Circuit Theory-based Method For Power Loss Estimation And Allocation In Distribution Systems With Distributed Generator

With the rapid developing of renewable energy,it has become a trend that a large number of distributed generations(DGs)integrate into distribution network.The change of transmission power caused by the access of distributed generation to distribution network makes the calculation and allocation of line loss more complicated.Existing distribution energy loss calculation method cannot quickly evaluate the effect of DGs on the distribution loss.Although distributed generation affects network loss,it does not share any loss of network.Aiming at this,this paper carries out related research.First of all,the application of circuit theory-based loss calculation method is discussed in distribution network with DGs.Meanwhile,a new code equivalence mode is carried out,loss composition is re-divided availably.Considering that DG has the ability of voltage regulation,namely it can play an important role in distribution voltage support,the grid connection nodes of DGs are equivalent to voltage source nodes,while the other load nodes are equivalent to current source nodes.Then the distribution loss are calculated in three parts:the loss caused by the voltage source alone,the loss caused by the single action of the current source,and the loss related to the both sources and network structure parameters.Then the characteristics of the three parts of the loss are analyzed.In addition,the influence of the location and capacity of DG grid connection on the loss of each part is studied,and the similarities and differences of three parts losses in a single DG distribution system and multiple DG distribution systems are analyzed and compared.This paper studies the influence of DG connecting to different nodes on the loss of distribution network.Secondly,according to the characteristic change law of three parts loss after DG is connected to distribution network,a fast estimation method of three parts loss of distribution network with DG is proposed.Loss calculation and discussion are done to the 33-bus test distribution system with DGs.By adjusting the power of distributed generation and the voltage of the node where the DGs are located,a fast evaluation method of distribution power is proposed under the condition of random change of distributed power.Taking the actual distribution system as an example,the practicability of the proposed method is verified.Further study the influence of DG grid connection on the distribution network voltage.Finally,according to the analysis of the calculation method of the power loss in the distribution network with DGs based on the circuit theory,a loss allocation method suitable for the distribution network with DGs is proposed.According to the different characteristics of three parts losses,this paper adopts the mixed allocation method based on different allocation principles.In order to encourage the development of distributed generation,some remuneration and penalties are allocated to DGs that cause the power loss of distribution network to change,so that the loss can be shared among grid participants fairly and reasonably.The proposed allocation rule can correspond to the responsibilities of all parties,and have the incentive effect of reducing losses.