Control Of Operation Modes Research Articles

Energy consumption analysis of trains based on multi-mode virtual coupling operation control strategies

Urban rail transit, as a main mode of travel, has always been concerned with the balanced relationship between energy consumption and transport efficiency. The advent of the virtually coupled train set (VCTS) has significantly enhanced the efficiency of existing railway lines. Both energy consumption and comfort during the operation of VCTS control technology have emerged as significant challenges for the development of VCTS since the inception of onsite testing. A review of the current research status of VCTS control systems has revealed that the majority of current formation control systems are focused on the safe operation of formation trains, the stability of train control systems, and safe train separation models. However, a case study has shown there is a strong correlation between train operating intervals, train control strategies, and train operating energy consumption. Therefore, it is necessary to design and plan the operation modes of formation trains for different train operation requirements. This paper presents four distinct control modes, developed through the integration of the most prevalent VCTS control strategies, operational modes, and operational requirements. The design of these control modes is guided by considerations of energy consumption, safety, and comfort during train operation. A case study of Beijing Subway Line 11 revealed a significant correlation between energy consumption, control mode, and safety under different control modes. In particular, the correlation between train running intervals and energy consumption in a high-precision tracking state provides valuable technical support for the future operation of VCTS technology in different periods, scenarios, and environments.

Application of artificial intelligence technologies at substantiation of effective control algorithms for the electrical engineering complex of urban electric transport traction electrical equipment

Background. Studies on the current state and development trends of urban ground public electric transportation in Russia highlight the urgent need for innovative technologies. These innovations should focus on designing and operating new types of rolling stock, traction electrical equipment, and promising types of electric traction. At the same time, special attention should be paid to building autonomous control systems for electric transportation using artificial intelligence technologies. Aim. This study aims to explore the application of neural networks to develop algorithms for effectively controlling the electrical engineering complex of traction electrical equipment in urban ground rail electric transport. Materials and Methods. The research utilized data from studies on the traction electrical equipment modes of rolling stock. These studies were conducted through both computer simulations and field experiments under real operating conditions of urban electric transport using different control algorithms. By applying probability theory and mathematical statistics, the analysis identified the correlations between operational and energy parameters of rolling stock movement and the operational mode of its traction electrical equipment. Results. The identified correlation dependencies informed the design of an effective network architecture, including its size and complexity, as well as the composition of their training samples. This led to the development of an original, simplified algorithm for determining effective control parameters for the electrical complex of traction electrical equipment during the movement of a vehicle on a given section of track. Conclusion. The research concluded that using “simple” neural networks for calculating the parameters of effective control of traction electrical equipment operation modes in urban electric transport provides higher speed and sufficient accuracy compared to complex neural network models. These results are valuable for developers of intelligent control systems for streetcar transportation.

A hierarchical energy management strategy for DC microgrid hybrid energy storage systems based on fractional-order sliding mode controller

A hierarchical energy management strategy (EMS) for a fuel cell (FC)-supercapacitor (SC)‑lithium battery hybrid energy storage system (HESS), based on a fractional-order sliding mode controller (FOSMC), is proposed to address the nonlinear behavior of low-voltage direct current (DC) microgrid HESS. To fully exploit the energy of the SC, the system management layer divides the EMS into maximum power operation mode and state machine control algorithm operation mode. For the first time in equipment control layer, a FOSMC, more suitable for handling nonlinear characteristics, is employed, and its stability is evaluated using the Lyapunov method. Finally, a 48 V HESS experimental platform is constructed for validation, demonstrating that the proposed EMS enhances the stability, response speed, and robustness of the HESS. Compared to conventional sliding mode controller (SMC) and integral sliding mode controller (ISMC), the adoption of a FOSMC reduces the steady-state error of the bus voltage by at least 9.1 % and increases the response speed by at least 11.1 %, while exhibiting good robustness to external disturbances and uncertainties in controller parameters. This fills the current research gap in parameter robustness validation.

An operating mode control method for photovoltaic (PV) battery hybrid systems

Depending on the PV power, load power, and battery status, the system may operate in different modes. The control loop may have to switch between operating modes. In practice, it is difficult to implement control loop switching because the transition and dynamic process are difficult to control. As a result, this paper presents a generalized mode control method that avoids loop switching across modes. First, system structure and topology are introduced. The operating conditions for both grid-connected and off-grid modes are then divided into six sub-cases. Furthermore, the control architecture, control loop, and reference transition for various scenarios are described. Finally, an experimental platform is built, and the results are presented to verify the proposed method.

Rule-Based Operation Mode Control Strategy for the Energy Management of a Fuel Cell Electric Vehicle

Hydrogen, due to its high energy density, stands out as an energy storage method for the car industry in order to reduce the impact of the automotive sector on air pollution and global warming. The fuel cell electric vehicle (FCEV) emerges as a modification of the electric car by adding a proton exchange membrane fuel cell (PEMFC) to the battery pack and electric motor, that is capable of converting hydrogen into electric energy. In order to control the energy flow of so many elements, an optimal energy management system (EMS) is needed, where rule-based strategies represent the smallest computational burden and are the most widely used in the industry. In this work, a rule-based operation mode control strategy for the EMS of an FCEV validated by different driving cycles and several tests at the strategic points of the battery state of charge (SOC) is proposed. The results obtained in the new European driving cycle (NEDC) show the 12 kW battery variation of 2% and a hydrogen consumption of 1.2 kg/100 km compared to the variation of 1.42% and a consumption of 1.08 kg/100 km obtained in the worldwide harmonized light-duty test cycle (WLTC). Moreover, battery tests have demonstrated the optimal performance of the proposed EMS strategy.

A low voltage microgrid protection scheme using digital instrument transformers

AbstractModern power systems have several measurement devices for reliable, safe, and improved operation and control. Due to the high infiltration of inverter‐based resources, protecting modern power systems has become challenging. This paper proposes a new protection scheme based on the computation of ‘discrepant impedance’ using real‐time protocol services for data exchange. The sampled values of voltages and currents are transmitted to a central processing unit to implement the protection scheme. With the development of digital instrument transformers (IEC 61869‐9), the current and voltage samples are directly interfaced wired or wirelessly to the IEC 61850‐9‐2 process bus. The proposed protection scheme is validated with grid forming and grid following inverters on Consortium for Electric Reliability Technology Solutions (CERTS) microgrid network using a real‐time digital simulator. The protection scheme is independent of the type of energy sources and their control philosophy, operation modes and topology of the microgrid network.

Utilization of Battery Energy Storage Systems (BESS) in Smart Grid : A Review

The uncertainty in fuel cost, the ageing of most existing grid, the lack of utilities’ supply capacity to respond to the increasing load demand, and the lack of automatically power restoration, accelerate the need to modernize the distribution network by introducing new technologies, putting the smart grid (SG) on spot. The aim of this paper is to carry out a detailed survey of the major requirements of (SG) and discuss the operational challenges arising from the integration of distributed generation (DG) in distribution networks (DN). These requirements dictate the necessity to review the energy and communication infrastructure, the automatic control, metering and monitoring systems, and highlight the features of smart protection system for a robust and efficient distribution grid. In addition, the paper aims to classify the energy storage systems (ESS) and explain their role for utilities, consumers and for environment. This includes the pumped hydro systems (PHS) and compressed air systems (CAS), battery energy storage systems (BESSs), double layer and superconductive capacitors, and electric vehicles (EVs). Since BESSs emerged as one of the most promising technology for several power applications, the paper presents an overview of their main features, management and control systems and operational modes. A survey about the utilization of BESSs in power system is presented.

Low Carbon Operation Control Technology for Smart Parks Combined with Intelligent Optimization Algorithms

Abstract This paper first calculates carbon emissions based on the carbon emission factor method and other methods and constructs a linear programming model for low-carbon operation of smart parks with economy, independence, and carbon emissions as objective functions, and constrains them from four aspects: power grid, natural gas pipeline network, equipment output, and energy storage battery limit. The problem can be solved using the sparrow optimization algorithm. Finally, the carbon emissions, power dispatching, and power consumption of the sample parks under the low-carbon operation control mode were analyzed. The results show that the carbon emissions of the park are reduced by 2035.93kg, and the total operating cost is reduced by 1680.11 yuan during the typical daily operation in summer after the intelligent optimization algorithm is used. The park’s carbon emissions decreased by 1686.53kg, and the total operating cost decreased by 1582.42 yuan during the typical daily operation in winter. The importance of this study lies in the low-carbon and modernization of smart parks.

Short-Term Prediction for Indoor Temperature Control Using Artificial Neural Network

Recently, data-based artificial intelligence technology has been developing dramatically, and we are considering how to model, predict, and control complex systems. Energy system modeling and control have been developed in conjunction with building technology. This study investigates the use of an artificial neural network (ANN) for predicting indoor air temperature in a test room with windows on an entire side. Multilayer perceptron (MLP) models were constructed and trained using time series data obtained at one-second intervals. Several subsampling time steps of 1 s, 60 s, 300 s, 600 s, 900 s, 1800 s, and 3600 s were performed by considering the actual operation control mode in which the time interval is important. The performance indices of the neural networks were evaluated using various error metrics. Successful results were obtained and analyzed based on them. It was found that as the multi-step time interval increases, performance degrades. For system control designs, a shorter prediction horizon is suggested due to the increase in computational time, for instance, the limited computing capacity in a microcontroller. The MLP structure proved useful for short-term prediction of indoor air temperature, particularly when control horizons are set below 100. Furthermore, highly reliable results were obtained at multi-step time intervals of 300 s or less. For the multivariate model, both calculation time and data dispersion increased, resulting in worsened performance compared to the univariate model.

Techno-Economic Analysis of the Peak Shifting Strategy Based on Time-of-Use Tariff for Cold Stores

The energy consumption in the cold store is growing day by day, 70% of which is consumed by the refrigeration system. Meanwhile, a significant amount of electricity generated by power plants is wasted during off-peak periods. Demand-side management (DSM) provides a viable solution for addressing the problem of the time and space inconsistency between energy supply and consumption, hence improving overall system efficiency. In this paper, an artificial intelligence model is developed for accurate cooling load forecasting. On this basis, a peak shifting control strategy with two optional modes combining temperature setpoint control and operation mode control is then proposed to realize cost reductions. Taking a large-scale cold store as a case study, the cooling capacity supply and temperature variation within two typical working days are investigated to illustrate the feasibility and applicability of the strategy. Detailed thermodynamic and thermo-economic analyses of the proposed strategy are then carried out to demonstrate the control effect. The results show that both modes have good peaking performances and the average cost reduction rate of the two modes reaches 40% and 13.4%, respectively.

Identifying suitable DC system models for an independent design of VSC controllers in MTDC grids

In AC-multi-terminal DC (MTDC) systems, if converter controllers are designed individually, the interactive system modes stemming from the dynamic couplings among the converters and the DC system components may result in the instability of the interconnected system (INTSYS). This paper presents a comparative system-level study to determine the suitable models for an individual design of converter controllers to prevent INTSYS instability. The goal is to identify suitable individual system (INDSYS) models that do not contain the internal dynamics of adjacent converters and only include the coupling dynamics corresponding to the interactive system modes among the converters. The use of these models for control design will result in the dynamic response of the INTSYS being close to that of the INDSYS models. Furthermore, such models can ensure INTSYS stability when converter controllers are designed individually without requiring the complete model of the INTSYS or internal dynamics of the adjacent converters. Both the master–slave and the droop control modes of operation are analyzed, and specific INDSYS models among those available in the literature are recommended for each operation mode. Time-domain simulations in PSCAD validate the accuracy of the INDSYS models. Furthermore, eigenvalue analysis along with the participation factor and sensitivity analyses for a large set of control parameters are employed to evaluate the efficacy of the recommended models.

System identification and control of the ground operation mode of a hybrid aerial–ground robot

System identification and control of the ground operation mode of a hybrid aerial–ground robot

Efficiency Improvement Methods of Independent Wind Electric Installation with Programmed Control

Relevance justification of effective automated control method of independent wind electric installation on the basis of voltage feedback and parameters of inductance x1, reduced inductance x′2, phase resistance of starter winding r1, reduced phase resistance of starter winding r′2 is made under different conditions of electric installation operation to minimize the time of phase voltage regulation transient process of wind turbine generator, that promotes quality improvement of self-excitation and reliability indicator improvement of energy supply of the basic control under insufficient information of meteorological and electric power conditions significaltly changing in time. The review of basic ways to control independent wind electric installations which has shown their negative sides is made, that revealed their negative sides like low execution speed and reliability, lack required voltage control quality, idle excitation current distortion leading to voltage sine curve distortion of the asynchronous generator, and providing no relay protection or the automatic switch and automation operating mode control. The differential equation of wind turbine rotor angular speed is composed. Transfer functions of dynamic links for generator phase voltage automatic control of wind turbine taking into account wind speed, rotor winding current, inductance, rotor winding phase resistance, reduced stator winding phase resistance are plotted. The block diagram imitating model is constructed and schedules of transient processes with zero and non-zero delay were plotted providing delay negative effect development decision making on stability of wind turbine generator phase voltage and to establish method of relevant system preparation to external disturbances vanishing above mentioned disadvantage.

Method of determination of the railway rolling stock coordinates within the track circuit

This work aims to solve one of the essential problems in railway transport – control over the position of moving units within the race. A method of constant monitoring of the track circuit with a determination of the coordinate of the train shunt placement in the shunt mode of working is proposed to solve this problem. Since the model includes the primary parameters of the track circuit, which may change their values over time, it is suggested to determine them in another (normal) working mode of the track circuit. Therefore, according to the proposed model, the secondary and primary parameters of the track circuit are first determined in the track circuit's normal work mode. Next, already in the shunt mode of its work, the obtained parameters are used to determine the coordinates of the moving unit. According to this method, firstly, the work mode of the track circuit is determined, which consists in determining the state by its input impedance. This step is performed in two stages. In the first stage, based on the state of the track relay, the fact that the track circuit doesn't work in normal mode is verified. In the second stage, the shunt mode is separated from the control mode by the value of the track circuit input impedance. In the shunt mode of the track circuit operation, the coordinate and, if necessary, the speed and acceleration of the moving unit located within the given track circuit are determined. In the normal mode of the track circuit line operation, the values of its secondary parameters are specified based on the measured values of current, voltage, and phase shift between them. This operation is performed to increase the precision of the speed and acceleration determination by solving an inverse problem. In the control mode of the track circuit operation, it is possible to determine the coordinates of damage. This method does not require a significant volume of calculations. It makes it possible to determine the secondary parameters of the track circuit and through them, the resistance of its insulation. Using this method makes it possible to determine the distance and, if necessary, the speed and acceleration of a moving unit within the track circuit. The resulting parameters can be used for positioning moving rolling stock on runs between stations. The application of this method can also be useful in sections of the railway crossings approach to implement a fixed warning time. In addition, thanks to the use of the outlined model, in the control mode of the track circuit operation, is possible to determine the damage coordinate. It will make it possible to reduce the time spent on damage detection and elimination.

Selecting a Demand Management Strategy for Efficient Operation of a Commercial and Industrial Microgrid

The recent years have seen a tendency toward a situation in which some consumers leave the Unified Energy System (UES) of Russia. Under such conditions, commercial and industrial microgrids (CIMs) are a solution that helps secure the power system reliability. A CIM is a local power area connected to the UES by a power line and containing its own power plants, an electric network system, and a consumer. The problem of controlling the CIM electrical operation modes subject to fulfilling the condition of maintaining the power flow from the UES becomes of special relevance if the CIM contains power plants operating on renewable energy sources. In this case, active consumers and energy storage systems play an important role in keeping a power balance in the CIM. The purpose of the study is to select a demand management program, which is a constituent part of the strategy for optimal control of the CIM operation modes aimed at maintaining the power flow from the UES within the specified range.

Study of coordinated control strategy for hybrid AC–DC microgrid in islanding mode

As a kind of generation and distribution system with autonomous control, AC–DC hybrid microgrid plays a pivotal role in the transformation and development of modern power grids. To address the problems of microgrid system instability that occur in islanding mode, the study proposes a coordinated control strategy for hybrid AC/DC microgrid in islanding mode. First, the bidirectional AC/DC interconnection converter is modelled and parametrically designed; second, the control strategy of the interconnection converter in islanding mode is raised, including both active power control with double-loop control and seamless switching of operation modes with pre-synchronous control, and in the end, the effectiveness of the strategy is examined. The data display that under this strategy, the real and reactive power output gaps between the micro sources in the hybrid microgrid do not exceed 0.01 kW and 0.03 kVAR, respectively, and the current during islanding switching is more stable up to 32 A. This shows that the strategy effectively improves the shortcomings of the traditional regulation method, realizes the accurate distribution of real and reactive power, improves the power sharing between DC and AC subgrids, strengthens the stability and reliability of the hybrid microgrid, and helps to promote the technological progress of the hybrid microgrid and escorts the efficient and green development of the smart grid.

A two-stage coordinated line loss reduction model based on elephant herding optimization and second-order cone programming

Aiming at the problem of high line loss caused by the access station of distributed generation (DG), a two-stage coordinated line loss reduction model based on elephant herding optimization (EHO) and second-order cone programming (SOCP) was put forward by using static var generators (SVG) and energy storage system (ESS) to reduce the line loss from reactive and active power aspects, respectively. Firstly, based on the elephant herding optimization, the location model of distributed generation, SVG and ESS was constructed and determined. On this basis, a cooperative line loss reduction model is proposed, which takes into account multiple line loss reduction methods, such as SVG reactive power compensation device and energy storage. By properly dealing with power flow constraints of distributed generation, the influence of operation control mode of distributed generation on optimal distribution and line loss reduction is precisely explained. The constraint is transformed into a second-order cone programming problem by using second-order cone relaxation. In this way, the coordinated reduction of line loss is realized, and the goal of line loss minimization and voltage stability maximization is achieved. Finally, a practical station is taken as an example to verify the correctness of the proposed model and algorithm and the effectiveness of the proposed method.

A high-reliability SEPIC converter with reconfigurable voltage conversion gain

A high-reliability SEPIC converter with reconfigurable voltage conversion gain is proposed, which is composed of a basic SEPIC converter and n extended units. Adopting an interleaved parallel structure on the input side of the converter not only achieves leg-level hardware redundancy but also reduces the input current ripple. When one branch of the converter suddenly changes or fails, due to the redundancy between branches, the converter can still to work, and the duty cycle of the other branches can be readjusted by using PI control without changing output voltage and power of the converter. This feature undoubtedly presents the reliability of the converter. On the contrary, when the converter works in normal operation, it can also actively control operation mode of each branch to achieve reconfigurable voltage conversion gain function. In addition, since the duty cycles of the switches are not limited, voltage conversion gain of the converter is widely, which makes it more suitable for the occasions where the input side fluctuates greatly. Section 2 details the working principle of the proposed converter and the voltage and current stress on components. Then, the reconfigurable voltage conversion gain of the converter and its high reliability characteristics are analyzed in Section 3. Finally, the correctness of the theoretical analysis is verified by experiments.

Development of Systems Energy Research: N.I. Voropai’s Contribution

The scientific works of N.I. Voropai in the systems research methodology of power engineering, including the key properties of electric power systems (EPSs) and development of their analysis methods, are analyzed. Special attention is paid to EPS reliability, survivability, stability, and cybersecurity. A scheme of cause-and-effect relations between various types of stability violations, including new ones, that occur in modern EPSs as a result of the ongoing innovation-technological transformations in them, and the corresponding states of EPS, is drawn up. The studies of EPS heterogeneity during transients, which manifest themselves as different degrees of coherence in the motion of generators, are considered. These studies are aimed, in particular, at identifying the groups of coherent generators and revealing weak cut sets between them. The studies of EPS dynamic properties and mechanisms governing the development of large-scale cascade accidents in the power systems of Russia are analyzed. Methods and systems for control of power system operation modes, including those when the power system properties undergo transformation, as well as emergency control methods and systems, are considered. A methodology and models for substantiating the development of power systems under modern conditions, as well as energy security analysis and assurance methods are presented. The prospects for development of interstate electric links between the Unified Energy System of Russia and the power systems of neighboring countries, and for the formation of Eurasian and Global super-grids are considered, and the main results obtained in the field of establishing integrated multi-energy systems are given. The invaluable contribution N.I. Voropai has made in the development of systems studies in power engineering and its importance for applied problems is shown.

Analysis and Design of Integrated Intelligent Anti-error System for Substation

A new comprehensive intelligent anti-error system that meets the requirements of smart substations is proposed. This new system can overcome the problem that the microcomputer anti-error system lacks operation error prevention technology for secondary equipment and also lacks operation and maintenance operations under the integrated control operation mode. Firstly, this paper analyzes the characteristics of the anti-error system, and the principle function of the judgment model. And then, an anti-misoperation process system is established for work scenarios such as information collection and monitoring, remote control operation error prevention, sequential control operation error prevention, local operation error prevention, secondary equipment, operation, and maintenance. This paper finally builds a realtime online anti-error system that can be intelligently analyzed for the whole business process to ensure the safety of intelligent substation equipment operation.