Research On The Method Of Loss Allocation For Distribution Network With Small Hydropower

With the rising demand for resources,energy shortage has been one of the major problems facing the world now.As a clean energy source,small hydropower has been developing rapidly with the advantages of low cost,green and clean.However,at present,small hydropower is not involved in loss allocation in the electricity market,and considering the impact of small hydropower operation on the distribution network,how to include small hydropower in the calculation of network loss allocation based on these impacts is an urgent problem to be solved.To this end,a study is conducted in this paper.Firstly,this paper analyzes the applicability of existing loss allocation methods to distribution networks based on the basic principles of loss allocation,and summarizes the current tidal current tracking method and the improved average network loss coefficient method for distribution networks;then,it analyzes the allocation principles of the two methods and points out the problem of not considering the impact of small hydropower access on distribution network voltage and network loss in their allocation,and explains the importance of small hydropower participation in network loss allocation.Second,through theoretical analysis and IEEE-33 system simulation verified that small hydropower access will have a certain lifting effect on the system voltage,but in the period of abundant water may lead to the upper limit of the system voltage,and with the increase of small hydropower capacity,the distribution network loss will show a trend of first decreasing and then increasing,and the distribution network load changes caused by the different capacity of small hydropower will also make its economy affected,which illustrates the need to consider the impact of small hydropower access for loss allocation.In addition,considering the high percentage of transformer losses in the distribution network and the problem of substandard power quality in the distribution network of small hydropower,the network loss allocation methods considering transformer economic operation and voltage constraints are proposed respectively.The two methods are based on the existing network loss allocation method,and based on the transformer economic operation interval and the system voltage change before and after the small hydropower access,the amount of network loss allocation for small hydropower or load is reasonably revised to achieve the purpose of reward and punishment.These two methods complement the power fiow tracking method and the improved average network loss coefficient method,and provide economic and safety signals for the results of network loss allocation,which provide guidance for the economic operation of distribution networks and the standardized management of small hydropower.Finally,the applicability of the loss allocation method in different operating conditions is analyzed in the light of different situations of small hydropower operation in practice,and the problem of unreasonable allocation in some cases of the power fiow tracing method is introduced.On this basis,a comprehensive loss allocation method for distribution networks containing small hydropower is designed,taking into account the complementarity of the two existing methods and the seasonality of small hydropower output,as well as the high requirements of distribution network parameters for the power fiow tracing method.Two branches of the method are designed separately: when the distribution network parameters are complete,the power fiow tracing method is used on the power side and the improved average network loss coefficient method on the load side during the abundant water period,and vice versa during the dry water period;when the distribution network parameters are vestigial,the improved average network loss allocationt method is used.Depending on the actual situation,the corresponding branch can be chosen for network loss allocation.Finally,the effectiveness and practicality of the method are verified by taking a distribution network containing small hydropower as an example.