阅读说明：本技术 一种真空度在线监测装置及方法 (Vacuum degree on-line monitoring device and method ) 是由 翟小社 王建华 耿英三 于 2021-08-31 设计创作，主要内容包括：本发明公开了一种真空度在线监测装置及方法,高压电源的高压端与真空灭弧室中的上触头及高压电容的一端相连接,高压电源的接地端与真空灭弧室中下触头及接地电容的一端相连接,接地电容的另一端及高压电容的另一端与锁相放大器的电压参考通道相连接,锁相放大器的输出端与信号采集模块相连接,高压电源的接地端与真空灭弧室下触头之间的线路上设置有电流互感器,其中,电流互感器的输出端与锁相放大器的测量输入通道相连接,磁控放电设备与真空灭弧室相连接,该装置及方法能够适用于气体压力小于0.1Pa时的真空度测量。(The invention discloses a vacuum degree on-line monitoring device and a method, wherein a high-voltage end of a high-voltage power supply is connected with an upper contact and one end of a high-voltage capacitor in a vacuum arc extinguish chamber, a grounding end of the high-voltage power supply is connected with a lower contact and one end of a grounding capacitor in the vacuum arc extinguish chamber, the other end of the grounding capacitor and the other end of the high-voltage capacitor are connected with a voltage reference channel of a phase-locked amplifier, an output end of the phase-locked amplifier is connected with a signal acquisition module, and a current transformer is arranged on a line between the grounding end of the high-voltage power supply and the lower contact of the vacuum arc extinguish chamber, wherein the output end of the current transformer is connected with a measurement input channel of the phase-locked amplifier, a magnetic control discharge device is connected with the vacuum arc extinguish chamber, and the device and the method can be suitable for measuring the vacuum degree when the gas pressure is less than 0.1 Pa.)

1. The vacuum degree on-line monitoring device is characterized by comprising a high-voltage power supply (1), a vacuum arc-extinguishing chamber (2), a magnetic control discharge device (3), a current transformer (4), a signal acquisition module (7), a phase-locked amplifier (8), a high-voltage capacitor (C1) and a grounding capacitor (C2);

the high-voltage end of a high-voltage power supply (1) is connected with an upper contact in a vacuum arc extinguish chamber (2) and one end of a high-voltage capacitor (C1), the grounding end of the high-voltage power supply (1) is connected with a lower contact of the vacuum arc extinguish chamber (2) and one end of a grounding capacitor (C2), the other end of the grounding capacitor (C2) and the other end of the high-voltage capacitor (C1) are connected with a voltage reference channel (4) of a phase-locked amplifier (8), the output end of the phase-locked amplifier (8) is connected with a signal acquisition module (7), a current transformer (4) is arranged on a line between the grounding end of the high-voltage power supply (1) and the lower contact of the vacuum arc extinguish chamber (2), the output end of the current transformer (4) is connected with a measurement input channel (6) of the phase-locked amplifier (8), and a magnetic control discharge device is connected with the vacuum arc extinguish chamber (2).

2. The vacuum degree on-line monitoring device according to claim 1, characterized in that the current transformer (4) is a straight-through current transformer.

3. An online vacuum degree monitoring method is characterized in that the online vacuum degree monitoring device based on claim 1 comprises the following steps:

the method comprises the steps of starting a high-voltage power supply (1) to add high voltage to an upper contact and a lower contact, dividing the voltage through a high-voltage capacitor (C1) and a grounding capacitor (C2) to obtain a voltage signal, inputting the voltage signal into a reference channel (4) of a phase-locked amplifier (8), inputting a current signal measured by a current transformer (4) into a measurement input channel (6) of the phase-locked amplifier (8), recording a direct-current voltage signal which is output by the phase-locked amplifier (8), is in the same phase as the reference voltage signal and is in proportion to field emission current through a signal acquisition module (7), establishing a corresponding relation between the direct-current voltage signal acquired by the signal acquisition module (7) and the vacuum degree of a vacuum arc-extinguishing chamber (2), and acquiring the vacuum degree of the vacuum arc-extinguishing chamber (2) according to the direct-current voltage signal acquired by the signal acquisition module (7) during monitoring.

4. The online vacuum degree monitoring method according to claim 3, further comprising: a preset distance is kept between an upper contact and a lower contact in the vacuum arc-extinguishing chamber (2), and the vacuum degree of the vacuum arc-extinguishing chamber (2) is measured and calibrated by using a magnetic control discharge device (3) through a magnetic control discharge method.

Technical Field

The invention belongs to the technical field of vacuum insulation and vacuum breaking, and relates to a vacuum degree on-line monitoring device and method.

Background

The maintenance of the necessary vacuum degree is a basic condition for ensuring the insulation characteristic and the arc extinguishing capability of the vacuum arc extinguishing chamber, and the vacuum degree detection of the vacuum arc extinguishing chamber of the current vacuum circuit breaker is divided into an off-line detection mode and an on-line detection mode. The offline detection technology is mature, but cannot meet the requirement of real-time monitoring. At present, no mature technology exists for an on-line monitoring method for the vacuum degree of the arc extinguishing chamber, and the research direction mainly comprises the following aspects.

The literature [ Gentsch D, fungal T.Measurements by Reactive Gas Analysis (RGA) inside Vacuum Interrupters/devices [ C ]. discharge and Electrical Insulation in Vacuum, International Symposium on IEEE,2008:169-172 ] uses a spectral absorption method to qualitatively analyze the relationship between the Gas content and the spectral parameters in the Vacuum arc-extinguishing chamber, and provides a concept for Vacuum degree detection of the arc-extinguishing chamber.

A method for evaluating the vacuum degree of a vacuum arc extinguish chamber based on X-ray amount change [ J ] high-voltage electric appliance 2008,44(04):315 puff 318 ] and a method for evaluating the vacuum degree of the vacuum arc extinguish chamber by using an X-ray method [ J ] high-voltage electric appliance 2015,51(01):92-97 ] are researched, and the possibility of evaluating the vacuum degree of the vacuum arc extinguish chamber by using X-ray absorption dose rate as a parameter is discussed.

A coupled capacitance method, a photoelectric conversion method and an electric field probe method are respectively proposed in the literature [ segmentandrosteron, Zhaozi jade, Zhouyan, vacuum arc-extinguishing chamber vacuum degree on-line detection [ J ]. high-voltage electric appliance, 2000,36(04):30-32 ], the literature [ li \36191, Li Weiguo, Li longu, etc. ] in the research on the influence of the novel coupled capacitance type electric field sensor on the electric field distribution of the arc-extinguishing chamber [ J ]. vacuum science and technology report, 2014,34(04):352 Bu 357, the literature [ Zhaozi jade, Li Mega, Chen fog, etc. ] in the literature [ J ]. high-voltage technology, 2003,29(10):29-31.] and the literature [ Chenhang long, rock, in-accumulated rock ], in-line monitoring [ J ]. vacuum arc-extinguishing chamber 2 vacuum degree on-line based on a proportional differential probe [ J ]. high-voltage electric appliance, 2009,45(06):124 Bu 127 ], the three methods all achieve the aim of indirectly measuring the vacuum degree of the arc extinguish chamber by measuring the potential of the shield cover of the arc extinguish chamber.

The method is characterized by comprising the following steps of (1) researching a vacuum degree online monitoring method of a vacuum circuit breaker based on penning discharge [ J ]. vacuum science and technology report 2017,37(2):225 plus 230 ], and by adding an excitation coil, generating an axial magnetic field in an arc extinguishing chamber to promote field emission electrons to generate penning discharge, so that the relation between the potential and the vacuum degree of a shielding cover of the arc extinguishing chamber is researched.

In summary, the resolution of the existing online measurement method for vacuum degree is limited by the measurement principle, most of the existing online measurement methods can only be used for vacuum degree measurement when the gas pressure is greater than 0.1Pa, and the novel optical measurement principle can only be used for qualitative analysis as a principle at present and is only suitable for a glass-shell type arc extinguishing chamber; similar to penning discharge measurement method of magnetron discharge method, the exciting coil is required to be added at the periphery of the arc extinguish chamber, and the introduction of the exciting coil and the power supply system thereof will undoubtedly cause certain influence on the original insulation structure design of the arc extinguish chamber and the distribution of electric field and magnetic field.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a vacuum degree on-line monitoring device and method, which can be suitable for vacuum degree measurement when the gas pressure is less than 0.1 Pa.

In order to achieve the aim, the vacuum degree on-line monitoring device comprises a high-voltage power supply, a vacuum arc-extinguishing chamber, a magnetic control discharge device, a current transformer, a signal acquisition module, a phase-locked amplifier, a high-voltage capacitor and a grounding capacitor;

the high-voltage end of a high-voltage power supply is connected with an upper contact and one end of a high-voltage capacitor in the vacuum arc extinguish chamber, the grounding end of the high-voltage power supply is connected with a lower contact and one end of a grounding capacitor in the vacuum arc extinguish chamber, the other end of the grounding capacitor and the other end of the high-voltage capacitor are connected with a voltage reference channel of a phase-locked amplifier, the output end of the phase-locked amplifier is connected with a signal acquisition module, a current transformer is arranged on a circuit between the grounding end of the high-voltage power supply and the lower contact of the vacuum arc extinguish chamber, the output end of the current transformer is connected with a measurement input channel of the phase-locked amplifier, and a magnetic control discharge device is connected with the vacuum arc extinguish chamber.

The current transformer is a straight-through current transformer.

The vacuum degree on-line monitoring method comprises the following steps:

starting a high-voltage power supply to add high voltage to an upper contact and a lower contact, inputting in-phase voltage signals obtained by voltage division of a high-voltage capacitor and a grounding capacitor into a voltage reference channel of a phase-locked amplifier, inputting current signals measured by a current transformer into a measurement input channel of the phase-locked amplifier, recording direct-current voltage signals which are output by the phase-locked amplifier, are in the same phase as high-voltage signals between the contacts and are in proportion to field emission current through a signal acquisition module, establishing a corresponding relation between the direct-current voltage signals acquired by the signal acquisition module and the vacuum degree of a vacuum arc extinguish chamber, and acquiring the vacuum degree of the vacuum arc extinguish chamber according to the direct-current voltage signals acquired by the signal acquisition module during monitoring.

Further comprising: and keeping a preset distance between an upper contact and a lower contact of the vacuum arc-extinguishing chamber, and measuring and calibrating the vacuum degree of the vacuum arc-extinguishing chamber by using a magnetic control discharge device through a magnetic control discharge method.

The invention has the following beneficial effects:

the invention relates to a vacuum degree on-line monitoring device and a method, which adopt a phase-locked amplification detection method to stably detect useful signals from noise voltage far greater than a signal to be detected, specifically, a micro-current signal is used as the signal to be detected of a phase-locked amplifier, voltage signals at two ends of a vacuum arc-extinguishing chamber are used as reference signals, and the micro-current signal and the voltage signals are respectively input into a measurement input channel and a voltage reference channel of the phase-locked amplifier, so that a direct current voltage signal which is proportional to the amplitude of the input signal and has the same frequency as the reference voltage is obtained by an output channel of the phase-locked amplifier, and the vacuum degree of the vacuum arc-extinguishing chamber is measured by the direct current voltage signal, so that the vacuum degree measurement when the gas pressure is less than 0.1Pa is realized.

Drawings

FIG. 1 is a schematic structural diagram of the present invention.

Wherein, 1 is a high voltage power supply, 2 is a vacuum arc-extinguishing chamber, 3 is a magnetic control discharge device, 4 is a current transformer, 5 is a voltage reference channel, 6 is a measurement input channel, 7 is a signal acquisition module, 8 is a phase-locked amplifier, C1 is a high voltage capacitor, and C2 is a grounding capacitor.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments, and are not intended to limit the scope of the present disclosure. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present disclosure. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

There is shown in the drawings a schematic block diagram of a disclosed embodiment in accordance with the invention. The figures are not drawn to scale, wherein certain details are exaggerated and possibly omitted for clarity of presentation. The shapes of various regions, layers and their relative sizes and positional relationships shown in the drawings are merely exemplary, and deviations may occur in practice due to manufacturing tolerances or technical limitations, and a person skilled in the art may additionally design regions/layers having different shapes, sizes, relative positions, according to actual needs.

Referring to fig. 1, the vacuum degree on-line monitoring device of the present invention includes a high voltage power supply 1, a vacuum arc-extinguishing chamber 2, a magnetron discharge device 3, a current transformer 4, a signal acquisition module 7, a lock-in amplifier 8, a high voltage capacitor C1 and a grounding capacitor C2;

the high-voltage end of a high-voltage power supply 1 is connected with an upper contact in a vacuum arc extinguish chamber 2 and one end of a high-voltage capacitor C1, the grounding end of the high-voltage power supply 1 is connected with a lower contact in the vacuum arc extinguish chamber 2 and one end of a grounding capacitor C2, the other end of the grounding capacitor C2 and the other end of the high-voltage capacitor C1 are connected with a voltage reference channel 4 of a phase-locked amplifier 8, the output end of the phase-locked amplifier 8 is connected with a signal acquisition module 7, a current transformer 4 is arranged on a circuit between the grounding end of the high-voltage power supply 1 and the lower contact of the vacuum arc extinguish chamber 2, the output end of the current transformer 4 is connected with a measurement input channel 6 of the phase-locked amplifier 8, a magnetic control discharge device is connected with the vacuum arc extinguish chamber 2, and the current transformer 4 is a through-core current transformer.

It should be noted that, in order to achieve sufficient amplification of the micro-current signal, the invention adopts a phase-locked amplification technology to perform measurement, specifically, the micro-current signal is used as a signal to be measured of the phase-locked amplifier 8, the voltage signals at two ends of the vacuum arc-extinguishing chamber 2 are used as reference signals, and the micro-current signal and the voltage signals are respectively input into the measurement input channel 6 and the voltage reference channel 4 of the phase-locked amplifier 8, so that the output channel of the phase-locked amplifier 8 obtains a direct-current voltage signal which is proportional to the amplitude of the input signal and has the same frequency as the reference voltage. In addition, since the micro-current signal passing through the vacuum interrupter 2 can be decomposed into a field emission current in phase with the voltage signal and a capacitive current leading by pi/2 (parasitic capacitance in the case where the vacuum interrupter 2 is open), the dc voltage signal outputted from the lock-in amplifier 8 corresponds to a measured value of the field emission current.

The vacuum degree on-line monitoring method comprises the following steps:

keeping a preset distance between an upper contact and a lower contact in a vacuum arc extinguish chamber 2, measuring and calibrating the vacuum degree of the vacuum arc extinguish chamber 2 by a magnetron discharge method by using a magnetron discharge device 3, starting a high-voltage power supply 1 to apply high voltage to the upper contact and the lower contact, inputting a voltage signal obtained by dividing the voltage by a high-voltage capacitor C1 and a grounding capacitor C2 into a voltage reference channel 4 of a phase-locked amplifier 8, inputting a current signal measured by a current transformer 4 into a measurement input channel 6 of the phase-locked amplifier 8, the signal acquisition module 7 records the direct current voltage signal which is output by the phase-locked amplifier 8 and is in phase with the reference voltage signal and is proportional to the field emission current, the corresponding relation between the direct current voltage signal acquired by the signal acquisition module 7 and the vacuum degree of the vacuum arc-extinguishing chamber 2 is established, and during actual detection, the vacuum degree of the vacuum arc-extinguishing chamber 2 can be obtained according to the direct-current voltage signal acquired by the signal acquisition module 7.

The invention has the following characteristics:

the invention adopts a phase-locked amplification detection method to stably realize the detection of the signal to be detected from the noise voltage far greater than the signal, thereby being suitable for extracting the field emission current of dozens of muA from a large amount of field background noise and further being used for vacuum degree monitoring.

The voltage of the upper contact and the lower contact in the vacuum arc-extinguishing chamber 2 is measured in a near-field coupling mode, so that the problems of large volume, complex insulating structure, inconvenience in installation and the like of a traditional voltage divider or PT are solved. The voltage measurement result can be used for a phase-locked amplified reference signal, lays a foundation for the realization and online application of a detection principle, and creates a convenient condition for engineering implementation.

In order to realize the online measurement of the vacuum degree, the invention adopts the feed-through current transformer 4 as a current measuring unit so as to realize the isolation of a weak current monitoring system and a primary loop, and the secondary side of the transformer is provided with a transformer magnetic core to ensure that the transformer magnetic core is in a saturated state under the condition of larger bus current, thereby limiting the power loss of the online measuring system under the condition of large current and ensuring higher measuring sensitivity under the condition of micro current.