A smart grid is an advanced electrical power distribution system that uses digital communication technologies to detect and react to changes in power demand and supply. It is designed to improve the efficiency, reliability, and sustainability of the electricity grid by integrating renewable energy sources, energy storage systems, and electric vehicles. The current technology needs to be modified and upgraded, and the energy management system needs to be designed in such a way that it can monitor itself if there is a malfunction.

Fig. 1. Smart grid architecture Source: IET Renewable Power Generation 

Ⅰ. Smart Grid Challenges

The recent findings demonstrate that there is a major gap to bridge between the conventional grid network and the smart grid network. The gap should include safe data transfer, strong data encryption, decryption protocols, a rapid technological interface, and other important hurdles that must be eliminated.

The smart grid would have the following difficulties:

l The bandwidth, protocol, and delay requirements for the power distribution system have to be fulfilled. If not, it will be relatively simple to hack the entire system.

l Each station's or level's connected devices must be very highly encrypted. They are the powerhouse of the data storage system. Cyberattacks on those devices could result in the loss of essential data.

l The entire system's networking is crucial to communication. The networking protocols should be adequate for authorized individuals to handle them. If not, it is at risk of losing control of the data flow.

Ⅱ. Cyberattacks

Only until the smart grid infrastructure is completely immune to all forms of cyberattacks can it be considered smart in operation. The grid is more vulnerable to online hackers because of the volume of real-time data it will process while in use. Once the data is leaked, the operation of the entire system is put in danger, and man-made mistakes could result in the system malfunctioning. To monitor and stop cyberattacks, it is crucial to implement security solutions on all of the infrastructure's various components. 

PLCs (programmable logical controllers), RTUs, and IEDs are frequently used in power distribution systems to provide remote performance monitoring. It might give attackers access to the devices and lead to misleading consumers by giving false information. They can also seriously harm the system by turning off the grid as a whole and messing with the equipment that is connected to it. With remote off switches, it becomes simple for an attacker to turn off hundreds of millions of smart meters. Therefore, having a fully-proof cyber-security system is crucial to prevent such attempts.

Ⅲ. Information and Communication Technologies

The smart grid needs a robust, adaptable, seamless, and dependable communication protocol that will reduce variation rate and latency and enable quick, effective information sharing. HAN and WAN are two categories for smart grid communication. Satellite communication is being used to connect the two networks. One of the required communication technology modules in a smart grid is power line communication. It typically operates between 1.8 and 250 MHz for broadband and 3-500 kHz for the narrow band. 

The imbalance in load on the other side results in reflection, which results in power loss and creates discontinuities. In general, discontinuity mostly affects wireless communication. The imbalance between the industrial and commercial frequency bands is the main reason for interference. Additionally, the radiation from high-voltage equipment slows down the wireless connection and increases latency. Additionally, one of the most important problems is equipment failure, so the communication system's backup mechanism needs to be strong.

Ⅳ. Networking and Management

One of the key areas that are vulnerable to cyber threats is networking. Data exchange between the systems and the sub-stations is done using the networking that has been installed throughout the entire infrastructure. Ethernet passive optical networks (EPON) are a dependable option for broadband access in the smart grid network for wired networks. It provides outstanding backward compatibility, affordable maintenance charges, and straightforward protocol. The next generation of gigabit Ethernet is thought to be EPON. For wireless networks, IEEE 802.11i would aid with the security of smart grid wireless deployment. 

A smart grid is made up of several microgrids. All microgrids are managed via a centralized SCADA system. Every local SCADA serves as a slave controller for the main controller, providing it with data about energy. The system's increased interoperability makes it more accessible to users, but it also puts it at risk for the previously mentioned events: (i) server downtime; (ii) system takeover; (iii) theft of private and public data; (iv) issuing of false bills; (v) acquiring a competitive advantage; and (vi) unintentional latencies caused by software shutdown.

Ⅴ. Power Electronics and Energy Storage Technologies

In the distributed network, power electronics are utilized to regulate the active, reactive, and terminal voltages. The adoption of the intelligent electrical power system network benefits from the use of these devices. Power electronics like the Static Synchronous Compensator, Thyristor-Controlled Series Compensator, and Unified Power Flow Controller add harmonics to the grid network, which also results in issues with voltage distortion. 

The use of high-power three-phase voltage inverters that operate on high switching principles is what causes the unbalanced voltage that is induced in the power lines. Additionally, the rectifiers attached to the converters lead to uneven current sharing. The main concern is the EMI and EMC problems that cause a coupling path that results in a significant imbalance of power in the lines. 

Another prominent source of EMI interfaces is power-switching events. With an increase in switching frequency, the EMI noises become considerably worse. These EMI noises are carried via the coupling channels, where they accumulate at the junctions of the circuits and significantly reduce power flow.

Ⅶ. Other Issues

The smart grid architecture's installation is expensive. In addition, ongoing maintenance is necessary to guarantee the network's smooth operation, which comes at a significant expense. Another significant difficulty is finding trained laborers to do routine maintenance. The devices and gadgets utilized in the smart grid network are highly expensive and extremely sensitive when in use. In the smart grid application, public and government awareness is a significant barrier. 

The government's laws regarding the distribution of power frequently make it extremely difficult to implement this architecture. Another crucial element in the development of the smart grid network is the geographic domain. There could be an imbalance in the output of electricity if solar panels are not installed equally throughout a country or city. As a result, using the devices connected to the smart grid may be challenging for end users.

Ⅷ. Summarizing with Key Points

l The smart grid infrastructure faces several challenges and potential security issues that need to be addressed to ensure safe and efficient operation.

l Cyber-attacks, unauthorized access, misrepresentation, and tampering are some of the major security concerns in the smart grid infrastructure.

l Information and communication technologies play a crucial role in enabling real-time monitoring, control, and analysis of smart grid systems.

l Power electronics and energy storage technologies are critical components of distributed networks that can help regulate active, reactive, and terminal voltages.

l Proper installation and maintenance of smart grid networks require trained laborers, which may increase costs significantly.