Composite sensor for detecting partial discharge ultrahigh frequency electromagnetic signal
Technical Field
The invention belongs to the technical field of partial discharge detection, and particularly relates to a composite sensor for detecting a partial discharge ultrahigh-frequency electromagnetic signal.
Background
At present, the sensors for detecting the partial discharge ultrahigh frequency electromagnetic signals have the modes of UHF, TEV, ultrasonic wave, HFCT and the like, and the single sensor arranged in a cable tunnel and a switch cabinet for detecting the signals sent by the partial discharge is unreliable. In order to avoid contingencies and to increase the reliability of the detection, it is necessary to arrange a plurality of different types of sensors simultaneously in the cable tunnel, in the switchgear cabinet. However, the distribution of a plurality of sensors in a narrow switch cabinet increases the degree of congestion in the tunnel and the cabinet, and makes it difficult to perform daily maintenance on other projects.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a composite sensor for detecting a partial discharge ultrahigh frequency electromagnetic signal.
In order to achieve the purpose, the invention adopts the following technical scheme, which is characterized by comprising a TEV sensor, a UHF antenna, a non-contact ultrasonic sensor, an HFCT high-frequency current transformer and a shell; the radio frequency connector is characterized by further comprising a radio frequency interface, a shell fastening piece and a mounting permanent magnet.
Furthermore, the TEV sensor adopts a ground transient voltage sensor, and can detect the voltage induced by the ultrahigh frequency electromagnetic signal on the metal cabinet body by utilizing the principle of capacitive coupling.
Furthermore, the UHF antenna adopts an Archimedes spiral antenna which consists of a double spiral arm and a balun.
Furthermore, the detection frequency range of the UHF antenna is 400 MHz-2.3 GHz, and the input impedance of a balun matched port is 50 omega. When partial discharge occurs, ultrahigh frequency electromagnetic waves can be generated, the bandwidth of the antenna can well cover the frequency range of electromagnetic signals during the partial discharge, and the electromagnetic waves emitted during the partial discharge can be effectively monitored.
Further, the non-contact ultrasonic sensor detects cabinet vibration caused by partial discharge in a direct contact mode, and whether partial discharge occurs is determined through analysis of vibration frequency.
Further, the HFCT high-frequency current transformer adopts a ring-shaped coil structure. The high-frequency current induced by the high-frequency electromagnetic field in the grounding wire can be detected, and the frequency and the magnitude of the current can be analyzed to be used as the basis for whether the partial discharge occurs.
Compared with the prior art, the invention has the beneficial effects.
Aiming at the defects of dispersed arrangement and unreliability of the existing sensors, the invention provides a multi-type sensor combined composite sensor device for detecting partial discharge signals, which has the advantages of small volume, high reliability and simple installation, and can realize effective acquisition of the partial discharge signals in cable tunnels and switch cabinets.
Drawings
The invention is further described with reference to the following figures and detailed description. The scope of the invention is not limited to the following expressions.
Fig. 1 is a schematic view of the overall structure of the embodiment.
Fig. 2 is a bottom view of an embodiment outer housing.
Fig. 3 is a top view of an embodiment outer shell.
FIG. 4 is a perspective view of the outer shell of the exemplary embodiment.
In the figure, 1 is an HFCT sensor, 2 is an UHF sensor, 3 is a TEV sensor, 4 is a balun, 5 is a non-contact ultrasonic sensor, 6 is a radio frequency connector, and 7 is a contact ultrasonic sensor.
Detailed Description
As shown in fig. 1-4, the present invention includes a TEV sensor, a UHF sensor, an ultrasonic sensor, an HFCT sensor, a housing, and a radio frequency interface; the TEV sensor is fixed on three 120-degree supports which are distributed at equal intervals, and a circular boss of 1.6 mm is arranged at the bottom right opposite to the sensor for ensuring the effectiveness of capacitive coupling.
Preferably, the TEV sensor adopts a three-point fixing method, and three rectangular clamping grooves are distributed on the sensor at 120-degree equal intervals and are matched with three supports of the shell to be rotationally fastened.
Preferably, the UHF sensor is composed of two parts, namely a spiral double arm and a balun, which are combined together by means of mechanical hole location matching, for example, four assembling holes are distributed on the edge, which facilitates the use of an assembling tool.
Preferably, four slots on the edge are matched with four brackets of the shell to fix the UHF sensor.
Preferably, one end of the contact type ultrasonic sensor is in contact with the surface of the cabinet body, and an opening is formed in the contact side of the shell and the cabinet body so as to ensure that the sensor is in close contact with the cabinet body.
Preferably, the other side of the contact ultrasonic sensor fixed with the shell is an annular base with a raised edge and a concave inner part, and the raised edge is provided with a notch for placing a radio frequency signal wire.
Preferably, one side of the non-contact ultrasonic sensor needs to be exposed in air to facilitate reception of ultrasonic signals, and the bottom is installed in a manner similar to that of the contact ultrasonic sensor.
Preferably, the HFCT sensor is completely enclosed inside the housing.
Preferably, the housing is made up of two parts, an upper shell and a lower shell, which are connected by four bolts.
Preferably, five radio frequency interfaces are respectively arranged on the lower shell and are fixed by nuts.
The composite sensor is adsorbed on the surfaces of a cable tunnel and a switch cabinet through a strong magnet at the bottom, and the ground wire penetrates through the annular opening.
The invention integrates four partial discharge detection sensors into a closed shell with a small volume, and solves the problem that a plurality of sensors are dispersedly installed and occupy a larger space in a cabinet. By integrating UHF, TEV, ultrasonic and HFCT sensors, the detection of the local discharge signal is completed by using a small integrated sensor, and a plurality of sensors of different types are checked with each other to improve the detection reliability.
It should be understood that the detailed description of the present invention is only for illustrating the present invention and is not limited by the technical solutions described in the embodiments of the present invention, and those skilled in the art should understand that the present invention can be modified or substituted equally to achieve the same technical effects; as long as the use requirements are met, the method is within the protection scope of the invention.