Study On Reactive Power Optimization Of AVC In Shandong Power Grid

With the continuous expansion of the power grid, the difficulty and complexity of reactive power and voltage control in power system is increasing gradually. So the realization of the uniform automatic voltage control (AVC) in the whole network is not only a hot spot, but also a difficult point. The reactive power optimization of the whole network is the core and foundation in the AVC implementation, so there are higher requirements for the calculation speed and its robustness. Although the study of reactive power optimization has a long history ,seeking a mature and practical method is still one of the focuses of nowadays' study, thinking of the complexity of the problem itself, the diversity of the control methods as well as the continuous expansion of the power system,This paper revolves around the actual AVC project of Shandong Power Grid. It tries to get a better understanding of the reactive power optimization and it's related technical issues and does achieve a good practical effect.Firstly, the theoretical research of traditional reactive power optimization is usually carried out in a time section, so the reactive power limits of synchronous generators are fixed. Since the reactive power optimization of AVC faces the ever-changing active power manner, it is necessary for synchronous generator to real-time change its reactive power limit. In this regard, this paper combines the PQ running limit of synchronous generators with the reactive power optimization, to establish a reactive power optimization model which adapts to the varying of active power manner, self- adapts to the changing of reactive power limit and satisfies to the requirement of AVC. To this model, a non-linear primal-dual interior point method and corresponding effective sparse means as well as some computing skills are used to solve the problem. Besides, a flexible and useful software is formed, which has been implemented on-line in Shandong Power Grid AVC and has get effective results.Secondly, because of the diversity of reactive power controls, the locality of distribution and the non-linear of effects, reactive power optimization problem has rich connotation and profound physical discipline. Based on the existing researches, this paper takes the Shandong power grid for the object, studies three solution states which reflect the restriction degree between the distribution of reactive power and the voltage level, namely, the ideal state, intermediate state and the critical state. This study will provide an important theoretical basis for the implementation andimprovement of the Shandong Power Grid AVC.Finally, based on the operation of Shandong Power Grid AVC, the paper elaborates on the composition and designing mentality of AVC system in Shandong Power Grid. Based on the energy management systems (EMS) and the tertiary voltage control, this AVC system executes reactive power optimization combined with a 24-hour load forecast. It uses the ultra-short-term load forecasting to improve the ability of real-time application and effectiveness of optimization measures. At the same time, it combines with the running states of the Shandong Power Grid AVC, to get the characteristic analysis in the running process as well as the performance analysis after its implementation in Shandong Power Grid.