CN215986347U

CN215986347U - Switch cabinet partial discharge detection circuit and detection system

Info

Publication number: CN215986347U
Application number: CN202122046381.5U
Authority: CN
Inventors: 刘观洪; 杨唐纯; 占黎斌
Original assignee: Wuhan Creation Electrical Automation Co ltd
Current assignee: Wuhan Creation Electrical Automation Co ltd
Priority date: 2021-08-27
Filing date: 2021-08-27
Publication date: 2022-03-08
Anticipated expiration: 2031-08-27

Abstract

The utility model discloses a switch cabinet partial discharge detection circuit and a detection system, which comprise an ultrahigh frequency sensing circuit, front-end detection equipment, a background terminal and a display, wherein a signal acquisition end of the ultrahigh frequency sensing circuit is arranged in a high-voltage switch cabinet, a signal output end of the ultrahigh frequency sensing circuit is electrically connected with an input end of the front-end detection equipment, a signal output end of the front-end detection equipment is electrically connected with a signal input end of the background terminal, a signal output end of the background terminal is electrically connected with the display device, and a fault part is determined by acquiring a pulse signal of a partial discharge part and comparing the pulse signal with a reference signal. The switch cabinet partial discharge detection circuit provided by the utility model has the effects of reducing interference signals in collected signals and combining a pulse current detection method or directly utilizing ultrasonic signals to physically position a partial discharge source.

Description

Switch cabinet partial discharge detection circuit and detection system

Technical Field

The utility model belongs to the technical field of switch cabinet detection, and particularly relates to a switch cabinet partial discharge detection circuit and a detection system.

Background

Under the condition that insulation defects or electric field distortion occur in the high-voltage switch cabinet, partial discharge can be induced, and physical phenomena such as sound, light, electricity and the like are often accompanied in the partial discharge process. In the process of on-line monitoring of the power equipment, the physical parameters representing the occurrence of partial discharge can be detected by the sensing equipment so as to judge whether the discharge phenomenon and the corresponding discharge position occur. The detection method of partial discharge is commonly used, for example, a pulse current method, an ultrasonic detection method, and a high-frequency detection method.

In the pulse current method, because the detection impedance and the amplifier have certain influences on the measurement accuracy, sensitivity, resolution, dynamic range and the like, when the capacitance of a sample is larger, the sample is limited by the coupling impedance, and the sensitivity of a test instrument is limited to a certain extent; the measurement frequency is low, the frequency band is narrow, and the amount of information contained is small.

The optical detection method is to detect by using light radiation generated by partial discharge. The wavelength of light emitted by each discharge is different, and is generally between 500 and 700 nm. In a laboratory, a test for analyzing a partial discharge characteristic by using a photometric method has been advanced, but the photometric method cannot be applied well in practice because the equipment required for the photometric method is expensive and has low sensitivity.

At present, the ultrasonic detection method still has a plurality of problems: for example, the ultrasonic sensor has low sensitivity, cannot measure the discharge signal well on the spot, and has poor anti-electromagnetic interference capability. Therefore, the ultrasonic detection method is mainly used for qualitatively judging whether the partial discharge signal exists or not, and is combined with a pulse current detection method or directly utilizes the ultrasonic signal to physically position the partial discharge source.

SUMMERY OF THE UTILITY MODEL

In view of the above problems, a switch cabinet partial discharge detection circuit and a detection system are provided, which aim to reduce interference signals in collected signals and combine with a pulse current detection method or directly utilize ultrasonic signals to perform physical positioning on a partial discharge source.

The specific technical scheme is as follows:

a switch cabinet partial discharge detection circuit comprises an ultrahigh frequency antenna, a pre-amplification circuit, a radio frequency detection circuit, a phase-locked amplification circuit and a reference signal generation circuit, wherein the ultrahigh frequency antenna is electrically connected with a signal input end of the pre-amplification circuit, a signal output end of the pre-amplification circuit is electrically connected with a signal input end of the radio frequency detection circuit, a signal output end of the radio frequency detection circuit is electrically connected with one signal input end of the phase-locked amplification circuit, the other signal input end of the phase-locked amplification circuit is electrically connected with an output end of the reference signal generation circuit, and a signal output end of the phase-locked amplification circuit is electrically connected with a signal input end of front-end detection equipment.

Furthermore, the reference signal generating circuit comprises an inductor and a square wave generating circuit, the inductor is electrically connected with a signal input end of the square wave generating circuit, and a signal output end of the square wave generating circuit is electrically connected with the other signal input end of the phase-locked amplifying circuit.

Further, the ultrahigh frequency antenna adopts an Archimedes spiral antenna.

The utility model provides a cubical switchboard partial discharge detecting system, includes high tension switchgear, front end check out test set, backstage terminal, display and foretell cubical switchboard partial discharge detection circuitry, the hyperfrequency antenna set up in the high tension switchgear for gather the signal of telecommunication because partial discharge produces in the high tension switchgear, the inductor also set up in the high tension switchgear, and be used for judging whether take place the condition of discharging in the high tension switchgear, phase-locked amplifier circuit's signal output part with front end check out test set's signal input part electricity is connected, front end check out test set's signal output part with the signal input part electricity of backstage terminal is connected, the signal output part of backstage terminal with the display electricity is connected.

In conclusion, the scheme has the beneficial effects that:

in the switch cabinet partial discharge detection circuit provided by the utility model, the fault position is determined by acquiring the pulse signal of the partial discharge position and comparing the pulse signal with the reference signal. The switch cabinet partial discharge detection circuit provided by the utility model has the effects of reducing interference signals in collected signals and combining a pulse current detection method or directly utilizing ultrasonic signals to physically position a partial discharge source.

Drawings

FIG. 1 is a block diagram of the structure of an ultra-high frequency sensing circuit of a partial discharge detection circuit of a switch cabinet according to the present invention;

fig. 2 is a block diagram of a switch cabinet partial discharge detection system according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. 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.

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

The present invention is further illustrated by the following examples, which are not to be construed as limiting the utility model.

Fig. 1 is a block diagram of an ultra-high frequency sensing circuit of a switch cabinet partial discharge detection circuit of the present invention, and fig. 2 is a block diagram of a switch cabinet partial discharge detection system of the present invention, as shown in fig. 1 and fig. 2, the switch cabinet partial discharge detection circuit and the detection system provided in this embodiment: the ultrahigh frequency antenna is electrically connected with a signal input end of the preamplification circuit, a signal output end of the preamplification circuit is electrically connected with a signal input end of the radio frequency detection circuit, a signal output end of the radio frequency detection circuit is electrically connected with one signal input end of the phase-locked amplification circuit, the other signal input end of the phase-locked amplification circuit is electrically connected with an output end of the reference signal generation circuit, and a signal output end of the phase-locked amplification circuit is electrically connected with a signal input end of the front-end detection equipment.

It should be noted that the lock-in amplifier circuit employs a lock-in amplifier of type M256128SR 844.

It should be noted that the radio frequency detector circuit is an ADL5502 radio frequency detector.

Preferably, the reference signal generating circuit comprises an inductor and a square wave generating circuit, the inductor is electrically connected with a signal input end of the square wave generating circuit, and a signal output end of the square wave generating circuit is electrically connected with another signal input end of the phase-locked amplifying circuit.

It should be noted that the inductor is used for inducing a discharging condition in the switch cabinet, and when a partial discharging condition occurs in the switch cabinet, the inductor receives a discharging signal and activates the reference signal generating circuit to generate a square wave reference signal, so that the monitoring equipment compares the square wave reference signal with the collected signal to determine a discharging position

Preferably, the ultrahigh frequency antenna is an Archimedes spiral antenna.

It should be noted that, compared with the equal-arm helical antenna, the archimedes helical antenna not only satisfies the non-frequency-varying characteristic of the broadband antenna, but also has the advantage of small "end effect" after the tail is cut off, and the volume is smaller than that of other planar helical antennas under the same limited working frequency.

In another preferred embodiment, the system comprises a high-voltage switch cabinet, a front-end detection device, a background terminal, a display and a switch cabinet partial discharge detection circuit in the above embodiment, the ultrahigh-frequency antenna is arranged in the high-voltage switch cabinet and used for collecting electric signals generated by partial discharge in the high-voltage switch cabinet, the inductor is also arranged in the high-voltage switch cabinet and used for judging whether discharge occurs in the high-voltage switch cabinet, a signal output end of the phase-locked amplification circuit is electrically connected with a signal input end of the front-end detection device, a signal output end of the front-end detection device is electrically connected with a signal input end of the background terminal, and a signal output end of the background terminal is electrically connected with the display.

The working principle is as follows: the ultrahigh frequency antenna collects an electric signal generated at a local amplification position, the electric signal is processed by the preamplification circuit and the radio frequency detection circuit and then input to the phase-locked amplification circuit, when local discharge occurs, the inductor senses the situation of the local discharge and generates an excitation signal to be output to the square wave generation circuit, the square wave generation circuit generates a standard reference square wave and outputs the standard reference square wave to the phase-locked amplification circuit, the phase-locked amplification circuit performs common comparison operation on the collected electric signal and the square wave reference signal, and amplifies and outputs the signal to front-end detection equipment after separating a specific carrier frequency signal from the signal, a specific discharge part is calculated, and a calculation result is transmitted to a background terminal and a display.

While the utility model has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the utility model.

Claims

1. A switch cabinet partial discharge detection circuit is characterized in that: the ultrahigh frequency antenna is electrically connected with a signal input end of the pre-amplification circuit, a signal output end of the pre-amplification circuit is electrically connected with a signal input end of the radio frequency detection circuit, a signal output end of the radio frequency detection circuit is electrically connected with one signal input end of the phase-locked amplification circuit, the other signal input end of the phase-locked amplification circuit is electrically connected with an output end of the reference signal generation circuit, and a signal output end of the phase-locked amplification circuit is electrically connected with a signal input end of front-end detection equipment.

2. The switch cabinet partial discharge detection circuit of claim 1, wherein: the reference signal generating circuit comprises an inductor and a square wave generating circuit, the inductor is electrically connected with a signal input end of the square wave generating circuit, and a signal output end of the square wave generating circuit is electrically connected with the other signal input end of the phase-locked amplifying circuit.

3. The switch cabinet partial discharge detection circuit of claim 2, wherein: the ultrahigh frequency antenna adopts an Archimedes spiral antenna.

4. A cubical switchboard partial discharge detecting system which characterized in that: the high-voltage switch cabinet local discharge detection circuit comprises a high-voltage switch cabinet, front-end detection equipment, a background terminal, a display and the local discharge detection circuit as claimed in any one of claims 2 to 3, wherein the ultrahigh-frequency antenna is arranged in the high-voltage switch cabinet and used for collecting electric signals generated by local discharge in the high-voltage switch cabinet, the inductor is also arranged in the high-voltage switch cabinet and used for judging whether discharge occurs in the high-voltage switch cabinet, the signal output end of the phase-locked amplification circuit is electrically connected with the signal input end of the front-end detection equipment, the signal output end of the front-end detection equipment is electrically connected with the signal input end of the background terminal, and the signal output end of the background terminal is electrically connected with the display.