Loss Reduction Measures Analysis Based On Line Loss Sensitivity Of Urban Power Grid

Network loss is an important problem in the economic operation of power system. The loss rate is a significant economical target of、power system, it’s also a main symbol of measuring the management and technical level of power companies.The lost power in all power transmission, substation and distribution sectors is called loss of power grid. In a same period, the percentile of the loss of electricity accounts for power supply is called loss rate. The loss issue mainly performance in two aspects:one is to take effective measures to reduce network losses, another is economic dispatch problem considering line loss, in other words, through calculating theoretical line loss to analyze loss for operation departments, and then to take measures to reduce line loss and achieve maximum economic benefit. Line loss analysis is used to find a variety of factors affecting line loss rate. According to the conclusion of line loss analysis, power companies can develop realistic measures of reducing line loss, formulate indicator of line loss in the future, master the variation trend and improve the management of line loss.At present, line loss is mainly analyzed by calculating theoretical loss. There are many methods of calculating theoretical loss, for example, equivalent resistance method, the maximum load hours method, the node equivalent power method and artificial intelligence algorithms proposed in recent years. However, these methods are rarely intuitive to see the extent of operating parameters and net parameters affecting line loss. Therefore, factors affecting line loss are analyzed from the point of sensitivity in this paper, it provides a basis for developing loss reduction measures.First, the concept of sensitivity is introduced and line loss calculating model is established. Net loss is calculated based on the flow calculation. Combined with sensitivity index, the loss of the system is reflected by the active power injected into the balance point. The line loss sensitivity to net parameters as resistance and reactance of transformers or transmission lines and loss sensitivity to operating parameters as voltages of PV nodes are calculated. Also, program of the algorithm is made; second, through estimating the annual comprehensive cost of the line and transformer and using line loss sensitivity index, reduction measures of line loss in urban power grid are studied; finally, power net work in an urban power grid as an example, through comparing the cost of changing lines and transformers and loss reduction benefits, those lines and transformers which influence line loss greatly are replaced, the reformation strategy is studied; according the sensitivity results, the effect of reduction loss by adjusting voltages of PV nodes are budget and reference advices are provided to operating personal.