Low-inertia power systems require more innovative operation, control, and protection strategies to maintain the operation secure and reliable. One of the challenges related to these systems is the need for knowledge of the inertia level (kinetic energy stored in the rotating masses) in real time. This paper proposes a framework for training and deploying machine learning methods for real-time power systems’ kinetic energy forecasting. Linear Regression and Long Short-Term Memory methods are implemented in the Python interpreter of the Typhoon HIL 404 real-time simulator for forecasting the kinetic energy of the Nordic Power System in real-time. This paper provides implementation details together with possible future expansions of the framework. Simulation results show that the trained models can predict the kinetic energy in a forecasting horizon of four hours with a Mean Absolute Error lower than other methods currently available in the literature.@en

Future carbon-neutral power systems impose many challenges; one is the urgent need for a simulation platform that allows replicating the complex systems’ actual dynamic performance. This paper shows the results of implementing a cyber-physical testbed co-simulation in real-time to analyse the system frequency response considering primary frequency control and emergency frequency control: under-frequency load-shedding (UFLS) protection schemes. The proposed testbed uses a physical layer of two real-time simulators from different vendors in a closed loop, Opal-RT OP4510 and Typhoon HIL 604, being the first simulator for test system modelling and the remainder used to implement the UFLS protection scheme. Two connections of the real-time simulators are considered: physical connection using wires to exchange analogue signals and cybernetic digital communication using ANSI C37.118 communication protocol. The cybernetic layer of the testbed models a test system, controls the real-time simulation, and implements digital communication between the simulators. A modified version of the P.M. Anderson 9-bus systems is used for testing purposes, including phasor measurement units (PMUs). Results of the real-time simulation show the appropriate performance of the proposed testbed.

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This paper is a step forward in the effort to create an appropriate open-access library of benchmark test systems for offline and real-time simulations. The library will consist of 13 test systems for steady-state and dynamic power system analysis considering different relevant features (topology, control mode and element details). In this scientific paper, the authors selected one of the test systems, the 5-bus test transmission system, in meshed topology. Details of its implementation using several power system analysis platforms for offline and online/real-time simulation. Offline steady-state performance results are presented using PowerWorld, DIgSILENT PowerFactory and IPSA. Plots of the main electromechanical variables of the time-domain response considering a generator outage are presented using offline simulations from PowerFactory and real-time simulation ePHASORSIM. Simulation results show very minimal discrepancies between the results considering different platforms.

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This paper presents a simple validation of ePHASORSIM's user-defined model of a Virtual Synchronous Machine (VSM) suitable for real-time simulations. The validation consists of a software-to-software comparison of the real-time simulator ePHASORSIM against the offline transient simulation tool PowerFactory. The comparison evaluates the models in the native library and user-defined models imported to ePHASORSIM. These user-defined models are coded in a Modelica environment and imported as a functional mock-up unit (FMU) model-the dynamic model of a voltage source converter operating as a VSM was implemented to test this functionality. A modified version of the IEEE 39-bus New England system was used for testing and validation. The time series from each (software) transient simulation were compared using the percentage error and the mean percentage error (MPE); the results demonstrate the suitability of the proposed approach.

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Using Ethernet networks and communication protocols for protection applications requires protection engineers to understand different tools and technologies. This paper presents an investigation focused on clarifying the process bus-related concepts considering some relevant hardware, software, and protocol implementation aspects that may lead to misassumptions when doing Process Bus tests and studies. The authors performed real-time simulations considering 23 ROCOF scenarios under six different network background traffic environments to investigate network devices' throughput performance. In addition, the authors created a MATLAB script to subscribe and interpret the generated SV data correctly.@en

The power system continuously deals with frequency fluctuations. When a power disturbance occurs, the transmission system operators rely on the underfrequency load shedding (UFLS) scheme to address severe underfrequency (UF) events to maintain the frequency at the permissible level and prevent blackouts. Defining settings of a conventional UFLS scheme is a very complex problem due to the nonlinear nature of the frequency response, and the size of the problem is vast because of the number of UF-relays spread on the power system. The under or over total load disconnection produced by the wrong setting of the UF-relays can create secondary frequency events or even a total blackout. This paper introduces a novel method to compute an optimally parametrized conventional UFLS scheme in specific given operating conditions by formulating it as a constrained problem and using the Improved Harmony Search (IHS) algorithm to solve it. Since there is no previous knowledge of using IHS to solve the UFLS scheme, a numerical parameter sensitivity analysis (PSA) is developed to tune the parameter of the IHS algorithm. The IEEE 39-bus system was modelled in DIgSILENT® PowerFactory™ and used as a test system. The optimally parametrized conventional UFLS methodology presented in this paper reveals superior results against the conventional UFLS scheme, and the suitability of using the IHS algorithm is confirmed.@en

Future carbon-neutral power systems impose many challenges; one of them is an advanced simulation platform that allows replicating the complex systems' actual dynamic performance. DIgEnSys-Lab is working toward proposing solutions to the most critical challenges to carbon-neutral energy systems. This paper shows preliminary results of implementing a cyber-physical testbed co-simulation real-time dedicated to analysing system frequency response. The testbed is a cyber-physical system where the physical layer is represented by two real-time simulators in a closed loop: Typhoon HIL 604 and Opal-RT OP4510. The cybernetic layer is used to model a test system and to control the real-time simulation. This paper shows the results of the system frequency response of a modified version of the P.M Anderson 9-bus system using phasor measurement units. Simulation results show the appropriate performance of the proposed testbed.@en