Research On Black Start Strategy Considering Microgrids

With the gradual growth of electricity customers needs and theincreasingly close relationship between different power system regions,the interrelationship of the power system increases. However, greatchallenges have been brought to the steady operation of power due to thecomplexity of system. Great economic losses and big social problem willoccur once a big black out occurs, some political problem like socialunrest will happen as well. Black start strategy focusing on reducinglosses has always been a hot topic in the academia of power system.Finding proper black start sources is an important subject in the researchof black start, as the microgrids distributed with flexible operation modeand enables fast switching loads, the use of micro power grid black startas a black start powe system is gradually being involved in domestic andforeign attention electrician community.On the basis of the existing conventional black-start program ofextensive research, the paper discusses how to use the relatively rapiddevelopment in recent years involved in micro-grid black start process, soas to probide a new idea for the relevant departments to develop the power system black-start program, and this paper includes the followingcontent.Black start power system that may occur during the phenomenon ofself-excitation and crew unloaded over-voltage and over-voltage wereintroduced, a brief introduction to the rapid development in recent yearsin terms of vanadium micro-grid energy storage battery system, whichhas external transport ability to stabilize large power. Combined powersystem dispatch department started the basic requirements for blackpower, output power and energy reserves from both studied micro-gridenergy storage device containing a large-scale involvement of thefeasibility of the grid black start.This paper uses graph theory to solve three basic methodologies forsolving the shortest path to start the power to be restored from the blackcrew shortest electrical distance. Start-up characteristics combined withconventional thermal power curve, this paper proposes a new unit weightcoefficient index, at a time constraint, power constraint, black bootpartition scheme is proposed under the premise of energy constraints andthe basic trend of the constraints, initially identified for each unit to berestored black-owned boot partition.Black boot partition scheme is formulated initially based on indexesproposed and the improved simulated annealing method is applied tooptimize the method considering both restoration power and restoration time, global optimization can be achieved. The restoration successful rateof lines and most expected power output for each unit porposed in thispaper is used as an index to determine each NBS unit belongs to wichsection, the unit-starting-sequence in each section can be determined.Single subsystem recovery time is too long and delay the global blackstart process can be avoided. IEEE39bus system is applied to discuss thenecessicty of optimizing the system.This paper describes how to choose the sub-region and networkoperation, and divide the whole re-operation into three different level.Basic requirements for each level have been discussed. A newload-restoration function model for reducing the load losses has beenproposed, the load-restoration problem swiches to a0-1package problemand the particle swarm algorithm method is applied to solve the problem.With IEEE118node, for example, the analysis is verified by an examplethat if micro-grids with large scale energy storage can participate in blackstart, the whole process can be accelerated sharply. The IEEE14nodesystem is used to tesify that the microgrid can accelerate the loadrecovery process.