# An Integrated Testbed for Power System Cyber-Physical Operations Training
## 1 Introduction
### Contribution  
Though the majority of the literature on CPSs focuses on technical aspects of power systems, there is little concern about investigating the testing methods and testing specifications. The literature elaborates on the infrastructures of the cyber-physical paradigm but lacks an emphasis on functional analysis. Only a few of the studies have embraced the challenges associated with developing new testbeds and testing methods. The current CPS reviews and surveys lack coverage of specifically non-functional attributes of CPS besides security. Other attributes such as data integrity, eavesdropping of packets, availability of the system, etc. need to be addressed [29]. In power systems, besides a security-oriented testbed, a control-oriented testbed is equally important, as it assures the correctness of the control logic from the SCADA system [30]. As SCADA systems are vital components of power systems, the cyber-physical interaction of the monitoring system with the power system must be considered as well. The authors in this paper noticed the research gap in existing CPS research, as well as the lack of detailed guidance for researchers and industry professionals and the need to investigate scalable testing platforms and noble testing methods. Research needs to improve the higher cost of implementation of the testbeds and needs to focus on effective models for generic instead of specific applications. In addition,other concerns involve the communication infrastructure, the accurate selection of test platforms, distributed and decentralized control, and the interoperability of the testbeds. The cybersecurity testbed at Texas Tech University (TTU) was designed after a thorough survey of the limitations and benefits of the existing CPS testbed. Since the testbed aims to aid research and train cybersecurity beginners in a realistic scenario, various industry professionals were interviewed regarding the current problems in the industry. The industry standard equipment to be used for HIL simulation was carefully selected and integrated. The TTU CPS testbed is a reconfigurable hardware-in-loop testbed designed for real-time experimental research and training programs. The testbed aims to study the functional aspects of smart grid technologies and investigate the vulnerabilities associated with them. It also provides a scalable platform to test noble cybersecurity solutions, SCADA system operations, and intrusion detection algorithms using intelligent electronic devices (IEDs) in a loop with a real-time simulation platform. This study develops a complete cyber-physical testbed for training industry professionals on different CPS scenarios and cases. Our primary objective is to fill the void of cybersecurity education in engineering disciplines and deliver education regarding CPS operation and security using hands-on experience. The main novelty presented in this paper is the design and implementation of a CPS testbed focused on training industry professionals on the interaction between physical and cyber layers and their performance under cyberattacks. With the intention of developing a reliable and realistic test environment using knowledge and expertise from the literature mentioned in the previous section, the testbed topology employs a combination of the HIL concept and the co-simulation concept. HIL co-simulation couples the continuous simulation of power systems and discrete event-based simulation of communication in combination with real-life equipment or a prototype for CPS studies. The study embraces and extends the fundamental concept of CPS operation and adds a broader dimension to the existing research paradigm. This is justified by the adoption of IEDs from the Schweitzer Engineering Laboratories (SEL) and the industry-scale SCADA software integrated into an OPAL-RT simulator using both analog/digital I/Os and DNP3, C.37 master/slave, and IEC 61850 GOOSE communication protocols [31].