Research On Optimal Dispatch Of Active Distribution Network Based On Dependent-chance Goal Programming

Distributed power sources such as wind power and photovoltaics have uncertainty.When the penetration rate is low,the uncertainty of its output can be ignored,but when the penetration rate is high,the source and load sides of the distribution network will show strong uncertainty.In addition,due to the access of distributed power sources,the distribution network will have more controllable resources,and the traditional passive control mode needs to be changed.In view of this,how to consider the uncertainties on both sides of the source and load and make full use of the controllable resources of the distribution network to realize the safe and economic operation of the distribution network is a problem that needs to be studied urgently.To this end,this article is based on stochastic optimization theory to study the optimal dispatch of active distribution networks.The main work and results are as follows:(1)This paper establishes a renewable energy output and load forecast error model,and studies the deterministic conversion method of chance constraints in the stochastic optimization theory and the solution method of the related chance objective programming model.In order to describe the uncertain power output and load,a wind power,photovoltaic and load forecast error model represented by a normal distribution is established.In addition,the deterministic transformation of opportunity constraints is achieved through sampling,which breaks through the limitations of traditional analytical methods on the number and distribution of random variables.Finally,for the related opportunity target programming model,it is solved by sampling and minimizing the target vector according to the priority structure.(2)In this paper,considering the influence of the uncertainty of the source and load on the dispatching model,a day-ahead dispatching model of active distribution network based on related opportunity objective planning is proposed.Considering the influence of uncertain variables on the power balance equation,a probabilistic power balance model is established based on related opportunity planning.In addition,considering the impact of uncertain variables on the reactive power output of renewable energy inverters,an inverter capacity constraint model is established based on opportunity constraint programming.On the basis of the above research,make full use of the active and reactive power resources of the distribution network to achieve day-ahead optimal scheduling of the active distribution network to reduce the amount of daily active power adjustment and the probability of forced adjustment of reactive power commands due to inverter capacity limitations.Through the analysis of numerical examples,the validity of the proposed model is verified.(3)In order to further alleviate the pressure of intraday dispatch,this paper proposes an active distribution network intraday rolling dispatch model based on relevant opportunity objective planning.Considering the influence of uncertain variables on the reserve capacity,a constraint model of reserve capacity is established based on chance constrained programming.At the same time,in view of the "near small and far big" characteristics of the forecast error,th e confidence level of the reserve capacity opportunity constraint is set to "near high and far low" in order to improve the economic efficiency of active distribution network operation.Finally,a numerical example is used to verify the effectiveness of th e proposed model.