Abstract
The generation and supply of electricity is currently about to undergo a fundamental transition that includes extensive development of smart grids. Smart grids are huge and complex networks consisting of a vast number of devices and entities which are connected with each other. This fact opens new variations of disruption scenarios which can increase the vulnerability of a power distribution network. However, the network topology of a smart grid has significant effects on urban resilience particularly referring to the adequate provision of infrastructures whereby the way in which a distribution network is divided into interconnected microgrids is of particular importance. Such decompositions enable the systematic protection of important infrastructures and furthermore allow new forms of resilient power supply avoiding large-scale power blackouts. Therefore, the authors introduce a concept of criticality adapted to a power system relying on an advanced metering infrastructure and thereby propose a metric for an integrated resilience assessment of power distribution networks.
TopIntroduction
The increase in distributed energy resources (DERs) and the paradigm shift from automated meter reading to advanced metering infrastructures (AMIs) (Kabalci, 2016; Muscas, Pau, Pegoraro, & Sulis, 2015; Parhizi, Lotfi, Khodaei, & Bahramirad, 2015) may be seen as the fundamental drivers for various design or methodological approaches to find optimal solutions regarding smart grid (SG) reliability and resilience issues including topological design patterns like microgrid (MG) decompositions (Cox & Considine, 2013; Melike, Burak, & Hussein, 2011). The common perception of the principles of power management and control within an SG is typically restricted to a hierarchical framework consisting of control mechanisms focusing on voltage and frequency stability as well as economic considerations (Ahumada, Cardenas, Saez, & Guerrero, 2016; Parhizi et al., 2015). These control mechanisms are important pillars of a reliable power distribution system. Resilience aspects of power systems applying SG technologies are moving more and more into the focus of scientific investigations where especially smart solutions are considered as one crucial building block for power system resilience (Panteli & Mancarella, 2015; Venkata & Hatziargyriou, 2015).
The smart meter (SM) roll-outs are accompanied by critical public debates which are essentially related to fundamental security worries and the generally noticed increasing vulnerability due to undesired manipulations from external parties (cf., Aloul, Al-Ali, Al-Dalky, Al-Mardini, & El-Hajj, 2012; Goel, Hong, Papakonstantinou, & Kloza, 2015).
The concept of urban resilience encompasses various types of resilience dimensions such as the social, economic or physical infrastructure dimensions (Bruneau et al., 2003; Cimellaro, 2016; Renschler et al., 2010). Critical infrastructure (CI) services, such as the supply of electricity, drinking water, and health care, provide vital services for the population. Thus, disruptions in or failures of these services are hazardous and can lead to injuries or even losses of life, property damage, social and economic disruptions, or environmental degradations. Therefore, CIs constitute a pivotal aspect in urban resilience considerations; establishing and implementing sophisticated continuity management (CM) concepts with respect to CIs may be regarded as one of the major factors for preserving or enhancing urban resilience. Most of the CIs, like the water supply, hospitals, pharmacies, and traffic- and transport systems, rely on electricity. The circumstance of massive dependencies of other CIs to electrical power warrants the electrical power grid to be considered as a high ranked CI. Further, the provisioning of electricity to other physical infrastructures, including households and companies, constitutes urban resilience. Approximately 99% of all enterprises are small or medium enterprises (SMEs) (Thiel & Thiel, 2010). Light- weighted Business Continuity Management (BCM) strategies for SMEs are desired (Reuter, 2015). A future decentralized power distribution system applying smart infrastructures can enable more refined and smarter power distribution mechanisms as a basic strategy to mitigate the impact of power scarcity (Liu, 2015; Panteli & Mancarella, 2015; Venkata & Hatziargyriou, 2015).
Key Terms in this Chapter
Energy Management System: A system of computer-assisted tools used by network operators to monitor, control and optimize the performance of the generation or transmission/distribution system. It can also be used in small systems such as microgrids.
Smart Meter: Device on an infrastructure’s premise that can be considered as a data interface between the infrastructure and the outer power distribution system, relaying power-infeed/consumption data and receiving information from the power distribution system. Upon this data, prosumer, i.e., consumer that are able to infeed power, and the energy management system can make automated or non-automated decisions.
Criticality: An attribute attached to an infrastructure or component, which reflects its importance compared to other infrastructures within a system, reflecting the severity of the direct and indirect consequences of a failure for the system. Building on the first definition, criticality with respect to a certain good, the infrastructure needs to fulfill its tasks, describes the adverse impacts of a reduced or insufficient supply of this good to the infrastructure on the system.
Microgrid: Small areas with own local resources being able to be self-sufficient for at least some time. Microgrids can be connected to or disconnected from an overall smart grid and can be interconnected.
Multi-Criteria Decision Analysis: A method that provides a ranking on a set of alternatives based on criteria evaluation. The alternative with the highest rank is assumed to be the most appropriate alternative. Criteria values may differ in magnitudes and require normalization before computing their scores and they may be of different importance, which is reflected in a weight for each criterion.
Resilience Metric: Is a metric that measures the quality of different aspects of resilience as robustness, redundancies, response-, and recovery strategies.
Urban Resilience: The ability of an urban system to maintain or rapidly return to desired functions in the face of unexpected adverse disruptions.
Smart Grid: Decentralized energy system with multiple energy sources is equipped with ICT-infrastructures and management units for transferring and processing energy data resp. that is linked to energy consumption, generation and further measurements in order to maintain reliable energy supply.