On-line insulation detection system for variable-frequency motor unit

Abstract

The utility model relates to the technical field of frequency converter group on-line detection, and discloses a frequency conversion motor group on-line insulation detection system, which comprises a main power supply circuit, an acquisition unit and a signal processing unit, the acquisition unit comprises a sheath insulation sensor, a line partial discharge mutual inductor, a motor partial discharge mutual inductor, an ultrasonic sensor and a frequency converter partial discharge detection sensor, and the sheath insulation sensor is installed on the grounding side of a cable shielding layer of the variable-frequency motor set; the line partial discharge mutual inductors are respectively installed on a cable between the frequency converter and the isolation transformer, the motor partial discharge mutual inductor is installed on a cable between the frequency converter and the motor, the ultrasonic sensor is connected to a cable terminal, and the frequency converter partial discharge detection sensor is installed on a frequency converter cabinet body; a plurality of matched sensors are arranged in a variable-frequency motor circuit, the sensors are convenient to install, the whole circuit structure is simple, implementation is easy, and the process is safe.

Description

Technical Field

[0001] The utility model relates to the technical field of frequency converter detection, in particular to an online insulation detection system for a variable frequency motor set. Background Art

[0002] In recent decades, with the rapid development of economy and the advancement of industrial modernization, the use of frequency conversion technology has become more and more widespread, and the requirements for the stable operation of frequency conversion systems are also getting higher and higher. Frequency conversion systems will have partial discharge due to equipment insulation aging, so the existing technology has collected partial discharge to detect the insulation performance and trend changes of system power equipment. Most of the existing collection equipment is set on the grounding side, but most of the existing frequency conversion systems need to connect to the collection equipment for data collection at a later stage. There are multiple grounding terminals, and it is difficult to collect partial discharge current through the grounding side, making it difficult to collect partial discharge. Utility Model Content

[0003] In view of the deficiencies in the prior art, the utility model aims to provide an online insulation detection system for a variable frequency motor set.

[0004] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0005] A variable frequency motor set online insulation detection system comprises a main power supply line, a collection unit and a signal processing unit, wherein the collection unit is electrically connected to the signal processing unit, the main power supply line comprises an isolation transformer, a frequency converter and a motor, the incoming line end of the frequency converter is connected to the isolation transformer, and the outgoing line end of the frequency converter is connected to the motor, the collection unit comprises a sheath insulation sensor, a line partial discharge mutual inductor, a motor partial discharge mutual inductor, an ultrasonic sensor and a frequency converter partial discharge detection sensor, the sheath insulation sensor is installed on the grounding side of the cable shielding layer of the motor, the line partial discharge mutual inductor is installed on the cable between the frequency converter and the isolation transformer, the motor partial discharge mutual inductor is installed on the cable between the frequency converter and the motor, the ultrasonic sensor is installed at the cable terminal, and the frequency converter partial discharge sensor is installed on the outer cabinet of the frequency converter.

[0006] In the utility model, preferably, the partial discharge transformer is also connected to the cable terminal.

[0007] In the utility model, preferably, the sheath insulation sensor is installed on the grounding side of the shielding layer of the cable of the main power supply line.

[0008] In the utility model, preferably, the line partial discharge transformer and the motor partial discharge transformer adopt high-frequency current sensors.

[0009] In the utility model, preferably, the partial discharge transformer comprises a first magnetic core, a Rogowski coil, a first filter sampling unit and a first electromagnetic shielding box, the Rogowski coil is wound on the magnetic core, and the Rogowski coil and the filter sampling unit are arranged in the electromagnetic shielding box.

[0010] In the present utility model, preferably, the sheath insulation sensor adopts a power frequency current sensor.

[0011] In the present utility model, preferably, the sheath insulation sensor comprises a second magnetic core, a second filtering and sampling unit and a second electromagnetic shielding box, and the second magnetic core and the second filtering and sampling unit are arranged in the second electromagnetic shielding box.

[0012] In the present utility model, preferably, the frequency converter partial discharge detection sensor adopts an ultra-high frequency current sensor.

[0013] Compared with the prior art, the beneficial effects of the utility model are:

[0014] The system of the utility model collects partial discharge current by setting a number of matching sensors at fixed positions in the variable frequency motor circuit. The sensor position is convenient for installation, and there is no need to change the connection method of the original main power supply line. There is no electrical connection with the main power supply line. The overall circuit structure is simple and easy to implement. The process is safe, the operation is reliable, the flexibility is high, and the signal collection is comprehensive. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The utility model is a structural schematic diagram of an online insulation detection system for a variable frequency motor set. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0017] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a component centered. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a component centered. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a component centered. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0019] Please also see Figure 1 A preferred embodiment of the utility model provides an online insulation detection system for a variable frequency motor group, which is mainly achieved by connecting a number of corresponding sensors in the cables of the variable frequency motor. The sensors are conveniently installed and can collect high-frequency partial discharge currents. The circuit structure is simple and easy to implement.

[0020] Specifically, it includes a main power supply line, a collection unit and a signal processing unit. The collection unit is electrically connected to the signal processing unit. The main power supply line includes an isolation transformer, a frequency converter and a motor. The incoming line end of the frequency converter is connected to the isolation transformer, and the outgoing line end of the frequency converter is connected to the motor. The collection unit includes a sheath insulation sensor, a line partial discharge mutual inductor, a motor partial discharge mutual inductor, an ultrasonic sensor and a frequency converter partial discharge detection sensor. The sheath insulation sensor is installed on the grounding side of the cable shielding layer of the motor, the line partial discharge mutual inductor is installed on the cable between the frequency converter and the isolation transformer, the motor partial discharge mutual inductor is installed on the cable between the frequency converter and the motor, the ultrasonic sensor is installed at the cable terminal, and the frequency converter partial discharge sensor is installed on the cabinet of the frequency converter.

[0021] In this embodiment, a partial discharge transformer is also connected to the cable terminal.

[0022] In this embodiment, the partial discharge transformer includes a line partial discharge transformer and a motor partial discharge transformer, wherein the line partial discharge transformer is connected in the cable between the isolation transformer and the frequency converter and at the cable terminal, and the motor partial discharge transformer is connected in the cable between the frequency converter and the motor.

[0023] In this embodiment, a sheath insulation sensor is installed on the grounding side of the shielding layer of the cables of the main power supply line.

[0024] Specifically, the line partial discharge transformer and the motor partial discharge transformer use high-frequency current sensors.

[0025] Specifically, the line partial discharge transformer or the motor partial discharge transformer includes a first magnetic core, a Rogowski coil, a first filter sampling unit and a first electromagnetic shielding box. The Rogowski coil is wound on the magnetic core, and the Rogowski coil and the filter sampling unit are arranged in the first electromagnetic shielding box. The first electromagnetic shielding box can suppress interference, improve the signal-to-noise ratio, and prevent rain and dust. The first electromagnetic shielding box adopts a rectangular frame or an annular frame, one side of which can be opened and closed, and a self-locking buckle is arranged at the opening and closing mouth, which is opened by pressing, so as to facilitate installation and ensure safety during operation.

[0026] Specifically, the sheath insulation sensor adopts an industrial frequency current sensor.

[0027] Specifically, the sheath insulation sensor includes a second magnetic core, a second filter sampling unit and a second electromagnetic shielding box, the second magnetic core and the second filter sampling unit are arranged in the second electromagnetic shielding box, and the second electromagnetic shielding box acts in the same manner as the first electromagnetic shielding box. The second electromagnetic shielding box adopts a circular ring structure, which is convenient for installation outside the cable, and does not contact the original main power supply line before and after installation.

[0028] Specifically, the frequency converter partial discharge detection sensor adopts an ultra-high frequency current sensor.

[0029] Working principle:

[0030] The input high voltage is transformed by the isolation transformer and then input into the inverter, which supplies power to the motor through the inverter. A line partial discharge transformer is installed on the outside of the connecting cable between the input end of the inverter and the isolation transformer. The line partial discharge transformer adopts a ring structure and can be directly set on the outside of the cable. The line partial discharge transformer is used to collect the instantaneous current value of the input inverter. A motor partial discharge transformer is installed in the connecting cable between the output end of the inverter and the motor. The motor partial discharge transformer also adopts a ring structure and is set on the outside of the cable to collect the instantaneous current value of the input motor; the sheath insulation sensor is installed on the outside of the shielding layer grounding wire of all cables in the main power supply line to collect the leakage current of the shielding layer of the inverter; the ultrasonic sensor is installed at the cable terminal of the main power supply line to collect the ultrasonic signal generated by the partial discharge of the cable terminal and convert the sound wave signal into an electrical signal; the inverter partial discharge detection sensor is installed on the cabinet of the inverter to collect the instantaneous current value inside the inverter. The signal collected by the acquisition unit is transmitted to the signal processing unit, which amplifies, filters, and detects the collected signal to eliminate high-frequency harmonics and clutter interference, so that the collected current signal has high accuracy and practical reference value. By reasonably setting different sensors inside the variable frequency motor to realize the collection of instantaneous current values ​​of high-frequency circuits, it can be implemented based on the existing variable frequency system. Each sensor is easy to install, the process is safe, and the collected signals are comprehensive.

[0031] The above description is a detailed description of the preferred feasible embodiment of the utility model, but the embodiment is not used to limit the scope of the patent application of the utility model. All equivalent changes or modified changes completed under the technical spirit suggested by the utility model should fall within the patent scope covered by the utility model.

Claims

1. An online insulation detection system for a variable frequency motor set, characterized in that: It includes a main power supply line, a collection unit and a signal processing unit, the collection unit is electrically connected to the signal processing unit, the main power supply line includes an isolation transformer, a frequency converter and a motor, the incoming line end of the frequency converter is connected to the isolation transformer, the outgoing line end of the frequency converter is connected to the motor, the collection unit includes a sheath insulation sensor, a line partial discharge mutual inductor, a motor partial discharge mutual inductor, an ultrasonic sensor and a frequency converter partial discharge detection sensor, the sheath insulation sensor is installed on the grounding side of the cable shielding layer of the motor, the line partial discharge mutual inductor is installed on the cable between the frequency converter and the isolation transformer, the motor partial discharge mutual inductor is installed on the cable between the frequency converter and the motor, the ultrasonic sensor is installed at the cable terminal, and the frequency converter partial discharge sensor is installed on the cabinet of the frequency converter.

2. The online insulation detection system for a variable frequency motor set according to claim 1 is characterized in that: The partial discharge transformer is also connected to the cable terminal.

3. The online insulation detection system for a variable frequency motor set according to claim 1 is characterized in that: The sheath insulation sensor is installed on the grounding side of the cable shielding layer of the main power supply line.

4. The online insulation detection system for a variable frequency motor set according to claim 3 is characterized in that: The line partial discharge mutual inductor and the motor partial discharge mutual inductor adopt high-frequency current sensors.

5. The online insulation detection system for a variable frequency motor set according to claim 1 is characterized in that: The partial discharge transformer comprises a first magnetic core, a Rogowski coil, a first filter sampling unit and a first electromagnetic shielding box. The Rogowski coil is wound on the magnetic core, and the Rogowski coil and the filter sampling unit are arranged in the electromagnetic shielding box.

6. The online insulation detection system for a variable frequency motor set according to claim 2 is characterized in that: The sheath insulation sensor adopts a power frequency current sensor.

7. The online insulation detection system for variable frequency motor set according to claim 6, characterized in that: The sheath insulation sensor comprises a second magnetic core, a second filtering and sampling unit and a second electromagnetic shielding box, wherein the second magnetic core and the second filtering and sampling unit are arranged in the second electromagnetic shielding box.

8. The online insulation detection system for variable frequency motor set according to claim 1, characterized in that: The frequency converter partial discharge detection sensor adopts an ultra-high frequency current sensor.

Images