4 The Transition of China’s Power System
147
4.4 Research on Coordinated Development of Generation
Mix, Grid and Load of Power System in China
4.4.1 Research on the Trend of Load Variation
In-depth analysis and accurate prediction of load characteristics are important guarantees for reliable, efficient and economical operation of power systems. In recent
years, major changes have occurred in the external environment affecting the load and
load characteristics of power grid, which are mainly shown in the following areas:
(1) the economy has entered a phase known as the “new normal”, with accelerated
structural adjustment that has exerted great impact on load composition; (2) marketbased reform and liberalization of electricity sales would make for closer interaction
between users and grid, hence changes in the load curve; (3) rapid growth in electric
vehicles and other new electricity loads would bring considerable impact on load
curve; (4) rapid development of distributed energy would be a useful supplement to
the main grid, hence the importance of managing the impact of distributed energy
development on grid load.
With the influence of multiple factors such as distributed energy, power market,
demand response, electric vehicles and energy storage, generalized load is featured
by:
(1) Diverse load components. Traditional loads mainly involve electric motors, electric furnaces, lighting equipment and other electrical equipment that consume
power externally. The generalized load not only involves the electrical equipment in the traditional load, but also distributed power such as distributed wind
and distributed PV, as well as active loads such as energy storage and electric
vehicles that can participate in demand side response.
(2) Diverse impact factors. Traditional load is mainly affected by macroeconomic,
demographic, meteorological and other factors, which also bring impact on the
generalized load. In addition, the generalized load is also subject to many other
factors. For instance, distributed wind and solar are affected by wind speed, wind
direction, light radiation, cloud cover and other natural elements. The load of
electric vehicles is under the impact of traffic conditions, user travel patterns,
among others. Active load participation in demand management is subject to
market price and demand response strategy. These factors often come together in
impacting generalized load, which renders load characteristics more complex.
(3) Both “load” and “generation” characteristics. When the output of distributed
power supply is less than the electricity demand at the access node, the node
would present the characteristics of load. And in case of greater distributed
energy output than power load at its access node, the remaining energy would
be transmitted to the grid, and the reverse power flow occurs, showing features of
power generation. With both “load” and “generation” characteristics, this type
of generalized load adds great difficulty to the planning of distribution network
and calculation of power flow.
147
4.4 Research on Coordinated Development of Generation
Mix, Grid and Load of Power System in China
4.4.1 Research on the Trend of Load Variation
In-depth analysis and accurate prediction of load characteristics are important guarantees for reliable, efficient and economical operation of power systems. In recent
years, major changes have occurred in the external environment affecting the load and
load characteristics of power grid, which are mainly shown in the following areas:
(1) the economy has entered a phase known as the “new normal”, with accelerated
structural adjustment that has exerted great impact on load composition; (2) marketbased reform and liberalization of electricity sales would make for closer interaction
between users and grid, hence changes in the load curve; (3) rapid growth in electric
vehicles and other new electricity loads would bring considerable impact on load
curve; (4) rapid development of distributed energy would be a useful supplement to
the main grid, hence the importance of managing the impact of distributed energy
development on grid load.
With the influence of multiple factors such as distributed energy, power market,
demand response, electric vehicles and energy storage, generalized load is featured
by:
(1) Diverse load components. Traditional loads mainly involve electric motors, electric furnaces, lighting equipment and other electrical equipment that consume
power externally. The generalized load not only involves the electrical equipment in the traditional load, but also distributed power such as distributed wind
and distributed PV, as well as active loads such as energy storage and electric
vehicles that can participate in demand side response.
(2) Diverse impact factors. Traditional load is mainly affected by macroeconomic,
demographic, meteorological and other factors, which also bring impact on the
generalized load. In addition, the generalized load is also subject to many other
factors. For instance, distributed wind and solar are affected by wind speed, wind
direction, light radiation, cloud cover and other natural elements. The load of
electric vehicles is under the impact of traffic conditions, user travel patterns,
among others. Active load participation in demand management is subject to
market price and demand response strategy. These factors often come together in
impacting generalized load, which renders load characteristics more complex.
(3) Both “load” and “generation” characteristics. When the output of distributed
power supply is less than the electricity demand at the access node, the node
would present the characteristics of load. And in case of greater distributed
energy output than power load at its access node, the remaining energy would
be transmitted to the grid, and the reverse power flow occurs, showing features of
power generation. With both “load” and “generation” characteristics, this type
of generalized load adds great difficulty to the planning of distribution network
and calculation of power flow.