Very high frequency monitoring device of frequency conversion system
By installing a VHF transformer on the input and output ends of the frequency converter system and the shielding grounding line, the problem of high-frequency harmonic masking in the frequency converter system is solved, and efficient and accurate local distribution signal acquisition is achieved to ensure the stable operation of the frequency converter system.
Patent Information
- Application Number
- CN202422004298.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-16
- Publication Date
- 2025-07-18
- Estimated Expiration
- 2034-08-16
AI Technical Summary
In frequency conversion systems, since the high-frequency harmonics generated by the frequency converter mask the signal of the high-frequency local discharge transformer, resulting in poor signal acquisition efficiency, it is difficult for the prior art to effectively monitor the local discharge current of the frequency conversion system.
The first, second and third VHF transformers are respectively installed on the outer layer of the power supply cable and the shielding layer grounding wire of the input and output ends of the frequency converter system, and locally distributed signals within the frequency range of 30M-300MHz are collected, and signal filtering is used for ring structure and electromagnetic shielding box to reduce noise interference.
It improves the accuracy and acquisition efficiency of locally distributed signals, reduces harmonic interference, is convenient to install, and has strong applicability, ensuring the stable operation of the frequency converter system.
Smart Images
Figure CN223123160U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of partial discharge current monitoring of a frequency conversion system, and particularly relates to a very high frequency monitoring device for a frequency conversion system. Background Art
[0002] Since using partial discharge for insulation monitoring of electrical equipment in a frequency conversion system is an effective method, but in a frequency conversion system, a large number of high-frequency harmonics are generated due to the rectification and inversion of the frequency converter. These harmonics are concentrated in the range of 1M - 40MHz, and the acquisition frequency of the high-frequency partial discharge mutual inductor (HFCT) is in the range of 3M - 30MHz. The high-frequency pulse signals will be masked by the harmonics of the frequency converter, resulting in many harmonics in the signals collected by the high-frequency partial discharge mutual inductor, and the signals need to be processed, with poor acquisition efficiency. Content of the Utility Model
[0003] Aiming at the deficiencies of the prior art, the purpose of the utility model is to provide a very high frequency monitoring device for a frequency conversion system.
[0004] In order to achieve the above purpose, the utility model provides the following technical solutions:
[0005] A very high frequency monitoring device for a frequency conversion system includes a first very high frequency mutual inductor sleeved on the outer layer of the power supply cable at the input end of the frequency conversion system, and a second very high frequency mutual inductor sleeved on the outer layer of the power supply cable at the output end of the frequency conversion system.
[0006] In the utility model, preferably, the first very high frequency mutual inductor is replaced by a third very high frequency mutual inductor sleeved on the shielding layer ground wire of the power supply cable at the input end of the frequency conversion system.
[0007] In the utility model, preferably, the shielding layer ground wire of the power supply cable at the output end of the frequency conversion system also passes through the inside of the second very high frequency mutual inductor in a reverse manner.
[0008] In the utility model, preferably, the first very high frequency mutual inductor, the second very high frequency mutual inductor, and the third very high frequency mutual inductor all adopt an annular structure, sleeved on the outer layer of the power supply cable, and have no electrical connection with the original frequency conversion system.
[0009] In the utility model, preferably, the first very high frequency mutual inductor, the second very high frequency mutual inductor, and the third very high frequency mutual inductor all include an electromagnetic shielding box made of non-metallic material.
[0010] In the utility model, preferably, the electromagnetic shielding box is an openable and closable annular structure, and a self-locking buckle is arranged at the opening and closing position, and the electromagnetic shielding box is fixed or opened through the self-locking buckle.
[0011] In the present utility model, preferably, it further includes a sheath insulation sensor, and the sheath insulation sensor is arranged on the shielding layer grounding wire of the power supply cable of the frequency conversion system.
[0012] In the present utility model, preferably, the sheath insulation sensor adopts a power frequency current sensor.
[0013] In the present utility model, preferably, the signal frequency ranges collected by the first very high frequency mutual inductor, the second very high frequency mutual inductor, and the third very high frequency mutual inductor are all 30M - 300MHz.
[0014] In the present utility model, preferably, the coils of the first very high frequency mutual inductor, the second very high frequency mutual inductor, and the third very high frequency mutual inductor are all made of ultra-microcrystalline alloy material.
[0015] Compared with the prior art, the beneficial effects of the present utility model are as follows:
[0016] The present utility model installs very high frequency mutual inductors outside the power supply cables at the input and output ends of the frequency conversion system, and on the shielding layer grounding wire of the power supply cable at the input end, to collect the partial discharge signals of the frequency conversion system. The collected partial discharge signals have weak harmonic interference, high accuracy, high collection efficiency, convenient and fast overall installation, and strong applicability. Brief Description of the Drawings
[0017] Figure 1 It is a structural schematic diagram of a very high frequency monitoring device for a frequency conversion system. Detailed Embodiments
[0018] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present utility model.
[0019] It should be noted that when a component is referred to as being "fixed to" another component, it can be directly on the other component or there may also be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component at the same time. When a component is considered to be "arranged on" another component, it can be directly arranged on the other component or there may be an intermediate component at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for the purpose of illustration.
[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this utility model pertains. The terms used in the description of this utility model herein are merely for the purpose of describing specific embodiments and are not intended to limit this utility model. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.
[0021] Please refer to Figure 1 , a preferred embodiment of this utility model provides a very high frequency (VHF) monitoring device for a variable frequency system, which is mainly used in the variable frequency system to collect the partial discharge current signals of the variable frequency system, and realizes the monitoring of the variable frequency system through the signal collection of local instantaneous pulses. When a partial discharge instantaneous pulse signal appears, the variable frequency system is repaired and maintained in time to ensure the stable and safe operation of the variable frequency system. The monitoring device mainly includes a plurality of VHF transformers. The first VHF transformer is sleeved on the outer layer of the power supply cable at the input end of the variable frequency system, and the second VHF transformer, and the second VHF transformer is sleeved on the outer layer of the power supply cable at the output end of the variable frequency system.
[0022] In this embodiment, the first VHF transformer is replaced with a third VHF transformer, and the third VHF transformer is sleeved on the shielding layer ground wire of the power supply cable at the input end of the variable frequency system. The third VHF transformer can make the collected partial discharge pulse signals in the variable frequency system more comprehensive, and the collected signals can more accurately reflect the current situation of the frequency converter.
[0023] In this embodiment, three first VHF transformers can be set, which are respectively sleeved on the outer layer of each cable of the three-phase power supply cable at the input end of the variable frequency system to collect instantaneous pulse signals respectively. The installation method of the first VHF transformer can be selected according to the specific installation environment, and the flexibility is high.
[0024] In this embodiment, the shielding layer ground wire of the power supply cable at the output end of the variable frequency system is also passed through the loop of the second VHF transformer in a reverse manner. Through this setting, the signals collected by the second VHF transformer from the shielding layer and the signals in the ground wire are equal in magnitude and opposite in direction, which can neutralize the noise signals and reduce the noise interference on the shielding layer and the ground wire.
[0025] In this embodiment, the first VHF transformer, the second VHF transformer, and the third VHF transformer all adopt a ring structure and are sleeved on the outer layer of the power supply cable without electrical connection to the original variable frequency system. The VHF transformer with a ring structure can improve the quality and stability of the signals. And with the ring structure, signal collection can be directly carried out by simply sleeving it on the outer layer of the power supply cable, without direct electrical connection to the original variable frequency system. It is convenient to install and can be retrofitted into the original variable frequency system later. It has high flexibility, is convenient for adjustment and optimization, and can meet different scenarios and performances.
[0026] In this embodiment, the first very high frequency transformer, the second very high frequency transformer, and the third very high frequency transformer all include an electromagnetic shielding box. The electromagnetic shielding box is an openable and closable ring structure, and a self-locking buckle is provided at the opening and closing position. The electromagnetic shielding box is fixed or opened through the self-locking buckle, which facilitates the installation and adjustment of the very high frequency transformer.
[0027] In this embodiment, it further includes a sheath insulation sensor. The sheath insulation sensor is arranged on the shielding layer grounding wire of the power supply cable of the frequency conversion system, and the sheath insulation sensor is communicatively connected to the signal conversion unit. The sheath insulation sensor adopts a power frequency current sensor.
[0028] Specifically, the signal frequency ranges collected by the first very high frequency transformer, the second very high frequency transformer, and the third very high frequency transformer are all 30M - 300MHz.
[0029] Specifically, the coils of the first very high frequency transformer, the second very high frequency transformer, and the third very high frequency transformer are all made of ultra-microcrystalline alloy material. The very high frequency transformer made of ultra-microcrystalline alloy material has a high magnetic permeability, a saturated magnetic induction intensity, and stable performance.
[0030] Working principle:
[0031] The frequency conversion system mainly includes an isolation transformer, an inverter, a motor, and a power cable. Among them, very high frequency transformers are installed on the outer layer of the power supply cable between the incoming line end of the inverter and the isolation transformer, and very high frequency transformers are installed on the outer layer of the power supply cable between the outgoing line end of the inverter and the motor; or very high frequency transformers are installed on the shielding layer grounding wire at the incoming line end of the inverter and on the outer layer of the power supply cable between the outgoing line end of the inverter and the motor. The very high frequency transformer adopts a ring structure and can be directly sleeved on the outer layer of the cable. The very high frequency transformer is used to collect very high frequency pulse currents with a frequency range of 30M - 300MHz at the input and output ends of the inverter, and can filter out harmonics generated by the inverter below 30M, so that the collected signal has less harmonic interference and is easy to process. The collected signal is transmitted to the signal conversion unit and is sent to the monitoring device after being processed by the signal conversion unit, realizing the monitoring of the partial discharge current of the frequency conversion system.
[0032] The above description is a detailed description of the preferred and feasible embodiment of the present invention, but the embodiment is not used to limit the patent application scope of the present invention. Any equivalent changes or modifications completed under the technical spirit disclosed by the present invention shall fall within the patent scope covered by the present invention.
Claims
1. A very high frequency monitoring device for a variable frequency system, characterized in that, It includes a first very high frequency mutual inductor sleeved on the outer layer of the power supply cable at the input end of the frequency conversion system, and a second very high frequency mutual inductor sleeved on the outer layer of the power supply cable at the output end of the frequency conversion system.
2. The very high frequency monitoring device for a variable frequency system according to claim 1, characterized in that Replace the first very high frequency mutual inductor with a third very high frequency mutual inductor, and the third very high frequency mutual inductor is sleeved on the shielding layer grounding wire of the power supply cable at the input end of the frequency conversion system.
3. A very high frequency monitoring device for a variable frequency system according to claim 1 or claim 2, characterized in that, The shielding layer grounding wire of the power supply cable at the output end of the frequency conversion system is also reversely passed through the loop of the second very high frequency mutual inductor.
4. A very high frequency monitoring device for a variable frequency system according to claim 2, characterized in that, The first very high frequency mutual inductor, the second very high frequency mutual inductor, and the third very high frequency mutual inductor all adopt an annular structure, are sleeved on the outer layer of the power supply cable, and have no electrical connection with the original frequency conversion system.
5. The very high frequency monitoring device for a variable frequency system according to claim 2, characterized in that, The first very high frequency mutual inductor, the second very high frequency mutual inductor, and the third very high frequency mutual inductor all include an electromagnetic shielding box made of non-metallic material.
6. The very high frequency monitoring device for a variable frequency system according to claim 5, characterized in that, The electromagnetic shielding box is an openable and closable annular structure, and a self-locking buckle is provided at the opening and closing position, and the electromagnetic shielding box is fixed or opened through the self-locking buckle.
7. A very high frequency monitoring device for a variable frequency system according to claim 1 or claim 2, characterized in that, It also includes a sheath insulation sensor arranged on the shielding layer grounding wire of the power supply cable of the frequency conversion system.
8. The very high frequency monitoring device for a variable frequency system according to claim 7, characterized in that, The sheath insulation sensor adopts a power frequency current sensor.
9. The very high frequency monitoring device of a variable frequency system according to claim 2, characterized in that, The signal frequency ranges collected by the first very high frequency mutual inductor, the second very high frequency mutual inductor, and the third very high frequency mutual inductor are all 30M - 300MHz.
10. The very high frequency monitoring device for a variable frequency system according to claim 2, characterized in that, The coils of the first very high frequency mutual inductor, the second very high frequency mutual inductor, and the third very high frequency mutual inductor are all made of ultra-microcrystalline alloy material.