Rapid detection device for total current loop

Abstract

The invention discloses a rapid detection device for a total current loop, which is used for detecting a secondary loop of a current transformer and comprises a detection control unit, a voltage acquisition unit and a current output unit, the detection control unit is used for controlling the current output unit to output detection current to an A-phase current loop, a B-phase current loop and a C-phase current loop of the secondary loop of the current transformer; the voltage acquisition unit is used for respectively determining A-phase voltage, B-phase voltage and C-phase voltage of the A-phase current loop, the B-phase current loop and the C-phase current loop, and sending the A-phase voltage, the B-phase voltage and the C-phase voltage to the detection control unit; therefore, the detection control unit determines respective resistance parameters of the A-phase current loop, the B-phase current loop and the C-phase current loop and determines the loop state of the secondary loop of the current transformer based on the resistance parameters. According to the technical scheme, the detection efficiency of the secondary circuit of the current transformer can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of circuit detection, and in particular to a full current loop rapid detection device. Background Art

[0002] The secondary circuit of the power system can obtain the current and voltage values ​​of each operating device of the power system in an online manner, and at the same time obtain the operating parameters of the power system such as the frequency, active power, reactive power, etc. of the power system, thereby reflecting the operating status of the power system in real time. Furthermore, relay protection devices such as safety automatic devices and metering devices analyze and measure according to the obtained operating parameters of the power system, and control and process the operating status of the power system based on them. Therefore, the secondary circuit of the power system plays an important role in the power system. Whether it can operate normally will directly affect whether the relay protection device can measure accurately, whether the relay protection and safety automatic devices in the power system can operate correctly, thereby ensuring the stability and reliability of the power system.

[0003] At present, the existing secondary circuit of the current transformer generally goes from the junction box of the current transformer body to the terminal box or intelligent component cabinet and other distribution devices, and then is transferred to the corresponding relay protection, safety automatic device and electric energy meter through the terminal at the distribution device through the cable. The current circuit connects various relay protection and safety automatic devices, electric energy meters, measurement and control devices and other relay protection devices with the secondary terminals of the current transformer through wiring terminals or test terminals and cables. However, during the on-site installation and commissioning process, common faults in the secondary circuit of the current transformer include multiple grounding points, reverse polarity, phase-to-phase short circuit, phase-to-ground short circuit, reverse phase sequence and broken wires. These faults will cause the secondary current sampling errors of the relay protection device, increase of unbalanced current, abnormal differential current or zero-sequence current, etc., which will lead to false operation or refusal of the relay protection device.

[0004] However, in recent years, with the increase in the types of relay protection devices, the secondary circuit of current transformers has become increasingly complex. When multiple devices are connected in series, hidden faults such as poor crimping of the terminal wires of the current transformer secondary circuit, poor contact of the test connector, or the existence of connectors in the cable often lead to power system equipment shutdown or incorrect operation of relay protection and safety automatic devices. The existing method of requiring staff to conduct inspections at each component connected to the secondary circuit of the current transformer has too low detection efficiency and cannot meet the detection requirements for the secondary circuit of the current transformer. Summary of the invention

[0005] In view of this, the present application provides a full current loop rapid detection device, the main purpose of which is to solve the technical problem of low detection efficiency of the secondary circuit of the current transformer.

[0006] According to a first aspect of the present invention, a full current loop fast detection device is provided, which is used to detect the loop state of a current transformer secondary loop, wherein the current transformer secondary loop includes an A-phase current loop composed of an A-phase secondary circuit and a neutral line, a B-phase current loop composed of a B-phase secondary circuit and a neutral line, and a C-phase current loop composed of a C-phase secondary circuit and a neutral line, and the device includes a detection control unit, a voltage acquisition unit, and a current output unit;

[0007] The detection control unit is used to control the current output unit to output a detection current of a preset current value to the A-phase secondary circuit, the B-phase secondary circuit, and the C-phase secondary circuit in sequence according to a preset order;

[0008] The voltage acquisition unit is used to respectively determine the A-phase voltage generated by the A-phase current loop based on the detection current, the B-phase voltage generated by the B-phase current loop based on the detection current, and the C-phase voltage generated by the C-phase current loop based on the detection current, and send the A-phase voltage, the B-phase voltage, and the C-phase voltage to the detection control unit;

[0009] The detection control unit is also used to determine the phase A resistance parameter of the A-phase current loop, the phase B resistance parameter of the B-phase current loop, and the phase C resistance parameter of the C-phase current loop through the phase A voltage, the phase B voltage, the phase C voltage, and the detection current, and determine the loop state of the current transformer secondary loop based on the phase A resistance parameter, the phase B resistance parameter, and the phase C resistance parameter.

[0010] Optionally, the current output unit has an A-phase output interface, a B-phase output interface and a C-phase output interface; the A-phase output interface is connected to the A-phase secondary circuit, for outputting the detection current to the A-phase secondary circuit; the B-phase output interface is connected to the B-phase secondary circuit, for outputting the detection current to the B-phase secondary circuit; the C-phase output interface is connected to the C-phase secondary circuit, for outputting the detection current to the C-phase secondary circuit.

[0011] Optionally, the voltage acquisition unit has a neutral line interface, which is connected to the neutral line; the voltage acquisition unit is also connected to the A-phase output interface, the B-phase output interface and the C-phase output interface respectively; the voltage acquisition unit determines the A-phase voltage generated by the A-phase current loop based on the detection current, the B-phase voltage generated by the B-phase current loop based on the detection current, and the C-phase voltage generated by the C-phase current loop based on the detection current, respectively, including: the voltage acquisition unit determines a first voltage difference between the A-phase output interface and the neutral line interface, and determines the first voltage difference as the A-phase voltage; determines a second voltage difference between the B-phase output interface and the neutral line interface, and determines the second voltage difference as the B-phase voltage; determines a third voltage difference between the C-phase output interface and the neutral line interface, and determines the third voltage difference as the C-phase voltage.

[0012] Optionally, the detection control unit includes a human-computer interaction interface and a central control unit; the central control unit is used to control the current output unit to output a detection current of a preset current value to the A-phase secondary circuit, the B-phase secondary circuit and the C-phase secondary circuit in a preset order; the central control unit is also used to determine the A-phase resistance parameter of the A-phase current loop, the B-phase resistance parameter of the B-phase current loop and the C-phase resistance parameter of the C-phase current loop through the A-phase voltage, the B-phase voltage, the C-phase voltage and the detection current, and determine the loop state of the current transformer secondary loop based on the A-phase resistance parameter, the B-phase resistance parameter and the C-phase resistance parameter; the central control unit is also used to send the loop state, the A-phase resistance parameter, the B-phase resistance parameter and the C-phase resistance parameter to the human-computer interaction interface, so as to display the loop state, the A-phase resistance parameter, the B-phase resistance parameter and the C-phase resistance parameter at the human-computer interaction interface.

[0013] Optionally, the central control unit determines the loop state of the secondary circuit of the current transformer based on the A-phase resistance parameter, the B-phase resistance parameter and the C-phase resistance parameter, including: the central control unit calculates the resistance parameter mean of the A-phase resistance parameter, the B-phase resistance parameter and the C-phase resistance parameter; respectively determines the A-phase parameter difference between the A-phase resistance parameter and the resistance parameter mean, the B-phase parameter difference between the B-phase resistance parameter and the resistance parameter mean, and the C-phase parameter difference between the C-phase resistance parameter and the resistance parameter mean; when the A-phase parameter difference, the B-phase parameter difference and the C-phase parameter difference are all less than a preset difference threshold, determines that the loop state of the secondary circuit of the current transformer is normal.

[0014] Optionally, the central control unit determines the loop state of the secondary circuit of the current transformer based on the A-phase resistance parameter, the B-phase resistance parameter and the C-phase resistance parameter, including: the central control unit determines whether the A-phase resistance parameter, the B-phase resistance parameter and the C-phase resistance parameter are all within a preset normal threshold range; when the A-phase resistance parameter, the B-phase resistance parameter and the C-phase resistance parameter are all within the normal threshold range, determining that the loop state of the secondary circuit of the current transformer is a normal state.

[0015] Optionally, the device also includes an alarm unit; the central control unit is also used to determine whether the A-phase resistance parameter, the B-phase resistance parameter and the C-phase resistance parameter are all within a preset resistance range, and when the A-phase resistance parameter, the B-phase resistance parameter and the C-phase resistance parameter are not all within the preset resistance range, control the current output unit to drive the alarm unit to send an alarm prompt signal.

[0016] Optionally, the alarm unit is an alarm indicator light or a buzzer.

[0017] Optionally, the current output unit includes a power supply unit and a relay switching unit; the power supply unit is used to output the detection current to the relay switching unit; the relay switching unit is used to be controlled by the central control unit to send the detection current obtained from the power supply unit to the A phase secondary circuit, the B phase secondary circuit or the C phase secondary circuit.

[0018] Optionally, the power supply unit includes an energy storage unit and an energy storage controller; the energy storage unit is used to output the detection current to the relay switching unit; the energy storage controller is used to monitor the power state of the energy storage unit in real time, and when the power state of the energy storage unit is a feeding state, issue a charging prompt message, and when the power state of the energy storage unit is an overload state, control the energy storage unit to stop outputting the detection current.

[0019] The present invention provides a full current loop rapid detection device, first, by inputting a detection current of a fixed current value into the A-phase secondary circuit in the secondary circuit of the current transformer, the A-phase voltage of the A-phase current loop is determined, the detection current of a fixed current value is input into the B-phase secondary circuit in the secondary circuit of the current transformer, the B-phase voltage of the B-phase current loop is determined, and the detection current of a fixed current value is input into the C-phase secondary circuit in the secondary circuit of the current transformer, and the C-phase voltage of the C-phase current loop is determined. Then, the A-phase resistance parameter of the A-phase current loop is determined based on Ohm's law through the A-phase voltage and the detection current, and similarly, the B-phase resistance parameter of the B-phase current loop is determined through the B-phase voltage and the detection current, and the C-phase resistance parameter of the C-phase current loop is determined through the C-phase voltage and the detection current. Finally, it is determined whether the loop state of the current transformer secondary loop is abnormal by the difference between the A-phase resistance parameter, the B-phase resistance parameter and the C-phase resistance parameter. The technical solution provided in the present application can quickly perform loop status detection on the three-phase current loop in the secondary circuit of the current transformer, and determine whether the loop status of the secondary circuit of the current transformer is abnormal through the resistance parameters of the three-phase current loop. There is no need to detect each component connected to the secondary circuit of the current transformer, thereby significantly improving the detection efficiency of the secondary circuit of the current transformer.

[0020] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0022] Figure 1 One of the structural schematic diagrams of a full current loop rapid detection device provided by an embodiment of the present invention is shown;

[0023] Figure 2 A schematic diagram of an equivalent structure of a full current loop rapid detection device provided by an embodiment of the present invention when measuring resistance parameters is shown;

[0024] Figure 3 A second structural schematic diagram of a full current loop rapid detection device provided by an embodiment of the present invention is shown;

[0025] Figure 4 A third structural schematic diagram of a full current loop rapid detection device provided by an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict.

[0027] At present, the common structure of the secondary circuit of the current transformer is as follows: Figure 1 As shown, the secondary circuit of the current transformer includes an A-phase secondary circuit, a B-phase secondary circuit, a C-phase secondary circuit and a neutral line. The A-phase secondary circuit and the neutral line form an A-phase current circuit, the B-phase secondary circuit and the neutral line form a B-phase current circuit, and the C-phase secondary circuit and the neutral line form a C-phase current circuit.

[0028] Here, the A-phase secondary circuit is divided into a first A-phase secondary circuit and a second A-phase secondary circuit by the first terminal in the power distribution device, and the first terminal includes a first wiring terminal 11, a second wiring terminal 12 and a first terminal connecting piece. When the first terminal connecting piece is turned on, the first wiring terminal 11 is turned on with the second wiring terminal 12, and when the first terminal connecting piece is turned off, the first wiring terminal 11 is turned off with the second wiring terminal 12. The first A-phase secondary circuit includes an A-phase inductor body winding, and the first end of the A-phase inductor body winding is connected to the first wiring terminal 11 as the first end of the first A-phase secondary circuit.

[0029] Furthermore, the B-phase secondary circuit is divided into a first B-phase secondary circuit and a second B-phase secondary circuit by a second terminal in the power distribution device, and the second terminal includes a third terminal 21, a fourth terminal 22, and a second terminal connecting piece. When the second terminal connecting piece is turned on, the third terminal 21 is turned on with the fourth terminal 22, and when the second terminal connecting piece is turned off, the third terminal 21 is turned off with the fourth terminal 22. The first B-phase secondary circuit includes a B-phase inductor body winding, and the first end of the B-phase inductor body winding is connected to the third terminal 21 as the first end of the first B-phase secondary circuit.

[0030] Furthermore, the C-phase secondary circuit is divided into a first C-phase secondary circuit and a second C-phase secondary circuit by the third terminal in the power distribution device, and the third terminal includes a fifth terminal 31, a sixth terminal 32 and a third terminal connecting piece. When the third terminal connecting piece is turned on, the fifth terminal 31 is turned on with the sixth terminal 32, and when the third terminal connecting piece is turned off, the fifth terminal 31 is turned off with the sixth terminal 32. The first C-phase secondary circuit includes a C-phase inductor body winding, and the first end of the C-phase inductor body winding is connected to the fifth terminal 31 as the first end of the first C-phase secondary circuit.

[0031] Further, the neutral line is divided into a first neutral line and a second neutral line by the fourth terminal, wherein the fourth terminal includes a seventh terminal 41, an eighth terminal 42 and a fourth terminal connecting piece, when the fourth terminal connecting piece is turned on, the seventh terminal 41 is turned on with the eighth terminal 42, and when the second terminal connecting piece is turned off, the seventh terminal 41 is turned off with the eighth terminal 42; further, the first end of the first neutral line is connected to the second end of the A mutual inductor body winding, the B mutual inductor body winding and the C mutual inductor body winding respectively and grounded, and the second end of the first neutral line is connected to the seventh terminal 41 of the fourth terminal. Here, the first terminal, the second terminal, the third terminal and the fourth terminal can be set in a power distribution device such as a terminal box or an intelligent group cabinet.

[0032] Further, the first end of the second A-phase secondary circuit is connected to the second terminal 12 of the first terminal. Here, the second A-phase secondary circuit is connected to the relay protection device so that the relay protection device analyzes the current parameters collected by the A-phase secondary circuit, and the second A-phase secondary circuit leads out the second end of the second A-phase secondary circuit after passing through the relay protection device. Similarly, the first end of the second B-phase secondary circuit is connected to the fourth terminal 22 of the second terminal, and the second B-phase secondary circuit is connected to the relay protection device so that the relay protection device analyzes the current parameters collected by the B-phase secondary circuit, and the second B-phase secondary circuit leads out the second end of the second B-phase secondary circuit after passing through the relay protection device; the first end of the second C-phase secondary circuit is connected to the sixth terminal 32 of the third terminal, and the second C-phase secondary circuit is connected to the relay protection device so that the relay protection device analyzes the current parameters collected by the C-phase secondary circuit, and the second C-phase secondary circuit leads out the second end of the second C-phase secondary circuit after passing through the relay protection device. Further, the first end of the second neutral line is connected to the eighth terminal 42 of the fourth terminal, and the second end of the second neutral line is led out after passing through the relay protection device; further, the second end of the second neutral line, the second end of the second A phase secondary circuit, the second end of the second B phase secondary circuit and the second end of the second C phase secondary circuit are connected to each other.

[0033] Furthermore, the loop formed between the A-phase secondary circuit and the neutral line is the A-phase current loop, the loop formed between the B-phase secondary circuit and the neutral line is the B-phase current loop, and the loop formed between the C-phase secondary circuit and the neutral line is the C-phase current loop.

[0034] Furthermore, the relay protection device may include multiple devices, such as a protection device, a temperature control device, and a fault recording device (not shown in the figure). The second A-phase secondary circuit, the second B-phase secondary circuit, the second C-phase secondary circuit, and the second neutral line may be connected to the above-mentioned protection device, temperature control device, and fault recording device in sequence, so that the protection device, temperature control device, and fault recording device can process the current parameters collected by the secondary circuit. Figure 1 Relay protection device is used to refer to the above-mentioned equipment. The number and types of equipment included in the relay protection device can be determined according to actual conditions.

[0035] However, in recent years, with the increase in the types of relay protection devices, the secondary circuit of current transformers has become increasingly complex. When multiple devices are connected in series, hidden faults such as poor crimping of the terminal wires of the current transformer secondary circuit, poor contact of the test connector, or the existence of connectors in the cable often lead to power system equipment shutdown or incorrect operation of relay protection and safety automatic devices. The existing method of requiring staff to conduct inspections at each component connected to the secondary circuit of the current transformer has too low detection efficiency and cannot meet the needs.

[0036] In view of the above problems, in one embodiment, Figure 1 As shown, a full current loop rapid detection device is provided, and the device is used to perform loop state detection on the secondary loop of a current transformer as an example for explanation. The device includes a detection control unit, a voltage acquisition unit and a current output unit.

[0037] Furthermore, the detection control unit is used to control the current output unit to output the detection current of the preset current value to the A-phase secondary circuit, the B-phase secondary circuit and the C-phase secondary circuit in sequence according to a preset order, so that the detection current flows into the A-phase current loop, the B-phase current loop and the C-phase current loop respectively; specifically, the detection control unit can be connected to the current output unit, and the detection control unit can make the current output unit output the detection current of the preset current value to the A-phase secondary circuit, the B-phase secondary circuit and the C-phase secondary circuit in sequence according to the preset order of the preset phase sequence, and here, the values ​​of the preset order and the preset current value can be determined according to actual conditions.

[0038] Specifically, the current output unit may have an A-phase output interface, a B-phase output interface, and a C-phase output interface; the A-phase output interface is connected to the A-phase secondary circuit, and is used to output the detection current to the A-phase secondary circuit; the B-phase output interface is connected to the B-phase secondary circuit, and is used to output the detection current to the B-phase secondary circuit; the C-phase output interface is connected to the C-phase secondary circuit, and is used to output the detection current to the C-phase secondary circuit. The detection control unit may control the current output unit to output the detection current to the A-phase secondary circuit, the B-phase secondary circuit, and the C-phase secondary circuit respectively through the A-phase output interface, the B-phase output interface, and the C-phase output interface. Here, the current output unit may be connected to the A-phase secondary circuit, the B-phase secondary circuit, and the C-phase secondary circuit respectively through test wires.

[0039] Furthermore, the voltage acquisition unit is used to respectively determine the A-phase voltage generated by the A-phase current loop based on the detection current, the B-phase voltage generated by the B-phase current loop based on the detection current, and the C-phase voltage generated by the C-phase current loop based on the detection current, and send the A-phase voltage, the B-phase voltage and the C-phase voltage to the detection control unit.

[0040] The voltage acquisition unit has a neutral line interface, and the neutral line interface is connected to the neutral line; the voltage acquisition unit is also connected to the A-phase output interface, the B-phase output interface, and the C-phase output interface, respectively. When determining the A-phase voltage, the B-phase voltage, and the C-phase voltage, the voltage acquisition unit can determine the first voltage difference between the A-phase output interface and the neutral line interface, and determine the first voltage difference as the A-phase voltage; similarly, the second voltage difference between the B-phase output interface and the neutral line interface can be determined, and the second voltage difference can be determined as the B-phase voltage; and the third voltage difference between the C-phase output interface and the neutral line interface can be determined, and the third voltage difference can be determined as the C-phase voltage.

[0041] Here, the process of determining the voltage of the current loop is described by taking the process of the voltage acquisition unit determining the A phase voltage as an example. Figure 2 As shown, the first end of the voltmeter V included in the voltage acquisition unit is connected to the A-phase circuit loop through the A-phase output interface. In the figure, the A-phase circuit loop is represented by the A-phase circuit loop equivalent resistance R. The second end of the voltmeter V is connected to the neutral line in the A-phase circuit loop through the neutral line interface. The voltage source Vs in the full current loop rapid detection device outputs voltage. The ammeter I in the full current loop rapid detection device is used to refer to the equivalent current source in the device. The circuit resistance r is used to refer to the resistance of the test wire.

[0042] Furthermore, the first end of the voltmeter V can be the A-phase output interface to which the voltage acquisition unit is connected, and the second end of the voltmeter V can be the neutral line interface of the voltage acquisition unit. When a detection current of a specific value is output to the A-phase circuit loop, the voltmeter V acquires the voltage difference across the A-phase circuit loop equivalent resistance R of the A-phase circuit loop, and determines the voltage difference as the A-phase voltage. That is, the voltage acquisition unit is connected to the A-phase secondary circuit through the A-phase output interface, and is connected to the neutral line through the neutral line interface. Because the neutral line is grounded, the voltage acquisition unit can determine the voltage difference between the A-phase output interface and the neutral line interface as the A-phase voltage. Furthermore, the method for determining the B-phase voltage and the C-phase voltage can refer to the above description, which will not be repeated here.

[0043] Furthermore, the detection control unit is also used to determine the A-phase resistance parameter of the A-phase current loop, the B-phase resistance parameter of the B-phase current loop, and the C-phase resistance parameter of the C-phase current loop through the A-phase voltage, the B-phase voltage, the C-phase voltage, and the detection current. Specifically, after respectively obtaining the A-phase voltage of the A-phase current loop, the B-phase voltage of the B-phase current loop, and the C-phase voltage of the C-phase current loop, since the detection current is known, the A-phase resistance parameter of the A-phase current loop, the B-phase resistance parameter of the B-phase current loop, and the C-phase resistance parameter of the C-phase current loop can be determined by Ohm's law. Among them, the resistance parameters include resistance value and impedance value.

[0044] Further, the detection control unit determines the loop state of the secondary circuit of the current transformer based on the A-phase resistance parameter, the B-phase resistance parameter, and the C-phase resistance parameter. Specifically, it can be determined whether the three-phase unbalance between the A-phase resistance parameter, the B-phase resistance parameter, and the C-phase resistance parameter meets the preset requirements. When the three-phase unbalance meets the preset requirements, it is determined that the loop state of the secondary circuit of the current transformer is a normal state. When the three-phase unbalance does not meet the preset requirements, it is determined that the loop state of the secondary circuit of the current transformer is an abnormal state. Here, the mean of the A-phase resistance parameter, the B-phase resistance parameter and the C-phase resistance parameter can be calculated, and the A-phase parameter difference between the A-phase resistance parameter and the mean, the B-phase parameter difference between the B-phase resistance parameter and the mean, and the C-phase parameter difference between the C-phase resistance parameter and the mean can be determined; further, it is determined whether the A-phase parameter difference, the B-phase parameter difference and the C-phase parameter difference are all less than a preset difference threshold. When the A-phase parameter difference, the B-phase parameter difference and the C-phase parameter difference are all less than the difference threshold, the three-phase imbalance between the A-phase resistance parameter, the B-phase resistance parameter and the C-phase resistance parameter meets the preset requirements. Conversely, when the A-phase parameter difference, the B-phase parameter difference and the C-phase parameter difference are not all less than the difference threshold, the three-phase imbalance between the A-phase resistance parameter, the B-phase resistance parameter and the C-phase resistance parameter does not meet the preset requirements.

[0045] Furthermore, the secondary circuit of the current transformer indicates that the primary current in the high-voltage power grid is transformed by the current transformer to form a secondary current acceptable to relay protection devices such as line protection, stabilization device and fault recording device. The secondary current is collected and distributed at the distribution device through the control cable by the secondary winding of the current transformer, and then flows through the relay protection device through the control cable. Specifically, in actual use, the steps of detecting the secondary circuit of the current transformer can be divided into three steps.

[0046] Step 1: First, before the primary equipment of the power system delivers power, disconnect the first terminal connection piece of the first terminal, the second terminal connection piece of the second terminal, the third terminal connection piece of the third terminal, and the fourth terminal connection piece of the fourth terminal in the power distribution device, and connect the A-phase output interface to the first wiring terminal 11, the B-phase output interface to the third wiring terminal 21, the C-phase output interface to the fifth wiring terminal 31, and the neutral line interface to the seventh wiring terminal 41. Then, the full current loop rapid detection device is turned on, and the detection control unit controls the current output unit to output the detection current to the A-phase secondary circuit, the B-phase secondary circuit, and the C-phase secondary circuit in sequence according to a preset order, and the current output unit does not output the detection current to the A-phase secondary circuit, the B-phase secondary circuit, and the C-phase secondary circuit at the same time. Further, the voltage acquisition unit acquires the A-phase voltage, the B-phase voltage, and the C-phase voltage, and sends the A-phase voltage, the B-phase voltage, and the C-phase voltage to the detection control unit. Finally, the detection control unit determines the phase A resistance parameter of the A phase current loop, the phase B resistance parameter of the B phase current loop and the phase C resistance parameter of the C phase current loop through the phase A voltage, the phase B voltage, the phase C voltage and the detection current, and determines the loop state of the current transformer secondary loop based on the three-phase imbalance between the phase A resistance parameter, the phase B resistance parameter and the phase C resistance parameter.

[0047] Here, if the three-phase unbalance between the A-phase resistance parameter, the B-phase resistance parameter, and the C-phase resistance parameter meets the preset requirements, it can be determined that the circuit state of the current transformer secondary circuit in the power distribution device and the transformer body winding is normal, that is, the circuit state of the first A-phase secondary circuit and the first neutral line in the A-phase current circuit, the first B-phase secondary circuit and the first neutral line in the B-phase current circuit, and the first C-phase secondary circuit and the first neutral line in the C-phase current circuit are normal. Conversely, if the three-phase unbalance between the A-phase resistance parameter, the B-phase resistance parameter, and the C-phase resistance parameter does not meet the preset requirements, it can be determined that the circuit state of at least one of the first A-phase secondary circuit and the first neutral line in the A-phase current circuit, the first B-phase secondary circuit and the first neutral line in the B-phase current circuit, and the first C-phase secondary circuit and the first neutral line in the C-phase current circuit is abnormal. At this time, the relevant staff can be notified to check the abnormality of the current transformer secondary circuit.

[0048] Step 2: First, connect the A-phase output interface to the second terminal 12, connect the B-phase output interface to the fourth terminal 22, connect the C-phase output interface to the sixth terminal 32, and connect the neutral line interface to the eighth terminal 42. Then, the detection control unit controls the current output unit to output the detection current to the A-phase secondary circuit, the B-phase secondary circuit, and the C-phase secondary circuit in a preset order. Further, the voltage acquisition unit collects the A-phase voltage, the B-phase voltage, and the C-phase voltage again, and sends the A-phase voltage, the B-phase voltage, and the C-phase voltage to the detection control unit. Finally, the detection control unit determines the A-phase resistance parameter of the A-phase current loop, the B-phase resistance parameter of the B-phase current loop, and the C-phase resistance parameter of the C-phase current loop through the A-phase voltage, the B-phase voltage, the C-phase voltage, and the detection current, and determines the loop state of the current transformer secondary loop based on the imbalance between the A-phase resistance parameter, the B-phase resistance parameter, and the C-phase resistance parameter.

[0049] Here, if the three-phase unbalance between the A-phase resistance parameter, the B-phase resistance parameter, and the C-phase resistance parameter meets the preset requirements, it can be determined that the circuit state of the current transformer secondary circuit in the power distribution device and the relay protection device is normal, that is, the circuit state of the second A-phase secondary circuit and the second neutral line in the A-phase current circuit, the second B-phase secondary circuit and the second neutral line in the B-phase current circuit, and the second C-phase secondary circuit and the second neutral line in the C-phase current circuit are normal. Conversely, if the three-phase unbalance between the A-phase resistance parameter, the B-phase resistance parameter, and the C-phase resistance parameter does not meet the preset requirements, it can be determined that the circuit state of at least one of the second A-phase secondary circuit and the second neutral line in the A-phase current circuit, the second B-phase secondary circuit and the second neutral line in the B-phase current circuit, and the second C-phase secondary circuit and the second neutral line in the C-phase current circuit is abnormal, and at this time, the relevant staff can be notified to conduct abnormality inspection on the current transformer secondary circuit.

[0050] The third step is to conduct the first terminal connection piece of the first terminal, the second terminal connection piece of the second terminal, the third terminal connection piece of the third terminal, and the fourth terminal connection piece of the fourth terminal in the power distribution device. Then, the detection control unit controls the current output unit to output the detection current to the A-phase secondary circuit, the B-phase secondary circuit, and the C-phase secondary circuit in a preset order. Further, the voltage acquisition unit collects the A-phase voltage, the B-phase voltage, and the C-phase voltage again, and sends the A-phase voltage, the B-phase voltage, and the C-phase voltage to the detection control unit. Finally, the detection control unit determines the A-phase resistance parameter of the A-phase current loop, the B-phase resistance parameter of the B-phase current loop, and the C-phase resistance parameter of the C-phase current loop through the A-phase voltage, the B-phase voltage, the C-phase voltage, and the detection current, and determines the loop state of the current transformer secondary loop based on the three-phase imbalance between the A-phase resistance parameter, the B-phase resistance parameter, and the C-phase resistance parameter.

[0051] Here, if the three-phase unbalance between the A-phase resistance parameter, the B-phase resistance parameter, and the C-phase resistance parameter meets the preset requirements, it can be determined that the overall loop state of the current transformer secondary circuit is normal, that is, the loop state of the A-phase current circuit, the B-phase current circuit, and the C-phase current circuit is normal. Conversely, if the unbalance between the A-phase resistance parameter, the B-phase resistance parameter, and the C-phase resistance parameter does not meet the preset requirements, it can be determined that the loop state of at least one part of the A-phase current circuit, the B-phase current circuit, and the C-phase current circuit is abnormal. At this time, the relevant staff can be notified to check the abnormality of the current transformer secondary circuit.

[0052] Furthermore, based on actual conditions, only the third step above can be used to detect the loop state of the secondary loop of the current transformer. Figure 1 The full current loop rapid detection device is connected to the first terminal 11, the third terminal 21, the fifth terminal 31 and the seventh terminal 41. In actual use, the full current loop rapid detection device can be connected to the distribution device and other terminals as needed, which is not limited here.

[0053] Here, in each of the above three steps, after the resistance parameters of phase A, phase B and phase C are determined, a detection current in the form of alternating current can be output to the phase A current loop, phase B current loop and phase C current loop, and the phase A AC voltage, phase B AC voltage and phase C AC voltage of the phase A current loop, phase B current loop and phase C current loop under the action of the detection current are detected, and the impedance parameters of the phase A current loop, phase B current loop and phase C current loop are determined based on the phase A AC voltage, phase B AC voltage, phase C AC voltage and the detection current, and whether there is a loop abnormality in the secondary circuit of the current transformer is determined by comparing the three-phase imbalance of the impedance parameters of the phase A current loop, phase B current loop and phase C current loop, so as to review and verify the detection result obtained by comparing the three-phase imbalance of the resistance parameters, so as to improve the accuracy of the loop detection.

[0054] A full current loop rapid detection device provided in this embodiment can quickly perform loop status detection on the three-phase current loop in the secondary loop of the current transformer, and determine whether the loop status of the secondary loop of the current transformer is abnormal through the resistance parameters of the three-phase current loop, thereby significantly improving the detection efficiency of the secondary loop of the current transformer.

[0055] In an optional embodiment, if Figure 3 As shown, the detection control unit includes a human-machine interaction interface and a central control unit; wherein the human-machine interaction interface can be used as a display module, which can be a display device with buttons, as an interface module of the device, and the central control unit can be a computing device such as an electronic controller (Electronic Control Unit, ECU). Specifically, the central control unit can be connected to the current output unit and the human-machine interaction interface. Furthermore, the current output unit, the voltage acquisition unit, and the central control unit can be arranged in a hard shell, and the hard shell serves as the shell of the full current loop rapid detection device. The human-machine interaction interface can be arranged on the outer surface of the hard shell to facilitate personnel to view the information displayed on the human-machine interaction interface.

[0056] Furthermore, the central control unit is used to control the current output unit to output a detection current of a preset current value to the A-phase secondary circuit, the B-phase secondary circuit and the C-phase secondary circuit in sequence according to a preset order.

[0057] Furthermore, the central control unit is also used to determine the phase A resistance parameter of the phase A current loop, the phase B resistance parameter of the phase B current loop, and the phase C resistance parameter of the phase C current loop through the phase A voltage, the phase B voltage, the phase C voltage, and the detection current, and determine the loop state of the current transformer secondary loop based on the phase A resistance parameter, the phase B resistance parameter, and the phase C resistance parameter.

[0058] Furthermore, the central control unit is also used to send the loop state, A-phase resistance parameter, B-phase resistance parameter and C-phase resistance parameter to the human-machine interface, so that the human-machine interface displays the loop state, A-phase resistance parameter, B-phase resistance parameter and C-phase resistance parameter. In the embodiment provided by the present application, the detected resistance parameters and test results can be displayed through the human-machine interface, so that relevant staff can intuitively view the test parameters and test results, and can accept input instructions from the test personnel through the buttons at the human-machine interface, thereby improving the convenience of use of the full current loop rapid detection device.

[0059] In an optional embodiment, the central control unit determines the loop state of the secondary loop of the current transformer based on the A-phase resistance parameter, the B-phase resistance parameter and the C-phase resistance parameter, including: first, the central control unit calculates the resistance parameter mean of the A-phase resistance parameter, the B-phase resistance parameter and the C-phase resistance parameter, that is, accumulates and averages the A-phase resistance parameter, the B-phase resistance parameter and the C-phase resistance parameter to obtain the resistance parameter mean.

[0060] Then, the A-phase parameter difference between the A-phase resistance parameter and the resistance parameter mean, the B-phase parameter difference between the B-phase resistance parameter and the resistance parameter mean, and the C-phase parameter difference between the C-phase resistance parameter and the resistance parameter mean are determined respectively.

[0061] Finally, determine whether the A-phase parameter difference, the B-phase parameter difference, and the C-phase parameter difference are all less than a preset difference threshold. When the A-phase parameter difference, the B-phase parameter difference, and the C-phase parameter difference are all less than the difference threshold, determine that the loop state of the secondary loop of the current transformer is a normal state. Wherein, the difference threshold can be determined according to actual conditions. Relatively, when the A-phase parameter difference, the B-phase parameter difference, and the C-phase parameter difference are not all less than the difference threshold, determine that the loop state of the secondary loop of the current transformer is an abnormal state.

[0062] Furthermore, the central control unit determines the loop state of the secondary loop of the current transformer based on the A-phase resistance parameter, the B-phase resistance parameter, and the C-phase resistance parameter, and further includes:

[0063] First, the central control unit determines whether the A-phase resistance parameter, the B-phase resistance parameter, and the C-phase resistance parameter are all within a preset normal threshold range; wherein the value range of the normal threshold range can be determined according to actual conditions.

[0064] Then, when the A-phase resistance parameter, the B-phase resistance parameter, and the C-phase resistance parameter are all within the normal threshold interval, the loop state of the secondary circuit of the current transformer is determined to be a normal state. Conversely, when the A-phase resistance parameter, the B-phase resistance parameter, and the C-phase resistance parameter are not all within the normal threshold interval, the loop state of the secondary circuit of the current transformer is determined to be an abnormal state. The embodiment provided by the present application can quickly determine the loop state of the secondary circuit of the current transformer, thereby improving the detection efficiency of the secondary circuit of the current transformer.

[0065] In an optional embodiment, if Figure 3 As shown, the device further includes an alarm unit, wherein the alarm unit may be an alarm indicator light or a buzzer. Further, the alarm unit may be connected to the current output unit.

[0066] Specifically, the central control unit is also used to determine whether the A-phase resistance parameter, the B-phase resistance parameter, and the C-phase resistance parameter are all within a preset resistance range, and when the A-phase resistance parameter, the B-phase resistance parameter, and the C-phase resistance parameter are not all within the preset resistance range, control the current output unit to drive the alarm unit to send out an alarm prompt signal. Here, the preset resistance range can be less than 100 ohms. When at least one of the A-phase resistance parameter, the B-phase resistance parameter, and the C-phase resistance parameter obtained by the central control unit is greater than 100 ohms or infinite, it can be determined that there is an open circuit in the secondary circuit of the current transformer. At this time, the central control unit controls the current output unit to supply power to the alarm unit, driving the alarm unit to send out an alarm prompt signal.

[0067] The embodiment provided by the present application can send out an audible and visual alarm signal through an alarm indicator light or a buzzer to remind the inspector that there is an open circuit in the current loop after the test point and that an inspection is required. At this time, the inspector checks whether there is an open circuit in the terminal or connecting piece at the rear end of the test point according to the device connected to the secondary current loop. After confirming that there is no open circuit, the test can be performed again, or it can be tested in sections to gradually determine the range of the resistance deviation, thereby improving the detection capability of the secondary circuit of the current transformer.

[0068] Further, such as Figure 4As shown, the current output unit includes a power supply unit and a relay switching unit; further, the power supply unit is used to output the detection current to the relay switching unit, wherein the power supply unit has a rechargeable lithium battery, an inverter circuit and a voltage stabilizing circuit, and the rechargeable lithium battery outputs current to the relay switching unit through the inverter circuit and the voltage stabilizing circuit, providing a variable, stable and high-precision DC power supply and AC power supply. Further, the relay switching unit is used to be controlled by the central control unit to send the detection current obtained from the power supply unit to the A-phase current loop, the B-phase current loop or the C-phase current loop. Here, the relay switching unit switches the power supply output according to the phase sequence or according to the switching instruction issued by the central control unit, and can inject high-precision low-ripple DC current or high-precision 50Hz industrial frequency AC current into the A-phase current loop, the B-phase current loop and the C-phase current loop respectively, and drive the corresponding relay output nodes at the same time. The embodiment provided in the present application can output a stable detection current through a power supply unit, and control the relay switching unit through a central control unit to output the detection current provided by the power supply unit to a three-phase current loop, thereby improving the quality of the current output to the current loop and the power stability of the full current loop rapid detection device, and improving the accuracy of loop status detection.

[0069] In an optional embodiment, the power supply unit includes an energy storage unit and an energy storage controller; wherein the energy storage unit may be a rechargeable lithium battery, and in actual use, an external power supply may be connected to the rechargeable lithium battery to power the rechargeable lithium battery. Specifically, the energy storage unit is used to output the detection current to the relay switching unit. Furthermore, the energy storage controller is used to monitor the power state of the energy storage unit in real time, wherein the power state includes a feeding state and an overload state.

[0070] Furthermore, the energy storage controller monitors the power of the energy storage unit in real time. When the energy storage controller detects that the current power of the energy storage unit is too low, it determines that the power state of the energy storage unit is a feeding state, and when the power state of the energy storage unit is a feeding state, it issues a charging reminder message to prompt relevant staff to charge the energy storage unit. Furthermore, when the power state of the energy storage unit is an overload state, the energy storage unit is controlled to stop outputting the detection current to ensure the safety of the device and the secondary circuit. The embodiment provided by the present application, by arranging an energy storage unit in the device, the device does not need to be connected to an external power supply when in use, thereby ensuring the portability and ease of operation of the device, and can monitor the state of the energy storage unit in real time, prompt the relevant staff to charge the energy storage unit when the power of the energy storage unit is too low, and control the energy storage unit to stop outputting the detection current when the energy storage unit is overloaded, so as to ensure the safety of the detection work.

[0071] The present embodiment provides a full current loop rapid detection device, which can quickly detect and evaluate the status of the secondary circuit of the current transformer before the primary equipment is powered on, to avoid incorrect operation of the relay protection and safety automatic devices due to abnormalities such as the open circuit of the secondary circuit of the current transformer, poor contact of the terminals and connecting pieces, or the existence of connectors in the cable. The full current loop rapid detection device can complete the detection of the three-phase current circuit at one time, and measure according to the device connected to the current circuit. It can quickly complete the detection of the normal, open, short circuit and abnormal status of the secondary circuit of the transformer at the distribution device such as the terminal box or the intelligent component cabinet, so there is no need to measure each component in the secondary circuit, which reduces the labor intensity of personnel, improves the detection efficiency and quality, and can effectively ensure the reliable operation of the power system. The technical solution provided by the present application can be widely used in power systems such as power plants and substations to detect the secondary circuit of current transformers in the power system. It can quickly evaluate the status of the secondary current circuit of the current transformer before the primary equipment is powered on, avoiding incorrect operation of the relay protection and safety automatic devices due to abnormalities in the current transformer. The use of a full current circuit rapid detection device can improve the efficiency of operation and maintenance, ensure the safety of personnel and equipment, reduce the duration of maintenance power outages, and ensure the safe and reliable operation of the power grid. It has good application prospects.

[0072] The above serial numbers of this application are only for description and do not represent the advantages and disadvantages of the implementation scenarios. The above disclosure is only a few specific implementation scenarios of this application, but this application is not limited to them, and any changes that can be thought of by technicians in this field should fall within the scope of protection of this application.

Claims

1. A full current loop fast detection device, used for detecting the loop status of the secondary loop of a current transformer, wherein: The secondary circuit of the current transformer includes an A-phase current circuit composed of an A-phase secondary circuit and a neutral line, a B-phase current circuit composed of a B-phase secondary circuit and a neutral line, and a C-phase current circuit composed of a C-phase secondary circuit and a neutral line, and is characterized in that the device includes a detection control unit, a voltage acquisition unit and a current output unit; The detection control unit is used to control the current output unit to output a detection current of a preset current value to the A-phase secondary circuit, the B-phase secondary circuit, and the C-phase secondary circuit in sequence according to a preset order; The voltage acquisition unit is used to respectively determine the A-phase voltage generated by the A-phase current loop based on the detection current, the B-phase voltage generated by the B-phase current loop based on the detection current, and the C-phase voltage generated by the C-phase current loop based on the detection current, and send the A-phase voltage, the B-phase voltage, and the C-phase voltage to the detection control unit; The detection control unit is also used to determine the phase A resistance parameter of the A-phase current loop, the phase B resistance parameter of the B-phase current loop, and the phase C resistance parameter of the C-phase current loop through the phase A voltage, the phase B voltage, the phase C voltage, and the detection current, and determine the loop state of the current transformer secondary loop based on the phase A resistance parameter, the phase B resistance parameter, and the phase C resistance parameter.

2. The device according to claim 1, characterized in that The current output unit has an A-phase output interface, a B-phase output interface and a C-phase output interface; The A-phase output interface is connected to the A-phase secondary circuit, and is used to output the detection current to the A-phase secondary circuit; The B-phase output interface is connected to the B-phase secondary circuit, and is used to output the detection current to the B-phase secondary circuit; The C-phase output interface is connected to the C-phase secondary circuit and is used to output the detection current to the C-phase secondary circuit.

3. The device according to claim 2, characterized in that The voltage collection unit has a neutral line interface, and the neutral line interface is connected to the neutral line; The voltage acquisition unit is also connected to the A-phase output interface, the B-phase output interface and the C-phase output interface respectively; The voltage acquisition unit determines the A-phase voltage generated by the A-phase current loop based on the detection current, the B-phase voltage generated by the B-phase current loop based on the detection current, and the C-phase voltage generated by the C-phase current loop based on the detection current, respectively, including: The voltage acquisition unit determines a first voltage difference between the A-phase output interface and the neutral line interface, and determines the first voltage difference as the A-phase voltage; Determine a second voltage difference between the B-phase output interface and the neutral line interface, and determine the second voltage difference as the B-phase voltage; A third voltage difference between the C-phase output interface and the neutral line interface is determined, and the third voltage difference is determined as the C-phase voltage.

4. The device according to claim 1, characterized in that The detection control unit includes a human-computer interaction interface and a central control unit; The central control unit is used to control the current output unit to output a detection current of a preset current value to the A-phase secondary circuit, the B-phase secondary circuit, and the C-phase secondary circuit in sequence according to a preset order; The central control unit is further used to determine the A-phase resistance parameter of the A-phase current loop, the B-phase resistance parameter of the B-phase current loop, and the C-phase resistance parameter of the C-phase current loop through the A-phase voltage, the B-phase voltage, the C-phase voltage, and the detection current, and determine the loop state of the secondary loop of the current transformer based on the A-phase resistance parameter, the B-phase resistance parameter, and the C-phase resistance parameter; The central control unit is also used to send the loop status, the A-phase resistance parameter, the B-phase resistance parameter and the C-phase resistance parameter to the human-computer interaction interface so that the loop status, the A-phase resistance parameter, the B-phase resistance parameter and the C-phase resistance parameter are displayed on the human-computer interaction interface.

5. The device according to claim 4, characterized in that The central control unit determines the loop state of the secondary loop of the current transformer based on the A-phase resistance parameter, the B-phase resistance parameter, and the C-phase resistance parameter, including: The central control unit calculates the resistance parameter mean of the A-phase resistance parameter, the B-phase resistance parameter and the C-phase resistance parameter; Respectively determining an A-phase parameter difference between the A-phase resistance parameter and the resistance parameter mean, a B-phase parameter difference between the B-phase resistance parameter and the resistance parameter mean, and a C-phase parameter difference between the C-phase resistance parameter and the resistance parameter mean; When the A-phase parameter difference, the B-phase parameter difference, and the C-phase parameter difference are all smaller than a preset difference threshold, it is determined that the circuit state of the secondary circuit of the current transformer is a normal state.

6. The device according to claim 4, characterized in that The central control unit determines the loop state of the secondary loop of the current transformer based on the A-phase resistance parameter, the B-phase resistance parameter, and the C-phase resistance parameter, including: The central control unit determines whether the A-phase resistance parameter, the B-phase resistance parameter, and the C-phase resistance parameter are all within a preset normal threshold range; When the A-phase resistance parameter, the B-phase resistance parameter, and the C-phase resistance parameter are all within the normal threshold range, it is determined that the circuit state of the secondary circuit of the current transformer is a normal state.

7. The device according to claim 4, characterized in that The device also includes an alarm unit; The central control unit is also used to determine whether the A-phase resistance parameter, the B-phase resistance parameter and the C-phase resistance parameter are all within a preset resistance range, and when the A-phase resistance parameter, the B-phase resistance parameter and the C-phase resistance parameter are not all within the preset resistance range, control the current output unit to drive the alarm unit to send an alarm prompt signal.

8. The device according to claim 7, characterized in that The alarm unit is an alarm indicator light or a buzzer.

9. The device according to claim 4, characterized in that The current output unit includes a power supply unit and a relay switching unit; The power supply unit is used to output the detection current to the relay switching unit; The relay switching unit is used to send the detection current obtained from the power supply unit to the A-phase secondary circuit, the B-phase secondary circuit or the C-phase secondary circuit under the control of the central control unit.

10. The device according to claim 9, characterized in that The power supply unit includes an energy storage unit and an energy storage controller; The energy storage unit is used to output the detection current to the relay switching unit; The energy storage controller is used to monitor the power state of the energy storage unit in real time, and send out charging prompt information when the power state of the energy storage unit is a feeding state, and control the energy storage unit to stop outputting the detection current when the power state of the energy storage unit is an overload state.

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