Study Of Energy Loss Calculation System For Multi-source Distribution Network And Its Key Application

The management of distribution line loss is an important component of power supply enterprise management. Locating the weakness in the operation of distribution network and determining constitution of energy losses throuth a series of real-time theoretical calculations for the line loss of distribution network, power enterprises are able to take reasonable methods of line loss reduction to enhance the utilization of power energy. Reducing the line loss of distribution network not only decreases the operating costs of power enterprises, but also plays an important role in the reactive power optimization and technical revamp of the distribution network, calculation of electrical cost, determination of efficient means of reducing line loss and oders of issueing the index signs.For the absence of the online collection of data and communication resources in the past, in the meantime, the traditional simplification methods strictly abided to some certain assumptions of which were made used to calculate theoretical loss, as a result of that, there are some problems with the precision and reliability of the result of calculations. With the evolution of computer and communication technology and their gradual aplications in power system and latest wave of smart grid for the expansion of the range of collection, the proportion of direct collection for the power supplies, lines and loads in distribution networks is increasing. With the advocacy for renewable energy and clean energy and the presence of their application, accessing to medium voltage or low voltage distribution network for small capacity of most new power supplies, therefore, the two major preconditions including the hypothesis of single power supply structure and lack of online measurement lost their values, depending on actual measurement data as much as possible to obtain a more realistic distribution network structure of the actual distribution network, particular the models and algorithms of theoretical calculation for multiple power supplies, dedicate to profound significance for history and reality.Focusing on reaseach on the arithmetic of realtime energy loss calculation for a number of power sources supplying distribution network and software development, the author introduced the basic theory, domestic and international status quo and prospects of loss calculation and analyzed several calculation methods applied for the line loss of the distribution.With the development of the techniques of communication, computer and intelligent devices, etc. and extention of the application of the field collection terminal, the precision was improved by taking full advantage of the data which reflected the distribution network real-time running information. The data such as voltage, active power, reactive power of substation, voltage, active power, reactive power of hydroelectric power stations used in line losses calculation were probably stored in different database in different systemes. The solution of interface between SCADA system, other relative system and line losses calculation system was stated.Analyzing the objects in distribution networks in Object-oriented methods, a main line/branch interval model based on common information model of IEC61970 standard was set up for analyzing distribution network topology and calculating real-time line losses. Distribution network database was designed and a new code methodwas put forward.In light of the characters of radial and multi-sources distribution network, a method base on measurements data resource and back/forward sweep is presented for the calculation of line loss. The algorithm could take full advantage of local real-time measured data , refers to the thought of grid state estimation and automated algebraic equation computes power, node voltage and line power loss through node load power and branch impedance as parameters with automatically generating simple network labeling of node, branch and its impedance. The program developed in pl/sql language was approved to be practicable, satisfy the request of precision and better than traditional methods after checking the test results of IEEE 33 nodes system and real system are given and comparing with the results that obtained in month average method. At last, the author introduced the program for distribution network line loss system.