Research On Power System Dispatch And Security In The Electricity Market And Energy Saving Dispatch Environment

The rapid expansion of power grid significantly increased the workload of network operators in the electricity dispatch and control centre, which inevitably has an adverse impact on the security of the network operation and monitoring. With the gradual establishment of electricity market and the deployment of government policy to reduce the emission and save energy, the responsibilities of the network operator are not only to secure the network operation but also to implement the energy saving dispatch and facilitate the electricity market. This necessitates the research on the grid dispatch mode.In the current stage, the main subject in electricity and energy industries in China is to improve the energy efficiency, save the energy, reduce the pollution and adjust the energy and electricity industry structure. In order to maximize the benefits of the energy to the society, the development of electricity industry is required to relish the new challenges of saving energy and reducing loss. This further brings a series of new problems to the system operation in terms of dispatch and security. In order to solve these problems, the system operator is required to improve the optimization algorithms of the large-scale generator combination and the network security verification as well as the methodology of energy saving dispatch.The government policy of saving energy and reducing loss gave arise a new problem to the automatic generation control (AGC) especially after adopting the energy saving dispatch. Therefore it is very necessary to study how to realize the energy saving dispatch and the transmission requirements to the AGC in order to adhere to the policy and realize the energy saving dispatch. On the other hand, in order to motivate the generator to provide the service of power frequency control in an interconnected grid, the system operator needs to assess and compensate the auxiliary service of AGC provided by the generator. Therefore, a mechanism to evaluate, review and monitor the AGC service should be established.This thesis systematically studies the above important problems and the following achievements have been made:Firstly, to meet the requirements of the dispatch operation and management in the electricity control centre with the rapid expansion of power grid, a novel dispatch mode is proposed by increasing the number of dispatch engineers, setting up a central control centre, increasing the dispatch layers so that the zonal dispatch and dispatch adjustment can be achieved.Secondly, a new energy saving dispatch mechanism is proposed based on the analysis of the six aspects affected by the new energy policy. And based on this proposal, a further improvement is achieved to take the electricity market and emission reduction into consideration.Thirdly, a mathematic model is established for the large scale of monthly generator dispatch combinations in order to study the generation combination requirements under the energy saving dispatch criteria. A lagrangian relaxation method based algorithm is proposed to find the solution of the problem. This algorithm is very robust and can be used to solve the general Lagrange relaxation problem. Furthermore the new algorithm incorporates the restriction of the loading and de-loading characteristics of the generator and the spinning reserve requirement as well as the dynamic energy saving dispatch algorithm.Fourthly, in order to study the network security verification in the energy saving dispatch environment, a predefined system operation mode based on the combination of the generators is proposed. This method optimizes the operation to minimize the adjust of the generator output by adopting the linear interior point algorithm based on the Lagrange and Newton algorithms as well as barrier function.Fifthly, a mathematic optimization model is proposed to realize the energy saving dispatch based on whether there is an electricity market, which uses the cost, energy loss and environment index as targets to optimize the generation dispatch based on the analysis of the major problems faced by the energy saving dispatch. The problems of how to realize the seamless combination between the energy saving dispatch and the construction of electricity market are also addressed.Finally, The AGC problems in the energy saving dispatch environment are analyzed and a comprehensive strategy is proposed to improve the AGC performance and enhance the CPS function. Based on the AGC mathematic algorithm, system operation mode and compensation method, a new power plant GCPS examination method is proposed.In conclusion this thesis studied the problems of power system dispatch and security in the environment of electricity market and energy saving dispatch. The major research achievements were summarized and the direction of further research in this aspect was also pointed out.