CN-224218286-U - Ultralow frequency sine high-voltage generator

CN224218286UCN 224218286 UCN224218286 UCN 224218286UCN-224218286-U

Abstract

The utility model provides an ultralow frequency sine high-voltage generator, which comprises a flyback switching power supply circuit, an ultralow frequency signal generator and a cascading linear amplifying circuit, wherein the flyback switching power supply circuit comprises a driving circuit, a switching device and a reaction type isolation transformer, the driving circuit is connected with the switching device, the switching device is connected with the reaction type isolation transformer, the driving circuit drives the switching device to regularly open and close so as to form square wave signals to be output to the rectifying side of the reaction type isolation transformer, the reaction type isolation transformer is also connected with the cascading linear amplifying circuit to supply power for the cascading linear amplifying circuit, and the electric isolation and cascading linear amplification of the sinusoidal signals can be realized by applying the technical scheme, so that the foundation is laid for developing the research of the ultralow frequency dielectric loss device of a high-voltage cable.

Inventors

ZHANG JUNFENG
HUANG YOUCONG
ZHENG ZHONGNAN
LIN ZIQI
ZHANG YING
FANG CHAOYING
WANG XIAOJIE
CHEN SHAOKANG
Cheng Yunchu

Assignees

国网福建省电力有限公司
国网福建省电力有限公司电力科学研究院

Dates

Publication Date: 20260508
Application Date: 20250511

Claims (6)

1. The ultralow frequency sinusoidal high-voltage generator is characterized by comprising a flyback switching power supply circuit, an ultralow frequency signal generator and a cascade linear amplifying circuit; The flyback switching power supply circuit comprises a driving circuit, a switching device and a flyback isolation transformer, wherein the driving circuit is connected with the switching device, the switching device is connected with the flyback isolation transformer, and the driving circuit drives the switching device to be regularly disconnected so as to form square wave signals to be output to the rectifying side of the flyback isolation transformer; The ultralow frequency signal generator comprises a low-voltage side main control chip, an optical fiber transmitter, a high-voltage side main control chip and an optical fiber receiver, wherein the low-voltage side main control chip and the high-voltage side main control chip are used for transmitting signals through optical fibers, the low-voltage side main control chip is connected with the optical fiber transmitter, the optical fiber transmitter is connected with the optical fiber receiver through an optical fiber channel, and the optical fiber receiver is connected with the high-voltage side main control chip; The cascade linear amplification circuit comprises six operational amplifiers, amplifies signals received by the high-voltage side main control chip and outputs 0-50kV high voltage.
2. The ultralow frequency sinusoidal high voltage generator according to claim 1, wherein the primary winding of the impact isolation transformer is provided with one group of enameled wires with 8-15 turns.
3. The ultralow frequency sinusoidal high voltage generator according to claim 1, wherein four groups of secondary windings of the impact isolation transformer are provided, each group of secondary windings is provided with 3 units, and 3-6 turns of enameled wires and 8-15 turns of enameled wires are respectively provided.
4. The ultralow frequency sinusoidal high voltage generator according to claim 1, wherein the impact isolation transformer is connected with an RCD peak absorption circuit, the RCD peak absorption circuit comprises a transient suppression diode, a resistor, a capacitor and a diode, the transient suppression diode, the resistor and the capacitor are connected in parallel, and the cathode of the diode is connected with one end of the resistor.
5. The ultralow frequency sinusoidal high-voltage generator according to claim 1, wherein the low-voltage side main control chip and the high-voltage side main control chip are both STM32F103VET6 chips.
6. The ultra-low frequency sinusoidal high voltage generator according to claim 1, wherein said operational amplifiers each employ OPA454 operational amplifiers.

Description

Ultralow frequency sine high-voltage generator Technical Field The utility model relates to the technical field of high-voltage electrical tests, in particular to an ultralow-frequency sine high-voltage generator. Background The high-voltage cable ultralow-frequency dielectric loss detection technology is a nondestructive testing method for evaluating the insulation performance of a cable, and has the advantages of low applied voltage, convenient operation, strong anti-interference capability, accurate information acquisition, no damage to insulation materials and the like as a novel nondestructive diagnosis technology. The energy loss of the cable insulation material under an alternating electric field due to electric conduction and polarization is called dielectric loss, and is an important index for measuring the insulation performance. In engineering, the characteristics of the XLPE cable such as integral insulation thermal aging, moisture and water tree degradation are often evaluated by adopting dielectric loss tangent (tan delta) under ultralow frequency 0.1Hz sinusoidal voltage excitation, and the insulation performance is poorer as the tan delta value is larger. However, because the insulation margin of the high-voltage cable is smaller, the application of the ultra-high and ultra-low frequency voltage causes the risk of space charge injection accumulation, and the research and development of the testing device and the basis for insulation state judgment are lacking at present, the technology is not yet applied to the high-voltage cable line of 110 kilovolts or more in China, and technical indexes of a plurality of brands of products such as B2, megger, baur and the like are focused on the medium-low voltage cable, so that the application case of the high-voltage cable is deficient. With the increase of urban power supply and offshore wind power capacity, the use amount of high-voltage cables is increased rapidly, and the high-voltage cables become large arteries of the power grid. Research on the ultra-low frequency dielectric loss measurement method and device of the high-voltage cable is carried out, the aging condition of the high-voltage cable is evaluated, the aging state of the XLPE cable is accurately obtained, and the method and device are significant for clean energy transmission and improvement of power supply reliability of a power system. The device for detecting the ultralow frequency dielectric loss of the high-voltage cable in the prior art is also lack of a device capable of providing stable power supply and reliable ultralow frequency signal transmission for the dielectric loss measuring device. Disclosure of utility model In view of the above, the utility model aims to provide the ultralow frequency sinusoidal high-voltage generator which can realize electrical isolation and cascading linear amplification of ultralow frequency sinusoidal signals, ensure safe, stable and reliable output of linear sinusoidal high-voltage ultralow frequency signals and lay a foundation for developing research on ultralow frequency dielectric loss devices of high-voltage cables. In order to achieve the aim, the utility model adopts the following technical scheme that the ultralow frequency sine high-voltage generator comprises a flyback switching power supply circuit, an ultralow frequency signal generator and a cascade linear amplifying circuit; The flyback switching power supply comprises a driving circuit, a switching device and a flyback isolation transformer, wherein the driving circuit is connected with the switching device, the switching device is connected with the flyback isolation transformer, and the driving circuit drives the switching device to regularly turn on and off so as to form square wave signals to be output to the rectifying side of the flyback isolation transformer; The ultralow frequency signal generator comprises a low-voltage side main control chip, an optical fiber transmitter, a high-voltage side main control chip and an optical fiber receiver, wherein the low-voltage side main control chip is connected with the optical fiber transmitter, the optical fiber transmitter is connected with the optical fiber receiver through an optical fiber channel, and the optical fiber receiver is connected with the high-voltage side main control chip; The cascade linear amplification circuit comprises six operational amplifiers, amplifies signals received by the high-voltage side main control chip and outputs 0-50kV high voltage. In a preferred embodiment, the primary winding of the impact isolation transformer is provided with one group of enameled wires with 8-15 turns. In a preferred embodiment, four groups of secondary windings of the impact isolation transformer are arranged, each group of secondary windings is provided with 3 units, and 3-6 turns of enameled wires and 8-15 turns of enameled wires are respectively arranged. In a preferred embodiment, the impact isolation transformer is