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Ecotourism is becoming dominant, especially after global disturbances such as the pandemic. In addition to the health segment, it must include the cognitive and educational segments, so attractions are an important element in creating eco-products in tourism. Whether they are natural or artificial attractions, they are often located in hard-to-reach areas and their function cannot be maximally valorized without basic infrastructure. The development and implementation of a system for the production of electricity from unlimited solar energy are important for the development of sustainable tourism. The paper aims to point out the importance of setting up independent electricity supply systems, including off-grid and hybrid setups, and to offer practical solutions for achieving energy self-sufficiency. Hybrid power systems (HPS) are especially important to rationalize costs. Fully autonomous power systems in inaccessible areas where access to the public network is difficult or completely disabled are crucial. [ABSTRACT FROM AUTHOR]

The main control loop of the synchronizer of the Grid Forming inverter can be synchronized with the voltage of the grid without using a phase-locked loop. However, in order to enable the inverter to realize the frequency regulation function accurately, a phase-locked loop is still required to obtain the grid's frequency information. Since the time constants of the phase-locked loop and P-f loop of grid forming control are at the same order of magnitude, the introduction of the phase-locked loop will affect the original dynamic performance of P-f loop. In this paper, small-signal modelling is performed on the P-f loop of the grid forming with considering phase-locked loop to obtain the transfer function of the system. The influence of the cutoff frequency of phase-locked loop on the system dynamics is mainly related to the expected damping of the P-f loop. When the P-f loop of the system is designed to be underdamped, decreasing the cutoff frequency of the phaselocked loop can increase the system damping, which increases the adjustment time and reduces the overshoot. The paper uses controller hardware-in-the-loop to verify the analysis results. [ABSTRACT FROM AUTHOR]

This paper proposes an ANN based adaptive Auto Reclosing AR which integrated of an operation of distance measuring relay in HV Over Head Transmission Line OHTL. This work is brought to enhance stability synchronism, and reliability during the transient faults of OHTL. Thus, it leads to increase the continuity of the electric power system, especially of hydropower plants are connected to utility grid. This work are used Matlab\Simulink environment to design and simulate a single-phase auto-reclosing, which depends on the Artificial Neural Networks ANN integrated with a distance relay DR. In addition, the simulation model consists of Boolean algebra circuits, and timers are utilised to build Auto-reclosure of a circuit breaker in each phase. The ANN is here trained to recognize angle values of actual impedances (in the positive sequence only) in which it can classify which phase exactly is line to ground fault. The simulation results show the ability of this combination to distinguish among various fault types and giving multi pulses-shot of tripping and reclosing for the specific circuit breaker with a successful mechanism. In this paper, a realistic system with real parameters was represented by the important transmission line (Mosul Dam-East Mosul), which currently is only the main and alone line that connects the northern Iraq network with a national grid. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to identify, analyze and develop a structural model for the identified factors that can influence the electricity distribution using Interpretive Structural Modeling (ISM) approach. From this study, the results specify that the key factors are demand fluctuations, personal protection, uninterrupted distribution, location, construction activities, consumption charges perspective, electrical subsidiary industries. The ISM framework has been developed in this paper, which is a first attempt to analyse the interrelationship among the electricity distribution impacting factors. This study will be useful for practitioners and power distribution companies (DISCOM) to understand the factors influencing electricity distribution. [ABSTRACT FROM AUTHOR]

The paper presents the characteristics and analysis of the directions of development of the modern electric power industry. The analysis was carried out from the standpoint of the influence of development directions on the main properties of electric power systems: reliability, efficiency, environmental, as well as on energy security. The paper also presents the requirements of modern electricity consumers to ensure the reliability of power supply. Based on the analysis, the requirements and tasks for assessing and ensuring system reliability for modern and future electric power systems are formulated. [ABSTRACT FROM AUTHOR]

This paper analyzes the variations in power flows along the main power transmission lines of the electric power system of Uzbekistan, taking into account the power generation by large PV power plants (PVP), which will be commissioned by 2024. The paper concludes with recommendations on the modernization of the electric power economy. [ABSTRACT FROM AUTHOR]

In order to prevent the major accidents caused by ice coating on optical fiber composite overhead ground wire (OPGW) in extremely cold weather in power system, this paper uses Brillouin optical time domain reflectometry (BOTDR) and the finite element software to establish a tight buffered OPGW cable ice monitoring model. Firstly, establishing the linear model of Brillouin frequency shift, the temperature and strain, the article eliminates the effect of temperature changes on Brillouin frequency shift and get the precise relationship between the strain of the fiber in the OPGW cable and the Brrillouin frequency shift. Secondly, using ANSYS Workbench software to model and simulate, the relationship between the ice thickness of OPGW cable and the strain of the fiber is obtained. Finally, the relationship between the thickness of the OPGW cable ice-coating and the Brillouin frequency shift in the fiber is achieved. The results show that the model can be combined with BOTDR technology to know the ice-coating status of OPGW cable. This model lays the foundation for real-time monitoring of OPGW cable ice-coating conditions [ABSTRACT FROM AUTHOR]

This paper summarizes the findings of Danish project - NSON-DK regarding the balancing requirements for future power system of North Sea countries with focus on the Danish power system and its regions DK1 and DK2. The study covers all the steps of the operation from the Day Ahead Market to the Real Time balancing of generation and demand. For that reason, DTU Balancing Tool Chain is used. The paper analyses a) the value of offshore grid on balancing of forecast errors, b) the impact of forecast errors on manual and automatic reserves and c) the quality of electrical frequency in the near future considering high VRE penetration d) value of including wake in the balancing studies with high share of renewables. Recommendations are provided in terms of balancing requirements for future power systems. [ABSTRACT FROM AUTHOR]

The development of wind turbines has been influenced by many different factors over the last decades. One is the integration of wind turbines and wind farms into the grid. Books and papers prove the controversy and the ongoing discussions and search to find clarification and define rules and standards in this field. The interest is equally driven by TSO and wind turbine manufacturers. Therefore grid connection and integration issues recently became a driving force and are changing wind turbine technology dramatically. Additionally to the common requirements of Voltage, Frequency and PQ capability, LV and HV ride through capabilities and protection requirements in particular, the wind turbine models are currently in focus for power system studies. This is driven by the search to find solutions to wind turbine integration and to verify behaviour patterns as well as to research the capabilities of the interaction of wind farms and the grid. While using existing wind turbine models and gaining experience, it became apparent that there is a discrepancy between the purpose and the capability of developed wind turbine models. This led to the urgent need to specify requirements for the development of specific models for power system studies. This paper will show an updated comparison of some chosen grid codes and will also present as well as discuss newly introduced model requirements from different countries [ABSTRACT FROM AUTHOR]

Nowadays, electric power generation (active and reactive power) is usually transmitted over long distances to consumers. The losses of power in transmission lines are always present due to the impedance of lines. The correction of the power factor (pf) has become a necessity to regulate both the flowing of reactive power and voltage levels of the electric power system. Flexible Alternating Current Transmission Systems (FACTS) are modern controller instruments, used to improve work performance and reduce losses in the network. In this paper, the use of a shunt static VAR Compensator (SVC) was studied to improve the power flow, which means the improvement of the power factor of the grid lines. A MATLAB model was simulated to calculate the amount of capacitive or inductive reactive power that is required for compensating. Also, the correction has been taken under various loads and different locations of the SVC along the AC line. The obtained results of compensation methods were analyzed and showed a high correction for power factor by a percentage of ninety-eight. [ABSTRACT FROM AUTHOR]

This paper emphases current sharing in Luo converters which are linked in parallel manner with solar input. The photovoltaic system supplies electric power which depends on the solar radiation and temperature. The suggested scheme comprises of dual parts, the first part is PV system followed by converters joined in a parallel manner at output to produce more current. For segmenting the current at output equally between two converters, the control structure has two control loops, a current loop and a voltage loop. P, PI and PID Controllers are designed for current and voltage loops and compared through MATLAB based simulation and PI is found to be satisfactory. [ABSTRACT FROM AUTHOR]

This paper describes an optimization study of wind power plants' inertial response for different wind speed and penetration levels in power systems. The paper is presenting an optimization method employing a genetic algorithm with an objective function, where the frequency nadir, the second-dip value and the time to reach the frequency steady state are taken into account. As the genetic algorithm is a minimization algorithm, distinct weighting factors of each component enables the adjustment of the optimization according to different specific requirements defined by transmission system operators. The results presented that for the above rated wind speed and medium wind speed operating regions, wind power plants can provide support to the frequency control and improve the performance regarding the frequency nadir and time to reach the steady state. However, the operation region which is closed to the rated wind speed can create a second frequency dip after the nadir. [ABSTRACT FROM AUTHOR]

Optimizing modes of the modern power system on active power is a complex problem of nonlinear mathematical programming. Despite the existence of many methods and algorithms for solving this problem, the issues of their improvement in the direction of correctly taking into account the factors that affect the regime remains an important problem. One of such factors is functional inequality constraints. The paper presents a new algorithm for optimising the modes of power system, taking into account losses in networks and functional constraints in the form of inequalities on power flows of controlled power transmission lines (PTL). A characteristic feature of the algorithm is taking into account the losses in branches by transferring them to the nodes of the electrical network. The algorithm's efficiency is investigated by the example of optimization of the mode of a complex electric power system with four thermal power plants participating in the optimization, ten PTL, in two of which the active power flows are controlled. In this case, the power flows in the controlled lines are determined by linearized formulas using the power distribution coefficients of the nodes. The economic effect on the total fuel consumption due to the use of the proposed algorithm is 0.45%. [ABSTRACT FROM AUTHOR]

This paper considers a unified approach to the analysis of electromechanical and electromagnetic transients in the electric power system and to the analysis of functioning of phasor measurement units (PMU). [ABSTRACT FROM AUTHOR]

In the world, special attention is paid to determining the stability margins of electrical systems in connection with the high growth rates of demand for electricity. In this regard, special attention is paid to research aimed at improving the stability and dynamic properties of electric power systems, including through the use of modern control methods based on intelligent systems. The application of HVDC and FACTS transmission technologies have added new control methods to the power system, increased the throughput of electrical networks, and improved monitoring capabilities. Power system stabilizers (PSS) are traditionally used to damp electromechanical low-frequency oscillations in the frequency range 0.2–1.5 Hz. This paper proposes the use of thyristor-controlled series capacitors (TCSC) control systems as a oscillations damper. For the compiled model of the POD-controller, a procedure was performed to optimize its parameters in order to minimize the deviation of the mutual load angle of the two power systems, and an algorithm for parametric optimization was presented. The simulation results on a digital model confirm the possibility of using TCSC regulators to suppress low-frequency oscillations in power systems. [ABSTRACT FROM AUTHOR]

The solution of problem of changing the indicators of the regime reliability of the Azerbaijan power system, associated with the expansion of the use of renewable energy sources (RES) in the structure of electric power production, as well as an increase in the transit of electrical energy through inter-system power transmission lines is considered in the paper. As a solution of the problem, the modernization of the emergency control automatics (ECA) system of the electric power system based on the transition from analog to digital control systems (digital transformation) with the implementation of an integrated innovative- measuring system SCADA / EMS - WAMS using the multi-agent principle (MAS) is considered. [ABSTRACT FROM AUTHOR]

The analysis of the features of the network and power structure of the Azerbaijan EPS, the development of traditional sources of electrical energy, the implementation of distributed generation based on small power plants and renewable energy sources (RES), operation in the structure of the Interconnection of the ES (IES of the South) of the Russian Federation, Georgia, Turkey and Iran with the near-term reaching of the interregional level is given in the paper. The features of the regime reliability state of the Azerbaijan EPS are analyzed, the nature of stability disturbances by voltage and frequency is demonstrated [1,2]. The necessity of modernization of the emergency control (EC) system with bringing it to the level of digital technology by 2050 is substantiated. The technology is based on an intelligent integrated system SCADA / EMS, DMS, OMS / WAMPAC, operating on the basis of synchrophasor measurements of the PMU device. The need to implement interaction and decentralized principle of operation of the elements of the EC system, which carries out the warnings and preventions of the emergency development to the system level (MAS), is considered. The digitalization of the stated intelligent technology allows for providing the monitoring of the quality and reliability of power supply, increasing the observability, measurement accuracy and efficiency of control of the regime reliability of the Azerbaijan EPS. [ABSTRACT FROM AUTHOR]

In this paper, a short history of the development of wind power and an overview of wind power system integration research in the Netherlands are presented. The aim of the paper is to present the milestones of modern wind energy development in the Netherlands and to illustrate the most relevant aspects of the system integration of wind power. The Dutch case is used as an illustration in order to facilitate discussions on these topics. [ABSTRACT FROM AUTHOR]

The increasing penetration of inverter-interfaced generation leads to declining power system inertia. When the system experiences low inertia values, greater and faster frequency deviations occur. Under these circumstances, the real time assessment of frequency response and specifically, the assessment of frequency nadir is necessitated. This paper introduces a method that identifies the parameters of a simplified frequency response model that represents the Nordic power system. To identify the parameters, the error residuals between the simulation model's and the actual system's measured frequency are minimized. This is accomplished by using historic event data from underfrequency events from the Nordic power system. After the parameter identification, the model is used to estimate the frequency nadir of other underfrequency events of the same system. The results show that the proposed method for nadir estimation performs better than the one that is currently employed by the Swedish system operator. [ABSTRACT FROM AUTHOR]

In large offshore wind power plants (WPP), it is of great importance to fulfill the harmonic requirements as stated in the Grid Codes. It is however not obvious how to determine the harmonic levels due to complex cable systems, a large number of harmonic generating wind turbines, background harmonics in the receiving network and any SVCs and STATCOMs used for reactive power support. This paper investigates how the impedance frequency profile, the amplification factors and the harmonic performance are affected when a wind power plant is connected to a utility grid. Analyses are made to determine the influence of tolerance variations of the equipment in the WPP, e.g. transformers, cables, as well as the system frequency. It is concluded in the paper that it is not enough to only consider the base case of the system with nominal parameters and component tolerances. Instead, calculations must be made for a large number of cases including tolerance variations. Moreover, the connection of the WPP affects the amplification factors between already existing buses in the system. This may affect already existing equipment in the system. Finally, the paper has shown that there is a need for accurate models in the frequency domain, with frequency dependency correctly modelled. An aggregation method for cables which keeps the correct frequency dependency is proposed. [ABSTRACT FROM AUTHOR]

To design motor drives for optimal motion control, and to obtain precise Brushless DC motor model, accurate measurement of motor parameters like phase current, speed and torque are required. Speed and current are also required to provide feedback between the BLDC motor and its controller to develop a robust BLDC motor control algorithm. In this paper, phase current, speed and torque measurement technique for Hub BLDC motor is presented to analyze its performance for low power electric vehicle applications. For the phase current measurement, the Hall-Effect current sensor ACS712 is used. The speed of the motor is calculated using an internal hall sensor that is connected to dsPIC33F's input capture pin that generates an interrupt whenever a change in the hall sensor signal value occurs. Further, an experimental setup is established in the laboratory to measure the torque at varying load and to determine the relationship between motor torque, input current, output power, speed and efficiency. [ABSTRACT FROM AUTHOR]

This paper provides an owner/operator’s experience of the implementation of testing of island and blackstart operations of a wind farm using a Grid Forming (GF) algorithm installed on the Wind Turbine Generators (WTGs). This paper describes the test system configuration, including the protection and control aspects necessary to create the conditions for operating the island and blackstart modes in a safe manner. [ABSTRACT FROM AUTHOR]

This paper addresses problems of power generation markets that arise under high shares of intermittent generation. After discussing the economic fundamentals of wind and photovoltaic investments, the paper introduces the concept of the “Merit order effect of renewables”. According to this concept electricity prices on wholesale power markets become smaller in periods during which large volumes of wind and photovoltaic generation is available and squeeze out relative expensive gas-fired power generation. The merit order effect of renewables has a couple of consequences. Among others it challenges the profitability of conventional power generation. If such generation capacities are still necessary, at least during a transitory period, a capacity mechanism may be put in place that generates an additional stream of income to the operators of conventional power generators. Another consequence of growing intermittent power generation is the need for concepts and technologies that deal with excess generation. Among these concepts are virtual and physical power storage capacities. In the last parts of the paper models are presented that are able to analyze these concepts from an economic point of view. [ABSTRACT FROM AUTHOR]

The opening of the sale side of electricity market is an important goal of the new round of power system reform in China, and it is necessary to speed up the establishment and development of the electricity selling companies to achieve this goal. First of all, this paper defines the key problems, which are needed to be solved in the establishment of the sale side market, such as demand side response, optimization of users' power consumption mode, profit mode of electricity selling companies and fair competition in the market. On this basis, this paper analyzes the business of electricity selling company, from the aspects of the transition of business ideas, improving the energy efficiency level, providing integrated energy solutions and innovating business management mode; and then, the service strategies of electricity selling companies are put forward. [ABSTRACT FROM AUTHOR]

With the increase in renewable generation in the power system, system planners have to account for the uncertainty introduced by these sources. However, in the time frame of a traditional transient stability simulation, the uncertainty can be assumed to be negligible. The importance of the uncertainty subsequently arises in the time period between two consecutive dispatch intervals. Further, with large number of uncertain sources, an enormous number of simulations are required to cover the entire search space. In this paper, the feasibility of longer time transient simulations with uncertainty is explored and the impacts of this uncertainty on the response of the system is observed. Further, the application of an analytical method of obtaining the statistical characteristics of the required output parameters is explored resulting in a computationally efficient analysis. [ABSTRACT FROM AUTHOR]

The Faroe Islands' national system operator SEV has deployed a 2.3 MW Lithium Ion (Li-Ion) Battery Energy Storage System (BESS) at the 11.7MW Húsahagi wind farm site. The BESS provides enhanced ramp rate control of the wind farm, and helps maximise wind energy utilisation, on a power system which sees up to 85% wind penetration levels. This paper presents an analysis of selected power system data from the BESS's first year of operation, examining its effects on ramp rates in steady-state operation. A first assessment of the increase in wind utilisation and resulting displacement of fossil fuel generation is presented, and the BESS's energy throughput is also examined. This paper is an early part of a body of work to examine the BESS's real-world performance and identify ways to optimise its effectiveness and lifetime. This is of special significance for system operators looking to BESS technology as a means to maximise wind utilisation whilst ensuring system security. [ABSTRACT FROM AUTHOR]

The amount of kinetic energy in the Nordic power system decreases due to structural changes in the power system. In this paper, the Nordic Transmission System Operators (TSOs) provide a summary of a survey, which was sent out to some small- and medium-sized synchronous areas, in order to learn from their experiences with low kinetic energy situations. The paper summarizes the responses received, thereby providing a view on: the current and future assessment of inertia in the system (including key drivers behind the change), and mitigation methods for low inertia situations. [ABSTRACT FROM AUTHOR]

This paper discusses and compares two approaches to address technical challenges in performing collaborative studies of power system dynamics. On one side, we consider the model migration approach which is an essential piece of dynamic model exchange. On the other side, we look at the co-simulation approach which is used to couple simulation tools together. The approaches are compared in terms of accuracy and the most probable reasons for discrepancy between dynamic responses are discussed. We complement the discussion and conclusions with the simulation results on a simple test system. [ABSTRACT FROM AUTHOR]

This paper proposes a critical analysis of performance and impact of regulated ancillary service environment on Indian electricity grid introduced through Reserves Regulation Ancillary Services (RRAS) by CERC. It includes the analysis of qualification criteria for participating plants, scheduling process, criteria for invoking ancillary services, components of cost for providing ancillary service, settlement mechanism and financing of overall ancillary service system. The paper also discusses about the impact on grid frequency profile, management of congestion and ramps due to RRAS. The paper also proposes a future roadmap for RRAS in India based on the undertaken analysis in order to better integrate the increasing share of RE in the electricity mix in the country. [ABSTRACT FROM AUTHOR]

This paper deals with actively studied terms "flexibility" and "resiliency" of electric power systems (EPS). Definitions and content of these new fundamental EPS properties are analysed. Objective trends in development of EPS with regard to these properties are discussed. Possible measures for improving flexibility and resiliency of EPS are suggested. [ABSTRACT FROM AUTHOR]

The integration of the voltage-source converter based high voltage direct current (VSC-HVDC) system makes the set-point of its active power adaptive to the changes in the power flow, and contributes to the curative congestion management. To further exploit the dynamic behavior of a hybrid AC/DC power system in curative congestion management scenarios, this paper investigates a novel control scheme for voltage angle droop controlled HVDC (VAD-HVDC) systems. The proposed scheme to alleviate the circuit overload is estimated firstly by calculating the severity index when the power flow changes under N-1 situations. Then the voltage angle controlled HVDC system is applied on the modified IEEE 39-bus 10-machine test power system for the time-domain simulation. The dynamic behavior in the HVDC station validates that the VAD control can stabilize the DC voltage and possess a good ability against interference. In addition, the dynamic characteristics analysis on the AC transmission lines proves that the hybrid AC/DC system integrated with the VAD controlled HVDC system are in possession of good stability after the N-1 contingency event. The VAD controller employed in the HVDC system is capable of effective congestion management to mitigate the critical loadings on the transmission lines. [ABSTRACT FROM AUTHOR]

Modern power systems include a growing number of wind turbine generators and other new system components. A vendor-specific model (VSM) of a component is developed by its manufacturer and aims to reflect essential characteristics of the component's dynamic response. Often, a VSM is implemented as a user-defined model (UDM). A VSM is supposed to be more accurate than standard/generic models of this component. Nevertheless, the current trend is that VSMs/UDMs are gradually supplanted by standard and generic models. This paper provides recommendations on how to enhance the quality of VSMs/UDMs: to make them more suited for interconnection stability studies, to help prevent modeling issues and to facilitate investigations when issues occur. Considered are model functionality, numerical solution, size and variables, intermittency of energy sources and additional verification testing. The recommendations are based on experience with a variety of VSMs/UDMs representing generation, transmission and energy storage facilities. [ABSTRACT FROM AUTHOR]

Power system starts to face problems of integrating thousands megawatts of wind power, which produce in a stochastic behaviour due to natural wind fluctuations. The rapid power fluctuations from the large scale wind-farms introduce several challenges to reliable operation and contribute to deviations in the planned power generation which would lead to power system control and power balancing problems. In this paper, the impact of large scale wind power integration on power balance is discussed. A scheme of Automatic Generation Control (AGC) system which includes large scale wind-farms is presented. The ability of the secondary control of conventional power generating units and the spinning reserve from Combined Heat and Power (CHP) units for maintaining the power balance are investigated. Control concepts to achieve active power balance with the increased wind power integration in power system are discussed. [ABSTRACT FROM AUTHOR]

In this paper an overview of the future role of inverters regarding frequency control in an interconnected system is given. The grid frequency of today's electrical power system is mainly stabilized by synchronous generators, especially concerning inertia and primary control reserve. As the power system characterized by large, conventional power plants has been changing towards an inverter-dominated one, these systems have to take over responsibility for grid stability and frequency control as well. Two types of inverters are presented in this paper: voltage control mode inverters and current control mode inverters. Both types are presented with their similarities and differences in functionality. Voltage control mode inverters are qualified for instantaneous reactions on frequency deviations, comparable to inertia from synchronous generators, whereas current control mode inverters are suited for delivering (fast) primary control reserve. Multiple laboratory measurements illustrate these different fields of application and validate the qualification of inverters for frequency control. [ABSTRACT FROM AUTHOR]

This paper examines the influence of aggregated power output fluctuation of photovoltaic power generation system (PVS) on the power system frequency, focusing on ramp-events of aggregated PVS power output. A numerical simulation model of economic load dispatching control (EDC) and load - frequency control (LFC) is utilized together with a PVS power output forecasting model and a unit commitment (UC) scheduling model developed in our preceding study. As a result, in the case of ramp event with long duration and rapid ramp rate, the frequency deviation from the acceptable rage occurs when the power output of controllable generators with high load following capability reaches to upper / lower limit even though the power output change of low load following capability generators is still available. If the load dispatching scheme is temporary switched from the conventional EDC using an equal incremental fuel cost rule to, for example, the dispatching based on the capacity without the consideration of fuel cost, the aggregated load-following capability can be preserved, avoiding the frequency deviation. [ABSTRACT FROM AUTHOR]

This paper deals with the mathematical and theoretical approach for multi-source considering renewable and non-renewable energy sources, multi-area electric deregulated power system with traditional controller for load fluctuation regulation. Renewable and non-renewable sources are merged to supply the better possible generating energy and better efficiency of the electric supply to discos. Here multi area aims to reduce the differences between the GENCOs and DISCOs set out limits. Due to production of electricity from renewable and non-renewable sources and frequency sudden changes at GENCOs and DISCOs, automatically frequency switching may possible. Classical PI controllers are set out to tackle the load frequency of electric system for frequency switching in set out range. In this research a mathematical approach for multi-source renewable and non-renewable sources, multi area with classical PI controller and ESD with TCPS devices is considered. [ABSTRACT FROM AUTHOR]

The present work describes a novel approach for studying frequency support by synthetic inertia from wind power plants. A model for representing synthetic inertia in PSS/E (Power System Simulator for Engineering) has been developed. It can be used irrespective of the existence of wind power models in the present power system. Additionally, the model allows for implementation of different control strategies in order to find the most suitable option for the particular power system. Simulation results show that the frequency nadir is reduced by about 50% for a load increase of 20 MW on Gotland (a Swedish island in the Baltic Sea) when there is a support of synthetic inertia in the grid. However, the sub-sequent frequency recovery is slower during support of synthetic inertia even though the frequency nadir is reduced. It can be seen that during specific conditions the synthetic inertia is interfering in an unfortunate manner with the normal frequency control, resulting in a delay in frequency recovery. This shows the need of system studies before specifying the parametrization of synthetic inertia in a power system. Furthermore, additional studies in the Nordic32 model show that a frequency derivative dependent characteristic with settings used so far is not the most beneficial characteristic to counteract the frequency nadir. Optimized settings will likely improve its performance significantly. The paper also shows the high potential for wind power to deliver inertia to the power system. From the paper it is believed that an adequate parameterization of the synthetic inertia can improve the frequency quality of the grid as well as the frequency stability of the grid [ABSTRACT FROM AUTHOR]

Nowadays, China’s energy demand sustained rapid growth, and the coal-based energy structure has adverse effects on the environment. The flexibility of demand side resource (DSR) will be greatly improved, and DSR can reduce electricity consumption actively and temporarily, and realize energy saving and emission reduction. But there are still some problems to introduce DSR in China. This paper proposes three practices for introducing demand side resources to improve the flexibility of power systems through demand resources. [ABSTRACT FROM AUTHOR]

The continuous penetration of renewable energy sources (RES) in the electricity supply poses stability and quality issues for the grid. One promising and elegant solution to smooth these problems is the use of battery systems (BS). This paper describes a simple and robust concept, dBATe, for an optimised and coordinated control of multiple battery systems distributed in a power distribution system, supporting the operation of the grid through regulation of voltages and power flows in the grid. [ABSTRACT FROM AUTHOR]

A well-behaved electric power system requires both the frequency and voltage to remain at standard values during the operation. The active power and reactive power balance should be maintained between the generation and utilization of the AC power. Any change in the supplied voltage from its rated value may damage the components that are connected in the electric power network since they are designed to operate at a certain rated voltage. Keeping the generator terminal voltage at the a value is done through the field current in the generator exciter. A proportional-integral-derivative (PID) controller has been used in the Automatic Voltage Regulator (AVR) system to keep the voltage approximately at the rated value. The general approach is to minimize the integral of the absolute errors between the rated and terminal voltage by tuning the proportional, integral and derivative gains of the PID controller. Several solutions were proposed on how to tune the PID parameters, including the classical Ziegler and Nichols methods. They are mainly for a controller design when no specifications are given, but the optimization to achieve the best behavior is not provided generally. In this paper, we adopt a metaheuristic optimization method called the Water Cycle Algorithm (WCA) to tune the PID controller parameters which are applied on the voltage deviation in a cost function for a single power area system. Two types of IEEE recommended standard excitation system models, DC2A and AC4A, are considered. The automatic voltage regulator with the proposed controller shows superior performance in terms of the overshoot and settling time against any voltage deviation [ABSTRACT FROM AUTHOR]

Power systems are currently experiencing a transition towards decarbonisation of electrical generation through large-scale deployment of renewable energy sources. These are gradually replacing conventional thermal power plants. Consequently, in case of a total/partial blackout, conventional black-start resources are not ready for operation. Offshore wind farms, with their large capacity and fast controllers, show potential as innovative black-start units. This introduces the need of a new design for the wind power system. In this paper, challenges and possible solutions in integrating black start service into offshore wind farm will be presented. A first challenge is represented by the implementation of a blackstart unit. The black-start unit should be capable of forming the wind farm power island, withstanding transient phenomena due to energisation. There could be several different solutions, e.g. the integration of grid-forming converters in the wind farm design. These could be battery energy storage systems (BESSs) and/or new generation grid-forming wind turbines. The selected challenges are analysed using simulation on a wind farm, and the proposed solutions discussed. It can be concluded that a system comprised of BESS, grid-forming wind turbines and STATCOM, in combination with novel technologies such as virtual synchronous machine, soft-charging, harmonic active filtering, etc. represent a good proposal for the integration of black start into offshore wind farms. [ABSTRACT FROM AUTHOR]

This paper presents an overview, status and outline of multi-frequency stability analysis in converter-based power systems. It provides concise definitions and literature review covering state-of-the-art of stability analysis in power systems dominated by converters. Some aspects of modelling and analysis methods are discussed and aided by examples. The paper describes the phenomena, consolidate definitions, and explain available methods for analyses with their advantages and disadvantages as well as provides a common understanding on modelling, analysis, evaluation and mitigation techniques. Guidelines regarding general approaches to such studies, about the availability as well as choice of tools are also given in the paper. [ABSTRACT FROM AUTHOR]

The operation of a system with 100% converterinterfaced generation poses several questions and challenges regarding various aspects of the dynamic characteristics of the system. The effects related to the power-frequency control are among the most relevant issues which need to be investigated. The paper takes into examination the case of an existing isolated power network of a geographical island assuming a completely converter-interfaced generation. The factors playing a fundamental role in the assessment of which sources should be designated to be grid-forming are identified with a smallsignal model formulation of a generic multiple oscillators system. Simulations and analysis performed on the case study of the island's power network performed with the software NEPLAN are used to show the impact of different aspects which can play a role in the design and the operation of the system: these aspects are the operating mode of power converters control, location and distribution of the generation sources with grid-forming capabilities, as well as number and ratings of these sources. The impact of relevant control parameters such as virtual inertia constant and virtual impedance is also investigated. [ABSTRACT FROM AUTHOR]

After the war 1999. Kosovo and Metohija (Kosmet) is constantly facing with electricity production and distribution problems. Also, electricity restrictions are present almost at daily basis. More than 95% electricity production on Kosmet come from one source -- thermal power plant Obilić. Pollution coming from coal burning at central Kosmet is everyday problem. On the other hand Kosmet has and some renewable energy (RE) potentials such as biomass, solar, wind and hydro. Question that arise here is why not to use RE? It would lead to sustainable development of Kosmet energetics. However, just like conventional electricity production and RE projects can have some environmental impacts. Goal of this paper is to asses renewable energy sources according sustainability indicators and to get RE priority list. For that purpose will be used analytical hierarchy process (AHP). [ABSTRACT FROM AUTHOR]

The new normalization of the economic situation and the implementation of a new round of electric power system reform put forward higher requirements to the daily operation of power grid companies. As an important day-today operation of power grid companies, investment management is directly related to the promotion of the company's operating efficiency and management level. In this context, the establishment of power grid company investment management optimization system will help to improve the level of investment management and control the company, which is of great significance for power gird companies to adapt to market environment changing as soon as possible and meet the policy environment requirements. Therefore, the purpose of this paper is to construct the investment management optimization system of power grid companies, which includes investment management system, investment process control system, investment structure optimization system, and investment project evaluation system and investment management information platform support system. [ABSTRACT FROM AUTHOR]

In recent years, because of the environmental burden, natural hazard and energy dilemma in Japan, renewable energy integration becomes a key technology in the development of power systems. As is well known, a terrible earthquake happened in eastern Japan in 2011, followed by nuclear power accidents pushed wind power to the forefront as an alternative energy to cover power demand. As of 2015, total amount of installed wind power capacity was about 3000MW. Although the capacity is still small, it will be an important issue to keep supply and demand balance due to uncertain output fluctuation in the near future as the penetration level increases. To this end, various frequency regulation methods have been considered to properly manage the balancing issue. In 2016, IEEJ developed a new simulation model for frequency regulation, AGC30, in order to simulate the supply/demand balance control considering both economic dispatching control (EDC) and load frequency control (LFC). On the other hand, balancing markets have been developed and utilized to ensure the security of frequency regulation with lower cost based on the market principle in European countries and regions. Hence, in this paper, supposing that the tertiary control reserves in terms of energy will be traded through balancing markets in Japan, authors developed a combined simulation model which covers both market simulation and automatic generation control. Multi-agent simulation with Q-learning was applied for market analysis while IEEJ AGC30 model was used for automatic generation control. Based on this model, we have analyzed the dynamic behavior of the supply and demand balance operation and frequency regulation supposing the conventional EDC is replaced with the balancing market. [ABSTRACT FROM AUTHOR]

With the increased deployment of renewable energy devices into power systems, more converters controlled by the standard D-Q axis Current Injection (DQCI) theory have been connected to the grid, displacing synchronous generators in the process. Due to the nature of the DQCl strategy, these converters cannot impose a reference voltage and frequency. A study in the simulation environment has been done in [7] where it is shown that, for a certain limit of DQCl converters connected to the grid (or level of penetration of converters), system-wide stability can be compromised. This work presents an experimental equivalent study. It is shown that the main contributor to the system stability and the level of penetration for DQCI-controlled converters is not the active power injected by synchronous generators, but the nominal power of the generators. An alternative converter control strategy which transforms the converter into a real voltage source of energy is tested experimentally on this paper; it is shown that the use of a combination of both algorithms in large electrical grids can provide a robust grid based purely on converters. [ABSTRACT FROM AUTHOR]

This paper follows four main objectives. Firstly, to provide an overview of the latest and most demanding Fault Ride Through requirements from various international jurisdictions. Secondly, to support power system operators in understanding Fault Ride Through capabilities of modern wind turbines. Thirdly, an overview of state of the art validation of FRT is provided. Finally, to give an outlook of what additional functionalities will be available from wind turbines in the near to medium future. [ABSTRACT FROM AUTHOR]

With a growing penetration of wind turbines in many power systems around the world, a need has arisen to accurately reflect their behaviour for stability simulations. To reduce the complexity of such simulations, generic models have been developed that can be used by grid operators. IEC standard 61400-27-1 proposes a set of such models. However, these models lack certain features, such as Delta Control, Active Power Reduction with Overfrequency or Emulated Inertia, which might play an important role in the future. This papers shows how existing IEC models can be extended by incorporating the aforementioned features in the type 3 IEC model. Subsequently, the enhanced IEC model is compared with two manufacturer models and, with an appropriate parametrization, similar behavior can be achieved. [ABSTRACT FROM AUTHOR]

Paralleled inverters with asynchronous carriers are increasingly emerging into renewable power plants and other power-electronic-based power systems. The sideband harmonics resulting from the pulse width modulation tend to be different from one inverter to another, which may trigger sideband harmonic resonances among the paralleled inverters. To address the sideband harmonic instability, the nonlinearity of the digital pulse width modulator is analyzed first in this paper based on the harmonic balance principle. It is revealed that the dynamic sideband components corresponding to a given small-signal perturbation can be far below the Nyquist frequency, and they may not be effectively attenuated by anti-aliasing filters. A multi-frequency impedance model is then developed for the inverter, which characterizes the dynamic coupling between the perturbed frequency component and the sideband frequency component. The impact of asynchronous carriers on the sideband harmonic instability of paralleled inverters can thus be analyzed, and the frequency and phase sequence of the resulting oscillation components are predicted. Experimental results of two paralleled inverters confirm the effectiveness of the developed model and the stability analysis. [ABSTRACT FROM AUTHOR]