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Submarine cables are indispensable for offshore wind farms (OWFs) connected to a power grid. The submarine cable can cause certain degrees of impact on the system performance due to its different lengths, characteristics, electrical parameters, etc. This paper employs the power-system simulation software of Power System Simulator for Engineering (PSS/E) for modeling a future-scheduled OWF, i.e., a large-scale doubly-fed induction generator-based OWF of 200 MW, connected to Jang-Bin distribution substation of Taiwan Power System through five feeders, five circuit breakers, two step-up power transformers, a commercial submarine cable, and an underground cable. This paper simulates and compares the electrical quantities of the studied OWF with different operating capacities under various lengths of three types of commercial submarine cable. The transient surge peak voltages at the common bus of the OWF and the bus of Jang-Bin distribution substation subject to the switching of one of the five circuit breakers of the studied OWF under different lengths of the three types of commercial submarine cable are also compared using the power-system simulation software of ATPDraw in Alternative Transients Program (ATP) version of Electromagnetic Transients Program (EMTP).

Gotland is a Swedish island that is connected to the grid only by two high voltage direct current (HVDC) cables. The growth of installed wind power on Gotland has been temporarily stopped due to concerns regarding the reliability of the operations. This study investigates the capability of a centralised energy storage system along with or without wind curtailment to support the growth of installed wind power capacity. The energy storage system is tested for maintaining frequency stability during unintentional islanding through dynamic studies using power system simulator for engineering (PSS/E). The results assess the ability of energy storage to prevent frequency instabilities and provide primary frequency response albeit of the absence of any rotating inertia. The analysis determines the requirements for the power and energy capacity of the energy storage system in relation to the exported power from the HVDC cables at the instant of fault, which eventually relates to the wind power capacity. Moreover, the study examines wind power curtailment as primary and/or secondary frequency response and the impact on the energy capacity. Finally, the study did not explore the effect of fast power ramps on the energy storage to leave the door open for all types of inverter-based energy storage technologies.

Wind energy is rapidly growing. While wind brings us clean and inexpensive energy, its inherent variability and uncertainty present challenges for the power grid. In particular, employing wind energy for power system restoration is very challenging. A fast and reliable restoration plays a vital role to achieve the self-healing power grid. This paper develops a novel offline restoration planning tool for harnessing wind energy to enhance grid resilience. The wind-for-restoration problem is formulated as a stochastic mixed-integer linear programming problem with generated wind energy scenarios. The problem is then decomposed into two stages and solved with the integer L-shaped algorithm. Numerical experiments have been conducted through different case studies using the modified IEEE 57-bus system. The developed tool can provide the scheduled wind power at each restoration time. The impact of wind energy is investigated from the aspects of location and inertia capability, as well as wind penetration, fluctuation, and uncertainty. Moreover, a dynamic response validation tool is developed to validate the results of optimization problem in a dynamic simulation software. Simulation results demonstrate that the optimal wind harnessing strategy can help improve system restoration process and enhance system resilience.

Renewable energy generation capacity in Korea is expected to reach about 63.8 GW by 2030 based on calculations using values from a power plan survey (Korea's renewable energy power generation project plan implemented in September 2017) and the &ldquo, 3020&rdquo, implementation plan prescribed in the 8th Basic Plan for Long-Term Electricity Supply and Demand that was announced in 2017. In order for the electrical grid to accommodate this capacity, an appropriate power system reinforcement plan is critical. In this paper, a variety of scenarios are constructed involving renewable energy capacity, interconnection measures and reinforcement measures. Based on these scenarios, the impacts of large-scale renewable energy connections on the future power systems are analyzed and a reinforcement plan is proposed based on the system assessment results. First, the scenarios are categorized according to their renewable energy interconnection capacity and electricity supply and demand, from which a database is established. A dynamic model based on inverter-based resources is applied to the scenarios here. The transmission lines, high-voltage direct current and flexible alternating current transmission systems are reinforced to increase the stability and capabilities of the power systems considered here. Reinforcement measures are derived for each stage of renewable penetration based on static and dynamic analysis processes. As a result, when large-scale renewable energy has penetrated some areas in the future in Korean power systems, the most stable systems could be optimally configured by applying interconnection measure two and reinforcement measure two as described here. To verify the performance of the proposed methodology, in this paper, comprehensive tests are performed based on predicted large-scale power systems in 2026 and 2031. Database creation and simulation are performed semi-automatically here using Power System Simulator for Engineering (PSS/E) and Python.

This paper proposes the exploitation of Multi-Terminal HVDC grids to improve transfer capability in power systems. Multi-Terminal HVDC systems based on voltage source converters (VSC-MTDC) have been recognized as a promising alternative for the wind power integration. Under low wind scenarios, these grids originally dedicated for wind power transmission can be exploited as an additional interarea transmission path, providing extra dynamic security. The paper focuses on small-signal stability assessment, especially in poor damped oscillations associated with interarea modes. Simulations performed through a generic computational framework have shown that the high level of flexibility and controllability provided by voltage source converters can considerably improve the transfer capacity, while preserving adequate dynamic performance.

Eastern Regional (ER) grid of India is one of the five regional grids consisting of voltage level 765 kV, 400 kV, 220 kV and numerous buses at lower voltage range. ER grid is the backbone of the Indian Grid as it is one of the main power generating hubs. Stability of the Indian Grid depends a lot on ER grid as it is the core of the generation and transmission system. For performing stability studies and to determine the weak area of the grid generally L-Index method is used. For detailed analysis like computation of voltage recovery time, maximum frequency deviation and critical clearing time of the buses of the system L-Index method is not suitable. Hence dynamic simulation is performed as it provides options to compute various parameters of ER Grid. The system has been studied using 197 buses of voltage levels 220 kV and above and transmission lines running over a length of 23,693 km. In this paper the power flow modelling, simulation and analysis of the Eastern Grid of India is performed. L-Index algorithm along with dynamic simulation provides the scope of computation of voltage recovery time, maximum frequency deviation and critical clearing time (by introducing an initial transient disturbance) along with the prediction of weak area of the system which gives a complete picture of transient stability of ER Grid.

This paper presents a novel harmonic domain (HD) approach that computes a two-port network equivalent of a switching converter for power flow studies. The equivalent stems from the harmonic domain admittance matrix (HDAM) of a switching converter which accounts for harmonics interaction. Power flow studies, involving switching converters, require modifying the Jacobian matrix via calculation and incorporation of the partial derivative terms corresponding to the switched part within the iterative solution process. The proposed approach is readily applicable to modern power systems involving electronic converters. Also, it avoids calculating partial derivative terms of the switching converter by including it as a simple, yet an effective, equivalent two-port network, i.e., by just modifying the admittance matrix within the iterative power-flow solution process. This paper demonstrates that the procedure to obtain the PI equivalent is general for any linear time-periodic system and does not rely on library components when embedded into a commercial software tool. The proposed approach is validated by two test networks which involve High-Voltage Direct Current (HVDC) systems. The obtained results are compared, in terms of accuracy, with those given by the Power System Computer-Aided Design/Electromagnetic Transients including Direct Current (PSCAD/EMTDC) software tool, which involves the detailed system model, once steady-state is reached. Also, the results of the proposed approach are verified against those obtained from a dedicated power flow software tool, i.e., Power System Simulator for Engineering (PSS/E).

This study presents an approach to build a reduced-order model (ROM) for the governor control systems of diesel-engine generators in an island power system. The hybrid particle swarm optimisation (PSO) is used in the parameter identification of the ROM. The reduced-order governor system model could be a useful and feasible model in the stability analysis of the island power system by using power system simulator for engineering. The results of the ROM and a sixth-order model have been compared. It is found that the ROM with the parameter values identified using the hybrid PSO is robust. Moreover, real-case validation of the ROM shows that it is usable to analyse stability and contingency in the power system.

Analyses and comparisons of generic models and a novel modeling method of line-commutated converter (LCC)-based high voltage direct current (HVDC) systems are presented for the power system simulator for engineering (PSS/E) simulation tool. The main purposes are to describe the dynamics of the DC voltage and current of HVDC system and to improve estimation of the maximum values using the generic and proposed HVDC models when AC line-to-ground faults are occurred. For the generic HVDC models, the characteristics and limitations as well as parameter investigations are conducted. Three modules are also are developed for the proposed HVDC model, which are composed of (a) AC/DC conversion; (b) controller selection; and (c) DC line model. Case studies were conducted considering the real-operated HVDC system in Korea under the PSS/E and power systems computer aided design (PSCAD) simulation environments. The simulation results were compared with measured data from the real-operated HVDC system and the results from the PSCAD HVDC models considering single- and three-phase line-to-ground faults. The case study results show that a specific generic HVDC model in PSS/E can simulate the dynamics of the DC voltage and current after the AC line-to-ground faults. The case studies also showed that the proposed modeling method is effectively improves the estimation of the maximum DC voltage and current values for the AC line-to-ground faults.

We describe a method for simulating an electromagnetic induction type wireless power transmission (WPT) device. This simulator was based on the finite-difference, time-domain method. To reduce computation time, two graphics processing units (GPUs) were used as accelerators for the electromagnetic field computation. The first GPU calculated the electromagnetic field for the non-resonance state, and the second GPU calculated the field for the resonance state. Only two physical quantities needed to be exchanged between the two GPUs: self-inductance and the magnetic coupling coefficient. Capacitors and a load resistance were virtually connected to the coils as lumped elements. The experimental and simulation results were in good agreement. It is expected that a transient response analysis of WPT devices will become possible in the future using this simulation architecture.

The paper discusses the modeling of emergency control system of turbine frequency and power regulators using a hybrid real time simulator of electric power system. It presents the results of pilot simulation of frequency and power regulators ensuring dynamic and static stability in an electric power system.

This paper presents a review on distributed generation planning in the distribution power system networks from different power system performances such as minimization of real and reactive power loss of the system, enhance power system loadability of the system, enhance power system stability of the system, enhance power system reliability of the system, enhance power system security of the system, available power transfer capacity of the system, enhance power system oscillations of the system, more flexible operation and bandwidth of the system, enhance voltage profile of the system buses, reduce short circuit capacity of the transmission line, more real and reactive power support and environmental friendly (green house gases) viewpoints. This paper also presents the current status of distributed generation planning in a distributed power system networks from different power system performance viewpoints. This survey article is very much useful for scientific persons, industrial persons and researchers in field of distributed generation planning in distribution power system networks.

Significant progress has been made in the development of the small pressurized water reactors (SPWR). Unique characteristics of the SPWR deliver challenges to its control system design. In order to facilitate the control system design process and enhance its efficiency, it is important and necessary to establish a control system design and validation platform. Using shared memory technology, an engineering simulator coupled with MATLAB/Simulink is employed to achieve this objective. Shared memory is an efficient method to exchange data within programs. Dynamic data exchange and simulation time synchronization methods are particularly treated. To verify the platform, an SPWR with its control system is modeled using the platform and the simulator. Thermal-hydraulic modeling of the SPWR is carried out using Relap5, and its nodalization is introduced. The objectives of the control strategy are to maintain the average coolant temperature linearly varying with the reactor power and steam pressure constant. A preliminary SPWR control system is designed with proportional-integral-derivative (PID) controllers, and is implemented in MATLAB/Simulink associated with the engineering simulator. Subsequently, in order to evaluate the performance of the established simulation platform, transients of abrupt load changes and wide range load changes are simulated and simulation results are verified against those obtained from the engineering simulator alone. It is demonstrated that simulation results of both platforms are consistent with each other, which proves that the coupling of engineering simulator and MATLAB/Simulink is successful. Therefore, the established simulation platform can be committed to control system design and validation. Furthermore, it is revealed that the designed control strategy is able to regulate the process parameters such as coolant average temperature and steam pressure to the desired values.

Modern power systems are designed prudently and then operated according to the permitted equipment limits set out in standards, policies, and procedures. To meet the growing demand, utilities apply transmission expansion tools for planning and updating their transmission assets. However, due to their unpredictable nature, transmission contingencies cannot be easily integrated during the planning stage. Although computationally cumbersome, probabilistic planning is an approach that could enable an objective comparison of the economic risk associated with a contingency event versus the cost of upgrades. In the context of the development of a generic assessment tool for such a process that could be employed by utilities, this study presents a systematic approach for transmission system expansion planning that includes consideration of an N − 1 contingency. The proposed method provides an estimate of the potential economic losses that could occur due to contingencies related to transmission, which are quantified as the cost of expected energy not supplied. The study then introduces a proposed formulation that computes an optimal plan for transmission system reinforcement that will eliminate the economic losses associated with N − 1 contingencies. The results reveal that in specific cases, upgrading the system has economic merit as well as offering the benefits to be derived from a robust transmission system.

Battery-Based Energy Storage Transportation (BEST) is a potential solution for optimizing the power system operations with a high penetration of wind energy. In this paper, we propose a scenario-based stochastic model for the BEST-integrated power system scheduling. In this model, load and wind energy forecasting inaccuracies and random disturbances are modeled as scenario trees using the Monte Carlo simulation method. Random disturbances represent forced outages of both power system and railway system components, including generation units, transmission lines, railway stations, and railway lines. Benders decomposition is adopted to solve the stochastic model. Two BEST-integrated power systems are used to illustrate the proposed model and the performance of the proposed solution algorithm. The first one is a 6-bus power system integrated with a 3-station and 3-line railway network. The second one is the modified IEEE 118-bus power system integrated with a railway network composed of 8 railway stations and 10 rail lines. Simulation results show that the BEST system implementation is a viable option for managing the large-scale integration of wind power which can reduce the curtailment of wind power and accordingly lower the operation cost of power systems.

This paper presents a software tool to simulate a practical problem in smart grid systems. A feature of the smart grid is a system self-recovery capability in the occurrence of anomalies, such as a recovery of a power distribution network after an occurrence of a fault. When this system has a capacity for self-recovery, it is called self-healing. The intersection among areas as computer science, telecommunication, automation and electrical engineering, has allowed power systems to gain new technologies. However, because it is a multi-area domain, self-recovery simulation tools in smart grids are often highly complex as well as presenting low fidelity by using approximation algorithms. The main contribution of this paper is a simulator with high fidelity and low complexity in terms of programming, usability and semantics. In this simulator, a computational intelligence technique and a derivative method for calculating the power flow were encapsulated. The result is a software tool with high abstraction and easy customization, aimed at a self-healing system for a reconfiguration of an electric power distribution network.

Submarine cable is indispensable for offshore wind farms (OWFs) connected to a power grid, and it can cause certain degrees of impact on system performance due to different lengths, characteristics, and electrical parameters of the employed submarine cables. This paper employs the power-system simulation software of Power System Simulator for Engineering (PSS®E) for modeling a future-scheduled OWF, i.e., a large-scale doubly-fed induction generator (DFIG)-based OWF of 200 MW, connected to Jang-Bin Distribution Substation in Taiwan through five feeders, five circuit breakers, two step-up power transformers, commercial submarine cables, and underground cables. This paper simulates and compares the electrical quantities of the studied OWF with different operating capacities under various lengths of three types of commercial submarine cable. The transient surge peak voltages at the common bus of the OWF and the bus of Jang-Bin Distribution Substation due to the switching of one of the five circuit breakers of the studied OWF under different lengths of the three types of commercial submarine cable are also compared using the power-system simulation software of EMTP/ATPDraw.

Voltage stability means the ability of the power system network to maintain steady-state voltage value at all buses in the system under normal condition and after being subjected to a disturbance. This research highlights the effect of solar photovoltaic (PV) as the subject of disturbance to the network system as this kind of energy source has emerged towards higher level of integration into the national grid. High penetration of solar PV into the grid may cause several issues of stability and security to the system particularly effecting the normal voltage and line overloading. This research is focused on the simulation of power flow to study the transmission network behavior with and without the solar PV interconnection. To accomplish the research objectives, the network system will be modelled in a software known as Power System Simulator for Engineering (PSSE). The simulation result will be discussed and analyzed using Voltage Stability Indices (VSI) to prove and strengthen the theory behind the literature review.

In response to the power impact effect resulting from merging large-scale offshore wind farms (OWFs) into the Taiwan Power (Taipower) Company (TPC) system in the future, this study aims to discuss the situation where the offshore wind power is merged into the power grids of the Changbin and Changlin areas, and study a Low-Voltage Ride-Through (LVRT) curve fit for the Taiwan power grid through varying fault scenarios and fault times to reduce the effect of the tripping of OWFs on the TPC system. The Power System Simulator for Engineering (PSS/E) program was used to analyze the Taipower off-peak system in 2018. The proposed LVRT curve is compared to the current LVRT curve of Taipower. The research findings show that if the offshore wind turbine (OWT) set uses the proposed LVRT curve, when a fault occurs, the wind turbines can be prevented from becoming disconnected from the power grid, and the voltage sag amplitude of the connection point during the fault and the disturbances after the fault is cleared are relatively small. In addition, according to the transient stability analysis results, the system can return to stability after fault clearance, thereby meeting the Taipower transmission system planning criteria and technical key points of renewable energy power generation system parallel connection technique.

The effects of incorporating large-scale offshore wind farms into the Taiwan Power (Taipower) Company's electricity system must be given attention. The goal of this study was to formulate a new Low-Voltage Ride-Through (LVRT) curve suitable for the Taiwan power grids by analyzing different fault scenarios and times of faults in power grids of the Changbin and Changlin districts after the integration of large-scale offshore wind farms. The proposed LVRT curve can alleviate the effects of circuit trips in the offshore wind turbines on the Taipower system. A power system simulator for engineering (PSS/E) software was employed to analyze the off-peak system of Taipower in 2018 and compare the proposed LVRT curve with the existing Taipower-specified LVRT curve. According to the analysis results, when deployed in the offshore wind turbine system, the proposed LVRT curve not only prevented the decoupling of the turbines and grids during faults, but also reduced the voltage dip at the point of common coupling and the disturbance after the fault clearance. Moreover, according to the transient stability and power generator motor angle analysis, the system could recover stability after fault clearances, thus satisfying the provisions of the Planning Guideline for Power Transmission System and Technical Points for Parallel Connection of Renewable Energy Power Generation System of Taipower Company.

For reliable operation of a power system, its situational awareness should be accurate. Similarly, for power system planning, correct post-mortem analysis of system events is required. A novel event assessment method based on the energy of system frequency and generator's rotational speed measurements has been proposed in this paper which can be used for both the real-time as well as off-line event assessment purposes. In this paper, event detection is carried out based on the magnitude of the second difference of the energy of machine's rotational speed/system frequency measurements. A detection threshold has been designed for this purpose. It successfully assesses multiple events occurring in small time interval. For event localization, a novel indicator named 'Sharpness Index' has been proposed in this paper. Performance of the proposed approach has been compared with a few existing methods and found to be more accurate and comprehensive. This proposed event assessment technique has been tested for various test cases simulated using PSS/E (Power System Simulator for Engineering) as well as real PMU (phasor measurement unit) measurements.

A detailed model of a full-conversion wind turbine (WT) is presented in this article. The developed model uses cosimulation by several freeware WT simulation tools-such as the turbulent wind simulator (TurbSim) and Fatigue, Aerodynamics, Structures, and Turbulence (FA ST), both from the National Renewable Energy Laboratory (NREL)-and commercial software to perform a detailed analysis of all WT components. An optimal level of model complexity is achieved to allow the design, analysis, and simulation of the controls and subsystem interactions within a turbine under various conditions. The article introduces a maximum power point tracking (MPPT) control for a variable-speed WT with stall power regulation and analyzes its influence on flexible blades and the drivetrain. The proposed simulation tools and the developed model reveal some stability issues and subsystem interaction complexities that are not visible in simpler models. In this article, modeling results are presented that detail the performance of the WT system.

Major power grid blackouts in various parts of the world are characterized by voltage collapse. This paper studies the blackout case in the Indian power grid due to voltage collapse in the inter-regional corridor. First, the computer simulation models are tuned to match responses from the phasor measurement units at various locations in the grid. The inter-area mode with the frequency of 0.3 and 0.5 Hz with reduced damping were observed and resulted due to switching actions that occurred during the disturbance. This paper simulates the complex power grid network for various loading conditions of Northern region using power system simulator for engineering. Further, the system variables are analyzed using Prony method to estimate the inter-area mode for different NR loading conditions. The eigen values associated with the 0.3 Hz mode depict the movement from open left half plane into open right half plane with a slight increase in the parameter indicating “hopf bifurcation.” This paper also discusses the maximum loading capacity for the inter-regional lines in-order avoid loss of small signal stability, and highlights the use of real time phasor measurement unit measurements in-order to estimate and track the oscillatory modes.

In this paper, an extensive review on power system studies with inclusion of wind generation has been attempted. The various basic aspects of wind generation including basics of wind power statistics, wind farm, wake-effect, and environmental effects on wind generation have also been discussed. For the practical analysis of power system with wind generation, accurate wind generation models must be developed with load flow methods that can be integrated in to the normal power system algorithm to cater the need of inclusion of uncertainty in power system. So, various wind turbine generator models and deterministic load flow methods for transmission and distribution system have also been reviewed. The intermittent and fluctuating nature of wind power injected into the grid causes variations in bus voltages and line power flows of transmission system which is going to be quite significant in the future. So, for the successful integration of wind generation in the grid, these variations need to be analyzed, estimated and quantified, which can be achieved through probabilistic load flow. The various probabilistic load flow methods along with application and extension have also been reviewed. The correlation between wind generators in a wind farm has also been discussed. For the successful operation of power system with wind, it is mandatory to have power system planning and contingency analysis with uncertainty. The different methods used in power system planning and contingency analysis have also been reviewed. For the integration of wind generation to be viable, it must be cost effective and free of technical abnormalities. A review on the technical and economic issues related to the integration has also been done. Finally, with the increase in installation of offshore wind farms, HVDC application with wind farms has also increased. So, HVDC techniques with wind generation have also been reviewed in detail.

The main objective of this paper is to study the implementation of a battery energy storage system (BESS) in order to improve the dynamic behaviour of an offshore wind farm. Special attention is given to the frequency excursions limitation in the sequence of a fault on the onshore grid. This goal is accomplished by setting up a case study in which an offshore wind farm is connected to an onshore grid through a high voltage direct current line commutated converter (HVDC-LCC) link. The Power System Simulator for Engineering (PSS/E) simulation tool is used to implement the whole system, including the onshore and offshore grids and the load flow and dynamic models of the conventional generators, the wind turbine generators (WTGs), the HVDC-LCC link and the BESS. With the BESS out of service, some protective actions of the DC link lead to the uncontrolled frequency increase of the WTG, which are consequently tripped out. The BESS proves to be essential, as it allows the offshore wind farm to keep runni...

This paper presents a simulator to help electrical engineering students and professionals in the learning process. The proposed tool embodies Virtual Reality technologies on the improvement of understanding equipment maneuvers in distribution power systems. The tool has a virtual didactic distribution network in which the students handle several real tasks related to operation and maintenance of distribution network through applied technology. We hope that this tool can contribute to develop and improve professional skills in engineering at a low cost and furthermore it supports laboratory and associated technical activities.

In the planning and operation of power systems, actions are taken in different processes and time-horizons. The purpose of these actions is to secure a high reliability level. Although the three main processes (grid development, assetmanagement, and system operation) are described in literature, there has been no explicit study on the time-horizons (long-term, mid-term, and short-term) and actual time-scale (decades, years, months, etc.) that these processes focuson. This study aims at making a review of the various activities performed by transmission system operators while reviewing the concept of each time-horizon and methodologies developed in literature. As decisions taken in differenttime-horizons can influence each other, the interactions and overlapping are discussed.

SUMMARY Chubu Electric Power Co., Ltd.’s hybrid power system simulator consists of analog models and hybrid models. The power system facilities are downsized as an analog model, while the synchronous generators and the loads are modeled as an actual current source model through the amplifier and the digital model. In recent years, there is a growing interest in analyzing power system dynamic phenomena caused by a high penetration of distributed generations. Therefore, the multifunctional generator model that can simulate distributed generation has been developed.

Now-a-days the Flexible AC Transmission Systems (FACTS) technology is very effective in improving the power flow along the transmission lines and makes the power system more flexible and controllable. This paper deals with overload transmission system problems such as (increase the total losses, raise the rate of power generation, and the transmission line may be exposed to shut down when the load demand increase from the thermal limit of transmission line) and how can solve this problem by choosing the optimal location and parameters of Unified Power Flow Controllers (UPFCs). which was specified based on Genetic Algorithm (GA) optimization method, it was utilized to search for optimum FACT parameters setting and location based to achieve the following objectives: improve voltages profile, reduce power losses, treatment of power flow in overloaded transmission lines and reduce power generation. MATLAB was used for running both the GA program and Newton Raphson method for solving the load flow of the system The proposed approach is examined and tested on IEEE 30-bus system. The practical part has been solved through Power System Simulation for Engineers (PSS\E) software Version 32.0 (The Power System Simulator for Engineering (PSS/E) software created from Siemens PTI to provide a system of computer programs and structured data files designed to handle the basic functions of power system performance simulation work, such as power flow, optimal power flow, fault analysis, dynamic simulations...etc.). The Comparative results between the experimental and practical parts obtained from adopting the UPFC where too close and almost the same under different loading conditions, which are (5%, 10%, 15% and 20%) of the total load. can show that the total active power losses for the system reduce at 69.594% at normal case after add the UPFC device to the system. also the reactive power losses reduce by 75.483% at the same case as well as for the rest of the cases. in the other hand can noted the system will not have any overload lines after add UPFC to the system with suitable parameters.

Power system contingency analysis plays a pivotal role in identifying potential weak spots and ensuring reliable operation of power systems. Voltage stability is a critical aspect of performance evaluation of power system reliability. The North American Electric Reliability Corporation demands utilities to perform compliance studies to make sure that their systems meet the requirements of adequacy and security aspects of reliability. This paper presents contingency studies performed for a real utility system. The voltage stability criteria are defined, and a general software package is used to perform analysis including regular ACCC analysis, PV analysis, QV analysis, voltage sensitivity analysis, and dynamic studies. The analysis can be carried out manually. In order to facilitate analysis and to avoid tedious steps of running the simulation, recording results, and processing and reporting results, software tools are developed to automate all sorts of tasks and steps based on Python language. The studies have demonstrated that the software tools are efficient for carrying out contingency studies. Example results are reported in the paper in order to illustrate typical study results for a real power utility system.

Power system stability is a major challenge in the secured operation of today’s interconnected power systems. Voltage stability as a branch of power system stability, is a major problem facing power systems in Ghana. The power system is subjected to major blackouts or collapses due to voltage instability. It is manifested by several distinguishing features: low system voltage profiles, heavy reactive line flows, inadequate reactive support, and heavily loaded power systems. Voltage stability depends on the ability of a power system to maintain acceptable voltage for system buses under normal conditions, and system disturbances. This paper evaluates the steady-state voltage stability of the power system through modelling and simulation using the Power System Simulator for Engineering power system analysis software and the results validated with MATPOWER. Load flow simulations using the Newton Raphson method under steady-state base load condition with and without contingencies were done. Simulation results revealed under normal, and contingency cases show the power system has voltage profile, that violates the voltage stability constraint of between 0.95 pu and 1.05 pu for normal system voltage, high transmission system losses and heavy congestion. The Flexible Alternative Current Transmission System (FACTS) devices was used to improve the power system stability. Three types of FACTS devices: SVC, STATCOM, and TCSC are selected and optimally placed in the power system to improve voltage stability. Generic algorithm as artificial intelligence-based method was used in MATLAB environment to optimally size and locate five (5) FACTS devices; one (1) STATCOM and four (4) SVC in the power system. The algorithm was found to be reliable as it yielded good results by the improvement in voltage stability and decreasing the transmission line active and reactive power losses significantly.

As a widely used power system analytical toolset in the world, Power System Simulator for Engineering (PSS/E) is also characterizing with its powerful user-defined function. This paper illustrates a study of user-defined modeling function in PSS/E through modeling a VSC-HVDC transmission system. The user-defined modeling (UDM) function of PSS/E is introduced in detail, then a modeling method for VSC-HVDC is proposed. Through comparing the simulation curves of user-defined VSC-HVDC in PSS/E with that simulated by PSCAD/EMTDC, the correctness of the VSC-HVDC user-defined model, the feasibility as well as the practicability of PSS/E’s user-defined function are validated. The modeling method proposed in this paper can provide guidance and a basis for the modeling of other complex components in PSS/E for simulations.

To damp the low-frequency oscillations which occurred due to the disturbances in the electrical power system, the generators are equipped with Power System Stabilizer (PSS) that provide supplementary feedback stabilizing signals. The low-frequency oscillations in power system are classified as local mode oscillations, intra-area mode oscillation, and interarea mode oscillations. Double input multiband Power system stabilizers (PSSs) were used to damp out low-frequency oscillations in power system. Among dual-input PSSs, PSS4B offers superior transient performance. Power system simulator for engineering (PSS/E) software was adopted to test and evaluate the dynamic performance of PSS4B model on Iraqi national grid. The results showed that after installing the PSS in a specific plant the oscillation of rotor angle, bus frequency, speed, power flow is better than without PSS during the disturbances that occurred during the simulations. All the PSS/E simulation and tests were done in the National dispatch center (NDC) laboratory, Ministry of Electricity.

Owing to the variability of large-scaled wind power system, the development of wind farm management technologies and related compensation methods have been receiving attention. To provide an accurate and reliable output power, certain wind farm adopts a specified management system including a wind prediction model and grid expectation solutions for considering grid condition. Those technologies are focused on improving the reliability and stability issues of wind farms, which can affect not only nearby system devices but also a voltage condition of utility grid. Therefore, to adapt the develop management system, an expectation process about voltage condition of Point of Common Coupling should be integrated in operating system for responding system requirements in real-time basis. This paper introduce a grid imposing method for a real-time based wind farm management system. The expected power can be transferred to the power flow section and the required quantity about reactive power can be calculated through the proposed system. For the verification process, the gauss-seidel method is introduced in the Matlab/Simulink for analysing power flow condition. The entire simulation process was designed to interwork with PSCAD for verifying real power system condition.

According to the demand of sustainable development and low-carbon electricity, it is important to develop clean resources and optimize scheduling generation mix. Firstly, a novel method for probabilistic production simulation for wind power integrated power systems is proposed based on universal generating function (UGF), which completes the production simulation with the chronological wind power and load demand. Secondly, multiple-period multiple-state wind power model and multiple-state thermal unit power model are adopted, and both thermal power and wind power are coordinately scheduled by the comprehensive cost including economic cost and environmental cost. Furthermore, the accommodation and curtailment of wind power is synergistically considered according to the available regulation capability of conventional generators in operation. Finally, the proposed method is verified and compared with conventional convolution method in the improved IEEE-RTS 79 system.

The deepening penetration of wind resources introduces major challenges into power system planning and operation activities. This is due to the need to appropriately represent salient features of wind power generation from multiple wind farm sites such as nonstationarity with distinct diurnal and seasonal patterns, spatial and temporal correlations, and non-Gaussianity. Hence, an appropriate model of multisite wind power production in systems with integrated wind resources represents a major challenge to meet a critical need. In this paper, we aim at defining a new methodology to improve the quality of generated scenarios by means of historical multisite wind data and effective deployment of time series and principal component (PC) techniques. Scenario-based methodologies are already available in power systems, but sometimes lack in accuracy: this paper proposes a methodology that is able to capture the main features of wind: it can both characterize spatio-temporal properties and be used to reduce size of data sets in practical applications without using any simplifying assumption. Extensive testing indicates good performance in effectively capturing the salient wind characteristics to provide useful models for various problems related to multisite wind production, including security assessment, operational planning, environmental analysis, and system planning. An application to security assessment is presented.

With larger penetrations of wind power, the uncertainty increases in power systems operations. The wind power forecast errors must be accounted for by adapting existing operating tools or designing new ones. A switch from the deterministic framework used today to a probabilistic one has been advocated. This two-part paper presents a framework for risk-based operations of power systems. This framework builds on the operating risk defined as the probability of the system to be outside the stable operation domain, given probabilistic forecasts for the uncertainty, load and wind power generation levels. This operating risk can be seen as a probabilistic formulation of the N − 1 criterion. In Part I, the definition of the operating risk and a method to estimate it were presented. A new way of modeling the uncertain wind power injections was presented. In Part II of the paper, the method's accuracy and computational requirements are assessed for both models. It is shown that the new model for wind power introduced in Part I significantly decreases the computation time of the method, which allows for the use of later and more accurate forecasts. The method developed in this paper is able to tackle the two challenges associated with risk-based real-time operations: accurately estimating very low operating risks and doing so in a very limited amount of time.

The concept of dynamic rating (DR) implies that the capacity of a component varies dynamically as a function of external parameters, while the rating traditionally is based on the worst-case. The value of DR thus lies in utilizing existing equipment to a greater extent. By implementing DR and correlating the new ratings with wind power generation, more generation can be implemented. The aim is hence to facilitate connection of renewable electricity production. This paper provides two main contributions: 1) a general dynamic line rating (DLR) calculation model on overhead lines; and 2) an economic optimization simulation model regarding wind power integration comparing DLR with more traditional approaches. These models can both be implemented together, but also separately. The DLR calculation model is easy to use by companies in daily operation where the dynamic line capacity is calculated as a function of static line capacity, wind speed, and ambient temperature. The DLR calculation model is furthermore compared with more comprehensive calculations that validate that the model is accurate enough. This paper also provides an application study where both proposed models are exemplified together and evaluated. Results from this study conclude that it is a significant economic potential of implementing DR within wind power integration. QC 20140902

Simulations of production costs, flows, and prices are crucial inputs to generation and transmission planning studies. To calculate average system performance for many alternatives over long time p ...

Long-term transmission and generation planning face numerous challenges to accommodate the integration of a high penetration of variable generation (VG). System flexibility, or the ability of a system to meet changes in demand and VG production, is one such issue receiving much attention. This paper presents a methodology to assess the flexibility of a power system while explicitly considering the limitations of the transmission network. By determining only the flexibility available from resources which could be realized in real-time operation due to transmission constraints, a more realistic assessment of a system's flexibility can be made. The flexibility of the IEEE Reliability Test System is assessed using two metrics. Transmission is shown to have a significant effect on the availability of flexibility and the risk posed to the system by net load ramps. The impact is seen to be strongly dependent on the variability of the net load and on the distribution of online resources. A nonlinear relationship between the installed VG and system flexibility is found, with regions of significant inflexibility occurring at certain VG penetrations.

Interconnection wide electric transmission system has been envisioned to facilitate the growth of renewable energy, enhance reliability, improve system operating efficiency, and reduce emissions. In this paper, we propose an explicit planning approach for transmission design at the national level. It has been applied to the U.S. system to design transmission overlays for multiple future generation scenarios. Associated simulation results suggest that a national transmission overlay provides economic, environmental, and system performance benefits.

In the future a growing amount of power electronics will lead to a transition of the power system to a structure with very low synchronous generation. Due to large transit power flows and uncertainties, transmission systems are being operated under increasingly stressed conditions and are close to their stability limits. Together with the integration of large amounts of renewable generation with power electronic interfaces and the addition of high-voltage direct current (HVdc) links into the power system, these challenges will necessitate a review of the operation and control of transmission networks. This article will demonstrate the need for R&D performed by network operators and explain a set of challenges, focusing on three main areas: transmission grid operation in a new power system environment, the need to increase overhead line (OHL) utilization, and the impact of reduced inertia on power system frequency.

This paper studies a new type of power transmission network and power communication transmission technology. First, the working principle and network topology form of power optical transmission network have been presented in this paper, the power budget of the optical transmission model has been given through the loss of optical system and dispersion limit theory. Then the power transmission network and power communication transmission have been simulated through EPOCHS software simulation software, which based on the design aspects of CP transport port, transport protocol and transmission signal, the simulation parameters has been set according to the transmission mathematical model, and the security and efficiency of power transmission network has been proved through the fault signal diagnosis and signal characteristics of delay and jitter. The result of simulation shows that power transmission network power transmission have shorter delay and less jitter, which provides the reliable theory basis for the development of electric power communication network and complex network.

The increased usage of renewable energy in conjunction with nonrenewable energy source is disturbing the reliability of generation system. This is mainly because of the variability of the power coming from renewable energy sources. Weather change is the main cause for the renewable energy variability. The weather not only disturbs generation, but also transmission line sag-tension and conductor length, thereby varies the voltage drop in the line. The combined transmission line loss, generation variability and load variation make punctual power flow analysis unreliable for planning and forecast purpose. This paper focuses on identifying the main driving forces for power uncertainty. A test case study is conducted and the result shows there is a high variation of the wind and solar energy that led to power variation.