The integration of large shares of renewable energy, improvements in the reliability of services, and the achievement of higher levels of energy efficiency will require power grids that are largely different from those of today, or the ‘smart grid’, with few if any parts of the world remaining exempt from this requirement.
But there is no one definition of the smart grid concept. Instead, smart grids are defined differently around the world to reflect local requirements and goals. To assist in the definition of a smart grid and its planning, the World Bank has produced a short document outlining the key building blocks at the various levels of automation in the distribution grid and other advice such as how to structure investment plans.
Smart grid building blocks
The three key building blocks of a smart grid are:
● Controllable, electrically operable power apparatus. To achieve maximum grid modernization benefits, automatic or remote control of power apparatus is essential. Controllable components that are fundamental to grid modernization include MV line switches, voltage regulators, and capacitor banks that are located distribution HV/MV substations and out on the feeders themselves.
● Intelligent sensors. Grid modernization requires intelligent sensors and controllers that are able to acquire “local” measurements from anywhere on the distribution system and transmit these pieces of information to centrally located operators and control systems.
● Telecommunication infrastructure. Digital communications between the distribution control centre and HV/MV substations is a starting point for grid modernization. But a telecommunication system that is able to reach the extremities of the distribution system is often needed to accomplish the ultimate vision for the modernization.
Levels of grid modernization
Up to four levels of grid modernization may be needed to accomplish a utility’s vision for grid modernization. These are:
● Level 0: Manual control and local automation, which defines a situation in which most processes are performed manually with little or no automation. This is a situation that exists at many utilities in developing countries.
● Level 1: Substation automation and remote control, builds on level 0 by adding intelligent electronic devices (IEDs) and data communication facilities to achieve greater monitoring and control capabilities at HV/MV substations.
● Level 2: Feeder automation and remote control, builds on level 1 by extending remote monitoring and advanced control to the feeders themselves. This level also includes information from communicating meters at some large customers for improved control and decision making.
● Level 3: Distributed resource integration and control and demand response, is the highest level of grid modernization described in the report, and adds energy storage, static VAr sources, and advanced communication and control facilities to effectively integrate and manage high penetrations of distributed resources on the distribution feeders. This level of grid modernization also includes deployment of AMI to enable on-demand reading of customer meters along with demand response capabilities.
Increasing levels of grid modernization represent a natural progression from manual paper-driven processes to electronic computer-assisted decision making with automation. However, it is possible (and in many cases recommended) that a utility that is presently at a low level of grid modernization bypasses one or more of the higher levels to achieve some of the benefits offered at the highest levels.
Smart grid investment plan
The next step is the development of a smart grid investment plan and the publication covers the broad steps to defining such a plan. It also includes a lot of other useful information on regulatory and financing issues and planning practices to further benefit from grid modernization.
Examples of smart grid roadmaps from utilities across the world are also included in a publication providing useful reading, particularly for utilities and other stakeholders such as regulators in the early stages of smart grid thinking. The authors are Marcelino Madrigal, senior energy specialist in the World Bank’s Energy and Extractives Global Practice, and Bob Uluski, who leads the distribution automation and distribution management system consulting practice at Utility Integration Solutions.