Analysis Of The Excess Loss And Operation Characteristics Of Transformer’s Harmonic

Non-linear electric equipment is widely used in electric power system, which will produce a large number of harmonic in the running process. It also leads to reduce the power quality of power grid, interferences with communications systems or normal operation of neighboring devices, and even causes directly economic losses to the power gird. Transformer is one of the most important electrical equipment. With the gradual increase of harmonics injected into the grid, transformer losses and its temperature will increase, life expectancy and efficiency will fall. Therefore, analyzing with the additional harmonic losses to transformer and the operating characteristics is very important to system security and economic operation of power.For the question of harmonic hazard from researching in transformer at present, the additional harmonic losses to transformer and the operating characteristics to transformer under the background of harmonic are mainly analyzed in power system. According to the mechanism of harmonic losses, the transformer harmonic model is build up, and how to choose its harmonic parameters is researched. The calculation method of harmonic losses, the transformer type impacting on the harmonic losses and the variation regular of harmonic components and transformer losses are also studied.According to the operating characteristics change of transformer capacity, temperature rise and life expectancy under the action of its harmonic, the relationship between K-factor and harmonic current distortion rate and reducing capacity coefficient D is analyzed. The calculation model of reducing capacity coefficient D and harmonic current distortion rate is established. It has been completed with the transformer actual capacity calculation under the condition of its harmonic existence. Drawing a lot of variation curves about the harmonic frequency and some changed factors such as transformer winding losses, top oil temperature, harmonic current distortion rate and life expectancy with polynomial fitting method. Finally, as an example of enterprise ought to measure and process the date of harmonic. Those actual measurement data processed can be used to calculate the transformer additional losses, and verify the validity of harmonic losses rules. It also calculates the electricity consumed of transformer harmonic losses as a percentage of inverter saving electricity section.It has the very most important theoretical significance and practical value for quantitative analysis of transformer harmonic hazards, such as reducing the harmonic losses of the transformer, prolonging the service life of the transformer, reducing the failure rate, improving the economic benefit and security of power supply system, and enhancing the energy efficiency of the frequency control system.