Residual current detection device and residual current action protection system
阅读说明:本技术 剩余电流检测装置及剩余电流动作保护系统 (Residual current detection device and residual current action protection system ) 是由 艾精文 赵宇明 王静 陈思磊 谢智敏 于 2019-09-24 设计创作,主要内容包括:本申请涉及一种剩余电流检测装置及剩余电流动作保护系统。上述剩余电流检测装置,包括互感器、脉冲发生器、采样元件和控制器。互感器包括多个抽头。控制器控制脉冲发生器向互感器发送一定频率和一定幅值的脉冲信号。互感器在脉冲信号的作用下感应待测直流导线上的剩余电流。控制器通过采集采样元件上的电压,进而获得待测直流导线上的真实剩余电流值。控制器通过控制抽头的通断,进而选择互感器的线圈匝数,进而改变剩余电流检测装置的量程。剩余电流检测装置能够在高检测精度的基础上,改变量程实现对宽范围的剩余电流进行检测。(The application relates to a residual current detection device and a residual current action protection system. The residual current detection device comprises a mutual inductor, a pulse generator, a sampling element and a controller. The transformer includes a plurality of taps. The controller controls the pulse generator to send pulse signals with certain frequency and amplitude to the mutual inductor. The mutual inductor induces residual current on the direct current wire to be detected under the action of the pulse signal. And the controller acquires the voltage on the sampling element so as to obtain the real residual current value on the direct current wire to be detected. The controller selects the number of turns of the coil of the mutual inductor by controlling the on-off of the tap, and then the measuring range of the residual current detection device is changed. The residual current detection device can detect the residual current in a wide range by changing the range on the basis of high detection precision.)
1. A residual current detection device, comprising:
the transformer (100) comprises a plurality of coils (112) for sensing residual current of a direct current wire to be tested, each coil (112) is provided with a tap (101), and the plurality of taps (101) comprise a first type tap (102) and a second type tap (103);
a pulse generator (120) comprising a first terminal (121), a second terminal (122) and a third terminal (123), the first terminal (121) being electrically connected to the first type tap (102);
a sampling element (130) electrically connected to the second end (122); and
a controller (140) comprising a sampling terminal (141), a pulse modulation control terminal (142) and a plurality of first control output terminals (143), wherein the sampling terminal (141) is electrically connected with the sampling element (130), the pulse modulation control terminal (142) is electrically connected with the third terminal (123), and each of the first control output terminals (143) is electrically connected with one of the second type taps (103).
2. The residual current detection device according to claim 1, characterized by further comprising:
a plurality of optical couplers (150), each of said optical couplers (150) comprising a first input (151), a second input (152) and an output (153), said first input (151) being electrically connected to said second type tap (103), said second input (152) being electrically connected to one of said first control outputs (143), said output (153) being electrically connected to said sampling element (130).
3. The residual current detection device according to claim 2, wherein the number of the plurality of taps (101) is four, the four taps (101) comprise one tap (102) of the first type and three taps (103) of the second type, and the number of the plurality of optocouplers (150) is three.
4. The residual current detection device according to claim 1, characterized in that said controller (140) further comprises a first serial communication terminal (144), said residual current detection device (10) further comprising:
a communication interface circuit (160) electrically connected to the first serial port communication terminal (144).
5. The residual current detection device according to claim 4, characterized in that said controller (140) further comprises a second serial communication terminal (145), said residual current detection device (10) further comprising:
and the display device (170) is electrically connected with the second serial port communication terminal (145).
6. The residual current detection device according to claim 5, characterized in that said controller (140) further comprises a second control output (146), said residual current detection device (10) further comprising:
and the alarm (180) is electrically connected with the second control output end (146).
7. The residual current detection device according to claim 1, characterized by further comprising:
and the filter (190) is electrically connected with the sampling end (141).
8. The residual current detection device according to claim 1, characterized in that said mutual inductor (100) further comprises:
and the coil (112) is wound on the magnetic core (111).
9. The residual current detection device according to claim 8, characterized in that the material of the magnetic core (111) and the material of the coil (112) are both flexible materials.
10. A residual current operated protection system, comprising:
the residual current detection device (10) of any one of claims 1 to 9; and
a circuit breaker (210) electrically connected to the residual current detection device (10).
11. The residual current operated protection system according to claim 10, further comprising:
and the test circuit (220) is electrically connected with the residual current detection device (10).
Technical Field
The present application relates to the field of electrical devices, and in particular, to a residual current detection device and a residual current operation protection system.
Background
Residual current is a big cause of electrical fire and personal electric shock accidents. The remaining reasons are various, such as insulation aging of electrical equipment due to lack of effective maintenance, irregular distribution installation, overload of distribution lines, reduction of insulation level of wires affected by natural environment under humid conditions, and the like. Meanwhile, the reasons also lead to complex and various residual current forms, and challenge is brought to the design and development of the residual current operated protector.
In the field of civil construction and municipal administration, the range of direct current residual current is wider from several mA to several A due to various reasons for generating the direct current residual current. In the traditional direct current residual current detection method, after the number of turns of a coil and the magnetic core parameters are determined, the detection range is fixed. Although the range can be changed in a small range by changing the external circuit parameters, the detection accuracy is lowered. Particularly, for portable residual current detection equipment, how to ensure the high precision of direct current residual current detection while the detection range is large becomes a problem to be solved urgently.
Disclosure of Invention
Therefore, it is necessary to provide a residual current detection device and a residual current operation protection system for solving the problem of single measurement range of the conventional dc residual current detection method.
A residual current detection device comprising:
the mutual inductor comprises a plurality of coils and a plurality of voltage transformers, wherein the plurality of coils are used for inducing residual current of the direct current lead to be detected, each coil is provided with a tap, and the plurality of taps comprise a first type tap and a second type tap;
the pulse generator comprises a first end, a second end and a third end, wherein the first end is electrically connected with the first tap;
a sampling element electrically connected to the second end; and
the controller comprises a sampling end, a pulse modulation control end and a plurality of first control output ends, wherein the sampling end is electrically connected with the sampling element, the pulse modulation control end is electrically connected with the third end, and each first control output end is electrically connected with one of the second taps.
In one embodiment, the method further comprises the following steps:
a plurality of optical couplers, each of which includes a first input terminal, a second input terminal and an output terminal, the first input terminal is electrically connected to the second tap, the second input terminal is electrically connected to one of the first control output terminals, and the output terminal is electrically connected to the sampling element.
In one embodiment, the number of the plurality of taps is four, four of the taps include one tap of the first type and three taps of the second type, and the number of the plurality of optical couplers is three.
In one embodiment, the controller further comprises a first serial communication terminal, and the residual current detection device further comprises:
and the communication interface circuit is electrically connected with the first serial port communication end.
In one embodiment, the controller further includes a second serial communication port, and the residual current detection device further includes:
and the display device is electrically connected with the second serial port communication end.
In one embodiment, the controller further comprises a second control output, and the residual current detection device further comprises:
and the alarm is electrically connected with the second control output end.
In one embodiment, the method further comprises the following steps:
and the filter is electrically connected with the sampling end.
In one embodiment, the transformer further comprises:
and the coil is wound on the magnetic core.
In one embodiment, the material of the magnetic core and the material of the coil are both flexible materials.
A residual current operated protection system comprising:
the residual current detection device of any one of the above embodiments; and
and the circuit breaker is electrically connected with the residual current detection device.
In one embodiment, the method further comprises the following steps:
and the test circuit is electrically connected with the residual current detection device.
The residual current detection device comprises a mutual inductor, a pulse generator, a sampling element and a controller. The transformer includes a plurality of taps. The pulse generator includes a first terminal, a second terminal, and a third terminal. The first end is electrically connected to one of the taps. The second end is electrically connected with the sampling element. The controller comprises a sampling end, a pulse modulation control end and a plurality of first control output ends. The sampling end is electrically connected with the sampling element. The pulse modulation control end is electrically connected with the third end. Each of the first control outputs is electrically connected to one of the remaining taps. The controller controls the pulse generator to send pulse signals with certain frequency and amplitude to the mutual inductor. And the mutual inductor induces the residual current on the direct current wire to be detected under the action of the pulse signal. And the controller acquires the voltage on the sampling element so as to obtain the real residual current value on the direct current wire to be detected. The controller controls the on-off of the tap, so that the number of turns of the coil of the mutual inductor is selected, and the measuring range of the residual current detection device is changed. The residual current detection device can detect the residual current in a wide range by changing the range on the basis of high detection precision.
Drawings
Fig. 1 is a diagram of a residual current detection device provided in an embodiment of the present application;
FIG. 2 is a block diagram of a transformer provided in one embodiment of the present application;
FIG. 3 is a diagram of a residual current detection device provided in an embodiment of the present application;
FIG. 4 is a graph of core current and residual current provided in an embodiment of the present application;
FIG. 5 is a graph illustrating the relationship between the detected current and the residual current provided in an embodiment of the present application;
fig. 6 is a diagram of a residual current operated protection system provided in an embodiment of the present application.
Description of the main element reference numerals
Residual
Sampling
Pulse
First serial
Second serial
Residual current operated
Detailed Description
In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the present application are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. This application is capable of embodiments in many different forms than those described herein and those skilled in the art will be able to make similar modifications without departing from the spirit of the application and it is therefore not intended to be limited to the embodiments disclosed below.
It will be understood that when an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
With the popularization and application of the direct current system, the direct current residual current becomes an important factor threatening the safe and reliable operation of the direct current system. In the field of civil construction and municipal administration, the range of direct current residual current is wider from several mA to several A due to various reasons for generating the direct current residual current. Particularly, for portable residual current detection equipment, how to ensure the high precision of direct current residual current detection while the detection range is large becomes a problem to be solved urgently. Therefore, referring to fig. 1, an embodiment of the present application provides a residual
The
Specifically, referring to fig. 2, the
The
Specifically, the
As shown in the core current curve of fig. 3, when the pulse voltage is +12V, the core current changes from a negative value to a positive value and gradually increases until the pulse voltage reverses to-12V, and the core current decreases from the positive value to the negative value and then increases in the opposite direction, and in such a cycle, the value of the sampling resistor is set to 100 Ω, so that the core repeats a deep saturated and unsaturated state.
Average value of core currentWherein
For the detected residual current value, K is a constant determined by the magnetic core material and the structure, ip is the real residual current value, N is the number of turns of the coil, and the negative sign indicates that the direction is opposite. As shown in fig. 3, when the residual current on the dc line to be measured is 10mA, the core current is also translated in the opposite direction, so that the average value of the core current isWhen N is set to K,the minus sign indicates that the direction is reversed.In this embodiment, the
Referring to fig. 4, in one embodiment, the residual
Specifically, the
In one embodiment, the
In one embodiment, the residual
wherein, the order n of the filter is 5, and the cut-off frequency omega of the filterc30 Hz. The result of the low-pass filtering is shown in fig. 5, and the detected current is the same as the real dc residual current and has the opposite direction.
Referring to fig. 6, an embodiment of the present application provides a residual current operated
In one embodiment, the residual current operated
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the claims. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
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