This paper summarizes the work performed in one of the work-package of the FP7 iTesla project. This work consisted in the development of a power system component library for phasor time domain simulation in Modelica. The models were used to build power system network models, used in experiments for parameter identification. The experiments were carried out with the RaPId toolbox, which has been developed at SmarTS Lab within the same project. The toolbox was written in MatLab, making use of FMI Technologies for interacting with Modelica models.

The increase of wind power share increasing has lead to operational challenges for its integration and impact on power grids. Regarding this, unexpected dynamic phenomena, such as oscillatory events around 13 Hz among different wind farms were recorded in the United States of America (USA) by Oklahoma Gas & Electric (OG&E). Such interactions differ from traditional inter-areaoscillations, and the ability to detect them is beyond measurement capabilities of most of existing measurement equipment and monitoring tools in energy management systems. This paper presents the development and implementation of algorithms for fast sub–synchronous oscillation detection, focusing on the aforementioned case. It proposes a real-time monitoring application that exploits synchronized phasormeasurements allowing real-time detection of sub–synchronous wind farm dynamics. This tool was built as a prototype for real-time application and utilizes Phasor Measurement Unit (PMU) data for enhanced monitoring and control. The paper focuses on the tool’s design and its algorithms. Also, it will briefly present three approaches carried out for testing and validating the PMU–based application, one of them compares the proposed tool with an existing tool at OG&E. Through such experiments the tool presented in the paper has been positively validated for real time applications

The share of wind power has strongly increased in electricity production, raising several issues concerning its integration to power grids. Unexpected dynamic phenomena, such as oscillatory events around 13 Hz have been recorded in the US by Oklahoma Gas & Electric (OG&E). Such interactions differ from traditional and well studied inter-area oscillations, and the ability to detect them is beyond the measurement capabilities of most of the existing measurement equipment and monitoring tools in Energy Management Systems (EMS) systems. This paper presents the development and implementation of algorithms for PMU-based real-time fast sub-synchronous oscillation detection, focusing on the aforementioned case. The paper focuses on the tool itself and its algorithms, briefly presents an approach carried out for testing and validating it. Experience from the use of the tool at OG&E is also described.

This article presents an open data repository, the methodology to generate it and the associated data processing software developed to consolidate an hourly snapshot historical data set for the year 2015 to an equivalent Nordic power grid model (aka Nordic 44), the consolidation was achieved by matching the model׳s physical response w.r.t historical power flow records in the bidding regions of the Nordic grid that are available from the Nordic electricity market agent, Nord Pool.

The model is made available in the form of CIM v14, Modelica and PSS/E (Siemens PTI) files. The Nordic 44 model in Modelica and PSS/E were first presented in the paper titled “iTesla Power Systems Library (iPSL): A Modelica library for phasor time-domain simulations” (Vanfretti et al., 2016) [1] for a single snapshot. In the digital repository being made available with the submission of this paper (SmarTSLab_Nordic44 Repository at Github, 2016) [2], a total of 8760 snapshots (for the year 2015) that can be used to initialize and execute dynamic simulations using tools compatible with CIM v14, the Modelica language and the proprietary PSS/E tool are provided. The Python scripts to generate the snapshots (processed data) are also available with all the data in the GitHub repository (SmarTSLab_Nordic44 Repository at Github, 2016) [2].

This Nordic 44 equivalent model was also used in iTesla project (iTesla) [3] to carry out simulations within a dynamic security assessment toolset (iTesla, 2016) [4], and has been further enhanced during the ITEA3 OpenCPS project (iTEA3) [5]. The raw, processed data and output models utilized within the iTesla platform (iTesla, 2016) [4] are also available in the repository. The CIM and Modelica snapshots of the “Nordic 44” model for the year 2015 are available in a Zenodo repository.

BabelFish (BF) is a real-time data mediator for development and fast prototyping of synchrophasor applications. BF is compliant with the synchrophasor data transmission IEEE Std C37.118.2-2011. BF establishes a TCP/IP connection with any Phasor Measurement Unit (PMU) or Phasor Data Concentrator (PDC) stream and parses the IEEE Std C37.118.2-2011 frames in real-time to provide access to raw numerical data in the LabVIEW environment. Furthermore, BF allows the user to select ‘‘data-of-interest’’and transmit it to either a local or remote application using the User Datagram Protocol (UDP) in order to support both unicast and multicast communication. In the power systems Wide Area Monitoring Protection and Control (WAMPAC) domain, BF provides the first Free/Libre and Open Source Software (FLOSS) for the purpose of giving the users tools for fast prototyping of new applications processing PMU measurements in their chosen environment, thus liberating them of time consuming synchrophasor data handling and allowing them to develop applications in a modular fashion, without a need of a large and monolithic synchrophasor software environment.

This paper presents a software implementation of a real-time power system mode estimator application which uses ambient synchrophasor data. The software is built using Statnett's Synchrophasor Software Development Kit (SDK) as a platform for fast prototyping of real-time synchrophasor applications. The SDK extracts synchrophasor data received in the IEEE C.37.118 protocol and provides them as LabVIEW signals. These signals are preprocessed and mode frequencies and damping ratios are calculated by Yule-Walker's method. The implemented LabVIEW software employs state machine logics which enables modifications and upgrades to the algorithm.

Traditional simulation tools for power system studies are, in general, shipped with built-in and closed model libraries. Typically, the models' implementation is not thoroughly documented, preventing the user to gain a full understanding of their implemented behavior. Previous efforts from the authors have focused on the development of an open source software library of power system components developed using Modelica: the Open-Instance Power System Library (OpenIPSL), which provides models that can easily be accessed and studied by the user. Recent developments have focused on the implementation of a software architecture facilitating collaborative developments on OpenIPSL. Employing the latest technologies available in the software development community, this paper details the implementation of a continuous integration workflow, providing automated testing and behavior verification of the library's models. This platform seeks to increase the library's stability and to provide more reliable models developed collaboratively by multiple individuals. Moreover, this software architecture only utilizes open source software, which can be hilly tailored to the specific needs of users and other library developers.

This paper presents the software implementation ofa Phasor Measurement Unit (PMU) data-based mode estimationapplication in a decentralized mode estimation architecture. Thiswork builds from previous efforts in the development of a modeestimator implemented using a centralized architecture, meaninga set of modes were estimated for the whole system in a singleprocessing location. One drawback of mode estimators that usecentralized mode architecture is that the observability and thereforeestimation of important low-damped local electromechanicalmodes can be affected by the higher observability of otherdominant modes of the systems (e.g inter-area modes). This workproposes, implements and tests a decentralized architecture inorder to increase the observation capability to provide betterestimates of local low damped oscillations. In this architecture,the data from a single PMU or a group of local PMUs couldbe processed by a processor to estimate the modal parametersobserved at a specific part of the grid or observed by specificgroup of PMUs. The decentralized architecture and results oftests are presented in this paper together with comparison witha centralized architecture.

This paper presents an overview of the software implementation of a real-time mode estimator application and its testing. The application was developed to estimate inter-area modes from both ambient and ring-down synchrophasor data from multiple phasor measurement units (PMU). The software application was implemented in LabVIEW using Statnett’s synchrophasor software development kit (S3DK), to receive real-time synchrophasor measurements. The different features of the application were tested using two types of experiments presented herein. The first experiment is performed using emulated signals from a simple linear model. The second experiment was designed to use a linearized representation of the KTH-Nordic32 power system model. These experiments are used to carry out quantitative analyses of the tool’s performance.

The iTesla Power Systems Library (iPSL) is a Modelica package providing a set of power system components for phasor time-domain modeling and simulation. The Modelica language provides a systematic approach to develop models using a formal mathematical description, that uniquely specifies the physical behavior of a component or the entire system. Furthermore, the standardized specification of the Modelica language (Modelica Association [1]) enables unambiguous model exchange by allowing any Modelica-compliant tool to utilize the models for simulation and their analyses without the need of specific mediator. As the Modelica language is being developed with open specifications, any tool that implements these requirements can be utilized. This gives users the freedom of choosing an Integrated Development Environment (IDE) of their choice. Furthermore, any integration solver can be implemented to simulate Modelica models. Additionally, Modelica is an object-oriented language, enabling code factorization and model re-use to improve the readability of a library by structuring it with object-oriented hierarchy. The developed library is released under an open source license to enable a wider distribution and let the user customize it to their specific needs.

Following the European network of transmission systemoperators for electricity (ENTSO-E) R&D Road Map,efforts of collaboration between the European transmissionsystem operators (TSO) have led to common researchprojects concerning power system operation suchas iTesla. iTesla aims to develop a common toolbox tosupport the future operation of pan-European power grid.This toolbox was developed to use Modelica models.

The work presented here encompasses the developmentof Modelica classes for power gird componentsused by Nordic TSOs to model the Nordic synchronousgrid. The performance of these Modelica models havebeen validated through different test cases implementedin both Power System Simulator for Engineering (PSS/E) as domain-specific tool and a Modelica simulation environment.The results from dynamic simulations with thepresence of different perturbations have been compared tothe PSS/E reference to validate the Modelica implementation,reaching almost identical records between simulationresults from both tools.

Power system studies seldom consider the interaction between transmission and distribution systems. This sort of analysis, however, have been gaining importance due to the progressive growth of renewable energy penetration in the distribution networks. In this context, the current study combines a positive-sequence transmission system model with a three-phase distribution system model. The connection between both systems is attained by a hybrid three-phase to single-phase interface element. The system model is written in Modelica language, and simulated using OpenModelica. A test system is built o top of the IEEE14 test system, where two load buses are expanded into three-phase distribution systems. Results of studied system are validated against the power system simulator, Simulight. Results also renders the presently analyzed hybrid model very promising for complimenting modern power systems studies.

The share of wind power has strongly increased in electricity production, raising several issues concerning its integration to power grids. Unexpected dynamic phenomena, such as oscillatory events around 13 Hz have been recorded in the US by Oklahoma Gas & Electric (OG&E). Such interactions differ from traditional and well studied inter-area oscillations, and the ability to detect them is beyond the measurement capabilities of most of the existing measurement equipment and monitoring tools in Energy Management Systems (EMS) systems. This chapter presents the development and implementation of algorithms for fast oscillation detection, focusing on the aforementioned case. It proposes two solutions for real-time monitoring application that exploits synchronized phasor measurements allowing real-time analysis of sub-synchronous wind farm dynamics. These tools were built as prototypes for real-time application which utilizes Phasor Measurement Unit (PMU) data for enhanced monitoring and control of wind farms. The software tools developed in the chapter serve as evidence of the flexibility offered by non-conventional software development systems for PMU applications which provide unlimited opportunities to conceive new software tools that will aid with the integration and management of renewable resources into power grids.

The share of wind power has strongly increased in electricity production, raising several issues concerning its integration to power grids. Unexpected dynamic phenomena, such as oscillatory events around 13 Hz have been recorded in the US by Oklahoma Gas & Electric (OG&E). Such interactions differ from traditional and well studied inter-area oscillations, and the ability to detect them is beyond the measurement capabilities of most of the existing measurement equipment and monitoring tools in Energy Management Systems (EMS) systems. This chapter presents the development and implementation of algorithms for fast oscillation detection, focusing on the aforementioned case. It proposes two solutions for real-time monitoring application that exploits synchronized phasor measurements allowing real-time analysis of sub-synchronous wind farm dynamics. These tools were built as prototypes for real-time application which utilizes Phasor Measurement Unit (PMU) data for enhanced monitoring and control of wind farms. The software tools developed in the chapter serve as evidence of the flexibility offered by non-conventional software development systems for PMU applications which provide unlimited opportunities to conceive new software tools that will aid with the integration and management of renewable resources into power grids.

This paper presents the latest improvements implemented in the Open-Instance Power System Library (OpenIPSL). The OpenIPSL is a fork from the original iTesla Power Systems Library (iPSL) by some of the original developers of the iPSL. This fork's motivation comes from the will of the authors to further develop the library with additional features tailored to research and teaching purposes. The enhancements include improvements to existing models, the addition of a new package of three phase models, and the implementation of automated tests through continuous integration.

This article provides an overview of the work performed at SmarTS Lab on power system modeling and system identification within the FP7 iTesla project. The work was performed using Modelica as the modeling language for phasor time domain simulation and FMI (Flexible Mock-up Interface) Technologies for coupling Modelica models with simulation and optimization tools. The article focuses on use case examples of these Modelica models in an FMI driven environment to perform parameter identification.

This paper describes the Rapid Parameter Identification toolbox (RaPId), developed within the EU FP7 iTesla project. The toolbox was designed to carry out parameter identification on models developed using the Modelica language, focusing in particular on power system model identification needs. The toolbox has been developed with modularity and extensibility in mind, using Matlab/Simulink as a plug-in environment, where different tasks of the identification process are carried out. The identification process uses different optimization algorithms to improve the fitting of the model’s response to selected criteria. The modular architecture of RaPId gives users complete freedom to extend and adapt the software to their needs, e.g. to implement or link external solvers for simulation or optimization. The compatibility with Modelica models is brought by the use of technologies compliant with the Functional Mock-up Interface (FMI) standard.

The Icelandic power system is characterized by two areas that oscillate against each other during stressed system operation, and may lead to an islanding of system. Conventional stabilizing methods are being used to their full capacity, thus new options are being explored to prevent system break-ups. There is potential in exploiting large industrial loads to enhance system stability. In this paper a hardware prototype of a synchrophasor-based active load controller for oscillation damping is presented. The performance of the controller is analysed using Real-Time Hardware-in-the-Loop (RT-HIL) approach.

The Icelandic power network has transmission constraintsthat often lead to inter-area oscillations. Although conventionalstabilization methods have been applied successfully inthe past, there is potential to exploit large industrial loads toenhance system stability during stringent operation conditions.This paper analyzes the performance of two damping controllers.The controllers can use both synchrophasor signals and localmeasurements as their inputs. Damping is achieved by loadmodulation generated by a phasor-based oscillation signal. Real-Time Software-in-the-Loop testing is performed using Opal-RT’s eMEGAsim Real-Time Simulator to derive hardware andcomputational requirements of a hardware prototype that willbe implemented in the future.

This paper presents the IDE4L project reference grid model developed to serve as a benchmark for studies on distribution grid dynamics within the project. The paper demonstrates a MATLAB/Simulink implementation of the reference grid to be used in real-time hardware-in-the-loop simulations. The simulations will be carried out to study distribution grid dynamics and to evaluate the techniques developed in IDE4L project for TSO/DSO interactions. Performance of the grid model is shown through sample real-time simulation results and a hardware-in-the-loop setup for PMU-based grid monitoring applications.

This paper presents the activities carried out in one of the work packages of the Nordic Energy Research funded project Smart Transmission Grid Operation and Control (STRONg²rid). The main objective of the work package is to deploy a state-of-the-art software and hardware for developing power system operation, protection, control and automation applications. Several PMUs have been deployed at partner universities and a network of synchrophasors has been set up. In addition the Smart Transmission System Laboratory (SmarTS-Lab) has been established. This laboratory serves as a test-bench to develop and verify smart transmission grid technologies. A software development kit (S³DK) was developed within the project. The S³DK has been used to implement PMU-based applications and deploy them in different targets, including smart phones and tablets. Several tools and software applications which utilize synchrophasor measurements (from the laboratory or the deployed university PMU network) to perform power system monitoring, sub-synchronous power oscillation detection, etc., have been developed and are presented herein.  

This article provides an overview of a monitoring application, its testing and validation process. The application was developed for the detection of sub-synchronous oscillations in power systems, utilizing real-time measurements from phasor measurement units (PMUs). It uses two algorithms simultaneously to both detect the frequency at which the oscillatory event occurs and the level of energy in the oscillations. The application has been developed and tested in the framework of SmarTS Lab, an environment capable of hardware-in-the-loop (HIL) simulation. The necessary components of the real-time chain of data acquisition are presented in this paper, as well as testing and validation results, to demonstrate the accuracy of the monitoring tool and the feasibility of fast prototyping for real-time PMU measurements based applications using the SmarTS Lab environment.

The electric power grids expose highly dynamic behaviors that can be mitigated by exploiting Wide-Area Monitoring, Protection And Control (WAMPAC) technologies. These technologies rely on utilizing the synchrophasor measurements provided by the Phasor Measurement Units (PMUs). The IEEE C37.118.2 standard defines a method for real-time communication of synchrophasor data between PMUs, Phasor Data Concentrators (PDCs) and other applications. This paper describes the Smart Transmission Grid Operation and Control (STRONgrid) library, which serves as a real-time data mediator (i.e. interface) between the IEEE C37.118.2 protocol and applications consuming PMU measurements. The STRONgrid library packages all the necessary components to allow the researchers to focus on the development of synchrophasor applications in higher level programming environments (e.g. LabVIEW).

A supplementary function of Excitation Control Systems (ECSs) for synchronous generators is that of a Power System Stabilizer (PSS). The PSS implementation in these ECSs only allows the use of a limited type of pre-defined local input measurements and built-in PSS algorithms. To adapt existing ECSs to take advantage of synchrophasors technology, this paper proposes and implements a prototype wide-area damping controller (WADC) that provides synchrophasor-based damping input signals to existing ECSs. The developed WADC comprise (i) a real-time mode estimation module, (ii) synchrophasor’s communication latency computation module, and (iii) phasor-based oscillation damping algorithm executing in a real-time hardware prototype controller.

Through Real-Time Hardware-in-the-Loop (RT-HIL) simulations, it is demonstrated that synchrophasor-based damping signals from the WADC can be utilized together with a commercial ECS, thus providing new options for selection of the best feedback signal for oscillation damping.

This paper presents validation experiments performed on a Phasor Measurement Unit (PMU) based fast oscillation detection application. The monitoring application focuses on the detection of sub-synchronous oscillations, utilizing real-time measurements from PMUs. The application was first tested through Hardware-In-the-Loop (HIL) simulation. Validation experiments were carried out with a different set-up by utilizing a micro grid laboratory. This second experimental set-up as well as the results of the validation experiments are presented in this paper.

This paper presents an approach to design laboratory experiments able to test the functional performance of a PMU-based application. The function of this application is to detect sub-synchronous oscillatory dynamics product of wind farm-to-grid interactions. The designed experiments are carried out in operation conditions similar to those that the PMU-based application would experience in field implementations, while the approach adopted for experiment design takes into account technical limitations of laboratory equipment. The experiments are performed in a laboratory which has been equipped with synchrophasor technology for the purposes of this work. Real PMU devices physically connected on a small replica of a three-phase low voltage micro-grid where oscillations can be systematically injected.