A multi agent system based control scheme for optimization of microgrid operation
Foo, Eddy Yi Shyh
Date of Issue2016
School of Electrical and Electronic Engineering
Traditional power systems employ centralized control techniques to manage the entire power network. These networks are usually known to be passive because power flows radially from the utility grid to the load. With the deregulation and restructuring of the power industry coupled with increasing penetration of renewables and other traditional generators such as Distributed Generators (DGs) at the microgrid level, the way power flows within the network changes. This type of network is known as active networks because power can flow bi-directionally either from the utility grid to the microgrid or vice versa. As a result, centralized control may not be able to effectively manage the DGs at the microgrid level because it is cost inefficient and may prove challenging to control DGs in the microgrid. Therefore, another type of control known as decentralized or distributed control is proposed as an alternative to centralized control. The objective is to show that the microgrid can be effectively managed in a distributed manner while the economic benefits of the microgrid are maximized simultaneously. In this thesis, Multi-Agent System (MAS) which is a type of distributed control is proposed for microgrids. The main idea is to utilize agents to solve large complex tasks. Agents are designed such that they exhibit intelligence and can make informed decisions without the intervention of a central controller. In addition, agents are adaptable to changes in environment and they can adjust to any disturbances or changes in the microgrid. One implementation of MAS is using the Java Agent DEvelopment framework (JADE) to simulate and monitor agent activities. Furthermore, JADE complies with IEEE’s Foundation of Intelligent and Physical Agents (FIPA) standards and can be readily used for agent implementation. The extension of JADE for MATLAB/Simulink which is known as multi agent control simulation JADE extension (MACSimJX) was also used to simulate real-time microgrid implementations. The first part of this thesis presents the design and implementation of user-defined agents in the proposed microgrid market clearing algorithm. A single-sided bidding mechanism is considered in the first part of the study. Agent objectives and a list of different test cases are defined in the simulation study. The agent-based concept is implemented in a basic microgrid setup. The simulation results show that the revenue and load costs of the respective Generation Agents (GAs) and Load Agents (LAs) vary based on the agent objectives. In addition, the transactions are either biased towards the GAs or LAs. Therefore, another new agent objective is required to promote unbiased transactions between the GAs and LAs and this is discussed in the next part of this thesis. The second part of this thesis extends the work done in the first part. It presents the use of IEEE FIPA compliant agent platform which include JADE and MACSimJX to coordinate distributed market operations and simulated real-time implementations. In particular, it considers the dynamic operation of a microgrid in Matlab/Simulink simulation environment while the market clearing engine which runs in JADE considers the average integrated MWh for each hourly interval. Both the t-domain dynamics of MW generation and bus voltages as well as market clearing price for each hourly interval are simulated. Furthermore, a double-sided bidding mechanism is considered. The scheduling and dispatch of DGs and loads in the microgrid are done based on a proposed market clearing algorithm. It models a market scenario where each energy seller or each energy buyer is represented by an agent that aims to maximize the benefits according to the defined agent objectives while ensuring the smooth operation and proper execution of microgrid operations under the simulated real-time environment. This is realized through agent interaction and coordination between MACSimJX and JADE agents. Three different agent objectives are defined which aim at maximizing the benefits of energy sellers and/or buyers through energy trading which considers LMP as part of the trading process. Each agent objective and the impact of marginal loss factors are analyzed. In addition, a list of agents is developed to verify the functionality of the proposed MAS approach. This approach is tested on a 7-bus microgrid system and further verified on an IEEE 14-bus power system. Simulation results show that maximizing the benefit for both energy buyers and sellers promotes unbiased transactions between them while ensuring the proper operation of the entire microgrid system. All these illustrate the applicability of MAS in the distributed management of microgrid operations.
DRNTU::Engineering::Electrical and electronic engineering::Electric power