Analysis And Research On Relevant Issues Of Quasi-online Calculation To Power Grid Theoretical Line Loss

Power grid theoretical line loss calculation is one of the technical means adopted bypower grid corporation analyzing and making a strategic decision in power system. It canprovide theoretical basis for saving energy and reducing loss by finding currentshortcoming in power grid structure and system operation. With the development of smartgrid and electric power automation in our country, power grid theoretical line losscalculation trends to online calculation in power grid corporation. Basic data in onlinecalculation is from Common Information Mode(CIM) of61970standard(IEC61970standard) drawn up by International Electrotechnical Commission(ICE), to be late forimplementation of IEC61970standard in our country, model and data of CIM need to beimproved, hence, power grid theoretical line loss calculation which is going to be online insome power grid corporation is in the mode of quasi-online. Power grid theoretical lineloss quasi-online calculation faces many problems to solve urgently now because of thelack of online calculation condition. Moreover, energy-saving and emission-reducing putforward in national “12th five-year” plan also make analysis of power grid theoretical lineloss facing new challenges. Hence, at the basis of delving into the existing problems inpower grid theoretical line loss quasi-online calculation， this paper provides thecorresponding methods and analyses the effection of energy-saving and emission-reducingon theoretical line loss. At the same time, illustrative numerical results are presented toprove the effectiveness of the proposed methods. The major contents of this paper arepresented as follows：Firstly, a scavenging grid computing platform fitting for power grid theoretical lineloss quasi-online calculation is offered. Adopting the Internet CommunicationsEngine(ICE) technology, a power grid theoretical line loss scavenging grid computingplatform making full use of idle processor resources and idle multi-core CPU isestablished to enhance parallel computing ability and lighten the burden of server.Centralized computing and distributed computing are compatible by standby grid.Combining ant colony algorithm and2-opt optimization, job scheduling allocating the taskaccording to load condition is researched. Secondly, a selection method of slack bus for power flow calculation is provided torealize the automation of power flow calculation and improve the accuracy of power flowcalculation. On the basis of research of slack bus selection condition, a node importantdegree model including node cohesion degree, injection power and node degree is offeredto select a slack bus according to the complex network theory. The actual power systemsimulation results show that a slack bus can be selected more accurately by the offerednode important degree model in conventional power flow calculation.Thirdly, in the light of the lack of Scalable Vector Graphics(SVG) or theinconsistency between SVG and CIM, an automatic plating method of single-linediagrams for power transmission networks is offered. The plating of single-line diagramstransformed into quadratic assignment problem adopts ant colony algorithm whose localoptimum is solved by3-opt optimization. Graphic block fixing substation position makespower grid layout more close to the actual. Simulation results show that clear layout andshort solving-time of the plating of single-line diagrams meet the demands of power gridcorporation.Fourthly, the frame of power grid theoretical line loss quasi-online calculation isestablished. Mapping relation between power grid theoretical line loss calculation andCIM is provided through studying the CIM carefully; the frame of power grid theoreticalline loss quasi-online calculation based on CIM is offered by researching computingplatform and selection method of slack bus and plating method of single-line diagrams intheoretical line loss calculation and IEC61970standard; in the light of the lack some dataof CIM applied to power grid theoretical line loss quasi-online calculation, model of CIMis extended to meet power grid theoretical line loss quasi-online calculation.Finally, under carbon emission reduction day index constraints, carbon captureemission reduction model is established, and the effection of power plants and power gridcoordination(plant-grid coordination) emission reduction on line loss is analysed.Considering the carbon emission reduction day index constraints, model of power plantsand plant-grid emission reduction with carbon capture is created, and Multi-Agent Systemis applied to dispatch strategy. The effection of various carbon emission reduction on lineloss and the effection of position of carbon capture device in power grid on line loss are researched in plant-grid coordination. It provides theoretical basis for analysis of powergrid theoretical line loss on carbon capture emission reduction.