CN215180510U - Online life monitoring and protecting device of thin film capacitor - Google Patents
Online life monitoring and protecting device of thin film capacitor Download PDFInfo
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- CN215180510U CN215180510U CN202120923536.6U CN202120923536U CN215180510U CN 215180510 U CN215180510 U CN 215180510U CN 202120923536 U CN202120923536 U CN 202120923536U CN 215180510 U CN215180510 U CN 215180510U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
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Abstract
The utility model discloses an online life monitoring and protecting device of a film capacitor, which comprises a sampling device and a module control device which are electrically connected, wherein the sampling device is used for collecting ripple current and ripple voltage of the film capacitor in real time and transmitting data to the module control device; the module control device is used for receiving the ripple current and the ripple voltage transmitted by the sampling device, prestoring a preset value of the capacitance of the film capacitor, and judging whether the capacitance value of the film capacitor is normal. Compared with a capacitor life model, the device for realizing the real-time prediction of the capacitor life by using the capacitance value is simple and effective.
Description
Technical Field
The utility model belongs to the technical field of flexible direct current transmission, concretely relates to film capacitor's online life-span monitoring and protection device.
Background
The flexible direct current converter valve is core equipment for flexible direct current transmission, has the functions of direct current-alternating current conversion and alternating current-direct current conversion, and is formed by cascading a plurality of half-bridge or full-bridge power sub-modules. The film capacitor is used as a key device for the direct current supporting function of the submodule, and the safety and the reliability of the film capacitor directly influence the operation of the converter valve equipment.
The film capacitor for flexible direct current transmission consists of a plurality of capacitor core strings connected in parallel and is sealed by metal materials such as stainless steel or aluminum and the like to form a capacitor with large capacity and high power; when the film capacitor has the problems of abnormal self-healing, overvoltage, overcurrent and the like, the internal temperature of the capacitor is rapidly increased, so that the internal air pressure of the capacitor is increased to cause safety accidents of explosion, combustion and the like of the capacitor. In order to ensure the safety of the film capacitor, a capacitor manufacturer often installs a pressure relief valve or a pressure switch and other devices in the capacitor for detecting the internal air pressure of the capacitor, and when the internal air pressure of the capacitor exceeds a threshold value, the two devices act to relieve the internal pressure of the capacitor. The safety device is a passive protection mode when the capacitor has a fault phenomenon, the capacitor can not be early warned in advance, and when the protection device can not effectively act, serious problems such as explosion and over-temperature ignition of the device can be caused.
Disclosure of Invention
The utility model provides a film capacitor's online life-span monitoring and protection device increases the initiative early warning protect function of condenser life-span monitoring to improve above-mentioned problem.
In order to achieve the above object, the present invention provides an online life monitoring and protecting device for a thin film capacitor, which comprises a sampling device and a module control device electrically connected to each other, wherein the sampling device is used for collecting ripple current and ripple voltage of the thin film capacitor in real time and transmitting data to the module control device; the module control device is used for receiving the ripple current and the ripple voltage transmitted by the sampling device, prestoring a preset value of the capacitance of the film capacitor, and judging whether the capacitance value of the film capacitor is normal.
Further, the output end of the module control device is connected with a module bypass device, and the module bypass device is used for receiving and executing a bypass instruction sent by the module control device.
Further, the module bypass device is a vacuum contactor, a high-power relay, a static switch or a controllable semiconductor device.
Furthermore, an alarm module is arranged in the module control device, and an alarm signal is sent out when the service life of the capacitor is abnormal.
Further, the sampling device comprises a voltage sampling module and a current sampling module.
Further, the current sampling module is a hall current sensor.
Further, the voltage sampling module is a voltage sampling circuit.
Furthermore, the module bypass device is connected with a bypass switch of the submodule where the film capacitor is located.
Furthermore, the module control device comprises a micro control unit, and the control unit is a digital controller.
Compared with the prior art, the utility model discloses following profitable technological effect has at least:
the utility model discloses a detect the important characterization parameter-capacitance value in thin film capacitor life-span and realize the device of capacitor life-span real-time prediction, compare when the condenser breaks down in the condenser, the condenser life-span model of just acting, the voltage and the current signal of condenser are gathered in real time to this device, the capacitance value of thin film capacitor is calculated according to the voltage and the current signal who gather, judge whether the condenser is suitable for normal work according to thin film capacitor's capacitance value, its reliability is higher, can effectively reduce to cause the device to explode and split, phenomenons such as excessive temperature catches fire. The utility model discloses can realize that initiative early warning condenser life-span is due and carry out real-time supervision in order to reach safety protection's purpose, compare in the passive increase excess pressure valve of condenser or pressure switch device safe more effective.
In addition, this application judges the life-span of condenser according to film capacitor's capacitance value, only need to gather voltage and electric current can, need not be with the help of the temperature of condenser, need not install temperature sensor on the condenser, simplified monitoring devices, also avoided the inaccurate and erroneous judgement that produces of temperature sensor measuring data.
Drawings
FIG. 1 is a block diagram of a topology of a modular converter valve and its sub-modules;
FIG. 2 is a schematic diagram of the present invention;
fig. 3 is a flowchart of a method for monitoring and protecting the lifetime of a capacitor provided by the utility model;
fig. 4 is a schematic diagram showing ripple voltage and ripple current of the film capacitor.
In the drawings: the device comprises a 1-converter valve, a 2-half bridge module, a 3-full bridge module, a 101-module bypass device, a 102-module control device and a 103-ripple voltage and ripple current acquisition unit.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, embodiments accompanied with figures are described in detail below.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are used merely for convenience of description and for simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified. In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Referring to fig. 1, an on-line life monitoring and protecting device for a thin film capacitor is applied to a flexible direct current converter valve and a sub-module topology structure thereof as shown in fig. 1. The converter valve 1 adopts a modular design and is formed by connecting a plurality of sub-modules in series; typical topologies of sub-modules are half-bridge module 2 and full-bridge module 3, the half-bridge module 2 and the full-bridge module 3 containing thin-film dry capacitors.
A schematic diagram of a device for monitoring and protecting the life of a thin film capacitor is shown in fig. 2, and the device for monitoring and protecting the life of a thin film capacitor comprises a module control device 102, a module bypass device 101, a ripple voltage and ripple current acquisition unit 103, and a converter valve sub-module.
The ripple current and ripple voltage acquisition units are connected with the thin film capacitors in the converter valve sub-modules, connected with the module control device and receive sampling commands of the module control device; the module control device is connected with a module bypass device, which is connected with a module port bypass switch S.
The ripple voltage and ripple current acquisition units are connected to two ends of the thin film capacitor and are in real-time communication with the module control device, the module control device controls the module control device to sample voltage and current, acquire a first ripple voltage U1 of the capacitor in a charging state, acquire a second ripple voltage U2 of the capacitor after a preset time delta t interval, and collect and acquire a maximum ripple current value i in the preset time;
and the module control device is used for controlling the working state of the converter valve sub-module, detecting and controlling the operation state of each device in the module, and comprises the steps of controlling the on-off of a fully-controlled power device, receiving and processing data transmitted by a capacitor ripple voltage and ripple current acquisition unit, prestoring a preset value of a thin film capacitor, detecting the operation parameter of the capacitor and controlling the action of the module bypass device. The module control device receives data of the ripple voltage and ripple current acquisition units, acquires n groups of data within a period T in order to reduce errors caused by single acquisition of data, wherein n is more than or equal to 2, and the data is acquired according to a formula
Calculating a capacitance value Cj of the film capacitor, wherein the capacitance value Cj is U2j-U1j, U2j represents the second ripple voltage collected at the j-th time, and U1j represents the first ripple voltage collected at the j-th time; the capacitance values C1 and C2 … … Cn of the film capacitor are calculated, and the average value of the capacitance values of the film capacitor is calculated
Average value of capacitance value through film capacitor
Characterizing capacitor life.
Calculating the average value of the capacitance values of the film capacitors
Then comparing with the preset value of the capacitance of the film capacitor, and when the average value of the capacitance of the film capacitor
When the current is smaller than the preset value of the capacitance of the film capacitor, the service life of the film capacitor is early warned to be insufficient; otherwise, judging that the service life of the capacitor is normal; the capacitance value requirement of the film capacitor is as follows: the actual capacitance value is reduced by no more than 10% compared to the factory capacitance value of the capacitor.
The module bypass device is used for receiving a command of the module control device and controlling a module port bypass switch, and is connected with the module control device, when the module control device calculates that the service life of the capacitor is insufficient according to collected data, the module control device uploads alarm information to the converter valve control system, the alarm capacitor is insufficient in service life and sends a request bypass command to the module bypass device through the converter valve control system, and after the bypass command is sent, the control module bypass device controls the bypass device to protect a sub-module where the film capacitor is located and quits a working state, so that the equipment is prevented from suffering major losses such as fire, explosion and the like.
The module bypass device should have a bypass function, including but not limited to a vacuum contactor, a high power relay, a static switch (STS), a controllable semiconductor device applied to bypass function, and the like.
The sampling device comprises a voltage sampling module and a current sampling module, wherein the current sampling module is a circuit or a unit with a current sampling function, such as a current divider, a sampling circuit, a Hall current sensor, a current transformer or a current transmitter, and preferably the Hall current sensor. The voltage sampling module is a circuit or unit with a voltage sampling function, such as a current divider and a sampling circuit, a voltage transformer, a voltage transmitter and the like, and preferably selects the current divider and the sampling circuit.
The module control device comprises a Micro Controller Unit (MCU), typically a logic chip (or Unit), a digital controller (ARM, DSP, CPLD/FPGA, etc.), preferably a digital Controller (CPLD). The MCU is used for calculating the capacitance value of the film capacitor according to the sampling signal collected by the sampling device, thereby being equivalent to the service life of the capacitor conveniently. If the capacitance exceeds the set threshold, the MCU will alert the valvetrain system and request bypass, if the bypass function is requested to be enabled, the capacitor will be bypassed.
Fig. 3 is a flow chart showing the operation of the on-line life monitoring and protecting device for the thin film capacitor, in which the voltage and current of the thin film capacitor are sampled by the voltage and ripple current collecting unit at a predetermined sampling time interval within a period T. Ripple voltage and ripple current data of the thin film capacitors, for example, for a converter valve with a voltage level of ± 800KV, are shown in fig. 4 for the capacitors on a single sub-module. The module control device controls and collects ripple voltage and ripple current values of a plurality of capacitor charging stages according to a formula
And calculating the capacitance value of the film capacitor, wherein the delta U is U2-U1. And when the capacitance value of the film capacitor does not meet the requirement, the module control device controls the module bypass device to perform bypass protection on the module. Compared with a capacitor applied in the current engineering and provided with a pressure relief valve or a pressure switch and other passive protection devices, the device adopted in the present invention adopts online active prevention, and the safety and the reliability are higher.
The above contents are only for explaining the technical idea of the present invention, and the protection scope of the present invention cannot be limited thereby, and any modification made on the basis of the technical solution according to the technical idea of the present invention all fall within the protection scope of the claims of the present invention.
Claims (9)
1. The device is characterized by comprising a sampling device and a module control device which are electrically connected, wherein the sampling device is used for collecting ripple current and ripple voltage of the thin film capacitor in real time and transmitting data to the module control device;
the module control device is used for receiving the ripple current and the ripple voltage transmitted by the sampling device, prestoring a preset value of the capacitance of the film capacitor, and judging whether the capacitance value of the film capacitor is normal.
2. The on-line life monitoring and protecting device of a film capacitor as claimed in claim 1, wherein the output terminal of the module control device is connected to a module bypass device, and the module bypass device is used for receiving and executing a bypass command sent by the module control device.
3. The on-line life monitoring and protecting device of film capacitor as claimed in claim 2, wherein said module bypass device is a vacuum contactor, a high power relay, a static switch or a controllable semiconductor device.
4. The on-line life monitoring and protecting device of thin film capacitor as claimed in claim 1, wherein said module control device is provided with an alarm module for sending out an alarm signal when the life of the capacitor is abnormal.
5. The on-line life monitoring and protecting device of thin film capacitor as claimed in claim 1, wherein said sampling device comprises a voltage sampling module and a current sampling module.
6. The on-line life monitoring and protecting device of thin film capacitor as claimed in claim 5, wherein said current sampling module is a Hall current sensor.
7. The on-line life monitoring and protecting device of thin film capacitor as claimed in claim 5, wherein said voltage sampling module is a voltage sampling circuit.
8. The on-line life monitoring and protecting device of film capacitor as claimed in claim 2, wherein said module bypass device is connected to the bypass switch of the sub-module in which the film capacitor is located.
9. The on-line life monitoring and protecting device of thin film capacitor as claimed in claim 1, wherein said module control device comprises a micro control unit, said control unit is a digital controller.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202120923536.6U CN215180510U (en) | 2021-04-29 | 2021-04-29 | Online life monitoring and protecting device of thin film capacitor |
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| CN202120923536.6U CN215180510U (en) | 2021-04-29 | 2021-04-29 | Online life monitoring and protecting device of thin film capacitor |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115201614A (en) * | 2022-09-15 | 2022-10-18 | 国网经济技术研究院有限公司 | Dry capacitor test method for flexible direct current converter valve |
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2021
- 2021-04-29 CN CN202120923536.6U patent/CN215180510U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115201614A (en) * | 2022-09-15 | 2022-10-18 | 国网经济技术研究院有限公司 | Dry capacitor test method for flexible direct current converter valve |
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