Polarity tester and polarity test system

Abstract

The invention discloses a polarity tester and a polarity testing system. The polarity tester comprises a switching and control unit, a polarity discrimination unit, a recording and protection unit and a charging and discharging unit. An interface of the switching and control unit is connected with a primary winding and a secondary winding of the current transformer to be detected, and is used for controlling the charging and discharging unit to discharge to the primary winding in the group to be detected after the charging and discharging unit is controlled to complete charging; the polarity discrimination unit is used for determining a polarity discrimination result of the secondary winding in the to-be-detected group; the recording and protecting unit is used for recording and storing the polarity discrimination result of the secondary winding in the group to be detected and protecting the polarity discrimination result of the secondary winding in the group to be detected; and the switching and control unit is also used for switching the group to be tested until all groups in the plurality of groups are tested. According to the scheme, the polarity of the current transformer can be automatically tested and recorded, manual operation is not needed, and the testing efficiency, accuracy and safety are improved.

Description

Technical Field

[0001] The invention relates to the technical field of electric power testing, and in particular to a polarity tester and a polarity test system. Background Art

[0002] Current Transformer (CT) is an instrument that converts large primary current into small secondary current for measurement based on the principle of electromagnetic induction. It is one of the key devices for realizing power conversion in power systems. The accuracy of current transformer directly affects the stability of power systems. Therefore, current transformers usually need to be tested for polarity before they are put into operation.

[0003] At present, the polarity test of the current transformer usually relies on testers: one tester uses a dry battery to perform "point and release" operations at the primary winding of the current transformer, and the other tester uses a microampere ammeter to measure at the secondary winding of the current transformer and observe the pointer deflection.

[0004] However, this testing method not only requires two testers to work together, but the current transformer often has multiple secondary windings. Manually replacing the primary winding and / or secondary winding detection points will make the testing process too long, time-consuming and labor-intensive. It is also impossible to avoid factors such as human operating errors, observation errors, and recording errors, which affect the accuracy of the test. Summary of the invention

[0005] The present invention provides a polarity tester and a polarity test system, which can realize automatic testing and recording of the polarity of a current transformer without manual operation, thereby improving the efficiency, accuracy and safety of the test.

[0006] According to one aspect of the present invention, a polarity tester is provided, comprising: a switching and control unit, a polarity determination unit, a recording and protection unit, and a charging and discharging unit; wherein:

[0007] The interface of the switching and control unit is connected to the primary winding and the secondary winding of the current transformer to be tested, and the output end of the switching and control unit is electrically connected to the polarity determination unit, the recording and protection unit, and the charge and discharge unit respectively. The switching and control unit is used to control the charge and discharge unit to discharge to the primary winding in the group to be tested after the charging of the charge and discharge unit is completed, wherein any combination of a primary winding and any secondary winding of the current transformer to be tested constitutes a plurality of groups, and the group to be tested is any one of the plurality of groups;

[0008] The polarity determination unit is electrically connected to the recording and protection unit and the charging and discharging unit respectively, and is used to determine the polarity determination result of the secondary winding in the group to be tested;

[0009] The recording and protection unit is electrically connected to the charge and discharge unit, and is used to record and store the polarity determination results of the secondary windings in the group to be tested, and to protect the polarity determination results of the secondary windings in the group to be tested;

[0010] The switching and control unit is also used to switch the groups to be tested until all the groups in the plurality of groups are tested.

[0011] Optionally, it also includes: a display unit and / or a printing unit;

[0012] The display unit is electrically connected to the recording and protection unit and is used to display the polarity determination result of the secondary winding in the group to be tested; the printing unit is electrically connected to the recording and protection unit and is used to print the polarity determination result of the secondary winding in the group to be tested.

[0013] Optionally, the switching and control unit includes: a micro control unit MCU, a relay and a winding terminal;

[0014] The winding terminal is provided with 2M+2N interfaces, and the 2M+2N interfaces include M first interfaces, M second interfaces, N third interfaces and N fourth interfaces; a first interface is connected to the polarity end of a primary winding of a current transformer to be measured, a second interface is connected to the non-polarity end of a primary winding of the current transformer to be measured, a third interface is connected to the polarity end of a secondary winding of the current transformer to be measured, and a fourth interface is connected to the non-polarity end of a secondary winding of the current transformer to be measured;

[0015] A relay is connected to an interface on the winding terminal, and the number of relays is 2M+2N; all relays connected to the first interface are electrically connected to the fourth output terminal of the switching and control unit, and all relays connected to the second interface are electrically connected to the third output terminal of the switching and control unit, all relays connected to the third interface are electrically connected to the first output terminal of the switching and control unit, and all relays connected to the fourth interface are electrically connected to the second output terminal of the switching and control unit;

[0016] The MCU is electrically connected to the charge and discharge unit and each relay respectively.

[0017] Optionally, the polarity determination unit includes: a first diode, a second diode, a first capacitor, a second capacitor, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor and a determination chip;

[0018] The output end of the first diode, the input end of the second diode, one end of the second capacitor, and one end of the second resistor are electrically connected to the first output end respectively; the input end of the first diode, the output end of the second diode, the other end of the second capacitor, and the other end of the second resistor are electrically connected to the second output end respectively;

[0019] One end of the fourth resistor is electrically connected to the second output end, the other end of the fourth resistor is electrically connected to one end of the third resistor, and the other end of the third resistor is electrically connected to the eighth pin of the identification chip;

[0020] One end of the fifth resistor is electrically connected to the second output end, the other end of the fifth resistor is electrically connected to one end of the sixth resistor, and the other end of the sixth resistor is electrically connected to the fourth pin of the identification chip;

[0021] The first pin, the fourth pin, and the seventh pin of the identification chip are respectively connected to the recording and protection unit, the second pin, the fifth pin and the first output terminal of the identification chip are electrically connected, the third pin of the identification chip is electrically connected to the other end of the fourth resistor, the sixth pin of the identification chip is electrically connected to the other end of the fifth resistor, and the fourth pin of the identification chip is electrically connected to the third output terminal;

[0022] One end of the first capacitor and one end of the first resistor are electrically connected to the eighth pin of the identification chip respectively, and the other end of the first capacitor and the other end of the first resistor are connected to the recording and protection unit respectively;

[0023] The fourth pin of the determination chip is grounded.

[0024] Optionally, a dual voltage comparator integrated circuit is provided in the determination chip.

[0025] Optionally, the recording and protection unit includes: a memory, a first photoelectric coupling element, a second photoelectric coupling element, a third photoelectric coupling element, a fourth photoelectric coupling element, a fifth photoelectric coupling element, a sixth photoelectric coupling element, a seventh resistor, an eighth resistor, a ninth resistor, a third capacitor and a fourth capacitor;

[0026] The anode of the light emitting diode of the first photoelectric coupling element is electrically connected to the eighth pin of the discrimination chip and the charge and discharge unit, the cathode of the light emitting diode of the first photoelectric coupling element is electrically connected to the anode of the light emitting diode of the third photoelectric coupling element, and the collector and emitter of the photosensitive transistor of the first photoelectric coupling element are electrically connected to the memory respectively;

[0027] The anode of the light emitting diode of the second photoelectric coupling element is electrically connected to the anode of the light emitting diode of the first photoelectric coupling element, the cathode of the light emitting diode of the second photoelectric coupling element is electrically connected to the anode of the light emitting diode of the fourth photoelectric coupling element, and the collector and emitter of the phototransistor of the second photoelectric coupling element are electrically connected to the memory respectively;

[0028] The cathode of the light-emitting diode of the third photoelectric coupling element is electrically connected to the anode of the light-emitting diode of the fifth photoelectric coupling element, the collector of the phototransistor of the third photoelectric coupling element is electrically connected to the anode of the light-emitting diode of the first photoelectric coupling element, and the emitter of the phototransistor of the third photoelectric coupling element is electrically connected to the cathode of the light-emitting diode of the sixth photoelectric coupling element;

[0029] The cathode of the light-emitting diode of the fourth photoelectric coupling element is electrically connected to the anode of the light-emitting diode of the sixth photoelectric coupling element, the collector of the phototransistor of the fourth photoelectric coupling element is electrically connected to the anode of the light-emitting diode of the second photoelectric coupling element, and the emitter of the phototransistor of the fourth photoelectric coupling element is electrically connected to the cathode of the light-emitting diode of the fifth photoelectric coupling element;

[0030] The cathode of the light-emitting diode of the fifth photoelectric coupling element is electrically connected to the other end of the first resistor and one end of the seventh resistor, the collector of the photosensitive transistor of the fifth photoelectric coupling element is electrically connected to the first pin of the discrimination chip, the emitter of the photosensitive transistor of the fifth photoelectric coupling element is electrically connected to the fourth pin of the discrimination chip; the other end of the seventh resistor is electrically connected to the first pin of the discrimination chip;

[0031] The cathode of the light-emitting diode of the sixth photoelectric coupling element is electrically connected to one end of the eighth resistor, the collector of the photosensitive transistor of the sixth photoelectric coupling element is electrically connected to the seventh pin of the discrimination chip, the emitter of the photosensitive transistor of the sixth photoelectric coupling element is electrically connected to the fourth pin of the discrimination chip; the other end of the eighth resistor is electrically connected to the seventh pin of the discrimination chip;

[0032] One end of the ninth resistor and one end of the third capacitor are electrically connected to the anode of the light emitting diode of the first photoelectric coupling element, respectively, and the other end of the ninth resistor and the other end of the third capacitor are electrically connected to one end of the eighth resistor, respectively;

[0033] One end of the fourth capacitor is electrically connected to the anode of the light emitting diode of the first photoelectric coupling element, and the other end of the fourth capacitor is electrically connected to the fourth pin of the determination chip.

[0034] Optionally, the charge and discharge unit includes: a power module, a first switch, a second switch, a fifth capacitor, a third diode, a tenth resistor and an eleventh resistor;

[0035] The negative electrode of the power module is electrically connected to the fourth pin of the discrimination chip, the positive electrode of the power module is electrically connected to the normally open end of the second switch, the common end of the second switch is electrically connected to the anode of the light emitting diode of the first photoelectric coupling element; the normally closed end of the second switch is disconnected;

[0036] One end of the tenth resistor is electrically connected to the positive electrode of the power module, and the other end of the tenth resistor is electrically connected to the normally closed end of the first switch;

[0037] The common end of the first switch is electrically connected to one end of the fifth capacitor, the other end of the fifth capacitor is electrically connected to the negative electrode of the power module and the input end of the third diode, and the output end of the third diode is electrically connected to the fourth output end;

[0038] The normally-open end of the first switch is electrically connected to one end of the eleventh resistor, and the other end of the eleventh resistor is electrically connected to the fourth output end.

[0039] Optionally, the power module includes: a DC power supply and a power switch;

[0040] The power switch is arranged between the DC power supply and the normally-open end of the second switch, and is used to control the opening and closing of the polarity tester.

[0041] Optionally, the power module further includes: a current converter;

[0042] The current converter is connected to an external power source and to a DC power source, and is used to convert AC power into DC power.

[0043] According to another aspect of the present invention, a polarity testing system is provided, comprising a current transformer to be tested and a polarity tester according to any one of the above embodiments.

[0044] The technical solution of the embodiment of the present invention is to design a polarity tester including a switching and control unit, a polarity discrimination unit, a recording and protection unit and a charging and discharging unit. The switching and control unit can control the charging and discharging unit to discharge to the primary winding in the group to be tested after the charging of the charging and discharging unit is completed, so that the polarity discrimination unit determines the polarity discrimination result of the secondary winding in the group to be tested, and the recording and protection unit records and stores the polarity discrimination result of the secondary winding in the group to be tested. In this way, the polarity of the current transformer can be automatically tested and recorded without manual operation, avoiding problems such as human operation errors, observation errors, and recording errors caused by manual operation, and improving the test efficiency, accuracy and safety. Further, the recording and protection unit can protect the polarity discrimination result of the secondary winding in the group to be tested, avoiding the influence of the insufficient discharge voltage of the charging and discharging unit on the polarity discrimination result, and ensuring the accuracy of the test result. In addition, the switching and control unit can also automatically switch the group to be tested, ensuring that all groups in several groups can be tested, without manual line change, further saving test time.

[0045] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0047] Figure 1 1 is a schematic diagram of the structure of a polarity tester provided by an embodiment of the present invention;

[0048] Figure 2 is a structural schematic diagram of another polarity tester provided by an embodiment of the present invention;

[0049] Figure 3 is a circuit structure diagram of a polarity tester provided by an embodiment of the present invention;

[0050] Figure 4 is a schematic diagram of the appearance of a polarity tester provided by an embodiment of the present invention;

[0051] Figure 5 The present invention provides a flowchart of a polarity tester. DETAILED DESCRIPTION

[0052] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0053] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0054] Figure 1 1 is a schematic diagram of the structure of a polarity tester provided by an embodiment of the present invention. The polarity tester is used to test the polarity of the secondary winding of a current transformer to be tested. Figure 1 As shown, the polarity tester includes: a switching and control unit 100 , a polarity determination unit 200 , a recording and protection unit 300 and a charge and discharge unit 400 .

[0055] The interface of the switching and control unit 100 is connected to the primary winding and the secondary winding of the current transformer to be tested, and the output end of the switching and control unit 100 is electrically connected to the polarity determination unit 200, the recording and protection unit 300, and the charge and discharge unit 400. The polarity determination unit 200 is electrically connected to the recording and protection unit 300 and the charge and discharge unit 400. The recording and protection unit 300 is electrically connected to the charge and discharge unit 400.

[0056] The switching and control unit 100 is used to control the charging and discharging unit 400 to charge after the polarity tester is turned on, and to determine whether the charging and discharging unit 400 is completed; when the charging and discharging unit 400 is completed, the charging and discharging unit 400 is controlled to discharge to the primary winding in the group to be tested, wherein any primary winding and any secondary winding combination of the current transformer to be tested constitutes several groups, and the group to be tested is any one of the several groups.

[0057] Usually, the current transformer to be tested includes three primary windings (i.e., a primary winding for phase A, a primary winding for phase B, and a primary winding for phase C, denoted as primary winding A, primary winding B, and primary winding C) and at least one secondary winding (denoted as secondary winding E1, secondary winding E2, ..., secondary winding En, n is a positive integer). The entire test process of the polarity tester needs to test all groups formed by the combination of primary windings and secondary windings in pairs. For example, assuming that the current transformer to be tested includes three primary windings and three secondary groups, the polarity tester needs to test: Group 1-primary winding A+secondary winding E1, Group 2-primary winding A+secondary winding E2, Group 3-primary winding A+secondary winding E3, Group 4-primary winding B+secondary winding E1, Group 5-primary winding B+secondary winding E2, Group 6-primary winding B+secondary winding E3, Group 7-primary winding C+secondary winding E1, Group 8-primary winding C+secondary winding E2, Group 9-primary winding C+secondary winding E3, a total of 9 groups.

[0058] When the charge-discharge unit 400 discharges the primary winding in the group to be tested, the polarity determination unit 200 can determine the polarity determination result of the secondary winding in the group to be tested, and send the polarity determination result of the secondary winding in the group to be tested to the recording and protection unit 300 for recording and storage. The recording and protection unit 300 can also protect the polarity determination result of the secondary winding in the group to be tested.

[0059] The switching and control unit 100 is also used to switch the groups to be tested until all the groups in the plurality of groups are tested, thereby ensuring that all the groups in the plurality of groups can be tested without manual line switching, thus saving test time.

[0060] Combination Figure 1 , Figure 2FIG. 1 is a schematic diagram of the structure of another polarity tester provided by an embodiment of the present invention. Figure 2 As shown, the polarity tester further includes: a display unit 500 and / or a printing unit 600 .

[0061] The display unit 500 is electrically connected to the recording and protection unit 300, and is used to display the polarity determination result of the secondary winding in the test group. Optionally, the display unit 500 may have a touch function, so that the user can input instructions (such as querying the polarity determination result, starting the printing function, etc.) through the display unit 500, thereby improving the usability and interactivity of the polarity tester.

[0062] The printing unit 600 is electrically connected to the recording and protection unit 300 and is used to print the polarity determination result of the secondary winding in the group to be tested.

[0063] In one embodiment, Figure 3 FIG. 1 is a circuit diagram of a polarity tester provided by an embodiment of the present invention. Figure 3 As shown, the switching and control unit 100 includes: a micro control unit MCU, a relay ( Figure 3 Marked as t1-t12) and winding terminals.

[0064] The winding terminal is provided with 2M+2N interfaces, and the 2M+2N interfaces include M first interfaces, M second interfaces, N third interfaces and N fourth interfaces. A first interface is connected to the polarity end of a primary winding of the current transformer to be measured, a second interface is connected to the non-polarity end of a primary winding of the current transformer to be measured, a third interface is connected to the polarity end of a secondary winding of the current transformer to be measured, and a fourth interface is connected to the non-polarity end of a secondary winding of the current transformer to be measured.

[0065] For example, Figure 3In the figure, M=3 and N=3 are used as examples. The upper terminal of the winding terminal is used to connect the secondary winding of the current transformer to be tested. E1 corresponds to a third interface F3 and a fourth interface F4, and F3 and F4 are respectively connected to the polarity end and non-polarity end of the secondary winding E1; similarly, E2 corresponds to a third interface F3 and a fourth interface F4, and F3 and F4 are respectively connected to the polarity end and non-polarity end of the secondary winding E2; E3 corresponds to a third interface F3 and a fourth interface F4, and F3 and F4 are respectively connected to the polarity end and non-polarity end of the secondary winding E3. The lower terminal of the winding terminal is used to connect the primary winding of the current transformer to be tested. A corresponds to a first interface F1 and a second interface F2, F1 and F2 are respectively connected to the polarity end and non-polarity end of the primary winding A; similarly, B corresponds to a first interface F1 and a second interface F2, F1 and F2 are respectively connected to the polarity end and non-polarity end of the primary winding B; C corresponds to a first interface F1 and a second interface F2, F1 and F2 are respectively connected to the polarity end and non-polarity end of the primary winding C.

[0066] One relay is connected to one interface on the winding terminal. Since the number of interfaces on the winding terminal is 2M+2N, the number of relays is also 2M+2N.

[0067] All relays connected to the first interface F1 (i.e., t10, t11, and t12) are electrically connected to the fourth output terminal d of the switching and control unit 100; all relays connected to the second interface F2 (i.e., t7, t8, and t9) are electrically connected to the third output terminal c of the switching and control unit 100; all relays connected to the third interface F3 (i.e., t1, t2, and t3) are electrically connected to the first output terminal a of the switching and control unit 100, and all relays connected to the fourth interface F4 (i.e., t4, t5, and t6) are electrically connected to the second output terminal b of the switching and control unit 100.

[0068] The MCU is electrically connected to the first switch S1 and the second switch S2 of the charge and discharge unit 400 and each relay. Figure 3In the figure, the first switch S1, the second switch S2 and each relay are controlled by the MCU in the form of dotted lines. The MCU is programmed with a related relay control program to control the conduction and disconnection of the relays, thereby realizing the switching of the groups to be tested. For example, the control program can first control the primary winding A (i.e., relays t7 and t10) to be turned on, and then switch the relays t1 and t4, t2 and t5, t3 and t6 to be turned on in sequence to realize the detection of the three secondary windings; then control the primary winding B (i.e., relays t8 and t11) to be turned on, and then switch the relays t1 and t4, t2 and t5, t3 and t6 to be turned on in sequence to realize the detection of the three secondary windings; finally, control the primary winding C (i.e., relays t9 and t12) to be turned on, and then switch the relays t1 and t4, t2 and t5, t3 and t6 to be turned on in sequence to realize the detection of the last three secondary windings.

[0069] In this way, the groups to be tested are automatically switched to ensure that all groups in a number of groups can be tested without manual line switching, thus saving test time.

[0070] The polarity determination unit 200 includes: a first diode D1, a second diode D2, a first capacitor C1, a second capacitor C2, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6 and a determination chip LM393.

[0071] like Figure 3 As shown, the output end of the first diode D1, the input end of the second diode D2, one end of the second capacitor C2, and one end of the second resistor R2 are electrically connected to the first output end a, respectively; the input end of the first diode D1, the output end of the second diode D2, the other end of the second capacitor C2, and the other end of the second resistor R2 are electrically connected to the second output end b, respectively.

[0072] One end of the fourth resistor R4 is electrically connected to the second output terminal b, the other end of the fourth resistor R4 is electrically connected to one end of the third resistor R3, and the other end of the third resistor R3 is electrically connected to the eighth pin of the determination chip LM393. One end of the fifth resistor R5 is electrically connected to the second output terminal b, the other end of the fifth resistor R5 is electrically connected to one end of the sixth resistor R6, and the other end of the sixth resistor R6 is electrically connected to the fourth pin of the determination chip LM393.

[0073] The first pin, the fourth pin, and the seventh pin of the determination chip LM393 are respectively connected to the recording and protection unit 300. The second pin and the fifth pin of the determination chip LM393 are electrically connected to the first output terminal a, the third pin of the determination chip LM393 is electrically connected to the other end of the fourth resistor R4, the sixth pin of the determination chip LM393 is electrically connected to the other end of the fifth resistor R5, and the fourth pin of the determination chip LM393 is electrically connected to the third output terminal c.

[0074] One end of the first capacitor C1 and one end of the first resistor R1 are electrically connected to the eighth pin of the identification chip LM393 respectively, and the other end of the first capacitor C1 and the other end of the first resistor R1 are connected to the recording and protection unit 300 respectively; the fourth pin of the identification chip LM393 is grounded.

[0075] Optionally, a dual voltage comparator integrated circuit is provided in the discrimination chip LM393. The fifth pin and the third pin of the discrimination chip LM393 are the positive input terminals of the comparator, the sixth pin and the second pin of the discrimination chip LM393 are the negative input terminals of the comparator, and the seventh pin and the first pin of the discrimination chip LM393 are the output terminals of the comparator.

[0076] The recording and protection unit 300 includes: a memory, a first photoelectric coupling element P1, a second photoelectric coupling element P2, a third photoelectric coupling element P3, a fourth photoelectric coupling element P4, a fifth photoelectric coupling element P5, a sixth photoelectric coupling element P6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a third capacitor C3 and a fourth capacitor C4.

[0077] The anode of the light-emitting diode of the first photoelectric coupling element P1 is electrically connected to the eighth pin of the discrimination chip LM393 and the charge and discharge unit 400, the cathode of the light-emitting diode of the first photoelectric coupling element P1 is electrically connected to the anode of the light-emitting diode of the third photoelectric coupling element P3, and the collector and emitter of the phototransistor of the first photoelectric coupling element P1 are electrically connected to the memory respectively.

[0078] The anode of the light-emitting diode of the second photoelectric coupling element P2 is electrically connected to the anode of the light-emitting diode of the first photoelectric coupling element P1, the cathode of the light-emitting diode of the second photoelectric coupling element P2 is electrically connected to the anode of the light-emitting diode of the fourth photoelectric coupling element P4, and the collector and emitter of the phototransistor of the second photoelectric coupling element P2 are electrically connected to the memory respectively.

[0079] The cathode of the light-emitting diode of the third photocoupler element P3 is electrically connected to the anode of the light-emitting diode of the fifth photocoupler element P5, the collector of the phototransistor of the third photocoupler element P3 is electrically connected to the anode of the light-emitting diode of the first photocoupler element P1, and the emitter of the phototransistor of the third photocoupler element P3 is electrically connected to the cathode of the light-emitting diode of the sixth photocoupler element P6.

[0080] The cathode of the light-emitting diode of the fourth photocoupler element P4 is electrically connected to the anode of the light-emitting diode of the sixth photocoupler element P6, the collector of the phototransistor of the fourth photocoupler element P4 is electrically connected to the anode of the light-emitting diode of the second photocoupler element P2, and the emitter of the phototransistor of the fourth photocoupler element P4 is electrically connected to the cathode of the light-emitting diode of the fifth photocoupler element P5.

[0081] The cathode of the light-emitting diode of the fifth photoelectric coupling element P5 is electrically connected to the other end of the first resistor R1 and one end of the seventh resistor R7, the collector of the photosensitive transistor of the fifth photoelectric coupling element P5 is electrically connected to the first pin of the discrimination chip LM393, the emitter of the photosensitive transistor of the fifth photoelectric coupling element P5 is electrically connected to the fourth pin of the discrimination chip LM393; the other end of the seventh resistor R7 is electrically connected to the first pin of the discrimination chip LM393.

[0082] The cathode of the light-emitting diode of the sixth photoelectric coupling element P6 is electrically connected to one end of the eighth resistor R8, the collector of the photosensitive transistor of the sixth photoelectric coupling element P6 is electrically connected to the seventh pin of the discrimination chip LM393, the emitter of the photosensitive transistor of the sixth photoelectric coupling element P6 is electrically connected to the fourth pin of the discrimination chip LM393; the other end of the eighth resistor R8 is electrically connected to the seventh pin of the discrimination chip LM393.

[0083] One end of the ninth resistor R9 and one end of the third capacitor C3 are electrically connected to the anode of the light emitting diode of the first photoelectric coupling element P1, respectively, and the other end of the ninth resistor R9 and the other end of the third capacitor C3 are electrically connected to one end of the eighth resistor R8, respectively. One end of the fourth capacitor C4 is electrically connected to the anode of the light emitting diode of the first photoelectric coupling element P1, and the other end of the fourth capacitor C4 is electrically connected to the fourth pin of the determination chip LM393.

[0084] The charge and discharge unit 400 includes: a power module, a first switch S1, a second switch S2, a fifth capacitor R5, a third diode D3, a tenth resistor R10 and an eleventh resistor R11.

[0085] The negative pole of the power module is electrically connected to the fourth pin of the identification chip LM393, the positive pole of the power module is electrically connected to the normally open end of the second switch S2, the common end of the second switch S2 is electrically connected to the anode of the light-emitting diode of the first photoelectric coupling element P1; the normally closed end of the second switch S3 is open.

[0086] One end of the tenth resistor R10 is electrically connected to the positive electrode of the power module, and the other end of the tenth resistor R10 is electrically connected to the normally closed end of the first switch S1; the common end of the first switch S1 is electrically connected to one end of the fifth capacitor C5, and the other end of the fifth capacitor C5 is electrically connected to the negative electrode of the power module and the input end of the third diode D3, and the output end of the third diode D3 is electrically connected to the fourth output end d. The normally open end of the first switch S1 is electrically connected to one end of the eleventh resistor R11, and the other end of the eleventh resistor R11 is electrically connected to the fourth output end d.

[0087] It should be noted that Figure 3 The first switch S1 and the second switch S2 shown in the figure are drawn based on the example of switching to the normally closed end.

[0088] Optionally, the power supply module includes: a DC power supply DY and a power switch S3; the power switch S3 is arranged between the DC power supply DY and the normally open end of the second switch S2, and the power switch S3 is used to control the opening and closing of the polarity tester.

[0089] During the test, the fifth capacitor C5 is charged in the initial state. When the first switch S1 is switched from the normally closed end to the normally open end, the fifth capacitor C5 is discharged to the primary winding in the test group through the MCU after passing through the eleventh resistor R11. At this time, the secondary winding will output the corresponding induced current to the polarity determination unit 200. Since the polarity determination unit 200 uses the determination chip LM393, when the secondary winding is a subtractive polarity structure, point a outputs a high potential. At this time, the potential of point a is greater than the potential of point e. The first pin of the determination chip LM393 outputs a low potential, and the seventh pin outputs a high potential (i.e. Figure 3 When the secondary winding is in the structure of adding polarity, point b outputs high potential. At this time, the potential of point b is greater than that of point f. The first pin of the LM393 chip outputs high potential, and the seventh pin outputs low potential (i.e. Figure 3 Point g is high potential, and point h is low potential). This potential change is used to distinguish the polarity results.

[0090] For the recording and protection unit 300, the first photoelectric coupling element P1 and the second photoelectric coupling element P2 in the dotted box ① are used to record the polarity discrimination result, the third photoelectric coupling element P3 and the fourth photoelectric coupling element P4 in the dotted box ② are used for polarity locking, and the fifth photoelectric coupling element P5 and the sixth photoelectric coupling element P6 in the dotted box ③ are used for self-maintenance of the loop.

[0091] Specifically, when the secondary winding is of a subtractive polarity structure, point g is of low potential and point h is of high potential. At this time, the first photoelectric coupling element P1, the third photoelectric coupling element P3, and the fifth photoelectric coupling element P5 in the loop are turned on, and the second photoelectric coupling element P2, the fourth photoelectric coupling element P4, and the sixth photoelectric coupling element P6 are not turned on. When the secondary winding is of an additive polarity structure, the result is the opposite.

[0092] The first photoelectric coupling element P1 and the second photoelectric coupling element P2 in the dotted box ① are used to record the polarity discrimination result: when the first photoelectric coupling element P1 is turned on, its photosensitive transistor is driven to be turned on, a high potential is input to the memory at point i, and the polarity discrimination result is subtractive polarity; when the second photoelectric coupling element P2 is turned on, its photosensitive transistor is driven to be turned on, a high potential is input to the memory at point j, and the polarity discrimination result is additive polarity.

[0093] The third photocoupler element P3 and the fourth photocoupler element P4 in the dotted box ② are used for polarity locking: when the third photocoupler element P3 is turned on, the photosensitive transistor inside it is turned on, and a high potential is turned on to point 1, then the second photocoupler element P2, the fourth photocoupler element P4, and the sixth photocoupler element P6 are locked and cannot be turned on; similarly, when the fourth photocoupler element P4 is turned on, the first photocoupler element P1, the third photocoupler element P3, and the fifth photocoupler element P5 are locked and cannot be turned on.

[0094] The fifth photoelectric coupling element P5 and the sixth photoelectric coupling element P6 in the dotted box ③ are used for self-holding of the loop: when the fifth photoelectric coupling element P5 is turned on, the photosensitive transistor inside it is turned on, point m and point g are turned on, point g and the negative electrode of the DC power supply DY are always kept in a conducting state, forming a self-holding loop, which is convenient for the memory to collect the polarity discrimination result; similarly, when the sixth photoelectric coupling element P6 is turned on, point h and point n are turned on, point h and the negative electrode of the DC power supply DY are always kept in a conducting state, forming a self-holding loop, which is convenient for the memory to collect the polarity discrimination result.

[0095] In this way, the circuit structure can be protected while avoiding the influence of insufficient discharge voltage of the charge and discharge unit on the polarity discrimination result, thereby ensuring the accuracy of the test result.

[0096] In addition, the polarity tester adopts a DC test method, discharges to the primary winding in the group to be tested through the fifth capacitor C5, and then collects the corresponding voltage change information at the secondary winding in the group to be tested for polarity discrimination. When the first switch S1 and the second switch S2 are in the normally closed state, the polarity discrimination unit is disconnected from the DC power supply DY, the DC power supply DY charges the fifth capacitor C5, and the fifth capacitor C5 is disconnected from the eleventh resistor R11, and the fifth capacitor C5 does not discharge to the primary winding in the group to be tested. During the test, the first switch S1 and the second switch S2 are switched to the normally open state, the polarity discrimination unit is connected to the DC power supply DY, the DC power supply DY is disconnected from the fifth capacitor C5, and the fifth capacitor C5 is connected to the eleventh resistor R11, and the fifth capacitor C5 discharges to the primary winding in the group to be tested. After all the groups in the several groups are tested, the polarity tester enters the reset mode, the first switch S1 and the second switch S2 are in the normally closed state, the polarity determination unit is disconnected from the DC power supply DY, all the photoelectric coupling elements are not powered, and the functions are restored to the original state. The DC power supply DY charges the fifth capacitor C5, and at the same time, the fifth capacitor C5 is disconnected from the eleventh resistor R11, and no discharge loop is formed.

[0097] Optionally, the power module further includes: a current converter; the current converter is connected to an external power source and is connected to a DC power source DY, and the current converter is used to convert AC power into DC power.

[0098] Figure 4 FIG. 1 is a schematic diagram of the appearance of a polarity tester provided by an embodiment of the present invention. Figure 4 As shown, the polarity tester comprises a housing 1, on the surface of which are arranged winding terminals 2, grounding holes 3, power sockets 4, switch buttons 5, as well as a display 5 and a printer 6. The switch button 5 is mechanically connected to the third switch S3.

[0099] Figure 5 FIG. 1 is a flowchart of a polarity tester provided by an embodiment of the present invention. Figure 5 As shown, when the polarity tester is working, first connect the power socket, press the switch button to make S3 in the closed state. Before the polarity discrimination begins, C5 needs to be charged, and S1 and S2 are kept in the normally closed state. At this time, C5 is in the charging state, and then a charging judgment is performed. If the charging is completed, the next step is entered. If the charging is not completed, the step of keeping S1 and S2 in the normally closed state is returned. After the charging is completed, the MCU operates the relay contacts to conduct the first group, and then the S1 and S2 switches are switched to the normally open state at the same time to perform a polarity discrimination. The polarity discrimination results are collected through the memory, and a data collection success judgment is entered. If the data recording is completed, the next step is entered. If it is not completed, it returns to the data input collection step. Enter again to determine whether the MCU has completed the conduction selection of all relay contacts. If there are other groups that have not been completed, return to the step of "switching S1 and S2 to the normally closed state" and recycle; if all are completed, the memory exports the polarity discrimination results and ends.

[0100] The technical solution of the embodiment of the present invention is to design a polarity tester including a switching and control unit, a polarity discrimination unit, a recording and protection unit and a charging and discharging unit. The switching and control unit can control the charging and discharging unit to discharge to the primary winding in the group to be tested after the charging of the charging and discharging unit is completed, so that the polarity discrimination unit determines the polarity discrimination result of the secondary winding in the group to be tested, and the recording and protection unit records and stores the polarity discrimination result of the secondary winding in the group to be tested. In this way, the polarity of the current transformer can be automatically tested and recorded without manual operation, avoiding problems such as human operation errors, observation errors, and recording errors caused by manual operation, and improving the test efficiency, accuracy and safety. Further, the recording and protection unit can protect the polarity discrimination result of the secondary winding in the group to be tested, avoiding the influence of the insufficient discharge voltage of the charging and discharging unit on the polarity discrimination result, and ensuring the accuracy of the test result. In addition, the switching and control unit can also automatically switch the group to be tested, ensuring that all groups in several groups can be tested, without manual line change, further saving test time.

[0101] An embodiment of the present invention further provides a polarity testing system, comprising a current transformer to be tested, and a polarity tester according to any one of the above embodiments.

[0102] The polarity tester comprises: a switching and control unit, a polarity determination unit, a recording and protection unit and a charging and discharging unit; wherein,

[0103] The interface of the switching and control unit is connected to the primary winding and the secondary winding of the current transformer to be tested, and the output end of the switching and control unit is electrically connected to the polarity determination unit, the recording and protection unit, and the charge and discharge unit respectively. The switching and control unit is used to control the charge and discharge unit to discharge to the primary winding in the group to be tested after the charging of the charge and discharge unit is completed, wherein any combination of a primary winding and any secondary winding of the current transformer to be tested constitutes a plurality of groups, and the group to be tested is any one of the plurality of groups;

[0104] The polarity determination unit is electrically connected to the recording and protection unit and the charging and discharging unit respectively, and is used to determine the polarity determination result of the secondary winding in the group to be tested;

[0105] The recording and protection unit is electrically connected to the charge and discharge unit, and is used to record and store the polarity determination results of the secondary windings in the group to be tested, and to protect the polarity determination results of the secondary windings in the group to be tested;

[0106] The switching and control unit is also used to switch the groups to be tested until all the groups in the plurality of groups are tested.

[0107] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A polarity tester, characterized in that: include: Switching and control unit, polarity determination unit, recording and protection unit and charging and discharging unit; wherein, The interface of the switching and control unit is connected to the primary winding and the secondary winding of the current transformer to be tested, and the output end of the switching and control unit is electrically connected to the polarity determination unit, the recording and protection unit, and the charging and discharging unit respectively. The switching and control unit is used to control the charging and discharging unit to discharge to the primary winding in the group to be tested after controlling the charging and discharging unit to complete charging, wherein any combination of a primary winding and any secondary winding of the current transformer to be tested constitutes a plurality of groups, and the group to be tested is any one of the plurality of groups; The polarity determination unit is electrically connected to the recording and protection unit and the charging and discharging unit respectively, and is used to determine the polarity determination result of the secondary winding in the group to be tested; The recording and protection unit is electrically connected to the charging and discharging unit, and is used to record and store the polarity determination results of the secondary windings in the group to be tested, and to protect the polarity determination results of the secondary windings in the group to be tested; The switching and control unit is further used to switch the groups to be tested until all the groups in the plurality of groups are tested.

2. The polarity tester according to claim 1, characterized in that: Also includes: a display unit and / or a printing unit; The display unit is electrically connected to the recording and protection unit, and is used to display the polarity determination result of the secondary winding in the group to be tested; The printing unit is electrically connected to the recording and protection unit, and is used for printing the polarity determination result of the secondary winding in the group to be tested.

3. The polarity tester according to claim 1, characterized in that: The switching and control unit comprises: a micro control unit MCU, a relay and a winding terminal; The winding terminal is provided with 2M+2N interfaces, and the 2M+2N interfaces include M first interfaces, M second interfaces, N third interfaces and N fourth interfaces; one of the first interfaces is connected to the polarity end of a primary winding of the current transformer to be measured, one of the second interfaces is connected to the non-polarity end of a primary winding of the current transformer to be measured, one of the third interfaces is connected to the polarity end of a secondary winding of the current transformer to be measured, and one of the fourth interfaces is connected to the non-polarity end of a secondary winding of the current transformer to be measured; One of the relays is connected to an interface on the winding terminal, and the number of the relays is 2M+2N; all relays connected to the first interface are electrically connected to the fourth output terminal of the switching and control unit, all relays connected to the second interface are electrically connected to the third output terminal of the switching and control unit, all relays connected to the third interface are electrically connected to the first output terminal of the switching and control unit, and all relays connected to the fourth interface are electrically connected to the second output terminal of the switching and control unit; The MCU is electrically connected to the charging and discharging unit and each of the relays respectively.

4. The polarity tester according to claim 3, characterized in that: The polarity determination unit includes: a first diode, a second diode, a first capacitor, a second capacitor, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor and a determination chip; The output end of the first diode, the input end of the second diode, one end of the second capacitor, and one end of the second resistor are electrically connected to the first output end respectively; the input end of the first diode, the output end of the second diode, the other end of the second capacitor, and the other end of the second resistor are electrically connected to the second output end respectively; One end of the fourth resistor is electrically connected to the second output end, the other end of the fourth resistor is electrically connected to one end of the third resistor, and the other end of the third resistor is electrically connected to the eighth pin of the identification chip; One end of the fifth resistor is electrically connected to the second output end, the other end of the fifth resistor is electrically connected to one end of the sixth resistor, and the other end of the sixth resistor is electrically connected to the fourth pin of the identification chip; The first pin, the fourth pin, and the seventh pin of the identification chip are respectively connected to the recording and protection unit, the second pin and the fifth pin of the identification chip are electrically connected to the first output end, the third pin of the identification chip is electrically connected to the other end of the fourth resistor, the sixth pin of the identification chip is electrically connected to the other end of the fifth resistor, and the fourth pin of the identification chip is electrically connected to the third output end; One end of the first capacitor and one end of the first resistor are electrically connected to the eighth pin of the identification chip respectively, and the other end of the first capacitor and the other end of the first resistor are connected to the recording and protection unit respectively; The fourth pin of the determination chip is grounded.

5. The polarity tester according to claim 4, characterized in that: The determination chip is provided with a dual voltage comparator integrated circuit.

6. The polarity tester according to claim 4, characterized in that: The recording and protection unit includes: a memory, a first photoelectric coupling element, a second photoelectric coupling element, a third photoelectric coupling element, a fourth photoelectric coupling element, a fifth photoelectric coupling element, a sixth photoelectric coupling element, a seventh resistor, an eighth resistor, a ninth resistor, a third capacitor and a fourth capacitor; The anode of the light emitting diode of the first photoelectric coupling element is electrically connected to the eighth pin of the discrimination chip and the charging and discharging unit, the cathode of the light emitting diode of the first photoelectric coupling element is electrically connected to the anode of the light emitting diode of the third photoelectric coupling element, and the collector and emitter of the photosensitive transistor of the first photoelectric coupling element are electrically connected to the memory respectively; The anode of the light emitting diode of the second photoelectric coupling element is electrically connected to the anode of the light emitting diode of the first photoelectric coupling element, the cathode of the light emitting diode of the second photoelectric coupling element is electrically connected to the anode of the light emitting diode of the fourth photoelectric coupling element, and the collector and emitter of the phototransistor of the second photoelectric coupling element are electrically connected to the memory respectively; The cathode of the light-emitting diode of the third photoelectric coupling element is electrically connected to the anode of the light-emitting diode of the fifth photoelectric coupling element, the collector of the phototransistor of the third photoelectric coupling element is electrically connected to the anode of the light-emitting diode of the first photoelectric coupling element, and the emitter of the phototransistor of the third photoelectric coupling element is electrically connected to the cathode of the light-emitting diode of the sixth photoelectric coupling element; The cathode of the light-emitting diode of the fourth photoelectric coupling element is electrically connected to the anode of the light-emitting diode of the sixth photoelectric coupling element, the collector of the phototransistor of the fourth photoelectric coupling element is electrically connected to the anode of the light-emitting diode of the second photoelectric coupling element, and the emitter of the phototransistor of the fourth photoelectric coupling element is electrically connected to the cathode of the light-emitting diode of the fifth photoelectric coupling element; The cathode of the light-emitting diode of the fifth photoelectric coupling element is electrically connected to the other end of the first resistor and one end of the seventh resistor, the collector of the phototransistor of the fifth photoelectric coupling element is electrically connected to the first pin of the discrimination chip, the emitter of the phototransistor of the fifth photoelectric coupling element is electrically connected to the fourth pin of the discrimination chip; the other end of the seventh resistor is electrically connected to the first pin of the discrimination chip; The cathode of the light-emitting diode of the sixth photoelectric coupling element is electrically connected to one end of the eighth resistor, the collector of the phototransistor of the sixth photoelectric coupling element is electrically connected to the seventh pin of the discrimination chip, the emitter of the phototransistor of the sixth photoelectric coupling element is electrically connected to the fourth pin of the discrimination chip; the other end of the eighth resistor is electrically connected to the seventh pin of the discrimination chip; One end of the ninth resistor and one end of the third capacitor are electrically connected to the anode of the light-emitting diode of the first photoelectric coupling element, respectively, and the other end of the ninth resistor and the other end of the third capacitor are electrically connected to one end of the eighth resistor, respectively; One end of the fourth capacitor is electrically connected to the anode of the light emitting diode of the first photoelectric coupling element, and the other end of the fourth capacitor is electrically connected to the fourth pin of the determination chip.

7. The polarity tester according to claim 6, characterized in that: The charging and discharging unit includes: a power module, a first switch, a second switch, a fifth capacitor, a third diode, a tenth resistor and an eleventh resistor; The negative electrode of the power module is electrically connected to the fourth pin of the identification chip, the positive electrode of the power module is electrically connected to the normally open end of the second switch, the common end of the second switch is electrically connected to the anode of the light emitting diode of the first photoelectric coupling element; the normally closed end of the second switch is disconnected; One end of the tenth resistor is electrically connected to the positive electrode of the power module, and the other end of the tenth resistor is electrically connected to the normally closed end of the first switch; The common end of the first switch is electrically connected to one end of the fifth capacitor, the other end of the fifth capacitor is electrically connected to the negative electrode of the power module and the input end of the third diode, and the output end of the third diode is electrically connected to the fourth output end; A normally-open end of the first switch is electrically connected to one end of the eleventh resistor, and the other end of the eleventh resistor is electrically connected to the fourth output end.

8. The polarity tester according to claim 7, characterized in that: The power supply module includes: a DC power supply and a power switch; The power switch is arranged between the DC power supply and the normally-open end of the second switch, and the power switch is used to control the opening and closing of the polarity tester.

9. The polarity tester according to claim 8, characterized in that: The power module further includes: a current converter; The current converter is connected to an external power source and to the DC power source, and is used to convert AC power into DC power.

10. A polarity testing system, characterized in that: It comprises a current transformer to be tested and a polarity tester as described in any one of claims 1 to 9.

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