Assessment method for loadable index of oil immersed power transformer

Abstract

The invention discloses an assessment method for a loadable index of an oil immersed power transformer. According to the method, the load capacity of the oil immersed power transformer in the future time period is discussed in three aspects of temperature limit restraint, failure rate restraint and economic gain and loss restraint; in the aspect of temperature limit restraint, the maximum load rate meeting the requirement of the safe operation time is assessed with the adoption of a predicted load rate and an environmental temperature, the defect that a conventional scheduling and operating regulation can only give a suggestion interval of the load rate of an overload is overcome, and the problem of an obscure strategy at the border is solved; in the aspect of failure rate restraint, the load amplitude of a device is restrained from the aspect that a failure rate happens to a slave device, and while the load rate is increased, the fault stoppage and the power grid disintegration which are caused by slave device levels are prevented; and in the aspect of economic gain and loss restraint, on the basis that only electric charge gains and impedance loss cost are considered in a traditional method, the checking of a life loss cost is added, so that gain and loss computing is more suitable for the process of overload operation.

Description

technical field [0001] The invention belongs to the technical field of power system device performance evaluation, and in particular relates to an evaluation method for loadability indexes of oil-immersed power transformers. Background technique [0002] With the rapid development of my country's economy, the problems of regional load growth and insufficient power transmission and transformation capacity of the old power grid have become increasingly prominent. Adding new transformers and other power transmission and transformation facilities requires huge funds, and at the same time, construction takes a long time. Especially in large and medium-sized cities, the expansion of substations and the opening of new line corridors will be constrained by land resources and ecological environment. At the same time, power outage maintenance, inaccurate load forecasting, outage accidents, emergency loads and other situations in daily power production and operation will cause overload...

AI Technical Summary

Problems solved by technology

However, in the relationship table, each factor is given in the form of an interval range, the scheduling strategy is not clear and accurate, and the scheduling strategy at the boundary is fuzzy.

[0004] On the other hand, the Chinese patent with publication number CN202362089U proposes a transformer overload early warning system, which establishes a trend pre-alarm mechanism for transformer overload operation based on the oil-immersed transformer hot spot temperature model, but fails to provide a The upper limit value of the load rate that can be increased before the upper limit warning value

[0005] The Chinese patent with the publication number CN102879696A proposes a method for automatically judging the feasibility of transformer overload operation to analyze the overload capacity of the transformer, which is determined only by the table relationship between the hot spot temperature value and the load rate value in the regulation of dispatching operation. The upper limit of the load rate is not accurate and flexible enough, and the upper limit of the load rate cannot be considered from the current operating state of the equipment

In addition, few scholars have evaluated the operation consequences of exceeding the nameplate from the perspective of failure rate, economic profit and loss, etc., and have failed to comprehensively evaluate the dynamic load capacity of oil-immersed power transformers.

[0006] The research on the upper limit of transformer loadability by the above existing methods mostly relies on the temperature constraint reference table between the allowable operating time and load rate in the transformer operation regulations, and fails to accurately follow the current ambient temperature and load rate of the equipment. and cooling methods, dynamically evaluate the upper limit of the load rate in a specific time interval in the next time period from multiple perspectives

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