The wage principle of the voltage transformer, the working principle of the voltage transformer

It is a step-down transformer, which represents high voltage with the same proportion of low voltage.

The working principle of a voltage transformer is as follows:

The basic principle of a voltage transformer is the same as that of a transformer. In terms of its structure, it is a transformer with small capacity and large voltage ratio. The basic structure is also the core and the primary and secondary BAI windings. It is characterized by a small and constant capacity, which is close to the no-load state during normal operation.

The voltage transformer uses the principle of electromagnetic induction, and on the closed core, there are two windings with different turns and mutual insulation, and the primary winding N1 is connected to the power supply side, and the output side is the secondary winding N2.

The role of voltage transformers

The function of the voltage transformer is to convert the high voltage into a standard secondary voltage of 100V or lower in proportion to the ratio for protection, metering and instrumentation devices.

At the same time, the use of voltage transformers can isolate high voltages from electrical workers. Although the voltage transformer is also a device that works according to the principle of electromagnetic induction, its electromagnetic structure relationship is just the opposite compared with that of the current transformer.

In fact, many people do not know why the transformer is needed for voltage transmission on the line, mainly because the power generation and the actual transmission of electricity and the demand for electricity will naturally lead to a large difference in voltage, and the voltage needs to be adjusted for use to avoid the risk of high voltage for ordinary household use.

<> "The Internal Structure of Voltage Transformer and Fault Repair".

The current transformer is a device commonly used in transformers to measure current, which is made according to the principle of electromagnetic induction. In the working state, it is basically close to the short-circuit state.

The basic role of the current transformer is introduced, and then we focus on its internal structure, so that we can check it in an orderly manner when the current transformer fails.

The basic structure of a voltage transformer is similar to that of a transformer, consisting of two windings: a primary winding and a secondary winding. Two windings are wound around the core.

The two windings are separated from each other and between the windings and the core by insulation, which is called galvanic isolation. When the voltage transformer is running, the primary winding N1 is connected in parallel on the ** road, and the secondary winding N2 is connected to the instrument or relay in parallel. Therefore, when measuring the voltage on the high-voltage line, although the primary voltage is high, the secondary voltage is low, so as to ensure the safety of the operator and the instrument.

The failure of the voltage transformer is due to the unreasonable design structure, which makes the potential suspension of the core grommet bolt during operation and discharge. Another common fault of voltage transformer is poor insulation bracket, followed by poor end sealing and moisture ingress. As shown in the figure, the statistics of the failure causes of 25 voltage transformers detected by gas in oil analysis.

We can solve the fault of the paired voltage transformer through the following 8 aspects:

1.The voltage three-phase indication indicates unbalanced or unstable: at this time, it may be that the fuse is broken, and it can be solved by checking the fuse.

2.The neutral point is not grounded: the three phases are unbalanced, which may be resonant or affected by arc suppression coils.

3.Multiple blows of the high-voltage fuse: resulting in severe damage to the internal insulation, and failures between layers and turns.

4.The neutral point is grounded, and the voltage fluctuates: this will show that the operation is in a series resonant state, and the lack of operation is the damage to the internal insulation.

5.Voltage indication is unstable: Check if the grounding is good.

6.Voltage transformer circuit disconnection: exit protection, check fuse and replace, check circuit.

7.Secondary voltage fluctuation of capacitive voltage transformer: It may be that the secondary damping is not properly matched. The secondary voltage is low, and the wiring may be broken or the voltage divider may be damaged. If the secondary voltage is high, it may be that the voltage divider is damaged.

8.Abnormal sound: Damage to the electromagnetic unit reactor or intermediate transformer.

Through the previous points, it can be basically seen that most of the damage to the current transformer is caused by insurance or insulation problems, so we must first check these two aspects, if other things are broken, there is no way but to replace them.

If there is a right or wrong, I hope that all the seniors will guide you and make progress together, and the apprentices will be grateful.

Voltage transformer is a positive conversion of the high voltage of the primary circuit into a secondary low voltage, which is supplied to measuring instruments, relay protection and other similar electrical appliances.

The purpose of the voltage transformer is to realize the conversion of the measured voltage value, and its output capacity is very small, unlike ordinary transformers. Generally, it does not exceed tens of volt-amperes or hundreds of volt-ampere, and the output power may be as low as milliwatts for electronic instruments or digitally protected transformers.