CN101251570A - Long wave front operation impulse voltage generator - Google Patents

Abstract

The long wave front operation impulse voltage generator is characterized in that: a charging resistor 1, a main capacitor 3, an ignition device 4, a wave tail resistor 9, a main capacitor 11, and a charging resistor 10 are connected in series as the primary unit of the impulse generator; the charging switch 2 is connected to Between the two stages, they are respectively connected to one end of the charging resistors of the two stages, and a charging switch is connected to each end of each stage; It is connected between the last stage wave tail resistor 9 and the main capacitor 3; the units of the shock generator have at least 12 stages. It can generate 1000-2500μs long wave front time operating impulse voltage, and its wave front time and amplitude can meet the needs of UHV transmission tests. When it is put into use, it is of great significance to study the air insulation characteristics under various waveforms generated by operating overvoltage. It can not only improve the transmission capacity of the line (reduce the wave impedance of the line), but also reduce the construction cost of the line.

Description

Long wave front operation impulse voltage generator

technical field

The invention relates to an operation impulse voltage generator, which can generate an operation impulse voltage with a wave front time of 250 μs-2500 μs to meet the needs of UHV tests, which is suitable for UHV transmission line air gap electrical tests and equipment external insulation tests, and can also be extended for use At 750kV, 500kV similar test.

Background technique

For long-distance and large-capacity transmission lines, the waveform of overvoltage generated during operation is related to line parameters, length, and system configuration. Especially for ultra-high voltage transmission lines with a million volts level, the wave front time of operating overvoltage may reach thousands of μs. At this time, if the external insulation test of the air gap is still only carried out with the operation shock waveform of the critical wave front time, the difference from the actual situation of the system will increase.

In order to ensure the reliability and economy of UHV transmission lines, the operating impulse voltage test hopes that the waveform of the test voltage is similar to the overvoltage waveform generated in the system. The long wave front time operating impulse voltage is important for the external insulation test of long-distance UHV transmission lines. It can be said that the test results of the long wave front time operation impulse voltage are the main basis for studying and selecting the air gap under the operation overvoltage of UHV overhead transmission lines. For UHV transmission lines, the air gap distance directly affects the cost of the line, reducing the gap distance, especially the phase-to-phase distance, can not only increase the transmission capacity of the line (reduce the line wave impedance), but also reduce the construction cost of the line, which requires The characteristics of air insulation under various waveforms generated by operating overvoltages have been extensively studied.

Existing impulse voltage generators can generate operating impulse voltages less than 1000μs with conventional methods, and cascaded transformers can generate operating impulse voltages with wave front times greater than 3000μs. It is difficult for these two methods to generate the operation impulse voltage of 2500μs.

Contents of the invention

In order to make up for the shortcomings of conventional impulse generators and cascaded transformers, the purpose of the present invention is to provide a long-wavefront operation impulse voltage generator, which uses the improved design of the impulse voltage generator to generate 1000-2500μs long-wavefront time operation impulse voltage. The previous time and amplitude can meet the needs of UHV transmission test. When it is put into use, it is of great significance to study the air insulation characteristics under various waveforms generated by operating overvoltage. It can not only improve the transmission capacity of the line (reduce the wave impedance of the line), but also reduce the construction cost of the line.

The technical solution adopted by the present invention to solve the technical problem is: long wave front operation impulse voltage generator, characterized in that: charging resistor 1, main capacitor 3, ignition device 4, wave tail resistor 9, main capacitor 11, charging resistor 10 connected in series As a first-level unit of the impact generator; the charging switch 2 is connected between the two stages, and is connected to one end of the charging resistors of the two stages respectively, and a charging switch is connected to each end of each stage; one end of the wave head resistance 5 is connected to the end of the current stage Between the wave tail resistor 9 and the main capacitor 11, the other end is connected between the latter stage wave tail resistor 9 and the main capacitor 3; the units of the shock generator have at least 12 levels.

The long-wavefront operation impulse voltage generator as described above is characterized in that: the unit level of the impulse generator is 25.

The present invention is characterized in that the charging resistors of each two stages are connected in parallel with each other, instead of being connected in series as in the traditional generator, and the connection between the stages is changed from charging resistors to charging switches. Using an improved bilateral charging circuit structure and introducing a charging switch, the energy leakage during discharge is reduced, and a high-efficiency 1000-2500μs long wave front time operation impulse voltage is generated.

Using an improved charging circuit can reduce the influence of charging resistance on charging unevenness, and improve charging speed and efficiency. The charging switch is closed when the generator is charging, which does not affect the charging, but also makes the charging voltage of each stage the same, and the voltage difference of each stage is almost zero. The charging switch itself does not need a high withstand voltage level, but only needs to be able to withstand a certain level of flow. . When discharging, the switch is turned off and bears the voltage of two capacitors on the first level. The main capacitor can only be discharged through the wave head resistance and wave tail resistance, which reduces the loss and improves the discharge efficiency, thereby generating high-efficiency long wave front time operation shock. .

According to the simulation calculation, the operation shock output efficiency of 2500μs wave front time is more than 70%. UHV requires long wave front operation shock operation peak voltage of more than 2200kV.

The beneficial effect of the invention is that it can generate long wave front time operation impulse voltage of 1000-2500μs, its wave front time and amplitude can meet the requirements of UHV transmission test, and the amplitude can reach more than 2500kV.

Description of drawings

Fig. 1 is a circuit schematic diagram of an operation surge voltage generator in the prior art.

Fig. 2 is a schematic circuit diagram of the present invention.

Detailed ways

Explanation of the labels in Figure 1: X1. Charging resistor, X2. Main capacitor, X3. Wave tail resistor, X4. Ignition device, X5. Impulse high voltage output terminal, X6. Test transformer, X7. Silicon stack, X8. Charging resistor, X9. Charging resistor, X10. Wave head resistor, X11. Main capacitor.

Explanation of the labels in Figure 2: 1. Charging resistor, 2. Charging switch, 3. Main capacitor, 4. Ignition device, 5. Wave head resistor, 6. Impulse high voltage output terminal, 7. Test transformer, 8. Silicon stack, 9. Tail resistor, 10. Charging resistor, 11. Main capacitor.

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Embodiment of the present invention is shown in Fig. 2, charging resistor 1, main capacitor 3, ignition device 4, wave tail resistor 9, main capacitor 11, charging resistor 10 are connected in series as one stage of impact generator; charging switch 2 is connected in two stages Between them, they are respectively connected to one end of the charging resistors of the two stages, and each end of each stage is connected with a charging switch; Between the primary wave tail resistor 9 and the main capacitor 3 . The shock generator has 25 stages, each stage has a voltage of 300kV, and the maximum charging voltage of the two main capacitors is ±150kV respectively. The test transformer 7 and the silicon stack 8 are used as the power supply of the shock generator, and a full-wave rectification circuit is used, which is connected before the first stage , the two silicon stacks are respectively connected to the two charging resistors in the first stage.

The unit of impact generator of the present invention has 12 grades at least, and the number of stages of its unit grade is relevant with following factor:

1) The wave front time of the operation shock has an impact on the generator efficiency: the generation efficiency of the standard operation shock wave front time of 250μs is 70%-80%, and the operation shock output efficiency of the 2500μs wave front time is 70%;

2) Requirements for the test product: UHV test requires that the minimum impulse peak voltage of the impulse output operation should be above 1700kV, and the peak value must reach 2500kV to fully meet the test requirements.

The units of the shock generator therefore have at least 12 stages.

In this embodiment, the generator consists of 25 stages, each stage has a maximum charging voltage of 300kV, and the total maximum charging voltage is 7500kV. The conductive material of the charging switch has a small resistance when it is turned on, and the insulation can withstand a voltage of more than 300kV when it is turned off. The insulating material transmits power between the stages to open or close the switch.

Claims (2)

1, long wave front operation impulse voltage generator is characterized in that: charging resistor (1), main capacitance (3), portfire (4), wave rear resistance (9), main capacitance (11), charging resistor (10) are connected as the primary unit of surge generator; Charge switch (2) is connected between the two-stage, links to each other with charging resistor one end of two-stage respectively, and every grade of two ends are connected to a charge switch; Wave front resistance (5) one terminates between the wave rear resistance (9) and main capacitance (11) at the corresponding levels, and the other end is connected between back one-level wave rear resistance (9) and the main capacitance (3); The unit of surge generator has 12 grades at least.

2, long wave front operation impulse voltage generator as claimed in claim 1 is characterized in that: the cell level of surge generator is 25 grades.

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