Parameter Identification Research Of Transformer Windings

Electrical transformer is important and valuable electric equipment in electrical power system. It's safely running related to electrical power system's stabilization. Transformer will occur kinds of accidents when it operating in power line long time. If broken the loss is very high. Through preventive test and gas chromatograph to judge transformer insulation condition is helpful method to prevent accident. But periodic preventative test may have excess maintenance and unnecessary stop, also can't find accident in time. But the on-line monitoring of winding deformation of transformer can forecast trouble in time, avoiding occur accident and reducing maintenance cost.Windings are the most fault components of transformer and its damage rate is about 60%～70% of all the transformer accidents. In the method of checking winding deformation, low voltage impulse method, frequency response analysis method and short-circuit reactance method, which can be used to measure and diagnose the deformation of power transformer winding are available in some extent, but they are all off-line monitoring. Accident can't be fund in time and not fit on-line measurement. Through on-line measuring the short-circuit reactance of power transformer to estimate transformer winding deformation is an effective method.According to the character of short-circuit reactance of power transformer is not change when transformer is normal work and short-circuit reactance will change when transformer occur accident, using identification principle and basing on measuring primary, secondary currents and voltages to calculate the short-circuit reactance of windings. It is a cinder box system model. Normal work short-circuit reactance is reference and compare to calculation value, can judge whether the winding is normal and which winding happen accident. Make sure transformer components can replace in time, prevent transformer stop operation abnormally.Using Fourier algorithm to solve parameters of voltage and current, and then finish winding parameter identification. But no consider decaying DC component. Fourier algorithm for signals including decaying DC component may make error, but least squares algorithm and Kalman filtering algorithm have good effect.At last introduce transformer winding's practical application of parameter identification and error analysis. Software and hardware may influence short-circuit reactance measurement. Introduce software design of parameter identification and put this software system in reality. Then verifying program is feasible.