The Study Of Network Planning Considering The Factor Of Electromagnetic Loop Network

Recently, with the fast development of power network ,the 500KV loop network has been finished, which is conjoined with the existing 220KV loop network , forming an electromagnetic loop with the two voltage levels. With the network becoming strong ,the short circuit current in some substations will exceed the rated value of 220KV circuit breakers. To limit the short circuit current , basing the load level and the network structure of the next year, analysis the schedule of opening the loop, which belong to the operation planning .Except of this ,some people begin to study the problem of electromagnetic loop network from the aspect of long term planning .The thesis study the characteristic of the electromagnetic loop network, and discuss it deeply. To avoid electromagnetic loop network radically, put the factor of electromagnetic loop network into network planning .It is the typical mixed and integral non-linear planning problem that there are many control variables and the complexity is high. Even the planning with the factor of electromagnetic loop network need to consider the problem of the network with different voltage levels correspond with each other. Thus increase the difficulty of the research the result of space .The problem was transformed into the problem of planning the low-voltage-level network in case of the high-voltage-level network was confirmed, thus decrease the quantity of calculation .Under the background of realizing the voltage-grading and the district-dividing in the network , this thesis analyze the characteristics of electromagnetic loop network ,and put the factor of electromagnetic loop network into the model of network planning. With the objective function of minimum investment cost and minimum operation cost ,the factor of N-1,overload,electromagnetic loop network ect., a model was present .