Power System Simulation Software Research Articles

Selection of power supply scheme for controlled excitation converters in traction electric motors of single-phase DC electric locomotives

The article focuses on the development of an effective design and algorithms for automatic control of singlephase DC electric locomotives according to the laws of constant traction force and power without switching electrical devices within power electric circuits. Methods of mathematical modelling for electromagnetic, electromechanical, and mechanical processes by MatLab, Simulink, and SimPowerSystems software were used to address this problem. The nonlinearities of the magnetisation curve were taken into account, along with the influence of eddy currents from the coils of the main and additional poles in traction motors. Structural and parametric synthesis of a power electrical circuit and control algorithms by controlled bridge IGBT converters were used in the simulation. The object of the research was an electrotechnical complex, including a 9840 kW three-stack electric locomotive 3ES5K “Ermak”. On the basis of the research results, it is recommended to use a power electrical circuit with two reversible converters for each of the three sections on the electric locomotive. These converters provide power to four 820 kW traction motors and a group power supply for controlled bridge IGBT converters shunting the field coils for axial traction control. The calculations confirmed the applicability of a scheme for individual control of traction electric motors and excitation currents, ensuring a smooth increase in the traction force of an electric locomotive. The developed algorithm of axial traction control ensures a smooth increase in this force and creates the optimal conditions for coupling the wheels of an electric locomotive with rails. These solutions can be used in the manufacture and modernisation of new and existing electric locomotives

Reinforcement Learning in Power System Control and Optimization

Abstract Reinforcement learning (RL) is area of Machine Learning (ML) and part of wide-range portfolio of the Artificial intelligence (AI) methods. Besides the explanations of the concepts and principles of RL, in the paper are presented practical RL models for control and optimizing operation of power system – controlling tap-changers for maintain voltage levels and model for techno-economical optimizing operation of energy storages of households in microgrid. Trained RL agent in the practical example synchronizes operation of tap-changers to maintain satisfactory voltage level for the consumers, even in the network with distributed generation. Energy storages are in wide use in households, especially in the combination with PV. In the second example, microgrid’s energy management system (EMS) RL agent after learning process act in the simulated environment with variable electrical energy prices, variable load profiles and efficiency of PV modules of households to maximize profit for the houseowners in the microgrid. Agent controls charging and discharging of energy storages and obtain maximal benefit in randomly determined conditions of microgrid operation and different tariff situations. Models are implemented in the Python programming environment Python with specialized power system simulation software (Pandapower) and RL libraries (RLib, OpenAI).

A Power System Reserve Configuration Solution That Satisfies the Frequency Stability Constraint Under the Given New Energy Index

Aiming at the problem of frequency stability and voltage stability of a new power system, this paper provides a new energy index method based on frequency stability constraints in the standby category of the new power system. Several concepts, such as maximum disturbance constraint and minimum reserve capacity, are proposed. Two constraints, power balance, and frequency constraint are set, and the factors to be considered, such as load frequency effect, security and control measure, demand-side response, and primary frequency change amplitude of each type of unit, are specified. Through analysis and study of regional data, the peak load of power grid new energy is a given index in a given scenario, according to the research of regional power grid in each category of a frequency modulation amplitude, the installed capacity is set to build a solution, to the problem of frequency stability caused by clean energy consumption, thus determine the ratio of each category of power output and heat capacity. Finally, according to the actual data of one regional power grid, the PSD-BPA power system simulation software is used to verify the effectiveness of the method.

Research on Calculation Method of Energy Storage Capacity Configuration for Primary Frequency Control of Photovoltaic Power Station

An energy storage capacity allocation method is proposed to support primary frequency control of photovoltaic power station, which is difficult to achieve safe and stable operation after a high proportion of photovoltaic connected to public power grid. In this paper, by taking the photovoltaic power plant containing energy storage as an example, and based on the fluctuation characteristics of photovoltaic power output and the performance requirements of primary frequency control response, the required battery storage capacity of photovoltaic power station for primary frequency control is calculated without considering the power abandonment and power limitation conditions, and the typical case is established based on power system simulation software to verify the reasonableness and effectiveness.

Optimal Modeling for Dynamic Response of Energy Storage Systems

Using energy storage systems with solar and wind energy can overcome the intermittence of these types of renewable energy. According to the regulations made by the utilities in each country, facilities that are connected to the power grid should be assessed on how they influence the power grid. Power system simulation software such as PSS/E, DIgSILENT, and DSATools are widely used by utilities. The default models in these kinds of software are defined by the Western Electricity Coordinating Council (WECC). Improper parameters will produce estimation results that are not informative, and the utilities may make wrong decisions. To avoid this problem, this study designed the process to find suitable parameters for real energy storage systems. Using models created by the WECC and reducing it according to the application condition decreased the burden of the optimization process. We used two algorithms and their improved versions to search for an appropriate value of variables that can represent a real energy storage system. We also compared the results between the BESS simplified model that we built and the original model from PSS/E.

Research on the judging method of the T-connected transmission line fault branch

When the T-connected transmission line fails, there is a certain relationship between the phases of the three-terminal power frequency fault current, which can be applied to protect the current differential of the T-connected line. In this paper, using the MATLAB/Simulink electric power system simulation software, when the T-connected transmission line is faulty, the power frequency fault current variation law monitored at the installation point is deeply studied, and the judgment method of the T-connected transmission line fault branch based on the power frequency current is proposed.

Voltage Sag Mitigation Effect Considering Failure Probability According to the Types of SFCL

The development of industrial technology is based on electronic devices that are sensitive to power quality. Thus, the demand for high-quality and reliable power supplies is increasing. Voltage sag results in severe problems in the manufacturing process of power quality-sensitive industrial loads. When a fault occurs in a multi-ground power distribution system, the magnitudes of the fault current and voltage sag in the faulted and nonfaulted feeders become high. Hence, installing a superconducting fault current limiter (SFCL) is an effective method of compensating for fault current limitation and voltage sag. This study evaluates the effects of improving the magnitude, duration, and frequency of the voltage sag according to the type of SFCL used. First, a fault in the power distribution system is analyzed using PSCAD/EMTDC, a power system simulation software, according to the fault current-limiting element (CLE) and the type of SFCL. Second, the expected voltage sag frequency caused by a feeder fault in the power distribution system is assessed. Finally, the voltage sag improvement effect according to the CLE and the type of SFCL are compared. The trigger-type SFCL with a resistor as a CLE has been evaluated and found to be effective in improving voltage sag.

Performance investigation of reweighted zero attracting LMS-based dynamic voltage restorer for alleviating diverse power quality problems

Dynamic voltage restorer (DVR) has proven to be the most coherent, effective and economic answer to voltage-based power quality problems. This work details the design, investigation and experimental validation of reweighted zero-attracting least mean square (RZA-LMS) based DVR addressing the issues like voltage sag, voltage swell, voltage harmonics, voltage imbalance and combination of these. The RZA-LMS based control algorithm is proposed for producing reference voltage signals. The features of proposed algorithm include finite-time convergence, simplicity and improvement in the robustness of the system against varying parameters. The viability of DVR controller is assessed by employing MATLAB/Simulink and Simpowersystem software. The performance of proposed DVR is experimentally investigated using digital real-time simulator.

PowerSAS.m—An Open-Source Power System Simulation Toolbox Based on Semi-Analytical Solution Technologies

In handling complex power system simulation tasks, semi-analytical solution (SAS) methods have proven to be numerically robust and computationally efficient. They provide a competitive alternative to traditional numerical approaches. Still, there is inadequate power system simulation software, especially the open-source tools, that implements this technology. This paper introduces PowerSAS.m, an open-source toolbox that closes this gap by providing SAS baseline simulation options for power system steady-state and dynamic simulations. At its core, it implements a novel SAS method and encloses various heuristics and simulation techniques to ensure enhanced computational performance. In case studies, we verify PowerSAS.m in benchmarking comparisons and demonstrate its functionalities in grid analysis scenarios.

Single-phase Grounding Fault Section Locating Technology for Distribution Network Based on Rough Set Algorithm

With the continuous development of distribution networks, the proportion of the power electronic equipment that accesses distribution networks is increasing, which increases the system capacitance current, making the probability of single-phase grounding fault via intermittent arc in the system significantly increased. However, most traditional locating technologies are suitable for single grounding fault type via stable resistance, and cannot locate the fault above, which seriously impairs the reliability of the power supply of distribution networks. In order to solve the problem above, this paper puts forward the single-phase grounding fault section locating technology for the distribution network based on a rough set algorithm. This technology is able to obtain the phase current signals in the system for judgment, and analyze multiple characteristics of current signals with a rough set algorithm, thus determining the fault types in the system correctly. Moreover, it is also able to determine fault sections with proper section locating algorithms based on different fault types. Furthermore, it is able to locate sections of various fault types, such as resistance fault and fault via intermittent arc, with an expanded feasible region. Besides, it only makes a judgment based on phase current without collecting the zero-sequence voltage of the system, ensuring adaptability. Additionally, it is able to supplement and optimize fault type identification categories by adding condition attributes of fault characteristic analysis in the rough set algorithm, having certain engineering application values. In the end, the feasibility of this locating technology was verified with ATP power system simulation software.

Analysis of imbalanced voltage on 35kV side after single phase replacement of 500kV transformer

After the B-phase of the 500kV transformer was replaced, the three-phase voltage on the 35kV low-voltage side was imbalanced and the neutral point displacement voltage was relatively high during the start-up test. For this problem, firstly, the calculation method of neutral point displacement voltage is given through the method of vector analysis and equivalent circuit, and the reasons for the imbalance of the three-phase voltage are analyzed. According to the measured parameters, the PSCAD/EMTDC power system simulation software is used to establish a model, and the steady-state operating characteristics of the system are simulated and calculated. Theoretical analysis and simulation calculation have determined that the cause of the imbalance of the three-phase voltage is the inconsistency between the ground capacitance of the low-voltage winding and the capacitance between the high-voltage and low-voltage windings of the B-phase transformer than that of the A-phase and C-phase. The impact of the capacitance between the high-voltage and low-voltage windings of the transformer is far greater than the capacitance of the low-voltage windings to ground on the imbalance of three-phase voltage to ground on the low-voltage side of the transformer.

Имитационная модель силового трехфазного трансформатора бронестержневой конструкции с витым магнитопроводом

Background. One of the areas of industry digitalization is associated with the concept of digital twins, which allow simulating the operation of real devices in various modes. At present, simulation models of a three-phase rod-type transformer have been developed in the MatLab Simulink SimPowerSystem environment. The models can serve as the basis to design a digital twin of a real device. The problem is to find the most universal method for mathematical description of a transformer of unspecified design to develop its simulation model. The purpose of this study is to develop a simulation model of a three-phase shell-type transformer core with a twisted magnetic circuit and to study this model when the transformer is operating in steady and transient modes. Materials and methods. The authors have applied the methods to model electrical circuits based on the theory of ordinary differential equations, a simulation method using the MatLab Simulink SimPowerSystem software package. Results. The structural futures of the transformers with shell-core design and the main assumptions when developing the simulation model have been assessed. A system of nonlinear equations has been developed to find the flows and MMF generated by the windings of the device. A simulation model of a three-phase shell-core transformer with a twisted magnetic core has been developed. It is based on the obtained equations using the Algebraic Constraint block with the Solver function in MatLab Simulink SimPowerSystem. The results of simulation of dynamic processes in the transformer in various modes are presented. Conclusions. The results of the study can be used to design power transformers in engineering companies and under production conditions. It is also possible to use the developed models in case of power transformer operation to analyze the static and dynamic modes of operation of sections of electrical networks.

Interfacing real-time and offline power system simulation tools using UDP or FPGA systems

This contribution proposes a coupling interface between the real-time simulation system RTDS Novacor and the Power System Simulation Software PSS/E for electromagnetic transient (EMT) and phasor (RMS) hybrid simulations to enable a performant connection between the domains. For the coupling interface, two implementations with different characteristics in latency and hardware requirements are presented. Firstly, an Ethernet (UDP) based connection and secondly a fiber-based connection using the Aurora protocol. The first approach is purely software based, while the second one requires additional hardware. The technical implementation of the interfaces is explained in detail. The functionality of the interfaces is verified on the basis of an EMT-RMS simulation in a small overhead line test system.

Detailed mathematical and simulation model of a synchronous generator

Synchronous generator theory has been known since the beginning of its use, but the modelling and analysis of synchronous generators is still very existent in the present-day. Modern digital computers enable development of detailed simulation models, thus individual power system elements, including synchronous generators, are represented by the highest degree order models in power system simulation software packages. In this paper, first, a detailed mathematical model of a synchronous generator is described. Then, a simulation model of a synchronous generator developed based on the presented mathematical model. Finally, a transient stability after a short-circuit is simulated using real generator parameters.

MATHEMATICAL MODELING OF THE MPPT-CONTROLLER FOR RENEWABLE ENERGY SOURCES ON MOSFET TRANSISTORS

This article discusses field tests and practical implementation of a low-voltage LED lighting system with renewable energy sources in an autonomous facility and the development of a model for optimal temperature control in an autonomous facility. The method of complex management of the power supply system using the Smart controller of the energy supply of the autonomous object is also considered. To implement the mathematical model, the Simulink and SimPowerSystems software for visual modeling included in the MatLab package was used. The use of this software allows you to simulate complex electrical systems. The advantage of using this program is the combination of methods of structural and simulation modeling, and this approach provides the flexibility of the system for the model being developed, greatly simplifies the model, and therefore increases the speed of calculations. When developing indoor temperature control systems, a number of problems arise, such as determining the time required the temperature to rise to provide the set values to the required moment, choosing the temperature control algorithm and determining the parameters of the selected algorithm. The task of choosing the control law and the type of controller is to choose such a controller, which at minimum cost and maximum reliability would provide the specified quality of regulation. In this article, the choice was made on the PID regulator, since with a jump-like change of the regulated value, the PID regulator at the initial moment of time has an infinitely large influence on the object of regulation. Then the magnitude of the influence drops sharply to the value determined by the proportional component, after which the integral component of the regulator begins to exert its influence constantly. The transient process in PID controllers has minimal deviations in amplitude and time compared to P and PI controllers (i.e., the highest speed).

The impacts of electric vehicles and heat pumps load profiles on low voltage distribution networks in Great Britain by 2050

The impacts of uptake and electricity load profiles of Electric Vehicles (EVs) and Heat Pumps (HPs) on the low voltage (LV) distribution networks were analyzed. The United Kingdom (UK) has a legally mandated policy concerning reduction of greenhouse gasses (GHGs) emissions. Therefore, the integration of low carbon technologies (LCTs) especially EVs and HPs at the LV networks is expected to increase in the drive to reducing the GHGs emissions. Future uptake scenarios, adapted from the National Grid studies, of EVs and HPs were developed for a real and typical urban LV distribution network in Great Britain (GB). Gridlab-D, an agent-based power system simulation software, was used to model the LV distribution network. The model was run for four different scenarios considering seasonal load profiles and projected EVs and HPs uptakes for each of the year 2020, 2030, 2040 and 2050 respectively. The results were analyzed in terms of transformer loading, voltage profiles of the feeders, and the ampacity loading of the cables for the different scenarios of the years.

Voltage stability analysis of wind power plant integration into transmission network of Nepal

Government of Nepal has realized that wind energy could become a major source of alternative energy to solve energy crisis in the country as well as serve the purpose of energy mix. Various studies have identified several locations with potential for wind power generation in Nepal. The integration of wind power plant to the national grid, however, raises concerns regarding the power system stability. The voltage stability of the grid is a key issue, the effect on which increases with the increase in wind power penetration in the grid. This study performs voltage stability analysis due to high penetration of wind power in Integrated Nepalese Power System (INPS). Both steady state and dynamic stability study is performed using the power system simulation software DigSILENT/PowerFactory for different types of wind turbine generators.

Modelling of Supercapacitor Banks for Power System Dynamics Studies

The paper presents accurate and simple dynamic model of a supercapacitor bank system for power system dynamics studies. The proposed model is derived from a detailed RC circuit representation. Furthermore, a complete control system of the supercapacitor bank is also presented. The proposed model is easy to integrate in any power system simulation software and consists of only up to four standard datasheet parameters. The performance of the proposed model in grid frequency control and low-voltage ride through is illustrated on IEEE 14-bus test system in DIgSILENT PowerFactory. It is shown that in case of transient stability simulations the ideal (simplified) model of the supercapacitor can be used while in case of frequency control the ideal representation may not always be appropriate.

Adaptive Underfrequency Load Shedding design based on generation losing estimation using Artificial Neural Network method

Under Frequency Relay (UFR) is used to prevent the frequency instability of a generation outage by balancing the load with the supply. The approach of this paper is to design an Adaptive Under Frequency Load Shedding (AUFLS) model in power system simulation software by estimating the magnitude of losing generation using artificial neural network (ANN) based on the early response of frequency after the disturbance occurred then the shed loads will be obtained based on this value estimation. The New England IEEE 39 bus system is used for this dynamic simulation. There are three operation scenarios planned with different dispatches of the generators, each generator is simulated by removing it from the system then the frequency system response is used as training data for the ANN model. The analysis is performed by comparing the frequency response of the system using Conventional 4 Steps Under Frequency Relay Load Shedding (UFLS) and the Adaptive Under Frequency Load Shedding (AUFLS). The results show that the frequency response after disturbance using the Adaptive Under Frequency Load Shedding (AUFLS) revert to the initial frequency closer and faster than using Conventional 1 Steps Under Frequency Relay Load Shedding (UFLS).

Test Method and Data Application of Physical Model of Power Distribution Network

This paper states the test method and data application of a kind of physical model of power distribution network. After the establishment of distribution automation physical simulation laboratory, the equipment in the platform is effectively controlled and reasonable test procedures are designed. The detailed solution is to record the test process during the physical simulation test.In the design of this test method, the main difficulty is that the data of each equipment at each stage in the system shall be recorded completely during the whole process for physical reduction of transient fault, and to design the interface with the power system simulation software; otherwise, the meaning of the test will be discounted heavily. The on-site operating environment of the distribution network can be restored furthest, all details in the test process can be presented to the testers clearly and intuitively, and the test data can be expanded and applied to provide strong support for technical research and analysis of distribution automation in this way.