What does the excitation characteristics of a current transformer indicate?

The excitation characteristics of current transformers indicate that excitation plays an important role in current transformers.

According to the different excitation methods of the DC motor, it can be divided into separate excitation, parallel excitation, series excitation, compound excitation, etc. During the rotation of the DC motor, the excitation is to control the voltage of the stator to produce Changes in the magnetic field change the speed of the DC motor, and changing the excitation also changes the speed.

According to the different power supply methods of the excitation winding, it can be divided into two types: self-excited type and separately excited type. In a self-excited DC exciter excitation system, the generator rotor winding is powered by a dedicated DC exciter.

In the separately excited DC exciter excitation system, the excitation winding of the separately excited DC exciter is powered by the auxiliary exciter, which is commonly known as "three-machine excitation". As the generator capacity increases, the required excitation current also increases accordingly. The excitation power unit of large-capacity units uses an AC exciter excitation system composed of an alternator and a semiconductor rectifier element.

According to the different rectification methods and rectification states of the exciter power supply, the AC exciter excitation system can be divided into separately excited AC exciter systems and self-excited AC exciter excitation systems.

Extended information

Due to the problems of easy saturation, nonlinearity and narrow frequency band of electromagnetic current transformers, electronic current transformers are gradually emerging. Electronic current transformers generally have the advantages of anti-magnetic saturation, low power consumption, and wide frequency band.

The representative electronic transformers in China include AnyWay variable frequency voltage sensor, AnyWay variable frequency current sensor and AnyWay variable frequency power sensor. Among them, AnyWay variable frequency power sensor is a combined voltage and current transformer.

The main features of this transformer are as follows:

1. It adopts front-end digital technology and has good electromagnetic compatibility.

2. The amplitude-frequency characteristics and phase-frequency characteristics are good, and high measurement accuracy can be obtained in a wide range of amplitude, frequency and phase.

3. It is a digital sensor. The secondary instrument will not introduce errors. The sensor error is the system error.

Baidu Encyclopedia-Current Transformer