase of the research project, short-term and/or long-term oscillations which can be possible for a MV distribution system operation embedded with Volt/VAr support DG are discussed. Typically, the short-term oscillations are occurred due to interactions among different DG units and their controllers (i.e., inter-unit electro-mechanical oscillations in synchronous machine based DG units) while the long-term oscillations occurred due to DG-voltage control device interactions. Also, sustained oscillations may occur due to tap changer limit cycle phenomenon. The concept of alert-state voltage control is introduced for mitigating the sustained oscillations subjected to OLTC limit cycles in the presence of high penetration of DG. The investigative studies in this thesis further emphasise the requirements of supplementary control and other mitigating strategies for damping the oscillations in modern active MV distribution systems. The proposed research will pave the way for managing increasing penetration of DG units, with different types, technologies and operational modes, from distribution system voltage control perspective

System identification and control of the standpipe in a cold flow circulating fluidized bed

Circulating fluidized beds (CFB) have been widely applied to many areas of industry such as chemical processing, petroleum refining, catalytic cracker processing, power generation, and waste treatment.;Recently, a mathematical model of the CFCFB standpipe was successfully developed and tested using an extended Kalman filter (EKF) and an Hinfinity estimator algorithm. Using this standpipe mathematical model requires a solids circulation rate (SCR) to be a measurable variable offered from a spiral installed in the standpipe of the CFCFB. In this research, a linear state space system model is developed in order to estimate the solids circulation rate, using a least squares estimator and a subspace algorithm.;In this research, a sliding mode estimator is applied in order to estimate the states and the bed-height using a mathematical model with the estimated SCR from the pressure drop profiles. The sliding mode estimator uses the Lyapunov stability criteria to obtain a gain that drives the estimator dynamic to a defined sliding surface, which usually is the first or second order differential equation of the error dynamic defined as the difference between the mathematical model equation and the estimator dynamic.;Although an entire CFCFB dynamic system has not been built, extensive experimental data sets are available, so a neural network is a strong candidate in building the entire CFCFB system dynamic model. In this research, the neural network is used to obtain the entire system model of the CFCFB for simulation purposes. In the neural network, back-propagation algorithms are adapted and tansig functions are used for the neurons. (Abstract shortened by UMI.)

Application of Advanced Early Warning Systems with Adaptive Protection

This project developed and field-tested two methods of Adaptive Protection systems utilizing synchrophasor data. One method detects conditions of system stress that can lead to unintended relay operation, and initiates a supervisory signal to modify relay response in real time to avoid false trips. The second method detects the possibility of false trips of impedance relays as stable system swings “encroach” on the relays’ impedance zones, and produces an early warning so that relay engineers can re-evaluate relay settings. In addition, real-time synchrophasor data produced by this project was used to develop advanced visualization techniques for display of synchrophasor data to utility operators and engineers

Modelling performance in a Balanced Scorecard : findings from a case study

Cet article s'intéresse à la mise en place de l'approche dite du "Balanced Scorecards" dans des unités opérationnelles plutôt qu'au niveau d'une direction générale. Il s'appuie sur une étude de cas. On propose de traiter les questions relatives à la coordination, à la fixation des objectifs et au contrôle en s'appuyant sur une méthodologie originale pour construire le modèle d'interaction entre les différentes entités de l'organisation. Cette méthodologie fait une part importante à l'apprentissage organisationnel permettant ainsi une compréhension mutuelle des degrés de liberté individuels et une meilleure observation réciproque. Cette approche "horizontale" est mieux adaptée à ce type de contexte que l'approche "verticale" plus traditionnelle du BCS.Pilotage;Tableaux de bord;Incitations;Apprentissage organisationnel