Power System Investment Planning And Pricing Strategies In Uncertain Environment

As an important part of the energy system and social economic system,a power system is closely related to other external parts.In rencent years,global climate change has resulted in more frequently happened extreme natural disasters;the extensive integration of distributed generation has led to the increasing coupling between a power distribution system and a natural gas distribution network concerned;the development of the electricity market has demonstrated the fluctuation of power demand and electricity price;the uncertain ouput of seasonal hydropower has led to the regular deviation of actual and designed power transmission quantities in the west-to-east power transmission projects in south China.With the increasing complexity and diversity of the environment with extensive uncertainties from society,economics and nature,power system investment planning and pricing issues have encountered new challenges.Given this background,this dissertation is devoted to addressing the investment planning of power distribution systems as well as the pricing and management of power transmission projects in uncertain decision-making environment.Specifically,the main contents of this dissertation can be summarized as follows:1)A two-stage robust optimization based joint expansion planning model is proposed for developing a resilient and integrated power distribution system and natural gas distribution network against natural disasters.In the first stage,the objective is to minimize the overall annual investment and operation costs under normal operation conditions while in the second stage,the feasibility of the investment decisions is checked against the minimum load shedding cost under the worst natural disaster scenario under a given confidence level.Based on the developed two-stage optimization model,an integrated power distribution system and natural gas distribution network with a given resilience level can be attained by optimizing the investment strategies of hardening and selective expansion of power distribution lines and natural gas pipelines,as well as the investment siting and sizing of natural-gas-fired distributed generation(DG).The proposed model is a mixed integer second-order cone programming(SOCP)and then a column and constraint generation(C&CG)algorithm based method is developed to seek the optimal solution.Finally,a sample integrated power and natural gas distribution system is employed to demonstrate the efficiency of the model and solution method developed.2)A real option valuation method is proposed to determine the optimal investment strategies for DG in distribution networks.Future power demands and electricity prices are modeled as stochastic variables in the electricity market environment,and the profit from investing in DG is modeled,where the benefits include the operation cost savings and capacity update deferral benefit compared with a no-DG-investment scenario over the study period.The candidate DG investment plans are considered as multiple mutually exclusive options,and the corresponding managerial flexibility for seizing opportunities and mitigating risk of loss upon an unfavorable unfolding of future uncertainties is assessed with real option analysis using the extended least square Monte Carlo method.Then,the optimal investment strategies for DG including the investment location,size and timing can be obtained.Finally,the distribution of future investment strategies and optimal initial investment threshold levels under various scenarios are analyzed in a case study to demonstrate the characteristics of the proposed framework and methodology.3)A conditional value at risk(CVaR)based negotiation model is developed for a transmission company and a power purchaser under incomplete information for achieving an agreeable capacity charging ratio.First,the annual allowed income for a cross-regional transmission project is determined using the well-established operation period method,and then the expected profit and risk loss measured by CVaR under different capacity charging ratios are analyzed considering the uncertainty of actual transmission trading electric quantity.Then,a CVaR-based negotiation model is presented under incomplete information,the objective for each side of the two negotiators is to minimize its risk loss under a given lowest expected profit constraint and the estimations of the opponent's risk tolerance ability and negotiation strategy,and then to determine an optimal offer.Finally,the west-to-east power transmission project in the southern region of China is employed to demonstrate the basic characteristics of the proposed model.4)A comprehensive Z-valuation based earned value method(EVM)is developed for the cost and schedule management of power transmission projects.Due to the fuzzy uncertainty of actural process measurement of the power transmission projects,related experts are firsly invited to provide their Z-valuation on the actual process;and then a quantifier guided ordered weighted averaging(OWA)operator is adopted to aggregate multiple Z-valuations so as to have a comprehensive and accurate estimation of the actual process of the power transmission project.Then,the fuzzy EVM based on comprehensive Z-valuations is proposed to evaluate the performance and estimate the cost/time at completion,and the centroid method is applied to quantify the fuzzy results.Finally,a power transmission project is employed to demonstrate the basic characteristics of the proposed method.The proposed methods and strategies are convinced to support the resilient joint planning of multiply energy systems,the investment planning of DG and the pricing and management of power transmission projects,and further enrich the existing theoretical system and application framework in the area of power system investment planning and pricing.