28-01-2013, 02:27 PM
A Dynamic Load Control Scheme for Smart Grid Systems
1A Dynamic Load Control.pdf (Size: 509.52 KB / Downloads: 36)
Abstract
In this paper, we propose a dynamic load control scheme for smart grid systems. The proposed scheme is based on
real-time information of different types of users’ consumptions and needs to increase the utilization of electricity.
Different types of users have different priorities. For example, hospital’s priority is higher than a residence
community. In the proposed scheme, a weighted utility function is adopted to determine the load reassignment. With
the proposed model, electric power reassignment not only is based on initial data of the electric power system, but it
also takes some real-time information into consideration. The load is always assigned in optimal. From the obtained
simulation results, it can be seen that the real-time information of system load can extremely be granted in improving
of the system utilization.
Introduction
The challenge of limited energy resources in the world is one of the most important issues. Modern
social needs are hard to meet with the traditional power supply system. Recently, many countries have
proposed a series of policies to encourage research institutes and organizations to pay more attention on
improving the utilization of power systems and energy saving.
In the past electric grid, the electricity power supplier provides enough power for the consumers based
on the raw data. However, the provided power may not meet the consumers’ needs due to the
consumptions of power is dynamically changed such as pink time, the fluctuation of consumptions, the
increasing and decreasing amount of users etc.
Redundant rate of power
Although the power suppliers provide the power to their users based on the raw data, there are still
some users who may have redundant power and some users who may need more power in different time
periods. If the power providers do not dynamically change the load for their users, the redundant power
becomes waste. It is observed that the utilization of power can be increased if the power providers can
reassign the redundant power to the users who need more electricity.
Numerical Results and Discussions
To evaluate the proposed dynamic load control scheme, d event-driven simulation method is used for
simulation. In the extensive simulations, we assume that there are ten electric generations and a large
number of users. As shown in Fig.1, the electric generations and users are randomly distributed in the
service area. We also assume that each user is connected with one electric generation and all the electric
generations are connected to each other as a distributed ad hoc network. In this paper, a user is defined as
a group of the same type of power consumers. For example, a single hospital is one user; one residence
community, another user etc. Since we consider a smart grid system, the real-time data is collected by the
smart metering and it can be transmitted to the electric generation center ideally. All the real-time
information can be exchanged among all the electric generations.
In the simulations, each user can be in any of three different states, normal use, overuse, and surpluses.
The time interval of state change is assumed to follow exponential distribution and the values in each
state is assumed to obey uniform distribution. Each electric generation periodically collects the real-time
data from its users and calculates the values of cost function for each user. Based the values of each user’s
cost function and the information obtained from other electric generations, the generation will reassign
the electricity among its users.
Conclusions
In this paper, we have proposed a dynamic load control scheme for smart grid systems. In the proposed
system, a cost function based method is adopted to determine the reassignment of redundant power.
Different types of users with different priorities are considered in the proposed system. Based on the
extensive simulations, the results showed that the proposed dynamic load control scheme can greatly
improve the utilization of redundant power.