The Joint Working Group C4/C2.58/IEEE was established to review voltage stability of power systems in the context of increased penetration of Inverter Based Resources (IBR) in electric power grids. The focus was to evaluate the adequacy of existing methods of voltage stability assessment in the present-day context. The developed technical brochure reviewed the definition of voltage stability and explained the role of voltage stability assessment within the voltage security assessment task of near real time power system operation. The overall conclusion is that the controllers implemented on IBRs makes a significant influence on short-term, but also long-term voltage stability. The presence of IBRs at distribution voltage levels contribute to the dynamic behavior of the power grid. Voltage stability assessment must incorporate these facts to ensure that the methods and tools accurately capture voltage stability limits.

The NEWEPS (Nordic Early Warning Early Prevention System) project aim has been to enhance the reliability and efficiency of the Nordic power system through the development and implementation of Wide Area Monitoring System (WAMS) and advanced Wide Area Monitoring, Protection, and Control (WAMPAC) solutions. This comprehensive report documents the vision, methodologies, and outcomes of the project, providing a roadmap for deployment and future developments.

Vision: Architectural, Data Quality, and Visualisation Perspectives

The report outlines a vision of a Nordic WAMS and WAMPAC system, emphasizing the importance of improved assessment, coordinated assessment between Nordic Transmission System Operators (TSOs), consistent situational awareness, and enhanced state estimation. The architectural perspectives highlight the need for a robust and integrated approach to wide area monitoring and controlling of the power system.

Important considerations raised for the architectural perspectives are that:

·       Coordination and pre-processing should be considered as common services to ensure fast data processing and consistency.  

·       When it comes to coordinated assessment, the level of autonomy may vary between different applications ranging from manually entered situational awareness information by operators to automatically issued control actions.

·       Since WAMS until recently has been considered complementary in Nordic TSOs power operation, bringing the dynamic conditions into awareness should be considered with the problematic nature of digital transformations. This motivates a flexible application architecture that allows a gradual implementation and adaption of application services.

·       More investigations are needed to provide guidance on whether to use a common or separate state estimator in different control systems (as SCADA/EMS and WAMS) as well as regarding if an in-house developed solution is needed to get the functionality required or if third party solutions would be the best option. However, all will introduce benefits and complexities.

·       When it comes to WAMPAC, the mechanisms for assessing and managing flexible control schemes is complex. Further investigations are needed for example regarding how to model and exchange information between local and distributed applications, distributed versus different level of centralised automated control and how to benefit from AI/ML and data labelling techniques.  

·       TSO should have unified functional requirements, but as the maturity over time may differ in their WAN architecture the implementation may be different. A unified design supporting SDN capabilities should however be implemented in the common Nordic inter-TSO WAN network to ensure both integrity and determinism.  

Data quality is a critical component of a WAMS or WAMPAC system. The report explores various methods for improving data quality, including system models and data-sharing architectures. With the large amount of time synchronised high-resolution data provided by Phasor Measurement Units (PMUs), the possibilities for advanced monitoring and control techniques are growing. However, high quality data is a prerequisite to be able to integrate such solutions into operation critical processes. 

Effective visualisation techniques support the human-system collaboration, enabling operators to increase their situational awareness in order to take informed decisions in real-time. The report addresses the increased importance of visualisation perspectives when more advanced systems, like WAMS and WAMPAC, are becoming integrated in the operation of the power system. 

The report also outlines possible strategies for platform flexibility, as scalable and virtualised computing environment, portable application architecture, a flexible integration layer and the advantages with staged development using Big Data analytic and simulation capabilities.

NEWEPS Test & Demonstration Platform

A significant achievement of the project is the development of the NEWEPS Test & Demonstration platform. This platform prototypes functionalities of a future Nordic WAMS and WAMPAC system, enabling testing and demonstration of various applications, including oscillation monitoring, voltage stability, and islanding detection. The Kafka stream processing framework has been selected for integrating applications in the platform and for establishing communication between individual applications.

NEWEPS Test & Demonstration platform interface to the operator in form of a graphical user interface and to the power system in form of standard based PMU data streams originating from historians from PMUs in the Nordic grid, simulation based emulated PMU data, and laboratory based synthetic PMU data. The platform also contains functionalities for issuing alarms and visualizing information related to alarms as well as a scheme for enabling coordinated communication between neighbouring TSOs.

The platform's architecture ensures scalability, modularity, and fault tolerance, bridging the gap between research and industrial application.

WAMS Applications

The report details the development and validation of WAMS applications focused on voltage stability monitoring, natural oscillation monitoring, and forced oscillations and resonance detection. These applications leverage PMU data to provide operators with detailed and accurate information about the grid's operational situation, enhancing situational awareness and decision-making capabilities.

There are several already existing applications for voltage stability monitoring, both model-based and pure measurement based. One great benefit with measurement-based approaches is that they do not depend on state estimators nor on the knowledge of the full power system model. In NEWEPS, the voltage stability index S-Z sensitivity Indicator (SZI), which focuses on sensitivities to define whether the system is stable or not from a voltage stability perspective, has been further developed and tested. The SZI is defined using the ratio of variations of the absolute value of the apparent power of the load and the load impedance. The proposed modifications are mainly intended to improve the SZI performance in relation to network reconfiguration events and operation of regulating devices.

There are also various methods available for detecting natural oscillations using measurement data. In NEWEPS, further development and testing of the stochastic subspace identification (SSI) method have been performed. The SSI method is selected due to its ease of implementation, numerical stability, and ability to work with ambient (non-disturbance) data. The developments include how to consider the observability of modes and to cluster these based on patterns. The clustering supports the ability to track the most important oscillations over time, thus enabling preventive measures to be implemented. 

Since the algorithms for detecting oscillations (system modes) using PMU measurements are generally not designed to operate in the presence of forced oscillations, they risk giving biased results if a force oscillation is present. It is therefore important the WAMS application for oscillation detection is able to distinguish between natural and forced oscillations. In NEWEPS a method that fits a Least Squares Autoregressive Moving Average plus Sinusoid (LS-ARMA+S) model to the PMU measurements data has been used to distinguish between natural and forced oscillations. The method was selected because the LS-ARMA+S model can accurately separate an oscillation from the background noise without losing the modal information contained in the noise at the oscillation frequency.  

WAMPAC Solutions

The WAMPAC solutions developed in the project aim to secure post-contingency states of the power system by identifying critical contingencies and suggesting the least expensive set of corrective actions for each critical contingency. The corrective actions can rapidly be deployed to secure the system operation in case when a critical contingency occurs. The solutions utilise optimisation methods based on detailed mathematical models of the system and operate in real-time. 

The input to the WAMPAC application is the current operating point, system model data, and a list of contingencies to evaluate. The solution is modular where the first part performs a steady state contingency analysis considering line loading limits, bus voltage limits, and bus voltage stability limits based on the sensitivity indicator SZI. The second part finds the optimal corrective actions for each critical contingency by minimising the overall costs of deploying corrective actions for the operational situation evaluating a set of most effective corrective actions. The set of most effective corrective actions are chosen by sensitivity analysis which is performed as a first step in the optimisation. The developed method is integrated as an independent application into the NEWEPS Test & Demonstration platform.

The developed solutions highlight that WAMPAC solutions can enable a secure increased utilisation of the power system.

Conclusions and future outlook

The NEWEPS project represents a significant advancement for methods enabling a secure operation of the increasingly complex power system. The integration of WAMS and WAMPAC solutions within the NEWEPS Test & Demonstration platform provides a robust foundation for future enhancements and real-world applications. 

The project demonstrates the potential for advanced monitoring and control systems to improve the reliability and efficiency of the power grid, paving the way for a more resilient and sustainable energy future.

This report concludes with an outlook, including a roadmap for deployment and future development towards a future Nordic WAMS & WAMPAC system.

NEWEPS-prosjektet har hatt som mål å forbedre påliteligheten og effektiviteten til det nordiske kraftsystemet gjennom utvikling og implementering av WAMS (Wide Area Monitoring System) og WAMPAC (Wide Area Monitoring, Protection, and Control). WAMS- og WAMPAC-løsninger utnytter høyoppløselige og synkroniserte visermålinger av strøm og spenning fra PMU-enheter for å gi systemoperatøren et mer nøyaktig bilde av gjeldende driftstilstand og muliggjøre automatiserte vern- og kontrollapplikasjoner.  

Visjon: Arkitektur, datakvalitet og visualisering 

I tillegg til de konkrete delene som er utviklet i prosjektet, har en sentral del vært å belyse viktige forutsetninger og krav til et nordisk system for WAMS og WAMPAC. De arkitektoniske perspektivene fremhever behovet for en robust og integrert tilnærming til overvåking og styring av kraftsystemet, med datakvalitet som en kritisk del av WAMS og WAMPAC. Effektive visualiseringsteknikker er også en svært viktig del som muliggjør en økt situasjonsforståelse for operatører til å ta hurtige og riktige beslutninger. 

NEWEPS test- og demonstrasjonsplattform

Et av hovedbidragene til prosjektet test- og demonstrasjonsplattformen som er utviklet. Denne modulære, skalerbare plattformen er designet for prototyping av funksjonaliteten til et fremtidig nordisk system for WAMS og WAMPAC, og muliggjør testing og demonstrasjon av forskjellige WAMS- og WAMPAC-applikasjoner. PMU-datastrømmene som mates til plattformen kan lastes inn fra historiske måledata, sanntidsmålinger eller fra fiktive datastrømmer generert via simuleringsprogram eller plattformens sanntidssimulator. 

WAMS-applikasjoner

Applikasjoner som er utviklet fokuserer på overvåking av spenningsstabilitet, naturlige pendlinger, og forserte pendlinger i kraftsystemet. Disse applikasjonene utnytter PMU-data for å adressere detaljer rundt systemdynamikk, og forbedrer dermed operatørens situasjonsforståelse og beslutningsevne. Applikasjonene er testet og validert på ulike måter, samt integrert i test- og demonstrasjonsplattformen.  

WAMPAC-applikasjoner

Applikasjoner med et tydeligere fokus på vern og kontroll er også utviklet og validert i prosjektet, samt integrert i test- og demonstrasjonsplattformen. Utviklede løsninger har som formål å opprettholde sikker og stabil drift nåt kritiske hendelser identifiseres og passende korrigerende tiltak foreslås for hvert feiltilfelle. De korrigerende tiltakene kan raskt iverksettes for å sikre stabil drift når en kritisk hendelse oppstår. Løsningene er i stor grad basert på informasjon fra PMU-målinger og bruk av optimaliseringsmetoder basert på detaljerte modeller av systemet, som er anvendelige i sanntid. 

Konklusjoner og fremtidsutsikter

NEWEPS-prosjektet representerer betydelige fremskritt innen metoder som muliggjør sikker drift av det stadig mer komplekse kraftsystemet. Evalueringen av ulike WAMS- og WAMPAC-løsninger og den utviklede plattformen er et viktig grunnlag for fremtidig utvikling og implementering. 

Prosjektet har demonstrert potensialet til avanserte overvåkings- og kontrollsystemer for å forbedre påliteligheten og effektiviteten til elektrisitetssystemet, og baner vei mot en mer motstandsdyktig og bærekraftig energifremtid.

NEWEPS-projektet har syftat till att förbättra tillförlitlighet och effektivitet av det nordiska kraftsystemet genom utveckling och implementering av WAMS (Wide Area Monitoring System) och WAMPAC (Wide Area Monitoring, Protection, and Control). WAMS- och WAMPAC-lösningar nyttjar högupplösta och detaljerade synkroniserade mätdata från PMUer för att ge systemoperatören en mer korrekt bild av det aktuella driftläget och möjliggöra automatiserade skydds- och kontrollapplikationer.  

Vision: Arkitektur, datakvalitet och visualisering 

Utöver de konkreta delar som utvecklats i projektet, har en central del varit att belysa viktiga beaktanden för att skapa bra grundförutsättningar för ett nordiskt system för WAMS och WAMPAC. De arkitektoniska perspektiven belyser behovet av ett robust och integrerat tillvägagångssätt för övervakning och styrning av kraftsystemet, med datakvalitet som en kritisk del av WAMS och WAMPAC. Även effektiva visualiseringstekniker är en mycket viktig del som möjliggör en ökad situationsmedvetenhet för operatörer att fatta snabba och korrekta beslut. 

NEWEPS Test- & Demonstrationsplattform

Ett av projektets huvudbidrag är den utvecklade test- & demonstrationsplattformen. Denna modulära, skalbara plattform är framtagen för prototypframställning av funktionaliteter hos ett framtida nordiskt system för WAMS och WAMPAC, och möjliggör provning och demonstration av olika WAMS och WAMPAC applikationer. De PMU-dataströmmar som matas till plattformen kan läsas in från historiska mätvärden, mätvärden i realtid eller från fiktiva dataströmmar som genererats via simuleringsprogram eller plattformens realtidssimulator. 

WAMS-applikationer

Applikationer med fokus på övervakning av spänningsstabilitet, naturliga oscillationer, samt forcerade svängningar har utvecklats inom projektet. Dessa applikationer utnyttjar PMU-data för att adressera detaljer kring systemets dynamik, vilket på så sätt förbättrar operatörens situationsmedvetenhet och beslutsförmåga. Applikationerna har på olika sätt testats och validerats, samt integrerats i test- & demonstrationsplattformen.  

WAMPAC applikationer

Även applikationer med tydligare fokus på skydd och kontroll har utvecklats och validerats inom projektet, samt integrerats i test- & demonstrationsplattformen. Utvecklade lösningar syftar till att säkerställa bibehållen driftsäkerhet, där kritiska händelser identifieras och lämpliga korrigerande åtgärder föreslås för respektive felfall. De korrigerande åtgärderna kan snabbt appliceras för att säkra systemets drift ifall motsvarande felfall skulle inträffa. Lösningarna är baserade på PMU-data och använder optimeringsmetoder baserade på detaljerade modeller av systemet, som är tillämpbara i realtid. 

Slutsatser och framtidsutsikter

NEWEPS-projektet representerar betydande framsteg för metoder som möjliggör en säker drift av det allt mer komplexa kraftsystemet. Utvärderingen av olika WAMS och WAMPAC lösningar och den utvecklade plattformen är en robust grund för framtida utveckling och implementering. 

Projektet har visat på potentialen av avancerade övervaknings- och kontrollsystem för att förbättra elsystemets tillförlitlighet och effektivitet, vilket banar väg mot en mer motståndskraftig och hållbar energiframtid.

Congestion is a major limiting factor preventing expansion of renewable energy production in distribution networks. However, with large shares of connected power electronic-interfaced generators in combination with new types of controllable loads, such as electric vehicles (EVs), there is a potential to greatly increase network operation flexibility. Utilising these available flexible resources effectively is crucial to boost network capacity in a cost-effective manner and allow for safe integration of additional renewable energy sources (RESs). In parallel, the reactive power flows in distribution networks are changing. This can be attributed to the increased RES production and increased charging currents due to expanding cable networks. Also contributing to the changing flows is the rising number of new household appliances and consumer electronics with non-linear load characteristics. This makes systemwide coordination of resources an even more pressing issue. For distribution system operators (DSOs), minimising undesired reactive power flows at the connection to the transmission system is key to meet inter-network requirements. In this paper we propose a centralised near real-time control algorithm for combined congestion management and reactive power control in distribution networks. Through updated communication and measurement protocols, together with more extensive use of the active and reactive power control capabilities of local flexibility resources – such as wind power plants (WPPs), photovoltaic (PV) units, and flexible loads – bottlenecks can be detected and eliminated. Flexibility is offered by local resources and dispatched by the DSO through a common platform, which is independent of any specific financial arrangement for the participating flexibility providers. Thus, market solutions and individual contractual agreements are not mutually exclusive and can be implemented in parallel. The inclusion of reactive power simplifies the DSO’s coordination of intra-network and inter-network operational requirements. We demonstrate selected algorithm features through simulations of a congestion scenario in a medium voltage benchmark network. Aspects of deploying the solution in actual distribution network operation are also outlined.

Power system resilience is an overarching concept covering the whole spectrum of the power system, from design and investment decisions to planning, operations, maintenance and asset management functions. Flexibility concerns the power system's ability to manage changes, with flexibility features able to improve the resilience characteristics of the system, provided that they are integrated into grid planning, in defence plans, and evaluated adequately in the energy market design. An analysis of ongoing worldwide initiatives provides relevant insight into ongoing worldwide initiatives. They provide relevant insight into how flexibility can support resilience, showing the prominence and potential values that can be unlocked, with potentially some low-hanging fruits to start. This paper introduces four innovative concepts: Alternative grid development, system integrity protection schemes, the next level of flexibility and LINK holistic approach to flexibility for resilience as solutions contributing to improving future power systems' resilience.

This Technical Brochure explores the integration of Wide Area Monitoring (WAM) and Wide Area Monitoring, Protection, and Control (WAMPAC) systems into decision support tools for control room processes of modern power systems. It highlights the need for synchronised measurement technologies as provided by Phasor Measurement Units (PMU) to observe and control the electrical grid effectively. The brochure discusses various applications and timeframes for decision-making processes using synchrophasor measurements, ranging from real-time control to post-event analysis. By sharing practical experience, it emphasizes the challenges and benefits associated with deploying WAM and WAMPAC systems into standard control room procedures and provides recommendations for areas of further research and development.

This paper will provide insights regarding the financial implications of non-conventional grid development solutions, which are intended to provide agile, flexible and supportive solutions and thereby enable a sustainable development of the power system. As complements to traditional grid expansion developments, Active Network Management (ANM) solutions provide new methods to plan and operate the power system. In the case of long-term investment planning, different grid development solutions are weighed against each other based on e.g., their resilience, cost, environmental impact, and time to operation. The results presented in this paper originate from the ongoing European research project ANM4L [1]. While the developments in the ANM4L project are based on three pillars (ANM control solutions, Business solutions, & ICT solutions), the activity in focus of this paper is on the discussion on necessary investment decisions by the DSO and whether to continue traditional operations or to apply ANM solutions. The pillars of the ANM4L project are collectively resulting in a toolbox developed to support the operation and planning of distribution grids, which functionality and replicability will be tested and demonstrated within the ANM4L project. The activity in focus of this paper lies within the second pillar and is on the discussion on necessary investment decisions by the DSO and whether to continue traditional operations or to apply ANM solutions.