The balance ratio of the transformer below 1600kV is 5 and the line is 2. Judge right from wrong. Fi

For all transformers. That is, this is required for oil-immersed transformers, dry-type transformers, and air-insulated transformers.

The capacity is less than 1600kva transformer winding frontal rent three-phase unbalance rate: phase electric shenji radical resistance socks are (), and the line resistance is 2%.

4% (correct answer).

Answer]: The rated voltage of the primary side winding of the C transformer is equal to the fixed voltage of the line, which is 220 kv, while the rated voltage of the secondary side winding is multiple of the rated voltage of the line, so it is 121 kv, so the conversion ratio is 220 121.

Summary. Answer: Hello: The secondary winding voltage is the power supply voltage of the user's entry equipment. For example, the primary voltage is 10 volts, and the secondary voltage is 400 volts.

For a three-phase power transformer, the voltage of the one-phase winding is 8kV, and the voltage of the secondary winding is 200V. Find the transformer.

Answer: Hello: The secondary winding voltage is the power supply voltage of the user's entry equipment. For example, the primary voltage is 10 volts, and the secondary voltage is 400 volts.

When the AC voltage U1 is applied to the first side of the transformer, and the current flowing through the -secondary winding is i1, the current will produce alternating magnetic flux in the iron core, so that the primary winding and the secondary winding have electromagnetic contact, according to the principle of electromagnetic induction, the alternating magnetic flux will induce electromotive force through these two windings, the period is small and the maximum value of the winding turns and the main magnetic flux is proportional, the voltage of the one side with more winding turns is high, and the voltage on the side with fewer winding turns is low, when the secondary side of the transformer is open, that is, when the transformer is no-load, - The voltage at the secondary end is proportional to the number of turns of the primary and secondary windings, i.e., u1 u2 = n1 n2, but the primary and secondary frequencies are consistent, so that the voltage changes. The implementation of the transformer: the transformer is a device that converts the AC voltage, current and impedance, when there is an AC current in the primary coil, the AC magnetic flux is generated in the iron core (or core), so that the voltage (or current) is induced in the secondary coil.

The transformer is composed of an iron core (or magnetic core) and a coil, the coil has two or more windings, of which the winding connected to the power supply is called the primary coil, and the rest of the windings are called secondary coils. In the generator, whether the coil movement through the magnetic field or the magnetic field movement through the fixed coil, can induce the electric potential in the coil, in both cases, the value of the magnetic flux is unchanged, but the number of magnetic flux intersecting the chain with the coil changes, which is the principle of mutual induction. A voltage device is a device that uses electromagnetic mutual induction to transform voltage, current and impedance.

Summary. Solution:1

Calculate transformer load and high-voltage outgoing voltage; 2.According to the rated voltage and rated load, determine the range of high-voltage bus voltage variation; 3.According to the transformer load obtained in the step and the high-voltage outlet voltage, determine the available tap; 4.

According to the actual application, select the appropriate tap.

Select the tap of the transformer.

A distribution transformer of type S11-6300 35 has a conversion ratio of .

35±2×。At maximum load, the incoming voltage on the high-voltage side is , and the transformer is in the middle.

The voltage loss calculated to the high side is 6%; At minimum load, the high-side incoming line voltage is 37kV, transformer.

The voltage loss attributable to the high-voltage side is . The voltage of the low-voltage bus of 10kV is required when the substation is running.

Not less than -7% of the rated voltage at the maximum load, and not more than +5% of the rated voltage at the minimum load.

A distribution transformer of type S11-6300 35 has a conversion ratio of .

Select the tap of the transformer.

Not less than -7% of the rated voltage at the maximum load, and not more than +5% of the rated voltage at the minimum load.

The voltage loss attributable to the high-voltage side is . The voltage of the low-voltage bus of 10kV is required when the substation is running.

The voltage loss calculated to the high side is 6%; At minimum load, the high-side incoming line voltage is 37kV, transformer.

35±2×。At maximum load, the incoming voltage on the high-voltage side is , and the transformer is in the middle.

A distribution transformer of type S11-6300 35 has a conversion ratio of .

z=u/i=380/i

i is the current value of the high-voltage side after loading, if it is an unknown quantity, the low-voltage side voltage 220V load impedance is used to calculate the current of the low-voltage side, and the divider ratio is converted into the current value of the high-voltage side.

(1) Primary side rated current: 10000 3300 = A (should be larger), secondary rated current 10000 220 = A.

2) The second can be connected to 40W, 220V incandescent lamps (COS X=1): 10000 40 = 250 (3) The second time to change to 40W, 220V, COS X= fluorescent lamps, can be connected: 10000*.

10kva=10000va

Primary side rated current i = 10000VA 3300V = secondary side current i = 10000VA 220V =

The secondary side incandescent lamp cosx = 1, so the apparent power = active power = 40va, you can connect 10000va 40va = 250 lamps.

40W fluorescent lamp, cosx=, so apparent power = active power cosx=40, can be connected to 10000VA.

Formula: apparent power s=ui, unit va; Active power p=uicosx=scosx, unit w; Reactive power q=uisinx=ssinx, unit var.

1) For transformers above 1600VA, the difference between the winding resistance of each phase should not be greater than 2% of the average value of the three phases, and the difference between the lines should not be greater than 1% of the average value of the three phases for the winding drawn from the neutral point

2) For transformers of 1600VA and below, the difference between phases is generally not more than 4% of the average value of the three phases, and the difference between the lines is generally not more than 2% of the average value of the three phases

Primary side rated current: s = 3 * u1 * i1 i1 = s 3 * u1 = 20 3 * 10 =

Secondary side rated current: s = 3 * u2 * i2 i2 = s 3 * u2 = 20 3 * = a

Number of quadratic turns: U1 N1 = U2 N2 N2 = N1 * U2 U1 = 3300 * 10 = 132 turns.