Date of Award

May 2019

Degree Type

Thesis

Degree Name

Master of Science

Department

Engineering

First Advisor

Lingfeng Wang

Committee Members

Jun Zhang, Zhi Zheng

Abstract

The climate change leads to more natural disasters which can lead to two results, one is that some generation and transmission infrastructures of energy will endure serious damages, and another is that cities and districts will probably be exposed to potentially large-scale blackouts. The pressures of energy and environment problems have prompted people to reflect on existing energy consumption patterns and begin to study the comprehensive utilization of various types of energy such as electricity, gas and heat. The concept of energy hub (EH) has emerged. It is a key hub within multi-energy network.

A Two-stage model for the operation of multi-energy hub system for resilience enhancement in natural disasters was established in this thesis. The system includes three different energy hub systems, each EH consists of electric transformer, Combined Cooling, Heating and Power (CCHP), Energy Storage System (ESS) and chiller which are responsible for energy conversion and transfer. Each EH is connected to the main electric network and natural gas network. There are also transmission lines and pipelines connected between them for energy communication.

The purpose of this model is to reduce the load shedding as much as possible while ensuring the maximum economic benefits including operation costs and load curtailment punishing fees of both two stages, so that each EH system can make a reasonable energy supply externally and maintain stable operation internally.

When disaster happens, the system will go through two stages, first stage is the one before disaster and second stage is the one when disaster occurs. The choices made by the system will be different at these two stages, including selling and purchasing value from the main network, storing and releasing energy value of ESS, conversion ratio for different energies within EH and the load shedding value of demand side because each stage has different transmission rate and load demand.

Three case studies have been done. YALMIP toolbox of MATLAB has been used to solve these problems. In case study one, the result shows that the total cost of two-stage model reduced by about 25% compared to the separate stage model, and load curtailment, especially electricity, was reduced sharply. In case study two, after load priority setting, load curtailment fee has been reduced obviously by 8.2%, shedding value of significant load has been reduced up to 26.9%. In case study three, the total cost of coordinated 3-EH model has been reduced by 57.59% compared to the model without coordination, and each EH has saved cost by 32.92%, 69.38% and 53.21% respectively. The result shows great advantages of this model, by using the two stage the total cost and load curtailment value reduced significantly for both whole system and each EH.

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