PC-E984-685 Suzhou Xunpeng FP power transmitter basic principle
Suzhou Xunpeng FP series power transmitter is a measuring instrument that converts the measured power (AC voltage, current, active power, reactive power, active power, reactive power, frequency, phase, power factor, DC voltage, current, etc.) into linear proportional DC current or voltage output (electrical pulse output). It is widely used in electric power, petroleum, coal, metallurgy, railway, municipal and other departments of electrical measurement, automatic control and dispatch system.
1. PC-E984-685 Basic measurement circuit
The basic measurement circuit of the power transmitter is generally composed of the following parts:
1. Signal input isolation
PC-E984-685 Since the power we need to measure is generally high voltage (57.7-380V) and high current (1A-10A), if they are not isolated and the amplitude is reduced, it will pose a serious threat to personal safety and equipment, signal input isolation is generally used voltage transformer (PT) and current transformer (CT), the basic requirements for this part are:
a. The voltage insulation performance of signal isolation is good, and the voltage should be >2kV.
b. Linearity is better, because PT, CT are made of ferromagnetic materials, their linearity is not good,
PC-E984-685 In the future circuit is difficult to compensate, therefore, must choose high-quality materials and advanced technology
The high linearity PT and CT manufactured can ensure the linearity measured by the transmitter.
c. The output load of PT and CT should be small, because the core cross section of PT and CT used by the transmitter is subject to volume
PC-E984-685 The limits are relatively small, so as the output load increases, its nonlinearity will increase sharply, generally
The output current of PT should be <1mA, the output current of CT should be <10mA(generally about 5mA), sampling
Resistance should be <200Ω.
2. Power conversion circuit
PC-E984-685 This part is the core of the power transmitter, through which the different measured power is converted into the corresponding output power, and different conversion circuits are used correspondingly for different measured power. The specific circuit will be described in detail later.
3. Output circuit
PC-E984-685 The function of this part of the circuit is to output the power required by the transmitter, and its basic requirements are:
A. has a certain load capacity;
b. Constant output. That is, within a certain load range, its output value is not affected by load changes, that is
When the voltage is output, it should be a constant voltage output and when the current is output, it should be a constant current output.