Biblio

Distributed wind is an electric energy resource segment with strong potential to be deployed in many applications, but special consideration of resilience and cybersecurity is needed to address the unique conditions associated with distributed wind. Distributed wind is a strong candidate to help meet renewable energy and carbon-free energy goals. However, care must be taken as more systems are installed to ensure that the systems are reliable, resilient, and secure. The physical and communications requirements for distributed wind mean that there are unique cybersecurity considerations, but there is little to no existing guidance on best practices for cybersecurity risk management for distributed wind systems specifically. This research develops an architecture for managing cyber risks associated with distributed wind systems through resilience functions. The architecture takes into account the configurations, challenges, and standards for distributed wind to create a risk-focused perspective that considers threats, vulnerabilities, and consequences. We show how the resilience functions of identification, preparation, detection, adaptation, and recovery can mitigate cyber threats. We discuss common distributed wind architectures and interconnections to larger power systems. Because cybersecurity cannot exist independently, the cyber-resilience architecture must consider the system holistically. Finally, we discuss risk assessment recommendations with special emphasis on what sets distributed wind systems apart from other distributed energy resources (DER).

The IEC 61850 protocol suite for electrical sub-station automation enables substation configuration and design for protection, communication, and control. These power system applications can be formally verified through use of object models, common data classes, and message classes. The IEC 61850-7-420 DER (Distributed Energy Resource) extension further defines object classes for assets such as types of DER (e.g., energy storage, photovoltaic), DER unit controllers, and other DER-associated devices (e.g., inverter). These object classes describe asset-specific attributes such as state of charge, capacity limits, and ramp rate. Attributes can be fixed (rated capacity of the device) dynamic (state of charge), or binary (on or off, dispatched or off-line, operational or fault state). We sketch out a proposed ontology based on the 61850 and 61850-7-420 DER object classes to model threats against a micro-grid, which is an electrical system consisting of controllable loads and distributed generation that can function autonomously (in island mode) or connected to a larger utility grid. We consider threats against the measurements on which the control loop is based, as well as attacks against the control directives and the communication infrastructure. We use this ontology to build a threat model using the ADversary View Security Evaluation (ADVISE) framework, which enables identification of attack paths based on adversary objectives (for example, destabilize the entire micro-grid by reconnecting to the utility without synchronization) and helps identify defender strategies. Furthermore, the ADVISE method provides quantitative security metrics that can help inform trade-off decisions made by system architects and controls.

The prevalent integration of highly intermittent renewable distributed energy resources (DER) into microgrids necessitates the deployment of a microgrid controller. In the absence of the main electric grid setting the network voltage and frequency, the microgrid power and energy management becomes more challenging, accentuating the need for a centralized microgrid controller that, through communication links, ensures smooth operation of the autonomous system. This extensive reliance on information and communication technologies (ICT) creates potential access points and vulnerabilities that may be exploited by cyber-attackers. This paper first presents a typical microgrid configuration operating in islanded mode; the microgrid elements, primary and secondary control functions for power, energy and load management are defined. The information transferred from the central controller to coordinate and dispatch the DERs is provided along with the deployable communication technologies and protocols. The vulnerabilities arising in such microgrids along with the cyber-attacks exploiting them are described. The impact of these attacks on the microgrid controller functions was shown to be dependent on the characteristics, location and target of the cyber-attack, as well as the microgrid configuration and control. A real-time hardware-in-the loop (HIL) testing platform, which emulates a microgrid featuring renewable DERs, an energy storage system (ESS), a diesel generator and controllable loads was used as the case study in order to demonstrate the impact of various cyber-attacks.