# Effects of Cyber Attacks on AC and High-Voltage DC Interconnected Power Systems with Emulated Inertia

^{*}

## Abstract

**:**

## 1. Introduction

#### 1.1. Related Work

#### 1.2. Contributions and Paper Organization

## 2. LFC Modeling in the Hybrid AC/DC System with Virtual Inertia

#### 2.1. The Conventional LFC Structure

#### 2.2. LFC for AC/HVDC Interconnected System

#### 2.3. LFC for AC/HVDC System with Emulated Inertia by ESS

#### 2.4. LFC System Model in the State-Space Form

## 3. DoS Attacks on the AC/DC Multi-Area LFC System with Virtual Inertia

#### 3.1. The Test LFC System under DoS Attacks

**Remark**

**1**

#### 3.2. Stability of the Test LFC System under DoS Attacks

**Lemma**

**1.**

**Proof**

**of Lemma 1.**

## 4. FDI Attacks on the AC/DC Multi-Area LFC System with Virtual Inertia

#### 4.1. The Test LFC Sytem under FDI Attacks: Basics

#### 4.2. A Type of Stealthy FDI Attack on the Test LFC System: Zero-Dynamics Attack

**Definition**

**1.**

## 5. Simulation Results

- Normal AC system.
- AC/DC interconnected system.
- AC/DC interconnected system with virtual inertia.

#### 5.1. DoS Attack Results

#### 5.2. FDI Attack Results

#### 5.3. Discussions

## 6. Conclusions

## Author Contributions

## Funding

## Conflicts of Interest

## Abbreviations

LFC | Load frequency control |

HVDC | High-voltage direct-current |

AC | Alternating-current |

DoS | Denial of service |

FDI | False data injection |

RES | Renewable energy resources |

ESS | Energy storage systems |

SCADA | Supervisory control and data acquisition |

GEN | Generation unit |

ACE | Area control error |

AGC | Automatic generation control |

SPMC | Supplementary power modulation controller |

ROCOF | Rate of change of frequency |

MITM | Man-in-the-middle |

ZOH | Zero-order hold |

MFD | Maximum frequency deviation |

SSFD | Steady-state frequency deviation |

MILP | Mixed integer linear program |

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**Figure 1.**The block diagram of the test system. The communication channels (the red line) for the transmission of wide-area measurements are very vulnerable, and therefore the cyber attacks of Denial of Service (DoS) and false data injection (FDI) in this article are mainly on the measurements side. To be noted, we assume that the channel for control signals is equipped with advanced encryption techniques and thus not attacked.

**Figure 2.**Results of both areas when there is a step load change in Load 1 of Area 1 in the two-area power system. (

**a**) Frequency deviation of Area 1. (

**b**) Frequency deviation of Area 2.

**Figure 3.**The maximum real part of the eigenvalues of $\mathsf{\Phi}\left(\lambda \right)={\mathsf{\Phi}}_{1}^{\lambda}{\mathsf{\Phi}}_{2}^{(1-\lambda )}$ for the three load frequency control (LFC) systems.

**Figure 4.**Case 1: results of both areas under a step-load change at 5 s and also DoS attacks that start from 1 s. (

**a**) Frequency deviation of Area 1. (

**b**) Frequency deviation of Area 2.

**Figure 5.**Case 2: results of both areas under a step-load change at 5 s and also DoS attacks that start from 6 s. (

**a**) Frequency deviation of Area 1. (

**b**) Frequency deviation of Area 2.

**Figure 6.**Case 3: results of both areas under a step-load change at 5 s and also DoS attacks that start from 12 s. (

**a**) Frequency deviation of Area 1. (

**b**) Frequency deviation of Area 2.

**Figure 7.**Results of both areas under a univariate attack with a magnitude of 0.1 Hz on the measurement of frequency in Area 2, at t = 10 s. (

**a**) Frequency deviation of Area 1. (

**b**) Frequency deviation of Area 2.

**Figure 8.**Results of both areas under multivariate attacks on power flow measurements of both AC and HVDC lines with magnitudes of 0.44 p.u. and −0.39 p.u., respectively, at t = 10 s. (

**a**) Frequency deviation of Area 1. (

**b**) Frequency deviation of Area 2.

**Figure 9.**State trajectory under zero-dynamics attacks on wide-area measurements with

**f**

_{0}(i) in (35) being the injection on the AC power flow measurement with a value of 0.5 p.u.. (

**a**) normal AC system; (

**b**) AC/DC system with virtual inertia.

**Figure 10.**State trajectory under zero-dynamics attacks on wide-area measurements with

**f**

_{0}(i) in (35) being the injection on the DC power flow with a value of 0.5 p.u. (

**a**) AC/DC system; (

**b**) AC/DC system with virtual inertia.

Parameters | Area 1 | Area 2 | ||
---|---|---|---|---|

GEN 1 | GEN 2 | GEN 3 | GEN 4 | |

${T}_{c{h}_{i,g}}$$\left(\mathrm{s}\right)$ | 0.38 | 0.38 | 0.36 | 0.39 |

${R}_{i,g}$$(\mathrm{Hz}/\mathrm{p}.\mathrm{u}.)$ | 2.4 | 2.5 | 2.5 | 2.7 |

${\varphi}_{i,g}$ | 0.5 | 0.5 | 0.5 | 0.5 |

${K}_{{p}_{i}}$$(\mathrm{p}.\mathrm{u}./\mathrm{Hz})$ | 102 | 102 | ||

${T}_{{p}_{i}}$$\left(\mathrm{s}\right)$ | 20 | 25 | ||

${\beta}_{i}$$(\mathrm{p}.\mathrm{u}./\mathrm{Hz})$ | 0.425 | 0.396 | ||

${K}_{{I}_{i}}$ | 0.7 | 0.7 | ||

${T}_{ES{S}_{i}}$$\left(\mathrm{s}\right)$ | 0.026 | 0.026 | ||

${T}_{A{C}_{i,j}}$$\left(\mathrm{s}\right)$ | 0.245 | |||

${K}_{1}$ | 0.3 | |||

${K}_{2}$ | 0.1 | |||

${K}_{AC}$ | 4.7 | |||

${J}_{e{m}_{1}}$ | 0.87 | |||

${J}_{e{m}_{2}}$ | 0.093 |

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## Share and Cite

**MDPI and ACS Style**

Pan, K.; Dong, J.; Rakhshani, E.; Palensky, P. Effects of Cyber Attacks on AC and High-Voltage DC Interconnected Power Systems with Emulated Inertia. *Energies* **2020**, *13*, 5583.
https://doi.org/10.3390/en13215583

**AMA Style**

Pan K, Dong J, Rakhshani E, Palensky P. Effects of Cyber Attacks on AC and High-Voltage DC Interconnected Power Systems with Emulated Inertia. *Energies*. 2020; 13(21):5583.
https://doi.org/10.3390/en13215583

**Chicago/Turabian Style**

Pan, Kaikai, Jingwei Dong, Elyas Rakhshani, and Peter Palensky. 2020. "Effects of Cyber Attacks on AC and High-Voltage DC Interconnected Power Systems with Emulated Inertia" *Energies* 13, no. 21: 5583.
https://doi.org/10.3390/en13215583