The smart grid is defined as the electrical distribution technology that uses computer-based remote control and automation to improve the delivery efficiency of electricity. In this section, issues with the smart grid implementation are discussed.
In the standard grid, information, and energy in the grid travel in one direction: from the point where it is generated to the point where it is consumed.
In the United States, the smart grid was initially called the Modern Grid Initiative was started (in the United States) at the National Energy Technology Laboratory (NETL) in January 2005.
The mission of the initiative was to accelerate grid modernization. Later, this initiative was renamed the Smart Grid Implementation Strategy (SGIS).
The smart grid will allow information to move to and from consumers when it is fully implemented. The smart grid concept has been embraced throughout the world, with huge turnouts to events like the International Smart Grid Expo.
One aspect of the smart grid is a centralized collection of information. For example, the electric meter in a residence or industrial location will have the ability to report details of how much energy is being consumed at all times.
In some cases, it will be able to send specific information from certain compatible appliances. (Appliance manufacturers are currently developing appliances that can report their energy use.) Data that is collected will enable improved predictions about energy use patterns.
Power companies could offer electricity at different prices during off-peak times so that consumers could operate certain loads when the cost of electricity is less. For example, more power is usually available late at night and early in the morning, when demand is less (called off-peak times).
It may be possible to shift certain usage (irrigation or water heating) to these off-peak times to save money. Another way the smart grid helps customers is to apply credit for any renewable electricity produced and provided to the grid.
Smart Grid Implementation Issues
The smart grid requires much more than just installing new smart meters for customers or monitoring their large appliances. The smart grid will need to address six issues, which are listed in Table 1. These issues are discussed in detail in the paragraphs that follow.
| 1. | Control of electrical distribution by automating substations and switchgear with digital protective relays, weather prediction system, software, and integration tools. |
| 2. | Sensing and measurement technologies that consist of wide-area monitoring systems, dynamic line-rating technologies, fiber-optic temperature monitoring systems, and special protection systems. |
| 3. | Improved interfaces and decision support technologies to enhance a person’s ability to interface and work with the grid when using appliances and other electrical equipment. |
| 4. | Advanced components for energy technologies, such as fuel cells, microgrid technologies, ultra-capacitors, sodium sulfur (NaS) and lithium (Li) ion batteries. |
| 5. | Integrated communications consisting of technologies such as broadband over power lines, fiber optics to the home, and hybrid fiber coax (HFC) architecture. |
| 6. | Cybersecurity standards to make the system resilient to attack and provide for rapid restoration capabilities because the new grid will have network capability. |
Table 1 Smart Grid Implementation Issues
Distribution Control
In addition to its other benefits, the smart grid will help with power distribution, automatic switching control to isolate problem areas, and provision of bidirectional information, which will help pinpoint outage areas precisely so that repairs can be made quickly.
Smart control will also allow faster response to problems by switching to backup systems as the need arises; a secondary benefit is less stress on the current infrastructure.
The smart grid, with residential and commercial controllers, will allow end users to enter into contracts with energy producers and agree to have some of their largest loads turned off by the smart grid for short periods of time when the grid is becoming overloaded.
A brownout has reduced the voltage from the grid when demand exceeds supply (the voltage drops 10% or more). If the brownout continues for a longer period of time, large electrical loads that have motors, such as air-conditioning compressors and pumps, may be severely damaged or overheated.
One method of alleviating a brownout is allowing the control system to remove some larger loads until the voltage level comes back up. The smart grid will allow large industrial users to permit sections of their electrical equipment to be turned off for short periods of time in return for better pricing.
Controllers may be able to avoid a brownout by routing electrical power from a nearby sector to the area that has the low-voltage problem.
Sensing and Measurement
Advanced sensing equipment allows the smart grid to determine the health and integrity of all switchgear and other equipment used to control the electrical power as it is moved over the grid.
When a major power outage occurs at a utility with a smart grid infrastructure and technology-enabled workforce, the utility is automatically notified which customers are affected via downed smart meters and other sensors.
These characteristics allow utilities to identify where the outage has occurred and where to send resources to get the service restored as quickly as possible.
The same sensors that monitor the grid will allow demand response (DR) control to reduce peak demand.
Peak demand is the period of greatest electrical energy consumption during a specific period of time.
The peak demand varies depending on the location, time of day, the day of the week, and the weather. Energy needs to be available to match the peak demand or a brownout will occur.
If electrical power cannot be redirected where the demand exceeds the supply, the affected region will have to be disconnected to prevent it from taking down a larger sector of the grid.
Sensors provide the information required by demand response control to reduce the high demand during peak times.
Interfaces and Decision Support
The grid sometimes has problems that require operators and managers to make decisions.
Decision support and improved interfaces in the smart grid will enable more accurate and timely human decision making at all levels of the grid, including the consumer level. The interface and decision support will also enable advanced operator training.
Homeowners will be able to set up their smart grid interface to provide power to certain electrical loads at off-peak times. This feature will allow them to better match the times when they consume electricity for some loads and match it to the time when the cheapest electrical energy is available.
On the transmission side, the smart grid will enable control of grid sectors that are using the most power so that it can be redistributed as needed.
It will also allow the interconnection system to identify problems, and to disconnect and isolate small sections with those problems faster, thus ensuring that they do not affect the entire grid.
Advanced Components
Some experts believe that as much as 30% of the power in the grid may be lost to inefficiency, either through heat loss due to older wiring or because of poor equipment and connections. Advanced components in substations and at customer sites will improve efficiency.
One component of great interest is advanced sodium-sulfur batteries, which allow for peak leveling. These batteries are long-lasting, compact, and efficient. They have been in use by some utilities to level peak loads.
They have been widely applied in Japan for storing energy when demand is low and using the energy when demand is high. These batteries may be particularly valuable additions to wind farms when winds are intermittent.
Another battery of interest is the Li-ion battery, which may help the smart grid become more efficient. In the case of electric trains, the process of stopping trains has required dissipating the energy of motion into braking resistors.
In conventional systems, the energy is fed back; however, there is usually too much energy for the grid to absorb all at once, so most of it is wasted as heat. By absorbing the energy in Li-ion batteries, the power can be recovered efficiently for aid in starting the train again.
The Li-ion batteries are located in a substation, and initial pilot projects have proven that the idea for electrical storage is a sound one.
Integrated Communications
The communication method employed by the smart grid is to identify each step in the transmission process and each end user with an Internet protocol (IP) address that allows selected equipment at that location to send and receive data. The data includes current energy demand, time of day, and temperature and other environmental conditions.
The smart grid will use the transmission lines as the means for sending and receiving this data. Because each point in the grid will have its own specific address, it can be accessed much like a large computer network, where information can flow to and from each node in the network.
The information is similar to a computer network, so it can be displayed on a small display monitor or on a computer screen in the home and at commercial or industrial establishments to enable consumers to understand their energy usage.
Cybersecurity
When information is put on the smart grid, it will be vulnerable to unauthorized access, just like computers on the Internet.
The smart grid will need cybersecurity measures to protect it from being hacked or interrupted by malicious intruders. Grid transmission must be protected and secured. As on the Internet, security threats can change, and security must be ever-vigilant to respond to these threats.
The requirements for optimum integrity and functionality of the grid is often incompatible with security procedures, so it is important for utility companies to implement security procedures that are similar to those used in information technology (IT): changing passwords, removing and disabling unused accounts and services, setting up firewalls, and maintaining event files in order to keep the grid safe.
Currently, computers control the grid at every level, including the generators, substations, and distribution systems. Most of the systems use common operating systems, well understood by hackers.
Even though these systems are generally not connected to the Internet, they are still vulnerable to attack. Some systems use radio commands sent via low-power radio that can be intercepted.
Another vulnerable area includes the business side of the utility, which a hacker could use to find usernames and passwords to simulate a legitimate employee who requires access to the control system.
In one simulated attack, government officials were able to infiltrate a site and create havoc by rapidly cycling an electronic circuit breaker, causing a generator to lose sync and be destroyed.
The consequences of a coordinated attack on any nation’s electrical grid could be devastating. Nearly all industrial production in the affected area would grind to a halt.
A lengthy outage would strain resources, from gasoline supplies to water treatment, sewage disposal, and more. Utilities must exercise tight control over all of the devices in their system.
Review Questions
- What is the smart grid?
- What are three communication strategies for the smart grid?
- Why is cybersecurity so important to the grid?
Answers
- An electrical distribution technology that uses computer-based remote control and automation to improve the delivery efficiency.
- Broadband over power line, fiber to the home, and hybrid fiber coax (HFC)
- To protect it from being hacked or interrupted by malicious intruders
