Research On Strategies And Models For Transmission Systems Security In Electricity Market Environment

The power industry worldwide is experiencing unprecedented restructuring for breaking traditional monopoly, introducing competition and establishing electricity markets. The power industry in China is now under the way of restructuring. In the new electricity market environments, the conflict between transmission systems security and economical operation is more and more severe. Compared to monopoly environments, power system operation mode and economic strategies of each participants is different considerably in market environments, transmission systems operation is the face of unprecedented challenge. Hence, how to develop security strategies for transmission systems security has become a major concern. This dissertation focuses on the study of security strategies and transmission models in the electricity market environment and some significant results are obtained.Power system stability is important problem in power system operation. In electricity market environments, transmission systems secure operation involve two aspects: First, how to activate market participants to maintain together power system security. Second, when transmission systems are in face of security risk, how to take measures to reduce risk within market rules. A comprehensive introduction to build security strategies for transmission systems secure operation is made from several aspects, including market rules, transmission grid programming, power system real time operation, stability control and other corresponding problems. In this paper, security strategies and transmission models are constructed mainly based on market rules, available transmission capability, congestion management, ancillary service and transmission pricing.Secondly, based on market rules and its effect to transmission systems security, after introduction of foreign electricity market rules and its strategies for security, regional electricity market, three gorges electricity market pattern and transaction mode of three gorges power station are constructed. Aiming at the specific characteristic of the interconnected network in our country in the future , considering the multi-layers market modes and nonlinear bidding, a transactions scheduling model revolved around power network were presented in this paper. The network and generator's physical and technological limitation have been accounted.Available transmission capability (ATC) is the important measure for transmission systems security. At present, ATC calculation methods were mostly based on power system stability operation, even if dynamic restrictions were considered, these restrictions were treated commonly as algebra equation. In fact, the results were not exact for transmission network having severe problem of transient stability. Considering the fact of transmission systems in China and feasibility of ATC result, an ATC calculation model is presented for the network having severe problem oftransient stability. Transient stability restriction and the probability level of generation output are considered together in this model. In order to solve the calculation problem of the large system, a fast calculation model based on the direct power flow is putted forward, and apply it to ATC calculation between large regional power systems in China.Based on physical character of power system, security strategies approved in the world were that transmission systems must be opened access and its operation must be monopolized. So, transmission service is dissertated importantly, including congestion management, study on wheeling cost allocation, ancillary service and transmission pricing. Correspondingly, mathematics models are established.Congestion management is the core of transmission system security. The objective of congestion management is to improve security and reliability of power system through controlling the output of generators and loads within a series of market rules, at the same time, to provide effective signal for long-term programming of power system. After the optimal models and approaches of...