CN202285032U - Electronic transformer harmonic influence testing device - Google Patents

Abstract

The utility model relates to an electronic transformer harmonic influence testing device, which includes a high power fundamental wave/harmonic wave composition power source, a harmonic standard current and voltage transformer, a standard current and voltage conversion device, and an electronic transformer harmonic calibrator, wherein the high power fundamental wave/harmonic wave composition power source is composed by a fundamental wave power source unit, a harmonic wave power source unit and a fundamental wave/harmonic wave composition output unit. The harmonic standard current and voltage transformer are connected with an output end of a primary and fundamental wave/harmonic wave composition output unit of a to-be-tested electronic current and voltage transformer; an output signal of the harmonic standard current and voltage transformer is connected to the standard current and voltage conversion device; an output signal of the standard current and voltage conversion device is connected with the electronic transformer harmonic calibrator; and the signal output end of the to-be-tested electronic current and voltage transformer is connected with the electronic transformer harmonic calibrator. The utility model provides an efficient method for harmonic calibration of the electronic transformer harmonic calibrator.

Description

An Electronic Transformer Harmonic Impact Test Device

technical field

The utility model relates to a testing device for the harmonic influence of an electronic transformer, which belongs to the technical field of verification and detection of electric equipment. the

Background technique

At present, the method used in domestic research on the harmonic characteristics of electronic transformers is the frequency characteristic method, that is, the current (voltage) signals of different frequencies are respectively connected to the primary side of the electronic transformer, and the corresponding errors are measured to obtain the electronic transformer. Frequency characteristics of transformers. However, there are differences between this test method and the actual operation of the electronic transformer. In actual operation, the signal added to the primary side of the electronic transformer is a signal synthesized by multiple harmonics, rather than a single frequency signal. the

The purpose of developing the electronic transformer harmonic characteristic calibration device is to study the harmonic measurement and protection characteristics of the electronic transformer under actual working conditions, to ensure the reliable operation of the power system, and to accelerate the construction of a unified strong smart grid in my country. the

Contents of the invention

The purpose of this utility model is to provide an electronic transformer harmonic characteristic calibration device. As a calibration measurement system, it establishes a high-power current voltage harmonic source, and outputs the fundamental wave signal and harmonic signal after synthesis, which can Simulate the actual operating conditions of the electronic transformer, and then conduct research on the harmonic characteristics of the actual operation of the electronic transformer through the harmonic error calibration system to fill in the gaps in this field. the

The technical scheme of the utility model is:

The electronic transformer harmonic influence test device includes: a high-power fundamental wave harmonic synthesis power supply 1, a harmonic standard current voltage transformer 5, a standard current voltage conversion device 7, and an electronic transformer harmonic calibrator 8;

The high-power fundamental wave and harmonic synthesis power supply 1 includes a fundamental wave power supply unit 2, a harmonic power supply unit 3, and a fundamental wave and harmonic synthesis output unit 4;

When calibrating the electronic current and voltage transformer 6 under test, the output signals of the fundamental wave power supply unit 2 and the harmonic power supply unit 3 inside the high-power fundamental wave harmonic synthesis power supply 1 are synthesized by the fundamental wave harmonic synthesis output unit 4 After passing through the current booster, the booster gets a large current and high voltage output;

Harmonic standard current voltage transformer 5 and the primary and fundamental wave harmonic synthesis output unit 4 of the electronic current voltage transformer 6 under test are connected: for the current transformer, it is connected in series, as shown in Figure 1; for the voltage transformer It is a parallel connection, as shown in Figure 2; the output signal of the harmonic standard current voltage transformer 5 is connected to the signal input terminal of the standard current voltage conversion device 7; the output of the standard current voltage conversion device 7 is connected to the harmonic calibration of the electronic transformer One signal input end of instrument 8; The output of tested electronic current voltage transformer 6 is connected to another signal input end of electronic transformer harmonic calibrator 8.

The high-power fundamental wave harmonic synthesis power supply 1 determines whether the output of the high-power fundamental wave harmonic synthesis power supply 1 is the fundamental wave or harmonic, or the synthesis of fundamental wave and harmonic through the selection of the superposition switch; The amplitude of the wave is adjusted by the output voltage adjustment module. the

The harmonic standard current transformer in the harmonic standard current voltage transformer 5 adopts a high-precision bipolar current transformer followed by a resistor, and the harmonic standard voltage transformer adopts bipolar voltage transformer cascading technology. the

Using the principle of direct comparison, the output data of the harmonic standard current (voltage) transformer 5 and the measured electronic current voltage transformer 6 are directly compared after signal processing; the ratio error is obtained by comparing the harmonic standard current voltage transformer 5 and The effective value of the fundamental wave component in the 6 frequency domain of the electronic current and voltage transformer under test is obtained. The phase difference is obtained by calculating FFT for spectrum analysis or interactive power spectrum analysis. the

The utility model provides an effective method for calibrating the harmonic characteristics of the electronic transformer, and its advantages are:

1) Establish a high-power current and voltage harmonic experimental platform. It can simulate the first harmonic large current or high voltage of the electronic transformer under actual working conditions;

2) The electronic transformer harmonic characteristic calibration test system has been developed, including the harmonic standard transformer and the electronic transformer harmonic calibration system.

Description of drawings

Fig. 1 is the functional block diagram of the utility model circuit (current transformers connected in series). the

Fig. 2 is a schematic block diagram of the circuit of the utility model (the voltage transformers are connected in parallel). the

Fig. 3 is the principle of the high-power current-voltage harmonic source of the utility model. the

Fig. 4 is a circuit diagram of the resistance connection of the harmonic current standard converter of the utility model. the

Fig. 5 is a block diagram of the harmonic calibration structure of the electronic transformer of the present invention. the

Fig. 6 is a flow chart of the harmonic calibration program of the electronic transformer of the present invention. the

Detailed ways

The following is a further description of the electronic transformer harmonic influence testing device of the utility model in conjunction with the accompanying drawings and embodiments. the

Marks in Figures 1 and 2: 1-high-power fundamental harmonic synthesis power supply, 2-fundamental wave power supply unit, 3-harmonic power supply unit, 4-fundamental wave harmonic synthesis output unit, 5-harmonic standard current ( Voltage) transformer, 6-electronic current (voltage) transformer under test, 7-standard current (voltage) conversion device, 8-electronic transformer harmonic calibrator. the

As shown in Figures 1 and 2, the utility model embodiment includes a high-power fundamental harmonic synthesis power supply 1, a harmonic standard current (voltage) transformer 5, a measured electronic current (voltage) transformer 6, a standard current ( Voltage) conversion device 7, electronic transformer harmonic calibrator 8. The high-power fundamental harmonic synthesis power supply 1 includes a fundamental wave power supply unit 2 , a harmonic power supply unit 3 and a fundamental harmonic synthesis output unit 4 . the

The schematic diagram of the high-power current-voltage harmonic synthesis power supply is shown in Figure 3. First, the crystal oscillator circuit generates a 50Hz signal all the way, and after passing through the D/A module, a 50Hz sinusoidal signal is generated and output to the power amplification link. The other channel generates various harmonic signals through frequency division technology. After phase setting, it outputs to the D/A module to generate various harmonic sine signals; the harmonic superposition switch selects whether to superimpose harmonics into the fundamental wave for power amplification. At the same time, the amplitude of the fundamental wave and each harmonic can be adjusted through the output voltage adjustment module; the fundamental harmonic synthesis signal output by the power amplification link is output after being filtered and isolated from the transformer. The current and voltage detection circuit detects the output current and voltage, and at the same time returns the detection signal to the power amplification link to achieve the purpose of current and voltage closed-loop control; the synthesized voltage signal output by the isolation transformer generates a large current (high Voltage). the

Harmonic standard transformer and electronic transformer harmonic calibration system. Among them, the harmonic standard current transformer adopts a high-precision double-stage current transformer followed by a resistor, and the resistor connection circuit is shown in Figure 4. The harmonic standard voltage transformer adopts double-stage voltage transformer cascading technology, and the experiment proves that the overall accuracy can reach 0.01%. the

The structure of the electronic transformer harmonic calibrator is shown in Figure 5. The standard channel data acquisition unit and the measured channel data acquisition unit use the NI5922 high-precision data acquisition card. NI 922 is a dual-channel variable resolution digitizer with The highest resolution and highest dynamic range currently on the market. The NI PCI-5922 can increase the resolution by reducing the sampling rate in the speed range of 24-bit 500kS/s to 16-bit 15MS/s. This superior flexibility and resolution comes from NI Flex IIADC technology, which uses a multi-bit delta-sigma enhanced converter and patented linearization technology. Combining PCI-5922 with software such as NI LabVIEW, its measurement performance can exceed that of traditional high-end instruments with similar functions. the

The digital acquisition channel is an Ethernet card with optical fiber or RJ45 interface. At the same time, it is equipped with a high-speed optical Ethernet converter. If the output of the combiner is optical fiber output, the signal will be converted to the RJ45 interface through the optical Ethernet converter, which is convenient. Connect to the calibrator and use it. the

In order to meet the needs of high-precision synchronous timing, the synchronous pulse can also be connected with an external GPS synchronous signal to track the GPS second pulse, and the synchronous precision is sub-microsecond level. At the same time, in order to meet different synchronous triggering requirements, optical input synchronization, electrical input synchronization, electrical output, and reverse function are set. The frequency of the sync pulse can also be set as required. the

The data processing and error display unit adopts the Labview graphical programming software, which is an innovative product of National Instruments - a development environment based on G language. It is collectively called "virtual instrument" with many acquisition and test boards of NI. The so-called virtual instrument means that on a general-purpose computer platform, users define and design instrument test functions according to their own needs. Its essence is to fully combine traditional instrument hardware with the latest computer software technology to realize and expand the functions of traditional instruments. Compared with traditional instruments, virtual instruments have obvious technical advantages in terms of intelligence, processing capacity, performance-price ratio, and operability. Developers can customize the software interface and functions according to customer requirements. the

The flow chart of the electronic transformer harmonic calibration program is shown in Figure 6. The principle of direct comparison is adopted, that is, the digital output data of the standard transformer and the measured transformer are directly compared after signal processing. The ratio error is obtained by comparing the effective value of the fundamental wave component in the frequency domain of the standard transformer and the measured transformer, and the phase difference is obtained by calculating FFT for spectrum analysis or cross-power spectrum analysis. the

During specific implementation, the high-power fundamental wave harmonic synthesis power supply 1 outputs fundamental wave and harmonic synthesis voltage signals, and the parameters of the fundamental wave and harmonics are controlled by the fundamental wave power supply unit 2 and the harmonic power supply unit 3 respectively; the high-power fundamental wave The output signal of the harmonic synthesis power supply forms a large current (high voltage) test circuit; the harmonic standard current (voltage) transformer 5 and the electronic current (voltage) transformer under test are simultaneously in the large current (high voltage) test circuit; The signal output by the standard current (voltage) transformer 5 passes through the standard current (voltage) conversion device 7 and then connected to the electronic transformer harmonic calibrator 8; the output signal of the measured electronic current (voltage) transformer is directly connected to The electronic transformer harmonic calibrator 8; the electronic transformer harmonic calibrator 8 collects and calculates the corresponding data of the two signals to obtain the harmonic error characteristics of the electronic transformer. the

Among them, the high-power fundamental wave and harmonic synthesis power supply 1 can adjust the amplitude, phase and order of the fundamental wave and harmonic as required. The fundamental wave and each harmonic can be adjusted independently, and multiple harmonics can be included at the same time, and the harmonic order can reach up to 11 times. It can simulate the harmonic current and voltage under the actual operating conditions of the electronic transformer, so as to calibrate its frequency characteristics. the

Claims (1)

1. electronic mutual inductor harmonic effects proving installation, it is characterized in that: said electronic mutual inductor harmonic effects proving installation comprises: high-power principal wave harmonic wave synthesizes power supply (1), harmonic standard current-voltage transformer (5), normalized current voltage conversion device (7), electronic mutual inductor harmonic wave tester (8);

High-power principal wave harmonic wave synthesizes power supply (1) and is made up of first-harmonic power supply unit (2), harmonic wave power supply unit (3), the synthetic output unit (4) of principal wave harmonic wave;

The output terminal of the synthetic output unit (4) of the elementary and principal wave harmonic wave of harmonic standard current-voltage transformer (5) and tested electronic current voltage transformer (VT) (6) is connected: for current transformer is to be connected in series, and is to be connected in parallel for voltage transformer (VT); The output signal of harmonic standard current-voltage transformer (5) is connected to the signal input part of normalized current voltage conversion device (7); The output of normalized current voltage conversion device (7) is connected to a signal input part of electronic mutual inductor harmonic wave tester (8); The output of tested electronic current voltage transformer (VT) (6) is connected to another signal input part of electronic mutual inductor harmonic wave tester (8).

Images