Development of a Great Britain Transmission System Reduced Model for Hardware-In-the-Loop Studies

© © 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.© 2020 IEEE. This paper presents the development of a reduced model of the Great Britain (GB) transmission system for Hardware-In-the-Loop (HIL) studies. The original reduced model of the GB system was designed for dynamic simulations using the power system software DIgSILENT PowerFactory. In this paper a reduced model is developed for real-time simulation and enhancements to the original DIgSILENT PowerFactory models have been implemented in order to use it with the real-time dynamic simulation tool of OPAL-RT Technologies, ePHASORSIM. In this paper it is demonstrated that the implemented enhancements do not have an adverse impact on model accuracy or efficacy. It is important to note that the developed model can be directly interfaced with the OPAL-RT real-time digital simulator for HIL studies. It is also important to note that the modelling interface methodology that is presented with regard to the development of the reduced model of the GB system is also applicable to a full system model of the GB transmission system.The research was sponsored by NGESO with Network Innovation Allowance funding from OFGEM (Office of Gas and Electricity Markets)

A Novel Hardware-in-the-Loop Approach to Investigate the Impact of Low System Inertia on RoCoF Relay Settings

Copyright: © 2022 by the authors. This paper presents a novel hardware-in-the-loop (HIL) approach as used to investigate the impact of the reduction in inertia on the Great Britain (GB) electrical power system with regard to rate of change of frequency (RoCoF) settings for Loss-of-Mains (LoM) protection. Furthermore, the research as presented in this paper updates, enhances, and validates a reduced model of the Great Britain transmission system, as originally developed in DIgSILENT PowerFactory by the National Grid Electricity System Operator. The enhanced model has been developed for integrated use with the OPAL-RT real-time HIL simulation toolkit and is validated against phasor measurement unit (PMU) data from actual disturbance events using novel automated interfacing between both integrated simulation platforms, PowerFactory from DIgSILENT and ePHASORSIM from OPAL-RT. The corresponding simulations show that the updated reduced model is capable of capturing the dynamic behaviour of the GB transmission system, including both local and inter-area oscillations, with satisfactory accuracy. Finally, the paper presents HIL study results with the reduced model to investigate the influence of decreasing system inertia on the response of LoM protection relays. The studies show that decreasing system inertia may have a significant impact on LoM relays using RoCoF detection, particularly relays using the legacy G59 setting of 0.125 Hz/s. Initial studies have also demonstrated the potential for a previously unrecognised interaction between system oscillations and the 500 ms operating delay, as specified in G59 and G99 Engineering Recommendations. Consequently, faster local oscillations (>1 Hz) reset the relay and decrease the sensitivity, whereas slower inter-area oscillations (<1 Hz) appear to cause the relay to overestimate the average RoCoF.National Grid Electricity System Operator with Network Innovation Allowance funding from OFGEM (Office of Gas and Electricity Markets)

Validation of dynamic GB transmission system models with PMU data for hardware-in-the-loop studies

Decarbonisation of the electrical power system in Great Britain (GB) has impacted the dynamic behaviour of the power system, not least due to the reduction in system inertia. Following disturbance events on the power system, Fast Frequency Phenomena (F2P) can be observed which may cause mal-operation of Loss-of-Mains (LoM) protection relays on distributed generation where the relays use Rate of Change of Frequency (RoCoF) or Vector Shift (VS) to detect loss of mains. The research presented in this paper aims to validate a full model of the GB transmission system using Phasor Measurement Unit (PMU) data from system events. The model is implemented in the DIgSILENT PowerFactory analysis software. Three types of F2P are compared in the period following the disturbance when LoM protection may be affected: simulation of electromagnetic (VS) phenomena shows some differences to actual PMU measurements, but the electromechanical and mechanical phenomena (affecting RoCoF) are in good agreement. The distribution of inter-area oscillation frequency modes following the disturbances are also closely represented in the model. Based on these studies, it can be concluded that the model is suitable for F2P studies using Hardware-in-the-Loop simulation with real LoM protection relays.National Grid ESO with Network Innovation Allowance funding from OFGEM (Office of Gas and Electricity Markets

Enhanced visualisation of fast frequency phenomena as exhibited in the Gb transmission system

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.© 2019 IEEE. This paper investigates fast frequency phenomena as exhibited in the Great Britain (GB) transmission system as a consequence of the relationship of system disturbances to the changing inertia of the system. Fast frequency phenomena are studied with specific reference to real case studies associated with GB transmission system disturbances as recorded by Phasor Measurement Units located across the transmission system. The intrinsic behavior of the phenomena is investigated, observed and analyzed using enhanced 2D and 3D visualization tools. The novel visualization tools and techniques have been developed using Matlab and the impact area of system disturbances with regard to Rate of Change of Frequency and Vector Shift can also be observed and analyzed via the developed visualization tool.National Grid Electricity System Operator; Office of Gas and Electricity Markets (OFGEM

A Novel Hardware-in-the-Loop Approach to Investigate the Impact of Low System Inertia on RoCoF Relay Settings

This paper presents a novel hardware-in-the-loop (HIL) approach as used to investigate the impact of the reduction in inertia on the Great Britain (GB) electrical power system with regard to rate of change of frequency (RoCoF) settings for Loss-of-Mains (LoM) protection. Furthermore, the research as presented in this paper updates, enhances, and validates a reduced model of the Great Britain transmission system, as originally developed in DIgSILENT PowerFactory by the National Grid Electricity System Operator. The enhanced model has been developed for integrated use with the OPAL-RT real-time HIL simulation toolkit and is validated against phasor measurement unit (PMU) data from actual disturbance events using novel automated interfacing between both integrated simulation platforms, PowerFactory from DIgSILENT and ePHASORSIM from OPAL-RT. The corresponding simulations show that the updated reduced model is capable of capturing the dynamic behaviour of the GB transmission system, including both local and inter-area oscillations, with satisfactory accuracy. Finally, the paper presents HIL study results with the reduced model to investigate the influence of decreasing system inertia on the response of LoM protection relays. The studies show that decreasing system inertia may have a significant impact on LoM relays using RoCoF detection, particularly relays using the legacy G59 setting of 0.125 Hz/s. Initial studies have also demonstrated the potential for a previously unrecognised interaction between system oscillations and the 500 ms operating delay, as specified in G59 and G99 Engineering Recommendations. Consequently, faster local oscillations (&gt;1 Hz) reset the relay and decrease the sensitivity, whereas slower inter-area oscillations (&lt;1 Hz) appear to cause the relay to overestimate the average RoCoF

Experimental Determinations of Mixing Times in the IronArc Pilot Plant Process

IronArc is a newly developed technology and an emerging future process for pig iron production. The long-term goal with this technology is to reduce the CO2 emissions and energy consumption compared to existing technologies. The production rate of this process is dependent on the stirring, which was investigated in the pilot plant process by measuring the mixing time in the slag bath. Moreover, slag investigations were done both based on light optical microscope studies as well as by Thermo-Calc calculations in order to determine the phases of the slag during operation. This was done because the viscosity (which is another important parameter) is dependent on the liquid and solid fractions of the slag. The overall results show that it was possible to determine the mixing time by means of the addition of a tracer (MnO2 powder) to the slag. The mixing time for the trials showed that the slag was homogenized after seconds. For two of the trials, homogenization had already been reached in the second sample after tracer addition, which means &le;8 s. The phase analysis from the slag indicated that the slag is in a liquid state during the operation of the process