The Research And Implementation In Power Network Line Loss Computation And Management System

Power loss (also called line loss) is one of the important indicators of the efficiency of power system. It has reflected the plan design, the production technology and the operation level of a power network.The analysis and calculation of power loss is one the common tasks carried on power system plan, design and operation.Calculating the power loss manually will take a longer time and have less accuracy, thus it will not meet the requirement of effectiveness and accuracy in power network management. Now it becomes very important to manage the data using computer, computing the power loss efficiently and accurately. Aimed to ensure the accuracy of power loss computation, reduce the work load of human, enhance the efficiency of power loss management, the Power Loss Computation Application Suite has been developed.The behind idea of the system design is based on the advantage of existing power loss computation software, according to the "Guideline for power loss computation in power network"and the specific requirements from Jilin Province Electric Company. The application suite has a friendly user interface and strong capability to query the database, it can also generate various customised reports. The application suite caters the requirement of line loss management by grade and district, thus makes it more useful in the real work. In this paper, before introducing the system, what is line loss is first presented, so as the methods for computing the line loss of high, middle, low voltage power networks. Active Power loss and line loss are generated by the various devices during the power transmission and distribution. Active Power loss is generated from transmission line via the medium of Electromagnetic Fields. The power of Electromagnetic Fields is leaded by the transmission line. The power loss of the transmission line which is converted from heat energy is also provided by electromagnetic fields. Under Alternating Current power transmission, there are 4 types of active power loss generated from the transmission line after the investigating to the single core coaxial cable Line loss is the totally power loss of power supply area or power network caused by power transmission, power transfer and power distribution within a specified area.(Including apportioned power network loss, power loss caused by Reactors and other reactive power compensation devices and unidentified power loss.) Though some parts of the line loss can be deduced from calculation or meter reading of special made meter for recording the line loss, but there is no way to get the totally line loss. Thus, most of the time, line loss is calculated by total supplied power minus totally sold power. In another word, line loss is a remainder. The precision of line loss is based on the accuracy of total supplied power and totally sold power. Totally supplied power is the power supplied by power station, power supply area or power network. It includes the line loss caused during power transmission and power distribution. PQ-Resolution is derived from Newton modified equation with some improving and simplifying. The main idea is that P and Q has no coupling, each time the iteration may carry on alone. H in the formula is treated by ignoring the affect to the imaginary part (L) of the admittance matrix caused by failure of capacitance charging and the none standard ratio of transformers. In order to speed up the process, H and L are pre triangular factorized. Thus, only one iteration is required when every time calculating the ?? and ?V. According to the experience, the iteration of PQ-Resolution has a high failure rate when R/X becomes bigger. In order to make the programme suitable for the low voltage network computing, H is modified so as it has less affect to the Resistance. To achieve this goal, beside ignoring the affect caused by caused by failure of capacitance charging and the none standard ratio of transformers, the Resistance of the transmission line has also been ignored. The programme has been tested in 66K voltage network and the result is satisfied.The programme has been passed the test of 1000 notes real power network, again it proves the programmes is a right solution for the real world.