CN211426763U - CT polarity tester based on waveform discrimination - Google Patents
CT polarity tester based on waveform discrimination Download PDFInfo
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- CN211426763U CN211426763U CN201921213940.3U CN201921213940U CN211426763U CN 211426763 U CN211426763 U CN 211426763U CN 201921213940 U CN201921213940 U CN 201921213940U CN 211426763 U CN211426763 U CN 211426763U
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Abstract
The utility model discloses a CT polarity tester based on waveform discrimination, which comprises a DC clamp meter, a signal amplification processing circuit, a CPU processor and an input/output functional module; the direct current clamp meter is used for collecting current response signals; the signal amplification processing circuit is used for amplifying the current response signal to obtain a forward and reverse current waveform or a reverse current waveform; the CPU is used for analyzing the current waveform and determining the test result of the CT polarity; the input and output functional module is used for realizing the output of the test result or the input of various functions. The utility model can test the polarity of the CT without disconnecting the secondary circuit of the CT, and eliminates the risk of open circuit of the secondary circuit of the CT after the polarity test; the CT polarity test result is clear, and the misjudgment risk caused by unobvious deflection of an ammeter or negligence of a tester is eliminated; the testing method is simple, saves labor and improves working efficiency.
Description
Technical Field
The embodiment of the utility model provides a relate to current transformer technical field, especially relate to a CT polarity tester based on waveform discrimination.
Background
Current transformers, abbreviated as CT. Polarity testing is a test item that must be performed after a new installation of a CT or after a winding replacement. The polarity test of the CT is related to the correctness of the sampling data of the secondary system and the load test result of the differential protection belt when the equipment is put into operation, and is very important for ensuring the safe and stable operation of the CT secondary circuit. The current polarity test of the current transformer adopts a mode that a dry battery is connected in series at a primary side, and a milliammeter is connected in series at a secondary side, namely, an instantaneous primary current is generated in a circuit by instantly connecting the dry battery at the primary side into the circuit, and then whether the wiring at two sides of the current transformer is polarity reduction is judged according to the deflection direction of the milliammeter connected in series at the secondary side. This approach suffers from several drawbacks:
(1) the current loop needs to be disconnected and then connected in series with the ammeter, so that the risk of open circuit of the CT secondary loop exists;
(2) the deflection of the pointer of the ammeter is observed by naked eyes, so that the possibility of misjudgment exists, particularly when the deflection of the ammeter is not obvious due to the battery problem or the circuit problem;
(3) the operation is inconvenient, at least two persons are required to finish the work of the current meter, one person holds the ammeter, the other person is connected in series by the meter pen, and the ammeter is required to be matched with the current people on the primary side, so that the working efficiency is influenced.
SUMMERY OF THE UTILITY MODEL
The utility model provides a CT polarity tester based on waveform discrimination to solve the not enough of prior art.
In order to achieve the above object, the present invention provides the following technical solutions:
the embodiment of the utility model provides a CT polarity tester based on waveform discrimination, which comprises a direct current clamp meter, a signal amplification processing circuit, a CPU processor and an input/output function module;
the direct current clamp meter is used for collecting current response signals;
the signal amplification processing circuit is used for amplifying the current response signal to obtain a forward and reverse current waveform or a reverse current waveform;
the CPU is used for analyzing the current waveform and determining a test result of the CT polarity;
the input and output function module is used for realizing the output of the test result or the input of various functions.
Further, in the CT polarity tester based on waveform discrimination, the dc clamp meter is a milliampere dc clamp meter.
Further, in the CT polarity tester based on waveform discrimination, the signal amplification processing circuit and the CPU processor are integrated in a shell to form a portable handheld device; the portable handheld device and the direct current clamp meter can be connected through an interface.
Further, in the waveform discrimination-based CT polarity tester, the input/output function module includes an LCD display screen, an LED indicator light, and a function key;
the LCD display screen, the LED indicator light and the function keys are arranged on the portable handheld device;
the LCD display screen is used for checking the acquired current waveform;
the LED lamp is used for displaying the polarity of the CT;
the function keys include a test key.
Furthermore, in the waveform discrimination-based CT polarity tester, the signal amplification processing circuit is composed of two stages of inverting amplifiers, which are a first-stage amplifier and a two-stage amplifier in sequence, and amplifies the micro current response signal;
the primary amplifier is used for raising and outputting the passing tiny voltage;
the secondary amplifier is used for controlling the output raising level through the CPU.
Compared with the prior art, the utility model discloses following beneficial effect has:
1. the traditional polarity test method is thoroughly changed, and the polarity of the CT is tested by adopting a brand-new test method under the condition that the secondary circuit of the CT is not required to be disconnected, so that the method is significant for relay protection profession, and the risk of open circuit of the secondary circuit of the CT after polarity test is thoroughly eliminated;
2. the CT polarity test result is clear, the test result can be prompted through an LED indicator lamp, and the test result can also be judged manually through the displayed waveform, so that the risk of misjudgment caused by unobvious deflection of an ammeter or negligence of a tester is eliminated;
3. the testing method is simple, the polarity can be tested only by clamping the testing loop according to the arrow direction of the direct current clamp meter, two meter pens are not needed to be connected in series with the loop, the labor is saved, and the working efficiency is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without inventive exercise.
Fig. 1 is a schematic structural diagram of a CT polarity tester based on waveform discrimination according to an embodiment of the present invention;
fig. 2 is a schematic circuit structure diagram of a signal amplification processing circuit in the first embodiment of the present invention;
fig. 3 is a schematic flow chart of a CT polarity testing method based on waveform discrimination according to an embodiment of the present invention.
Reference numerals:
the direct current clamp meter comprises a direct current clamp meter 10, a signal amplification processing circuit 20, a CPU 30 and an input/output functional module 40.
Detailed Description
In order to make the objects, features and advantages of the present invention more obvious and understandable, the embodiments of the present invention are clearly and completely described with reference to the drawings in the embodiments of the present invention, and obviously, the embodiments described below are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
In the description of the present invention, it is to be understood that 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. When a component is referred to as being "disposed on" another component, it can be directly on the other component or intervening components may also be present.
Furthermore, the terms "long", "short", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships illustrated in the drawings, and are only for convenience of describing the present invention, but do not indicate or imply that the device or element referred to must have the specific orientation, operate in the specific orientation configuration, and thus, should not be construed as limiting the present invention.
The technical solution of the present invention is further explained by the following embodiments with reference to the accompanying drawings.
Example one
Referring to fig. 1, an embodiment of the present invention provides a CT polarity tester based on waveform discrimination, which is characterized in that the CT polarity tester includes a dc clamp meter 10, a signal amplification processing circuit 20, a CPU processor 30 and an input/output function module 40;
the direct current clamp meter 10 is used for collecting current response signals;
the signal amplification processing circuit 20 is configured to amplify the current response signal to obtain a forward and reverse current waveform or a reverse current waveform;
the CPU 30 is configured to analyze the current waveform and determine a test result of the CT polarity;
the input/output function module 40 is used for outputting a test result or inputting various functions.
Preferably, the dc clamp meter 10 is a milliampere dc clamp meter 10.
Preferably, the signal amplification processing circuit 20 and the CPU processor 30 are integrated in a single housing to form a portable handset; the portable hand-held device and the direct current clamp meter 10 can be connected through an interface.
Preferably, the input/output function module 40 includes an LCD display screen, an LED indicator light and a function key;
the LCD display screen, the LED indicator light and the function keys are arranged on the portable handheld device;
the LCD display screen is used for checking the acquired current waveform;
the LED lamp is used for displaying the polarity of the CT;
the function keys include a test key.
Referring to fig. 2, the signal amplification processing circuit 20 is composed of two stages of inverting amplifiers, which are a first-stage amplifier and a two-stage amplifier in sequence, and amplifies the small current response signal;
the primary amplifier is used for raising and outputting the passing tiny voltage;
the secondary amplifier is used for controlling the output raising level through the CPU.
Specifically, in the signal amplification processing circuit 20, the positive input end of the primary amplifier is raised and output through a tiny voltage, when the response current of the pincer is in different directions, the response voltage of the output end of the amplifier is compared with the raised voltage so as to distinguish the current direction flowing through the pincer-shaped mutual inductor, and the adding and subtracting performance of the CT can be judged through the method; the secondary amplifier positive input end controls the raising level of the operational amplifier output through the CPU, so that the flexibility of the CPU detection reference can be increased, and the applicability of different direct current clamp meters 10 is also increased.
Referring to fig. 3, the method for testing CT polarity based on waveform discrimination, which is executed by the CT polarity tester based on waveform discrimination, includes the following steps:
s1, initializing each module;
s2, displaying a display interface by the LCD display screen;
s3, detecting whether the wireless module is started successfully; if yes, go to step S4, otherwise, go to step S3;
s4, configuring parameters of the wireless module;
s5, zeroing the direct current clamp meter;
s6, displaying a display interface by the LCD display screen;
s7, the CPU processor detects whether the test key is pressed; if yes, go to step S8, otherwise, go to step S7;
s8, carrying out CT polarity test;
s9, the CPU controls the wireless module to send command data of CT polarity test, and then waits for receiving feedback data;
s10, judging whether feedback data of the CT polarity test is received or not; if yes, go to step S12, otherwise go to step S11;
s11, judging that the communication is abnormal;
s12, starting sampling, and performing waveform display and CT polarity calculation;
s13, if the CT polarity is larger than the reference, the CT polarity is judged to be plus polarity;
s14, if the measured value is equal to the reference value, judging that the measurement is abnormal;
and S15, if the CT polarity is less than the reference, the CT polarity is judged to be the polarity reduction.
Specifically, the CPU firstly initializes the driving of each peripheral, then displays a display interface, controls the wireless module to send command data for CT polarity measurement if the CPU detects that a test key is pressed down, then waits for the reply of a signal source, and performs AD sampling of an operational amplifier after the reply of a wireless signal is detected, so as to perform waveform display and calculation and judgment of CT polarity; when the wireless data reply is not detected after the waiting time is overtime, the CPU judges that the communication is interrupted, and further judges that the CT polarity measurement is invalid.
The embodiment of the utility model provides a CT polarity tester based on waveform discrimination can test CT polarity under the state that does not need to break off the CT secondary circuit, has eliminated the risk that the CT secondary circuit opens a way after the polarity test; the CT polarity test result is clear, and the misjudgment risk caused by unobvious deflection of an ammeter or negligence of a tester is eliminated; the testing method is simple, saves labor and improves working efficiency.
The above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention in its corresponding aspects.
Claims (5)
1. A CT polarity tester based on waveform discrimination is characterized by comprising a direct current clamp meter, a signal amplification processing circuit, a CPU processor and an input/output functional module;
the direct current clamp meter is used for collecting current response signals;
the signal amplification processing circuit is used for amplifying the current response signal to obtain a forward and reverse current waveform or a reverse current waveform;
the CPU is used for analyzing the current waveform and determining a test result of the CT polarity;
the input and output function module is used for realizing the output of the test result or the input of various functions.
2. The CT polarity tester based on waveform discrimination according to claim 1, wherein the dc clamp meter is a milliamp dc clamp meter.
3. The waveform discrimination based CT polarity tester of claim 1 wherein the signal amplification processing circuit and CPU processor are integrated into a single housing to form a portable handset; the portable handheld device and the direct current clamp meter can be connected through an interface.
4. The CT polarity tester based on waveform discrimination of claim 3, wherein the input and output functional module comprises an LCD display screen, an LED indicator light and a functional key;
the LCD display screen, the LED indicator light and the function keys are arranged on the portable handheld device;
the LCD display screen is used for checking the acquired current waveform;
the LED indicator light is used for displaying the polarity of the CT;
the function keys include a test key.
5. The CT polarity tester based on waveform discrimination as claimed in claim 1, wherein the signal amplification processing circuit is composed of two stages of inverting amplifiers, namely a first-stage amplifier and a second-stage amplifier in sequence, and is used for amplifying the micro current response signal;
the primary amplifier is used for raising and outputting the passing tiny voltage;
the secondary amplifier is used for controlling the output raising level through the CPU.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921213940.3U CN211426763U (en) | 2019-07-30 | 2019-07-30 | CT polarity tester based on waveform discrimination |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921213940.3U CN211426763U (en) | 2019-07-30 | 2019-07-30 | CT polarity tester based on waveform discrimination |
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| CN211426763U true CN211426763U (en) | 2020-09-04 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110244177A (en) * | 2019-07-30 | 2019-09-17 | 广东电网有限责任公司 | A kind of CT polarity tester and test method based on waveform differentiation |
| CN112666502A (en) * | 2020-12-03 | 2021-04-16 | 广东电网有限责任公司中山供电局 | Hand-held type CT polarity tester device |
-
2019
- 2019-07-30 CN CN201921213940.3U patent/CN211426763U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110244177A (en) * | 2019-07-30 | 2019-09-17 | 广东电网有限责任公司 | A kind of CT polarity tester and test method based on waveform differentiation |
| CN112666502A (en) * | 2020-12-03 | 2021-04-16 | 广东电网有限责任公司中山供电局 | Hand-held type CT polarity tester device |
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