Power System Analysis Software Research Articles

Research on the Influence of Traction Load on Transient Stability of Power Grid Based on Parameter Identification

The traction load of electrified railways is a special user of the power system, which will have a significant impact on and pose a challenge to the power system after grid connection. Considering the impact and fluctuation of traction load connected to the power grid, this paper proposed a method to study the influence of traction load on the transient stability of the power grid based on parameter identification. Firstly, according to the operation characteristics of traction load, a comprehensive traction load model based on the measurement-based method of induction motor parallel power function model is selected, and the objective function of parameter identification is determined. Then, the specific steps of using the improved gray wolf optimizer (IGWO) algorithm to achieve the parameter identification of the traction comprehensive load model are introduced, including chaotic map, nonlinear convergence factor, and individual position update. Next, with the IEEE39 bus system as the network background, the load parameters identified by the measured data of a line of the Beijing–Shanghai high-speed railway are imported into the Power System Analysis Software Package (PSASP) 7.0 for transient simulation to analyze the impact of traction load on the transient stability of the power grid. Finally, three typical load models are compared with the traction load model to draw relevant conclusions, and it is verified that the traction load characteristics are different from the general load model, which provides reference for the connection of electrified railway traction load to the power grid and the economic and technical construction of the power system.

Optimal Configuration of Battery Energy Storage for AC/DC Hybrid System Based on Improved Power Flow Exceeding Risk Index

After the fault disturbance (DC bi-polar blocking) in the AC/DC hybrid system, when the battery energy storage system (BESS) near the fault location is used to eliminate the power transfer, some sensitive and vulnerable transmission lines still have the problem of power flow exceeding the limit value. Therefore, an optimal configuration of BESS for AC/DC hybrid systems based on power flow exceeding risk index is proposed, which is used to eliminate the impact of power transfer on transmission lines. Firstly, considering the line outage distribution factor, the power flow exceeding risk index is established, which is used to judge the sensitive and vulnerable transmission lines on the shortest path power flow after the fault in the AC/DC hybrid system. The shortest path power flow is found by using the Dijkstra algorithm; the transmission lines nodes of the shortest path power flow are selected as candidate nodes for BESS configuration. Secondly, considering the safe and stable operation capability of the transmission lines, a multi-objective optimal mathematical model of BESS configuration for the AC/DC hybrid system is established, which minimizes the annual investment cost of BESS and maximizes the sum of the power flow exceeding risk index. Finally, the CEPRI36V7 power grid model in Power System Analysis Software Package (PSASP) is used for simulation analysis to verify the effectiveness of the proposed method.

Research on Distributed Photovoltaic Grid-connected Mode Based on PSASP

With the continuous implementation of the carbon peak and carbon neutrality, a large number of distributed solar power stations have been integrated into the grid, which has caused a strong impact on the safe and stable operation of the traditional power system. Based on this, the grid-connected mode of distributed solar power stations is studied, and three types of grid connection are proposed. Mode A is merged into the 66 kV bus side of the 220 kV substation through the 66 kV dedicated line; Mode B is merged into the 66 kV bus side of the 66 kV substation through the 66 kV dedicated line; Mode C is T-connected to the 66 kV transmission line through 66 kV dedicated line. By using a power system analysis software package (PSASP), we can build a model of a certain regional power grid and study the effects of the above three grid-connected modes on system voltage stability, short-circuit current, and network loss. The study shows that the three modes are all feasible. Mode A has the smallest change in voltage quality and short-circuit current of the grid-connected substation and has the smallest network loss of the three modes.

Dynamic Equivalents of Nonlinear Active Distribution Networks Based on Hammerstein-Wiener Models: An Application for Long-Term Power System Phenomena

In traditional power systems, the load consumption inside the distribution networks has a relatively passive behavior. Consequently, transmission system operators have commonly aggregated the load centers using static loads such as exponential load models. This is a practical approach for bulk power system stability studies. In modern systems, the impact of distributed generation units on the system dynamics can no longer be neglected. Static load models fall short to represent the highly dynamic behavior of active distribution networks. This paper proposes a methodology for equivalencing such networks while conserving the dynamics of interest for long-term stability studies. The methodology is based on Hammerstein-Wiener models that use only boundary variables measured at the distribution network point of common coupling. Therefore, unlike gray-box models, no previous knowledge about the system is required. Furthermore, the proposed methodology has a transparent relationship to linear systems and a convenient block representation that can be implemented in commercial power system analysis software using only standard elements. This allows for easy implementation, overcoming a barrier for a rather conservative sector such as power systems planning and operation. The conclusions are derived from time-domain simulations on the IEEE test system for voltage stability assessment.

Research on Influence of Battery Energy Storage System on Voltage Transient Stability

In view of the current transient stability of the grid voltage, this paper studies the reactive power support of the access point when the energy storage system is connected to the power grid by studying the four-quadrant working mode of the energy storage system. Using the energy storage system built in the Power System Analysis Software Package PSASP and the CEPRI36 node example, the transient stability changes of the power system voltage before and after the energy storage connection are simulated and compared. The results show that the energy storage has a restraining effect on the voltage fluctuation.

Study on power grid transient stability control assisted by large-scale energy storage

With the development of energy storage technology, energy storage power station has gradually become one of the main means to solve the voltage instability of the main network caused by uHV DC bipolar phase lock. Therefore, energy storage model has become a difficulty in research. Firstly, the structure model of power storage station participating in power grid voltage transient stability control system is constructed, and the control strategy of power storage station is analyzed. Secondly, in the power system analysis software package (PSASP), the ES model of transient voltage stability control is established by using user-defined modules, and each module in the model is introduced in detail, so as to realize the purpose of enhancing voltage transient stability control of energy storage power station connected to the power grid. Finally, the simulation results show that compared with the adjustable camera, the voltage recovery speed is faster when the same capacity ES is connected in the same place. For example, the voltage recovery speed of 110kV bus decreases from 2.42s to 1.69s, and the recovery speed is increased by 30.17%. And PCS of ES power station has enough short time (<1s) overload capacity, then the ES configuration capacity can be less than the camera capacity.

Comparison of Radial and Zonal DC Distribution System for Hybrid-Powered Trimaran Vessels Power Flow Analysis

Two types of power grid structures have been applied to the shipboard, namely the radial and the zonal networks. These two distribution systems have different power characteristics transmitted to the bus panel. The power characteristics affect the power density of each bus at each level. This paper explores the power characteristics of the radial type and the zonal type power grid structures in a DC distribution system. The power flow of both distribution system types has been determined by the Adaptive Newton-Raphson method and simulated based on ship operation conditions using Electrical Power System Analysis Software (ETAP). In determining the power flow for the DC distribution system, one-line diagram modelling is developed in radial type and zonal type. The simulation parameters are adjusted to the operating conditions of the ship, namely sailing, manoeuvring, loading-unloading, and at the port. After that, a power flow simulation has been carried out using ETAP and has showed what had successfully implemented the power flow in the DC distribution system for radial and zonal types. The capacity of Power generation is adequate all through a ship operation. The characteristics of the transmitted power show that the zonal type has a higher efficiency rate than the radial type. The zonal type has a backup bus so that the electrical system's reliability is higher than the radial type. However, the power distributed to the equipment bus from the load bus, both the radial type and the zone type, has the exact power requirements.

Demand Side Management Techniques for Home Energy Management Systems for Smart Cities

In this paper, three distinct distributed energy resources (DERs) modules have been built based on demand side management (DSM), and their use in power management of dwelling in future smart cities has been investigated. The investigated modules for DERs system are: incorporation of load shedding, reduction of grid penetration with renewable energy systems (RES), and implementation of home energy management systems (HEMS). The suggested approaches offer new potential for improving demand side efficiency and helping to minimize energy demand during peak hours. The main aim of this work was to investigate and explore how a specific DSM strategy for DER may assist in reducing energy usage while increasing efficiency by utilizing new developing technology. The Electrical Power System Analysis (ETAP) software was used to model and assess the integration of distributed generation, such as RES, in order to use local power storage. An energy management system has been used to evaluate a PV system with an individual household load, which proved beneficial when evaluating its potential to generate about 20–25% of the total domestic load. In this study, we have investigated how smart home appliances’ energy consumption may be minimized and explained why a management system is required to optimally utilize a PV system. Furthermore, the effect of integration of wind turbines to power networks to reduce the load on the main power grid has also been studied. The study revealed that smart grids improve energy efficiency, security, and management whilst creating environmental awareness for consumers with regards to power usage.

An Improved Crow Search Algorithm Applied to the Phase Swapping Problem in Asymmetric Distribution Systems

This paper discusses the power loss minimization problem in asymmetric distribution systems (ADS) based on phase swapping. This problem is presented using a mixed-integer nonlinear programming model, which is resolved by applying a master–slave methodology. The master stage consists of an improved version of the crow search algorithm. This stage is based on the generation of candidate solutions using a normal Gaussian probability distribution. The master stage is responsible for providing the connection settings for the system loads using integer coding. The slave stage uses a power flow for ADSs based on the three-phase version of the iterative sweep method, which is used to determine the network power losses for each load connection supplied by the master stage. Numerical results on the 8-, 25-, and 37-node test systems show the efficiency of the proposed approach when compared to the classical version of the crow search algorithm, the Chu and Beasley genetic algorithm, and the vortex search algorithm. All simulations were obtained using MATLAB and validated in the DigSILENT power system analysis software.

A Case Study of an Industrial Power Plant under Cyberattack: Simulation and Analysis

For critical infrastructures, technological developments regarding real-time data transmission and processing improve the system’s operability and reliability. However, vulnerabilities are introduced in the case of implementing new remote access methods or where redundancy is low. At the national level, most critical infrastructures are connected, and, therefore, achieving a level of security and resilience is based on identifying a multitude of risks. In this respect, the reduction of risk to acceptable levels directly affects the quality of citizens’ lives and decreases losses in the industry. This study starts from the threats to power systems, namely cyberattacks, which are much more dangerous, although less visible, to operators, and almost invisible to the public or the media. From this point of view, it was proved that the most vulnerable parts of the power system were human–machine interfaces, electrical equipment, Surveillance, Control, and Data Acquisition (SCADA) systems. This paper’s main achievements include the simulation of cyberattacks on existing electrical equipment from a petrochemical plant (case study), which consists of modifying the remote data transmitted by the SCADA system. Two locations were submitted to simulated cyberattacks that were considered critical for the overall plant operation. Furthermore, the changes that occur following each fault resulting from the cyberattack and the influence of the electrical parameter changes upon the process flow were analyzed. Furthermore, by using Electrical Power System Analysis Software—ETAP—the changes that occur following each fault due to the cyberattack and the influence of the electrical parameter changes upon the process flow were analyzed. By considering the two malfunction events, the resilience assessment of the system was analyzed. In the second case, only partial resilience action, up to 40%, restored the operability of the industrial power plant.

Advanced teaching method for learning power system operation based on load flow simulations

AbstractCurrent power systems are undergoing a rapid and complex transformation due to the integration of distributed generation. Load flow analysis is increasingly necessary to evaluate not only the operating point of the existing power system but also the design of future expansions. There are a wide variety of power system analysis packages used for load flow analysis. Of these, PowerFactory, one of the tools most widely used by network operators, is implemented for the present learning approach. In fact, one of the challenges for electric utility companies is the lack of experts who are familiar with this type of commercial tool. In the present work, several scenarios were defined and implemented using PowerFactory, covering common real‐life situations in power systems, such as the connection of a new line or a capacitor bank, or the installation of a renewable energy power plant. In this regard, the goal of the present teaching method was to complement the educational competences of power system engineers. As such, the proposed method was implemented in both an Electrical Engineering Degree course and a Master's Degree course in Industrial Engineering, where useful application feedback from students was obtained. Furthermore, the proposed approach is easily replicable for teaching/learning activities at other academic institutions.

A mho type phase comparator relay guideline using phase comparison technique for a power system

This paper presents a mho distance relay simulation based on the phase comparison technique using a typical electrical power systems analysis software for two cases: when the operation state is close to the static voltage limit and during a dynamic perturbation in the system. The paper evaluates the impedance variations caused by complex voltage values, the mho polarization, and the comparator operating region into the complex plane. In addition, the paper found the information for the dynamic perturbations from the outputs considering a mid-term stability program. The simulation of the mho-phase comparator in the static voltage proximity limit detects unit distance elements with impedance measured close to reach the threshold in the steady-state. Dynamic mho simulations in the complex plane are successfully tested by plotting time phase difference curves on the comparator input signals. Relay programmers can use these curves to analyze other phase comparators applications and the corresponding models in the complex plane.

Research on Reactive Power Compensation Configuration of Wind Farm Integration

The large-scale wind power integration into power system brings great impact on the grid voltage stability. In order to reduce the influences of grid-connected wind power on the power system and improve the safety of wind power integration, it is necessary to conduct research on reactive power compensation configuration of wind farm integration. Firstly, based on the actual situation of wind power project, the principle of reactive power compensation configuration is studied. Secondly, a theoretical calculation method of reactive power compensation configuration is proposed. On this basis, combined with the practical 300MW wind farm project, the reactive power compensation configuration example is analyzed. Finally, through the modeling and simulation by power system analysis software package (PSASP), the accuracy and effectiveness of the calculation method proposed by this paper are verified. This paper put forward a reactive power compensation configuration method which is applicable to all wind farms connected to the power system. This provides important support for voltage stability in the wind power integration project.

Оптимальное размещение средств компенсации реактивной мощности с помощью метода дифференциальной эволюции

Reactive power compensation in high voltage power grids is and should be used for energy efficiency and reliability purposes. Several grid indicators must be maintained, from required voltage levels and permissible current loads to the rated power factors and electricity loss reduction. Optimizing the capacity and placement of compensation devices is a multivariable task that requires deep complex grid modeling and special mathematical optimizations given that the return on investment is of importance. This paper presents a method based on metaheuristic differential evolution for optimal placement of compensation devices based on maximizing the net present value criterion with adjustment for the allowed period-specific electricity loss and required substation bus voltage. DIgSILENT PowerFactory 2020 is the software used for simulation and calculations. PowerFactory is the leading integrated power system analysis software, which covers the full range of functionality from standard features to highly sophisticated and advanced applications, which provides unrivalled calculation accuracy. The proposed approach helps find the best placement and configuration for reactive power compensation devices from the a user-predefined model range; it also makes adjustments for the limitations of the grid and for the per-unit costs valid over any planning period, which is demonstrated on a 14-node IEEE

Research on the wear and life of copper tungsten alloy contacts of high voltage SF6 circuit breakers

Three phase short circuit and two phase short circuit grounding fault of power system have a significant influence on the electrical life of circuit breaker contact. In this paper, the mathematical model of each component is established by Power System Analysis Software Package (PSASP), and the simulation model is built to simulate the dynamic state of the circuit breaker after different short-circuit faults. The simulated result confirms that contact electrical wear quantity related to the type of short circuit fault and the position of short circuit point. The size of short circuit current will directly impact electrical wear quantity and electrical life of circuit breaker contact.

Comparison of Industrial Substation Arrangements

This paper presents a comparative analysis for two alternatives of industrial substation arrangement with selective secondary radial type: first with one main transformer and one reserve and the second one with two main transformers and one reserve. The analysis are based on the power flow calculation, short circuit and reliability indices using the Electrical Power System Analysis Software (ETAP) and on the acquisition costs of equipment and materials. The analysis' methodology application in both alternatives is presented and the results are analyzed and compared as well.

Implementation of Transient Stability Model of Compressed Air Energy Storage Systems

This paper discusses the implementation of a transient stability model of Compressed Air Energy Storage (CAES) systems in a power system analysis package. A block-diagram based model of a two-machine CAES system is proposed, including specific controls for active power, reactive power, and State of Charge (SoC), which consider limits associated with the cavern pressure. As an application, the model is implemented in Powertech's TSAT software connected to the 9-bus WSCC benchmark power system, which is then used to study the impact of a CAES facility in the transient and frequency stability of the system. Several contingencies are simulated comparing the CAES performance to a gas turbine and a base-case without storage, demonstrating that the CAES system improves the system transient stability due to its charging stage, controls, and additional inertia. Finally, the CAES model is used to study the effects of cavern sizes in the frequency of the system. It is shown that CAES systems have certain special characteristics that make them attractive as a storage technology to provide stability and regulation services, besides their energy arbitrage capabilities.

Power System Stability Improvement of Ghana’s Generation and Transmission System Using FACTS Devices

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.

Research on Probability Model of Non-independent Fault of Nuclear Power Units Based on Power Grid Operating Parameters

Nuclear power plants have the characteristics of high safety and reliability requirements, unlike the conventional thermal power plants adopting an independent fault probability model, the probability of its fault is closely related to the operation status of the power grid. To solve this problem, a non-independent fault probability model of nuclear power plants considering power grid operation parameters is proposed in this paper. This research firstly simulates N-1 fault scenarios of each power component in the grid, then the influences of the fault scenarios on the voltage and frequency of nuclear power plants access point are simulated through the power system analysis software tools (PSD-BPA), the possibility of its outage is determined according to the corresponding protection thresholds of nuclear power plants, and then the occurrence probabilities of these fault scenarios are taken into account, finally the non-independent fault probability of nuclear power plants which is relevant with power grid operation parameters will be obtained. The model lays the foundation for the evaluation of the operational reliability and risk of power grid with nuclear power plants accessed to.

Field validation of a standard Type 3 wind turbine model implemented in DIgSILENT-PowerFactory following IEC 61400-27-1 guidelines

Transient stability analyses are one of the key tools used to ensure grid stability and safeguard security of electricity supply, as well as to comply with different countries grid interconnection agreements. Transmission and distribution system operators require validated wind turbine models to perform these studies. This is becoming increasingly important in current power systems because wind energy penetration is constantly expanding, and its integration has a significant impact on power grid planning and operation. The definition of generic wind turbine models by international standard IEC 61400-27-1, first released in February 2015, aims to deal with this issue. Therefore, since the validation process of the most widely used model defined by this standard and one of the most technically advanced, the generic type 3 wind turbine, i.e., the doubly-fed induction generator, has only been conducted using non-specialised software tools in the field of electrical engineering, the present paper addresses the validation process of this WT when simulated in one of the leading electric power system analysis software tools: DIgSILENT-PowerFactory. The model is subjected to voltage dips of varying magnitude and duration, under both full and partial load conditions. The results are compared to field measurement data according to IEC 61400-27-1 guidelines, and validation errors are estimated.