Test Case 25

Cyber Security of Digital Substations and Impact Analysis

Identification

ID

25

Author

Petra Raussi (VTT), Vetrivel Subramaniam Rajkumar (TUD)

Version

1

Project

ERIGrid 2.0

Date

19/4/2021

Test Case Definition

Name of the Test Case

Cyber Security of Digital Substations and Impact Analysis

Narrative

The energy transition towards a carbon neutral and clean energy system requires increased power grid digitalization. This is seen as the most cost-effective path in developing smart grids. An essential part of any functional power system are substations; thus, their digitalization is crucial. While the digitalization of power system brings several benefits from cost savings to more optimized operations and investments, it also raises concerns related to cybersecurity. To ensure safe and resilient operation of digital substations even in the case of cyber attacks or incidents, it is necessary to investigate their cyber resilience. This can aid in impact analysis of cyber attacks on digital substations, and help to gain deeper understanding of which components must be most secured

Function(s) under Investigation (FuI)
  • Grid stability and operation when impacted by cyber-attacks/incidents
  • Cyber resilience of digital substations
Object under Investigation (OuI)

Digital substation components and communication systems:

  • substation bays (busbars, disconnectors, circuit breakers, current and voltage transformers),
  • merging units,
  • Ethernet switches,
  • HMIs,
  • time servers,
  • IEDs,
  • centralized protection and control units,
  • station control systems,
  • process bus, and
  • communication gateways.
Domain under Investigation (DuI)
  • ICT
  • Electrical power system
Purpose of Investigation (PoI)

To carry out impact analysis of cyber-physical events on digital substations and quantify impact on grid operations.

System under Test (SuT)

In power system domain: digital substation including substation bays, merging units, Ethernet switches, HMIs, time servers and IEDs centralised protection and control units, station control systems, etc. A substation bay comprises of busbars, disconnectors, circuit breakers, current and voltage transformers, etc.

In ICT domain: communication within the substation via local operating networks (process bus) at bay level using communication protocols such as IEC 61850 and LAN at the station level for communication with the control centre via dedicated communication gateway and protocols such as IEC 104 and DNP3. Hence, to realize this test case, the following components are required:

  • Real-time grid simulator such as RTDS or OPAL-RT that supports Hardware-in-Loop (HIL) studies
  • Substation network elements: 1. At least one ethernet switch and time server. At least two or more physical IEC 61850 capable IEDs 1. RTUs, MUs, other HIL devices
  • A dedicated communication network emulator to model disturbances/cyber attacks

The testing involves interfacing the real-time grid simulator with all hardware components in a HIL setup to mimic a digital substation. Furthermore, the real-time grid simulator also needs to be interfaced with the network emulator to model and input communication related effects such as latency, packet loss, loss of service, etc.

Source: Centralized Protection and Control. ABB Whitepaper, 2020. Link: https://library.e.abb.com/public/6b20916a4d2e412daabb76fbada1268e/Centralized_Protection_and_Control_White_paper_2NGA000256_LRENA.pdf

Functions under Test (FuT)
  • Capability of test setup to exchange data using IEC 61850 and IEC 60870-5-104
  • Automation and protection functionality realized by OuI
  • Behaviour and performance of substation, when subjected to specific cyber attacks/threats
Test criteria (TCR)
  • Equipment response and performance under normal operating conditions
  • Equipment response and performance when subjected to specific cyber attacks/threats.
  • Impact of particular attack/threat on overall system performance
Target Metrics (TM)

Cyber security performance and resilience testing

  • This TC assumes that the substation is conformant to IEC 62351-6 and tests its implementation for resiliency.
  • For e.g., through Denial-of-Service attacks, malformed authentication codes, etc.

Impact on Power system

  • KPIs: loss of load, voltage deviations, frequency fluctuations, etc.
Variability Attributes (VA)
  • Overall substation configuration and topology
  • Network emulator characteristics
  • Redundancy (N-1, N-2…. N-k): Number of components or communication links which can fail before system operation is at risk
  • Topology and type of simulated power system (transmission vs distribution)
Quality Attributes (QA)
  • System performance under cyber attacks
  • Pass: all KPIs within maximum limits/bounds
  • Fail: at least one KPI maximum limits

Qualification Strategy

The PoI are mainly addressed by characterizing and verifying the impact of cyber attacks in digital substations on grid operations. This can be achieved by determining how substation functionality and thereby power system stability and operations are directly affected by cyber-physical attacks.

Test Specification TC25.TS1

Impact analysis of Denial-of-Service (DoS) attack in a digital substation