【正文】
ion and noncontinuity on pensation, there is a topology structure of PWM main circuit and nonpower theory on active filter the waves technique and builds flat proof on the ground of Saber Designer and proves to be practical. Meanwhile, it analyzes and designs the way of nonpower need of electric work tre nds and decreasing line loss bined with DA, which have been tested its objective economic benefit throu gh counting example. Sixthly, not only do the dissertation design a way founded on the magrginal electric price fitted to our present national electric power market with regards to future trends of electric power market in China and fair trade under the government surveillance, that is group petitio n in shortterm trade under the way of grouped price and quantity harmony, but also puts forward bination arithmetic, math model of trading plan and safty economical restriction. It can solve the original contradiction between medium and long term contract price and short term petitive price with improvement on petitive percentage and cut down the unfair ine difference of electric factory, at the same time, it can optimize the electric limit for all electric factories and reduce the total purchase charge of electric power from burthen curve of whole electric market work. The distribution work is an important link among the power system. Its neutral 3 grounding mode and operation connects security and stability of the power system directly. At the same time, the problem about neutral grounding is associated with national conditions, natural environment, device fabrication and operation. For example, the activity situation of the thunder and lightning, insulating structure and the peripheral interference will influence the choice of neutral grounding mode Conversely, neutral grounding mode affects design, operation, debugs and developing. Generally in the system higher in grade in the voltage, the insulating expenses account for more sizable proportion at the total price of the equipment. It is very remarkable to bring the economic benefits by reducing the insulating level. Usually such system adopt the neutral directly grounding and adopt the autoreclosing to guarantee power supply reliability. On the contrary, the system which is lower in the voltage adopts neutral none grounding to raise power supply reliability. So it is an important subject to make use of new type earth device to apply to the distribution work under considering the situation in such factors of various fields as power supply reliability, safety factor, overvoltage factor, the choice of relay protection, investment cost, etc. The main work of this paper is to research and choice the neutral grounding mode of the l0kV distribution work. The neutral grounding mode of the l0kV work mainly adopts none grounding, grounding by arc suppressing coil, grounding by reactance grounding and directly grounding. The best grounding mode is confirmed through the technology parison. It can help the work run in safety and limit the earth electric arc by using autotrack