Competition in restructured deregulated power systems is the most important factor in electric energy trade. Recognition and determination of accurate and precise energy transmission from one place to another point in the network, reactive power support for this contract and transmitting the loss are the most issues in the new changing trade world. Carrying out modified Ybus method for active and reactive power tracing, and obtained results, in this article two subjects, i.e. providing reactive power support, and loss related to each transaction contract are discussed simultaneously together by introducing and indicating power injection vector and signifying distributed slack bus idea. The proposed method is experimented on a test system. The results show that the features of this method are large in scope, in compliance with network mathematical equations, and also physical power flow perception in multiple multi transaction power systems.