Distributed Energy Storage Operation Control And Optimization Planning For New Power Systems

With strategies of peak carbon emission,carbon neutrality and building new power systems,the proportion of renewable energy generation is increasing,which brings great challenges to the stable operation of power grids due to its random output.As a regulated resource with source-load characteristics,distributed energy storage systems(DESSs)can smooth out fluctuations in random renewable energy generation output and represent an important part to ensure stable operation of energy systems in the future.However,how to ensure that the planning of DESSs fits the actual requirements of distribution networks under uncertainty,and how to build energy conversion equipment in a reasonable way to realize DESSs and renewable energy grid-connected is still a very challenging research direction.Targeting DESSs planning and control,this paper explores DESSs planning method with network constraints under uncertainty and energy conversion devices with smaller switching losses and higher transfer efficiency.The theoretical and implementation methods for DESSs planning and control are developed to provide strong support in practical applications.This paper focuses on the research work as follows:Firstly,renewable energy connection into distribution networks leads to voltage limits and network losses,which triggers higher marginal costs at buses.Aiming at minimizing the cost of distributed power generation,a linearized power flow model is developed based on the voltage limits and network losses in the distribution network.Then,a distribution location marginal price(DLMP)model for the distribution network containing energy cost component(ECC),voltage cost component(VCC)and loss cost component(LCC)is established,which provides a deeper analysis of the impact on voltage limits and line losses of the distribution network.Based on the marginal cost of different buses,the influence of DESSs access on the distribution network is analyzed.It is concluded that the access location and capacity of DESSs have a large impact on voltage limits and network losses of the distribution network,which provides a pavement for the research content of this paper.Secondly,aiming at disorderly DESSs planning is not only increasing the investment cost but also making it difficult to ensure the stable operation of the distribution network.An area-to-bus planning method is proposed,which obtains vulnerable areas of the distribution network as candidate buses for DESSs planning based on DLMP with time and regional characteristics.Describe preliminary area planning of DESSs as a DLMP problem with maximum uncertainty fluctuation boundary.Use price signals to guide distribution system operator(DSO)regarding the rational allocation of resources.After that,a planning method is proposed to determine locations and capacities of DESSs in vulnerable areas with network constraints under uncertainty.The process develops a two-stage stochastic robust optimization problem that avoids too-conservative decisions for robust optimization.Simulation results show that the area-to-bus planning approach can improve computational efficiency,ensures the optimal investment cost for DESSs planning under uncertainties and reduces voltage deviation and network loss.Finally,a simple PWM phase shift control strategy is proposed to handle the challenges of low transmission efficiency,high voltage stress and high current stress in the dual active bridge converter under the conventional phase shift control method.This method simplifies the converter operation process by using relevant characteristics of clamp switch.Inter phase shift is replaced without affecting the control degrees of freedom.Operating principles and characteristics of the clamp converter are introduced.A linear large-signal model is constructed to ensure that the clamp converter achieves smaller switching losses and higher transmission efficiency.The smaller current stress can extend the component life and reduce the operating cost.Moreover,simplifying the control process of the switch greatly reduces the complexity of the control and extends the controlling idea of the clamp converter.The experimental results show that the simple PWM phase shift control strategy is effective.