Thursday 9 December 2010

Research Methodology Assignment: Introduction

By the year 2050 the UK government has made it mandatory that we reduce our carbon emissions by 80%. In order to meet this target, lower carbon technologies such as the electrification of heating and transport will need to be introduced. Unfortunately this rising demand for electricity cannot be sustained with the current electricity infrastructure. Therefore a smart grid capable of incorporating an increasing number of generators is required.
These generators need to be coordinated efficiently in order to supply loads within the network whilst satisfying thermal limits of the transmission lines. The proposed solution is to model the network as a constraint satisfaction problem and then solve using constraint programming. However this is a centralised approach and therefore will have scaling issues when applied to a larger network.
To address these shortcomings we propose a decentralised message passing algorithm, max-sum, which scales well with the size of the network; since the size and number of messages sent, is only dependant on a local neighbourhood. Max-sum has been extended to incorporate thermal constraint satisfaction and to give priority to generators that use renewable resources while curtailing non-renewable generators.

The rest of this paper is organised as follows...

Tuesday 7 December 2010

Electricity

This week I will be learning all things to do with electricity. I have also written an introduction for my Research Methodology course, here it is:


By the year 2050 the UK government has made it mandatory that we reduce our carbon emissions by 80%. In order to meet this target, lower carbon technologies such as the electrification of heating and transport will need to be introduced. Unfortunately this rising demand for electricity cannot be sustained with the current national electricity structure. A more dynamic two-way electricity network is needed that incorporates decentralised generators, renewable resources and storage devices managed in an efficient manner.

However incorporating these devices will be difficult without revised management techniques. The proposed solution is to split the national electricity structure into multi-agent managed micro-grids which are able to run as isolated electricity networks capable of meeting electrical demand efficiently. One aspect of the management system involves decentralised generator coordination to determine the output of each generator needed to satisfy the loads on the network when thermal constraints apply.

Previous work in this area has used constraint optimisation techniques to find an optimal solution; however this is in a centralised manner, therefore posing potential security and reliability issues due to the central point of failure. DPOP, a coordination algorithm that uses message passing, has been applied to this setting and is almost completely decentralised. However the size of the messages increases exponentially with the size of the network and thus this technique does not scale well.

We propose an extension of the novel algorithm called MAX-SUM which uses message passing to coordinate renewable and non-renewable generators within a micro-grid. Specifically the MAX-SUM algorithm has been extended to incorporate thermal constraint satisfaction and to give priority to generators that use renewable resources while curtailing non-renewable generators. The extended MAX-SUM algorithm coordinates in a decentralised manner, with the size and the number of messages dependant only on a local neighbourhood therefore scaling well.

Wednesday 1 December 2010

Power Flow Analysis

Since last time I have finally implemented a properly working max-sum algorithm. I have also applied to work for Google on a summer internship in either north America or Sydney, Australia so fingers crossed. TODO: For the remainder of the week I plan to research the background of power flow analysis and how to do AC and DC power flow of electricity networks.