CN217085087U

CN217085087U - Detection apparatus for three-phase four-wire is zero line dual supply residual current altogether

Info

Publication number: CN217085087U
Application number: CN202120988342.4U
Authority: CN
Inventors: 于德斌; 王伟; 常小波; 刘人恺; 袁桃; 郑博仁; 明亮; 杨豪
Original assignee: Chongqing Bojin Technology Co ltd
Current assignee: Chongqing Bojin Technology Co ltd
Priority date: 2021-05-10
Filing date: 2021-05-10
Publication date: 2022-07-29
Anticipated expiration: 2031-05-10

Abstract

The application provides a detection apparatus for two power supply residual current of three-phase four-wire common zero line, include: the device comprises a dual-power-supply change-over switch, a first residual current transformer, a second residual current transformer, a first current detection unit, a second current detection unit and a residual current main control unit, wherein the residual current main control unit is used for sampling data and analyzing and obtaining a three-phase four-wire common-zero-line dual-power-supply residual current according to the sampling data. The application provides a three-phase four-wire common zero line dual supply residual current detection device can accurately measure its residual current, avoids sharing zero line dual supply power in, effectively avoids remaining inaccurate or the malfunction of the residual current that leads to with zero line electric current of the supply cable of load disconnection non-zero, obtains accurate residual current simultaneously.

Description

Detection apparatus for three-phase four-wire is zero line dual supply residual current altogether

Technical Field

The utility model relates to a low voltage distribution network technical field especially relates to a detection apparatus of two power supply residual currents of three-phase four-wire common zero line.

Background

The residual current refers to the current vector sum of all phases (including neutral lines) in the low-voltage distribution line, and the current is not zero. In a three-phase four-wire system power supply system, because a neutral point of a power supply transformation is directly grounded, when a phase line insulation resistance of the power supply system or electric equipment is reduced (or electric leakage is generated), the leakage current forms a loop through the neutral point of a transformer. Among the current residual current monitoring devices, residual current transformer rear end zero line remains independent, if there is the zero line of sharing in the residual current transformer rear end, can cause the deviation because of the unbalanced three phase current in the zero line, leads to unable accurate monitoring residual current. However, at present, a three-pole double-power-supply switching device widely exists in the field of low-voltage power distribution, and the condition of sharing a zero line exists during switching.

Therefore, a detection device capable of accurately measuring the residual current is needed.

SUMMERY OF THE UTILITY MODEL

In view of this, the utility model provides a detection device of two power supply residual currents of three-phase four-wire common zero line, its characterized in that: the method comprises the following steps: the system comprises a dual-power transfer switch, a first residual current transformer arranged at a main power supply inlet wire end of the dual-power transfer switch, a second residual current transformer arranged at a standby power supply inlet wire end of the dual-power transfer switch, a first current detection unit arranged at a main power supply, a second current detection unit arranged at a standby power supply and a residual current main control unit used for receiving sampling data of the dual-power transfer switch, the first residual current transformer, the second residual current transformer, the first current detection unit and the second current detection unit and analyzing the sampling data to obtain a three-phase four-wire common-zero-line dual-power supply residual current.

Further, the first current detection unit comprises current transformers which respectively penetrate through cables of the A phase, the B phase and the C phase of the main power supply, and output ends of the current transformers are electrically connected with the residual current main control unit.

Furthermore, the second current detection unit comprises current transformers which respectively penetrate through cables of the A phase, the B phase and the C phase of the standby power supply, and output ends of the current transformers are electrically connected with the residual current main control unit.

Further, the residual current main control unit comprises an STM32F407 chip.

The utility model has the advantages of: the three-phase four-wire common zero line dual-power-supply residual current detection device can accurately measure the residual current, and can effectively avoid inaccurate residual current or misoperation caused by non-zero line current of a power cable disconnected with a load in the power supply of the common zero line dual-power supply; the method is suitable for the detection device, and accurate residual current of the common-zero-line dual-power supply is obtained by detecting the residual current of the power supply electrically connected with the load and the vector sum of the phase current of the zero-phase cable of the power supply disconnected with the load.

Drawings

The invention will be further described with reference to the following figures and examples:

fig. 1 is a schematic structural diagram of the detection device of the present application.

Detailed Description

The invention is further explained by the following combined with the attached drawings of the specification:

the utility model provides a detection apparatus for two power supply residual current of three-phase four-wire common zero line, its characterized in that: the method comprises the following steps: the system comprises a dual-power transfer switch, a first residual current transformer arranged at a main power supply inlet wire end of the dual-power transfer switch, a second residual current transformer arranged at a standby power supply inlet wire end of the dual-power transfer switch, a first current detection unit arranged at a main power supply, a second current detection unit arranged at a standby power supply and a residual current main control unit used for receiving sampling data of the dual-power transfer switch, the first residual current transformer, the second residual current transformer, the first current detection unit and the second current detection unit and analyzing the sampling data to obtain a three-phase four-wire common-zero-line dual-power supply residual current. In this embodiment, to be less than residual current transformer and second residual current transformer and set up in dual power change over switch's inlet wire end for the accurate residual current that detects the power cable that is connected with the load electricity, need not to detect the residual current with the power cable of load disconnection promptly, detect the phase current of power cable through first current detecting element and second current detecting element, acquire dual power change over switch's real-time status through the residual current main control unit and gather the phase current with the power cable of load disconnection, this basis phase current come the zero phase current of confirming the power cable with the load disconnection. In a three-phase four-wire power distribution network, if a zero line is shared, the current on the zero line is the sum of the current of a main power supply zero line and the current of a standby power supply zero line, if the accurate residual current of a power cable electrically connected with a load needs to be obtained, the occurrence of personal electric shock, electric fire accidents and the misoperation of a dual-power-supply change-over switch are avoided, the residual current of the power cable electrically connected with the load needs to be accurately obtained, and the zero-phase current of the power cable disconnected with the load needs to be subtracted from the residual current.

In this embodiment, the first current detection unit includes current transformers respectively passing through a phase a, a phase B and a phase C cables of the main power supply, and output ends of the current transformers are electrically connected to the residual current main control unit. The phase current of the main power supply cable is collected in real time through the residual current main control unit, and data support is provided for subsequently determining the zero-phase current of the main power supply.

In this embodiment, the second current detection unit includes current transformers respectively passing through the standby power supply a-phase, B-phase and C-phase cables, and output ends of the current transformers are electrically connected to the residual current main control unit. The phase current of the standby power supply cable is collected in real time through the residual current main control unit, and data support is provided for subsequently determining the zero-phase current of the main power supply.

In this embodiment, the residual current main control unit includes an STM32F407 chip. The inside 12 bit bisynchronous AD analog-to-digital converter that is provided with of STM32F407 chip, 12 passageway AD signal synchronization collection, wherein 6 passageway AD gather the analog signal of the three phase current of main power source and stand-by power supply simultaneously, the value of first residual current transformer and second residual current transformer is gathered to 2 passageways, dual power change over switch's real-time status is gathered to 1 passageway, convert analog signal into digital signal simultaneously, supply follow-up main control chip to confirm the residual current.

It should be noted that, the specific type selection of the residual current transformer and the like related to the present patent application should be regarded as the prior art, the specific structure and the operation principle of the technical features and the control mode and the spatial arrangement mode which may be related to the present patent application are conventional in the art, and should not be regarded as the inventive point of the present patent application, and the present patent application is not further specifically described in detail.

Finally, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the present invention can be modified or replaced by other means without departing from the spirit and scope of the present invention, which should be construed as limited only by the appended claims.

Claims

1. The utility model provides a detection apparatus for two power supply residual currents of three-phase four-wire common zero line which characterized in that: the method comprises the following steps: the system comprises a dual-power transfer switch, a first residual current transformer arranged at a main power supply inlet wire end of the dual-power transfer switch, a second residual current transformer arranged at a standby power supply inlet wire end of the dual-power transfer switch, a first current detection unit arranged at a main power supply, a second current detection unit arranged at a standby power supply and a residual current main control unit used for receiving sampling data of the dual-power transfer switch, the first residual current transformer, the second residual current transformer, the first current detection unit and the second current detection unit and analyzing the sampling data to obtain a three-phase four-wire common-zero-line dual-power supply residual current.

2. The device for detecting the residual current of the dual power supplies of the three-phase four-wire common zero line according to claim 1, is characterized in that: the first current detection unit comprises current transformers which respectively penetrate through cables of a phase A, a phase B and a phase C of a main power supply, and output ends of the current transformers are electrically connected with the residual current main control unit.

3. The device for detecting the residual current of the dual power supplies of the three-phase four-wire common zero line according to claim 1, is characterized in that: the second current detection unit comprises current transformers which respectively penetrate through cables of the A phase, the B phase and the C phase of the standby power supply, and output ends of the current transformers are electrically connected with the residual current main control unit.

4. The device for detecting the residual current of the dual power supplies of the three-phase four-wire common zero line according to claim 1, is characterized in that: the residual current main control unit comprises an STM32F407 chip.