Power Grid Simulation Research Articles

Impact of grid partitioning algorithms on combined distributed AC optimal power flow and parallel dynamic power grid simulation

The complexity of most power grid simulation algorithms scales with the network size, which corresponds to the number of buses and branches in the grid. Parallel and distributed computing is one approach that can be used to achieve improved scalability. However, the efficiency of these algorithms requires an optimal grid partitioning strategy. To obtain the requisite power grid partitionings, the authors first apply several graph theory based partitioning algorithms, such as the Karlsruhe fast flow partitioner (KaFFPa), spectral clustering, and METIS. The goal of this study is an examination and evaluation of the impact of grid partitioning on power system problems. To this end, the computational performance of AC optimal power flow (OPF) and dynamic power grid simulation are tested. The partitioned OPF-problem is solved using the augmented Lagrangian based alternating direction inexact Newton method, whose solution is the basis for the initialisation step in the partitioned dynamic simulation problem. The computational performance of the partitioned systems in the implemented parallel and distributed algorithms is tested using various IEEE standard benchmark test networks. KaFFPa not only outperforms other partitioning algorithms for the AC OPF problem, but also for dynamic power grid simulation with respect to computational speed and scalability.

Pandapipes: An Open-Source Piping Grid Calculation Package for Multi-Energy Grid Simulations

The increasing complexity of the design and operation evaluation process of multi-energy grids (MEGs) requires tools for the coupled simulation of power, gas and district heating grids. In this work, we analyze a number of applicable tools and find that most of them do not allow coupling of infrastructures, oversimplify the grid model or are based on inaccessible source code. We introduce the open source piping grid simulation tool pandapipes that—in interaction with pandapower—addresses three crucial criteria: clear data structure, adaptable MEG model setup and performance. In an introduction to pandapipes, we illustrate how it fulfills these criteria through its internal structure and demonstrate how it performs in comparison to STANET®. Then, we show two case studies that have been performed with pandapipes already. The first case study demonstrates a peak shaving strategy as an interaction of a local electricity and district heating grid in a small neighborhood. The second case study analyzes the potential of a power-to-gas device to provide flexibility in a power grid while considering gas grid constraints. These cases show the importance of performing coupled simulations for the design and analysis of future energy infrastructures, as well as why the software should fulfill the three criteria.

Study on the Joint Optimization Mode of Electric Energy and Regulation Market

Introduction As the guarantee for the stable of the power system， the marketization of the regulation auxiliary service has been put on the agenda. The energy-regulation joint optimization becomes a mode of market organization. This paper aims to study the combined optimization model of the electric energy-regulation market considering the performance difference of frequency modulation resources in the PJM market background. Method Regulation auxiliary service pricing adjustment model and the joint clearing model of electric energy and regulation market considering the difference of fast and slow regulation resources and regulation performance was proposed in this paper， which were applied to the simulation of a real power grid to compared with domestic electric energy - regulation step clearing market. Two typical scenarios were set up in wet season and dry season. The clearing of regulation resources， the influence on the electricity purchase cost in the spot market and the active degree of regulation market were studied in detail. Result In the stepwise clearing mode， the rapid regulation resource has obvious advantages and causes the increase of electricity purchase cost in the electricity market. In the electricity-regulation joint optimization model， the clearing results of fast and slow regulation resources are affected by the pricing adjustment strategy and the increase rate of electricity purchase costs in the power market is smaller than that in the stepwise model， and the clearing price and fluctuation degree in the regulation market are higher than that in the stepwise clearing mode model. Conclusion The combined optimization mode of electric-regulation modulation with reasonable price adjustment strategy is helpful to realize reasonable competition among units with different regulation performance and stimulate market vitality.

Analysis of coupling factors between high proportion wind power and ultra-high voltage DC

Due to the imperfect construction of supporting thermal power units, when wind power sources are in full swing, if DC low-power operation will inevitably lead to wind power abandonment, if DC high power operation is subject to fault transient overvoltage operation constraints, it will also cause power curtailment of wind power sources. In order to promote wind power consumption and lean management of DC influencing factors, this paper analyzes the number of supporting thermal units started, supporting unit power changed, wind power and connected substation power to find out the key factors of DC operating limit and wind power consumption. The validity of this paper was verified by a DC power grid simulation in a certain area.

Applications of time parallelization

This review article serves to summarize the many advances in time-parallel computations since the excellent review article by Gander, “50 years of Time Parallel Integration” (Gander, in: 50 years of time parallel time integration. Multiple shooting and time domain decomposition, Springer, Berlin, 2015). We focus, when possible, on applications of time parallelism and the observed speedup and efficiency, highlighting the challenges and benefits of parallel time computations. The applications covered range from numerous PDE-based simulations (both hyperbolic and parabolic), to PDE-constrained optimization, powergrid simulations, and machine learning. The time-parallel methods covered range from various iterative schemes (multigrid, waveform, multiple shooting, domain decomposition) to direct time-parallel methods.

Research on Performance of Real-Time Simulation Based on Inverter-Dominated Power Grid

This paper proposes two methods to improve the performance in real-time simulation. The increased inverter-based generations are gradually shifting the operation of the power grid. Consequently, the investigation for the safe operation and further application is essential in the inverter-dominated power grid. As the simulated number of non-linear switch elements like inverter increases, the numerical complexity of the simulation model rises exponentially. Accordingly, the scale of the simulated power grid with inverters is normally constricted by taking account of the burdensome numerical calculation. The emerging of real-time simulator provides the opportunity to enable the simulation of the large-scale power grids. Nevertheless, the simulation boundary condition is still exceeded in the inverter-dominated model. Hence, the improvement of the performance to extend the limitation in real-time simulation is constituted in this paper. The first method proposed is co-simulation. This approach is to simulate the power grid and inverters by models in different deep levels. The phasor model and electrical-mechanical-transient model are utilized to develop the co-simulation model. The second method is network reduction. Based on the dynamic feature of the inverter, it is reduced to an equivalent current source, which decreases the complexity of the model and retains its characteristics. The evaluation of the methods is demonstrated by two indexes: real-time capability and the similarity degree.

Multi-objective optimization design of passive filter based on particle swarm optimization

Using particle swarm optimization algorithm, aiming at the investment cost, filtering effect and reactive power compensation ability of passive filter, the weight of each objective function is determined according to the dispersion order method, and the passive filter is designed by multi-objective optimization. In addition, the actual calculation is carried out by taking the power grid parameters of the self-elevating and self-propelled petroleum engineering ship of “Feng Long 01” as an example. Further, a ship power grid simulation model is built under the Matlab/Simulink environment to verify the practicality of the optimized passive filter design.

Power Grid Simulation Testbed for Transactive Energy Management Systems

To effectively engage demand-side and distributed energy resources (DERs) for dynamically maintaining the electric power balance, the challenges of controlling and coordinating building equipment and DERs on a large scale must be overcome. Although several control techniques have been proposed in the literature, a significant obstacle to applying these techniques in practice is having access to an effective testing platform. Performing tests at scale using real equipment is impractical, so simulation offers the only viable route to developmental testing at scales of practical interest. Existing power-grid testbeds are unable to model individual residential end-use devices for developing detailed control formulations for responsive loads and DERs. Furthermore, they cannot simulate the control and communications at subminute timescales. To address these issues, this paper presents a novel power-grid simulation testbed for transactive energy management systems. Detailed models of primary home appliances (e.g., heating and cooling systems, water heaters, photovoltaic panels, energy storage systems) are provided to simulate realistic load behaviors in response to environmental parameters and control commands. The proposed testbed incorporates software as it will be deployed, and enables deployable software to interact with various building equipment models for end-to-end performance evaluation at scale.

The Method of Improving the Performance of Network Analysis Application for the Whole Power Grid

With the rapid development of UHV AC / DC hybrid power grid, it is required that the Network Analysis Application have the ability of unified analysis and high-performance computing. In this paper, the time-consuming analysis of each sub-function of Network Analysis Application is carried out to realize the performance bottleneck analysis of the whole process of network analysis. It is proposed that the performance of network analysis should be improved in three aspects: data input and output, topology analysis and core computing of Network Analysis Application. In the aspect of data input, the grid model data service is constructed to realize the combination of measurement reading and model reading, and the parallel model verification and boundary equivalence are completed; In the aspect of data output, it can be parallelized by table, block and equipment; In the aspect of topology analysis, the shared memory programming model OpenMP is adopted, and based on the fork/join parallel mode, its parallelization is realized; In the aspect of core computing, the existing parallel computing methods are summarized, and through the actual power grid simulation analysis, it puts forward the parallel computing mode applicable to different scale power grids and different applications. Finally, the effectiveness of this method is verified by comparing the optimized performance of state estimation.

Application of a Smart Grid Interoperability Testing Methodology in a Real-Time Hardware-In-The-Loop Testing Environment

Interoperability testing is widely recognized as a key to achieve seamless interoperability of smart grid applications, given the complex nature of modern power systems. In this work, the interoperability testing methodology proposed by the European Commission Joint Research Centre is applied to a specific use case in the context of smart grids. The selected use case examines a flexibility activation mechanism in a power grid system and includes DSO SCADA, Remote Terminal Unit and flexibility source, interacting to support a voltage regulation service. The adopted test bed consists of a real-time power grid simulator, a communication network emulator and use case actors’ models in a hardware-in-the-loop setup. The breakdown of the interoperability testing problem is accomplished by mapping the use case to the SGAM layers, specifying the Basic Application Profiles together with the Basic Application Interoperability Profiles (BAIOPs) and defining the design of experiments to carry out during the laboratory testing. Furthermore, the concepts of inter- and intra-BAIOP testing are formalized to reflect complementary interests of smart grid stakeholders. Experimental results prove the applicability of the methodology for testing the interoperability of large-scale and complex smart grid systems and reveal interesting features and possible pitfalls which should be considered when investigating the parameters responsible for the disruption of a system interoperability.

Critical Section Channel Maintenance Evaluation Method for Double HVDC Feed-in Grid

In order to ensure stable operation of DC, the dual DC feed grid structure needs to ensure a certain grid strength, but it is necessary to study how to evaluate the impact of critical section maintenance on the AC system. Firstly, the strength evaluation index of the receiving power grid is analyzed. Secondly, an index that characterizes the effects of two DC couplings is proposed. Finally, a critical section channel maintenance evaluation method for double ultra-high voltage DC feed grid is proposed. The effectiveness of the proposed method is verified by the HN Power Grid simulation.

Design and Implementation of an Intelligent Decision-making System for Power Grid Planning

In order to effectively cope with the situation of large amount of data, complex decision-making and lack of technical means in power grid planning, an intelligent assistant decision-making system for power grid planning based on platform design, visualization and advanced decision support function is designed and implemented. The system is closely integrated with Geographic Information System (GIS) and embedded in an integrated database. It has the functions of adaptability evaluation, investment priority decision-making, power grid reconfiguration scheme analysis and data interface of power grid simulation software. In the process of assistant decision-making, the coordinated evaluation of power supply and power grid is realized by the simulation of power grid dispatch, the investment priority of the project is determined by imitating the principle of static security analysis, the backbone network of power grid is identified by graph theory algorithm, and the data of the planning scheme is extracted from the newly developed simulation software data interface to reconstruct the topology and initialize the data of model.

Technology and engineering application of cross area HVDC interconnection system high-precision simulation modeling based on ADPSS

In recent years, a large number of high voltage direct current (HVDC) transmission projects have been connected to AC systems. This has started to have an impact on AC/DC hybrid power grids, particularly receiving terminal power grids. An HVDC system is a large-scale power electronic integrated nonlinear system, and it includes a primary system and a control and protection system. Hence, the precision and degree of detail of HVDC systems directly affect the actual effect of simulation. In recent years, in the case of the normal operation and failure of AC power grids, the abnormal fluctuation and even locking of HVDC systems caused by the inappropriate strategies of the control and protection system component have strongly affected power grids. This has significantly affected the safety and stability of receiving power grids and normal operation. In this study, the actual engineering HVDC control logic provided by a manufacturer is analyzed and simulated based on the user defined component library of the ADPSS electromagnetic transient calculation program, and an HVDC control model based on an actual system is established. The accuracy of the DC control custom model based on ADPSS is verified through the simulation of an actual power grid.

Large Time Step Electromagnetic Transient Simulation of Large Scale Power System Based on Time Domain Transformation Method

Electromagnetic Transients (EMT) simulation is an effective approach to study the dynamic behavior of complex AC/DC power grids. However, with increasing applications of the electronic equipment and the expansion of power grid, conventional EMT simulation tools are facing significant challenges with regard to simulation speed and scale. In order to improve the performance of EMT simulation, some approaches have been proposed. A time domain transformation methodology [1] has recently been proposed. In this paper, based on the large time step EMT algorithm, an electromagnetic transient simulation program has been developed and is used to study large scale power system dynamic behaviors. The result shows that the new EMT algorithm can not only guarantee the simulation accuracy, but also effectively improve the speed of full electromagnetic transient simulation of large scale complex power grids.

A Resilience Toolbox and Research Design for Black Sky Hazards to Power Grids

A structured collection of tools for engineering resilience and a research approach to improve the resilience of a power grid are described in this paper. The collection is organized by a two‐dimensional array formed from typologies of power grid components and business processes. These two dimensions provide physical and operational outlooks, respectively, for a power grid. The approach for resilience research is based on building a simulation model of a power grid which utilizes a resilience assessment equation to assess baseline resilience to a hazards’ profile, then iteratively selects a subset of tools from the collection, and introduces these as interventions in the power grid simulation model. Calculating the difference in resilience associated with each subset supports multicriteria decision‐making to find the most convenient subset of interventions for a power grid and hazards’ profile. Resilience is an emergent quality of a power grid system, and therefore resilience research and interventions must be system‐driven. This paper outlines further research required prior to the practical application of this approach.

Framework for artificial intelligence analysis in large-scale power grids based on digital simulation

The planning, design, operation, control and scientific research of power systems all require a variety of simulation analysis. Thus power grid simulation analysis is a fundamental supporting technology of large-scale power grids. In power grid simulation analysis, in addition to simulation calculations, there are many links for analysis and decision-making, relying on specialists. The introduction of advanced artificial intelligence technology provides a new method to improve the efficiency and accuracy of power grid simulation analysis. Nevertheless, the research of the related artificial intelligence technologies face a great deal of new challenges due to the complexity of the large-scale power grid simulation data, including massive volumes, high dimensionality, strong coupling and complex correlations. Also a great deal of knowledge and experience need to be integrated in the process of analysis. In order to deal with these challenges, based on the existing works, this paper focuses on the core scientific problem of artificial intelligence analysis and decision making related to the massive simulation results of large-scale power grids, and proposes an artificial intelligence analysis method framework for large-scale power grids based on digital simulation, which includes the power grid simulation analysis knowledge model with application method, the power grid simulation knowledge mining method and the artificial intelligence models with transfer learning ability of diversified grids as well as analyzing and calculation adjusting for large-scale power grid simulation results, etc. This work is expected to open up a new technical approach for large-scale power grid simulation analysis and provide strong technical support for the safe and stable operation of large-scale power grids.

A comparative study on common power flow techniques in the power distribution system of the Tehran metro

Overall, a power-flow study is a steady-state assessment whose goal is to specify the currents, voltages, and real and reactive flows in a power system under a given load conditions. This paper presents a comparison of common power flow techniques in the Tehran metro power distribution system at the presence of non-linear loads. Moreover, a modelling, simulation and analysis of this power distribution system is implemented with the Electrical Transient Analyser Program (ETAP) software. In this assessment, common power flow techniques including the Newton-Raphson (NR), Fast Decoupled (FD), and Accelerated Gauss-Seidel (AGS) techniques are provided and compared. The obtained results (total generation, loading, demand, system losses, and critical report of the power flow) are analysed. In this paper, we focus on the detailed assessment and monitoring by using the most modern ETAP software, which performs numerical calculations of a large integrated power system with fabulous speed and also generates output reports. The capability and effectiveness of the power flow analysis are demonstrated according to the simulation results obtained with ETAP by applying it to the power distribution system of the Tehran metro. In developing countries such as Iran, off-line modelling and simulation of power grids by a powerful software are beneficial and helpful for the best usage of the electrical energy.

CIMverter\u2013a template-based flexibly extensible open-source converter from CIM to Modelica

Over the last decade, the Common Information Model (CIM), as specified by IEC 61970 / 61968, has become an important document format for the storage of power grid data. Its object-oriented design makes it easily maintainable and extensible for many use cases in the energy sector. As a result, more and more power grid analysis and simulation tools allow the import and export of CIM based power grid data. Unfortunately, many of them are proprietary and therefore not convenient in the research area since their component models and numerical back-ends often cannot be modified by the user. Thus, open-source alternatives are in demand, such as simulation environments based on the popular modeling language Modelica. Therefore, this paper presents our approach of a template based CIM to Modelica converter. The usage of templates makes it easily adaptable for the generation of Modelica system models targeting arbitrary Modelica libraries. The presented approach is implemented in an open-source project called CIMverter, evaluated on a real-world case with two Modelica power system libraries, and validated against a proprietary simulation tool.

Modelling of an Electric Power Grid for New Power Plant Evacuation

Injection of a new power system component into an existing power grid often cause change in the behaviour of the power grid to which it is injected. Therefore, forecasting possible unsafe condition(s) of the power grid using an efficient power study tool is essential; and, provision of necessary mitigation actions to ensure a reliable grid is important. This paper, therefore, presents evacuation study of a 400 MW power plant connecting to the 15 GW planned transmission network of the Transmission Company of Nigeria (TCN). The NEPLAN power system analytical software was used in the modelling and simulation of the electric power grid. In the research, load flow, short circuit, transient stability, and contingency analyses were performed on the case study. From the short circuit study, it is observed that if TCN network expansion program is fully implemented, the short circuit level will go beyond the existing switchgear ratings in major substations of the network. However, with the introduction of substation splitting at Omotoso and ongoing Ogijo substations, the short circuit level will be reduced by 15%; leading to improvement in the overall system stability. Keywords—Load flow, short circuit study, transient stability study, and contingency analysis

A Global Real-Time Superlab: Enabling High Penetration of Power Electronics in the Electric Grid

The Global Real-Time Superlaboratory (Global RT Superlab) represents a vendor-neutral distributed platform based on the virtual interconnection of digital real-time simulators (DRTSs) and hardware-in-the-loop (HIL) setups hosted at eight geographically distributed laboratories in the United States and Europe (Figure 1). This article describes the efforts toward the realization of this largescale virtual infrastructure and explains a demonstration of the multilab setup for simulation and testing of next-generation global power grids.