Ponderings and Strategies of Power Loss Allocation - Application of United Electrical Dissection of ac Branch and Bus

摘要

There exists many methods for power loss allocation, but it is very hard to obtain same results for them even if to a same problem. Why? It is because that cognitions about these methods exists divergences in nature, and because that each method has its emphasis on considering conditions and factors when used to solve problems. These reasons lead methods to exist theoretic shortcomings in different degrees, so the application effects are hard to coincide with each other for various methods. Based on in-depth ponderings of problem's influencing factors, this paper puts forward three viewpoints about power loss allocation problem. The first is that problem nature is of electrical analysis; the second is that the problem should have one and only correct solution if state of electric power network is determined; the third is that standards, used to check up if the allocating results are correct, should be electrical principium and laws of electric power network. According to these viewpoints, this paper presents strategy and method to solve the universal problem of ac branch power loss allocation after three especial problems were analyzed and their solving strategies and methods were presented. The theory key of strategies and methods is united electrical dissection (UED) of ac branch and bus. UED can dissect one branch into several sub-branches, which strictly complies with electrical principium and laws, such as Kirchhoff s Laws, Ohm's Law, Power Balance Principe, Energy Conversation Law and etc. All the dissected sub-branches retain all characters of the original branch, such as topology, state, parameter and power type, so they can be returnable and completely equivalent to the original branch electrically. The power losses of all the dissected sub-branches are the power losses that should be allocated to the corresponding sources or flows of the original branch. The sum of all the power losses of all the dissected sub-branches is equal to the power loss of the original branch. Numerical examples show UED method is correct electrically and becomes a powerful tool for looking for the one and only solution of power loss allocation and for analyzing the relationship between the problem of power loss allocation and its non-linearity.