What does impedance matching of transformer mean 15

The output impedance of the amplifier is equal to the input impedance of the load through the transformer.

Short circuit of the transformerImpedance, also known as the impedance voltage of the transformer, it indicates that the transformer passesCurrent rating, the voltage loss (percentage) generated on the impedance of the transformer itself.

The impedance voltage of the transformer is an important parameter of the transformer, which is of great significance to the parallel operation and economic operation of the transformer, and it is also to calculate the short-circuit current of the transformer.

and an important basis for the valuation of protection.

Significance. The resistive voltage of the transformer is an important parameter of the transformer, which is of great significance to the parallel operation and economic operation of the transformer, and is also an important basis for calculating the short-circuit current and protection value of the transformer.

1) The larger the impedance voltage of the transformer, the smaller the short-circuit current flowing through the transformer and the lighter the impact on the transformer when a short circuit occurs on the secondary side of the transformer.

2) The larger the impedance voltage of the transformer, the greater the change range of the voltage on the load side of the transformer when the load changes, and the voltage stability is poor.

3) The larger the impedance voltage of the transformer, the reactive power consumed by the transformer winding under the same load in operation.

also larger.

1. The current national standard for transformers is called "short-circuit impedance", and there was a period of time when it was called "Short-circuit Impedance Voltage", "Short-circuit Voltage" and so on. They usually denote it in terms of a scaled unit value (percentage).

2. "Impedance Voltage" comes like this: when the secondary winding of the transformer is short-circuited (steady-state), the voltage value to be applied is called the impedance voltage (or short-circuit voltage) UK (this value is the voltage value, the unit is V), but usually the "Impedance Voltage" uz is expressed as a percentage (standard unit value) %, that is, uz=(uk u1n)*100% (where u1n is the rated voltage on the primary side, the unit is v). This can be found in the transformer short circuit test.

Press the transformer. The principle of ampere turn balance on the first and secondary side, at this time, the rated current value should also flow through the secondary winding.

3. Although on the surface, it is expressed as a percentage of voltage (standard unit value). In essence (physical substance), it is the (internal) impedance characteristics of the transformer that reacts violently. Therefore, later transformer experts thought that it was more appropriate to call it short-circuit impedance, and it has been used to this day.

4. I think so, they are the same thing, and of course the standard value is the same.

The main reason is that the transformer in the process of operation due to the external current will cause the terminal voltage of the transformer to change accordingly, the impedance of the large power consumed in the transformer, the voltage of the output end will be a little lower, then the impedance of the transformer will reverse the power supply to cause circulation, can be used to represent the relationship between the output current of the transformer and the voltage of the end muchun can be expressed.

When doing the transformer load loss test, the measured test voltage (line voltage) is the impedance voltage uz of the transformer, also known as short-circuit impedance or short-circuit voltage, which is expressed as a percentage of the rated voltage uz%, and the impedance voltage should also be converted to the corresponding value when 75.

The allowable deviation of the impedance voltage is related to the magnitude of the impedance voltage. When the impedance voltage value of the main tap is greater than or equal to 10%, the allowable deviation is 10%.

The impedance voltage is small, and the short-circuit current is large. The impedance voltage is too small, the short-circuit current is too large, and when the output is short-circuited, the transformer is easily damaged by excessive electric power. Therefore, the national standard stipulates that the minimum value of the impedance voltage is shown in the following table.

Article**1What is the short-circuit impedance (impedance voltage of the transformer) of the transformer?

The short-circuit impedance of the transformer, also known as the impedance voltage of the transformer, indicates the voltage loss (percentage value) generated on the impedance of the transformer itself when the transformer passes through the rated current; For double-winding transformers, the measurement method is to short-circuit the secondary side of the transformer, and the voltage added when the rated current flows through the primary side, and then convert it into a percentage of the rated voltage; The impedance voltage of the transformer is an important parameter of the transformer, which is of great significance to the parallel operation and economic operation of the transformer, and is also an important basis for calculating the short-circuit current and protection value of the transformer.

1) The larger the impedance voltage of the transformer, the smaller the short-circuit current flowing through the transformer when a short circuit occurs on the secondary side of the transformer, and the lighter the impact on the transformer.

2) The larger the impedance voltage of the transformer, the greater the change range of the voltage on the load side of the transformer when the load changes, and the voltage stability is poor.

3) The larger the impedance voltage of the transformer, the greater the reactive power consumed by the transformer winding under the same load in operation. The transformer data you mentioned above is the data of a three-winding transformer;

High-medium: indicates that the impedance voltage of the transformer's high-voltage winding to the medium-voltage winding is;

High-Low: indicates that the impedance voltage of the transformer's high-voltage winding to the low-voltage winding is;

Medium-Low: indicates that the impedance voltage of the medium-voltage winding of the transformer to the low-voltage winding is.

The impedance voltage corresponds to the rated capacity of the transformer.

There are relevant requirements in and GB6451, etc.

6 10 kV class power transformer is 4; The power transformer of the 35 kV class is; 110 kV class power transformer 8 9%; Power transformers of the 220 kV class reach 12-14%.

Transformer impedance refers to the impedance of the windings of the coil in the transformer, including resistance, inductive reactance, and capacitive reactance.

The standards for transformers have clear provisions on impedance and loss. After some users increase or decrease the impedance voltage, the loss is still unreasonable according to the standard requirements. If the impedance voltage becomes smaller, a reasonable change is:

If the no-load loss is good, the surplus becomes larger, and the load loss becomes smaller; If the impedance voltage becomes larger, the reasonable change is: the no-load loss becomes smaller, and the load loss becomes larger.

The standard value of the impedance voltage of the transformer (now called "short-circuit impedance" in the standard) is expressed as the percentage of defects (standard unit value). The standard values of different transformers are clearly specified in the national standards for transformers.

However, errors can occur during transformer manufacturing. The margin of error is: between + to (previously +-10%).

If the transformer is short, the standard value of the circuit impedance is 4%, and the transformer impedance range should be qualified according to the previous 10%. And to put this data on the transformer nameplate. <>