Ground insulation detection device, system, method, equipment, medium and product

Abstract

According to the ground insulation detection device, system, method, equipment, medium and product of the direct-current operation power supply system, the ground insulation condition of the direct-current operation power supply system can be rapidly detected in the on or off state of the power supply branch, and due to the fact that the ground insulation condition is detected with the power supply branch as the unit, the detection efficiency is improved. Therefore, the method can achieve the positioning of the abnormal ground insulation condition, facilitates the troubleshooting of a fault point, and guarantees the safe operation of DC.

Description

Technical Field

[0001] This application relates to the field of power technology, and in particular to a device, system, method, equipment, medium and product for detecting the ground insulation of a DC operating power supply system. Background Art

[0002] Currently, DC operating power supply systems are mainly applied to DC operating power supply systems in power plants (hydropower, wind power, thermal power, nuclear power), substations, and communication high-voltage etc. The safety and reliability of DC operating power supply systems affect the safe operation of power stations, substations, communication data rooms, etc., and are related to the production safety of the entire power grid. As DC operating power supply systems are increasingly used in power, communication, etc., the systems are becoming more and more complex.

[0003] DC operating power supply systems generally adopt a floating non-grounded system. The power industry standard requires adding a ground insulation detection device to the DC operating power supply system. Currently, it generally takes more than 30 seconds for the insulation detection device to find an insulation reduction fault. When there is an insulation reduction of less than 30 seconds (greater than 50 mS), the fault occurrence point cannot be located, it is difficult to troubleshoot the fault point, and there are factors that can cause a re-grounding fault, affecting the safe operation of the DC. Summary of the Invention

[0004] This application provides a device, system, method, equipment, medium and product for detecting the ground insulation of a DC operating power supply system, which can solve one of the problems in the background art.

[0005] To achieve the above object, this application adopts the following technical solutions:

[0006] In a first aspect, a device for detecting the ground insulation of a DC operating power supply system is provided. The device includes:

[0007] A balanced bridge resistor unit configured on a power supply branch. The power supply bus supplies power to a load through the power supply branch, and a first switch for controlling the on / off of the power supply branch is provided on the power supply branch;

[0008] A DC injection power supply;

[0009] A voltage sampling unit for sampling the voltage of the power supply branch; and

[0010] A detection unit for detecting the state of the first switch. When the state of the first switch is off, it controls the DC injection power supply to supply power to the balanced bridge resistor unit, and judges the ground insulation situation according to the sampled voltage; when the state of the first switch is on, it judges the ground insulation situation according to the sampled voltage.

[0011] Based on the above technical solution, the ground insulation condition of the DC operating power supply system can be quickly detected whether the power supply branch is connected or disconnected. And since the ground insulation condition is detected in units of power supply branches, the location of abnormal ground insulation conditions can be determined, which is beneficial to troubleshooting fault points and ensuring the safe operation of the DC system.

[0012] It can be understood that in specific implementation, the first switch may be a physical switch or a combination of multiple physical switches, and the same applies to other circuit components such as resistors.

[0013] In a possible design of the first aspect, a bus balance bridge resistor is further configured on the power supply branch. The bus balance bridge resistor includes a positive bus bridge resistor and a negative bus bridge resistor. The balance bridge resistor unit includes a detection positive bridge resistor and a detection negative bridge resistor. The DC injection power supply is supplied through a second switch and output to the bridge connection point of the detection positive bridge resistor and the detection negative bridge resistor, and the second switch is controlled by the detection unit.

[0014] It can be understood that in specific implementation, the second switch may be a physical switch or a combination of multiple physical switches.

[0015] In a possible design of the first aspect, a leakage current sensor is further configured on the power supply branch. The detection unit is further used for:

[0016] When the first switch is in the off state, calculate the first ground resistance according to the sampled voltage, the resistance value of the detection positive bridge resistor, and the resistance value of the detection negative bridge resistor, and judge the degree of decrease of the ground resistance based on the comparison result between the first ground resistance and a preset threshold.

[0017] When the first switch is in the on state, calculate the second ground resistance according to the sampled voltage, the resistance value of the positive bus bridge resistor or the negative bus bridge resistor, and the resistance value of the detection positive bridge resistor or the detection negative bridge resistor, or calculate the second ground resistance according to the sampled voltage and the current detection value of the leakage current sensor, and judge the degree of decrease of the ground resistance based on the comparison result between the second ground resistance and a preset threshold.

[0018] In a possible design of the first aspect, the detection unit is further used for: when the first switch is in the on state and the detected ground insulation condition is abnormal, control the first switch to turn off. Based on the above technical solution, (technical effect deduction)

[0019] In a second aspect, a ground insulation detection system is provided. The system includes the above-described device disposed on a plurality of power supply branches, and a master control unit electrically connected to the device for overall control of the device. The device reports the detected ground insulation condition to the master control unit.

[0020] In a third aspect, a ground insulation detection method is provided. The method is based on the above-described device, and the method includes:

[0021] Detect the state of the first switch.

[0022] When the state of the first switch is off, control the DC injection power supply to supply power to the balance bridge resistance unit, and determine the ground insulation condition according to the sampled voltage.

[0023] When the state of the first switch is on, determine the ground insulation condition according to the sampled voltage.

[0024] In a fourth aspect, an electronic device is provided. The electronic device includes a processor and a memory coupled to the processor. The memory is used to store a computer program. The processor is used to execute the computer program stored in the memory so that the electronic device executes the method described in the third aspect.

[0025] In a fifth aspect, a computer-readable storage medium is provided, including a computer program or instruction. When the computer program or instruction runs on a computer, the computer is caused to execute the method described in the third aspect.

[0026] In a sixth aspect, a computer program product is provided, including a computer program or instruction. When the computer program or instruction runs on a computer, the computer is caused to execute the method described in the third aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are only some embodiments of the embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0028] Figure 1 It is a schematic diagram of the installation scheme of the DC insulation detection and switch control device provided by the embodiment of the present application;

[0029] Figure 2 It is a schematic diagram of the structure scheme of the DC insulation detection and switch control device provided by the embodiment of the present application;

[0030] Figure 3 It is a schematic circuit diagram of the DC insulation detection and switch control device provided by the embodiment of the present application when K1 is disconnected;

[0031] Figure 4 It is a schematic circuit diagram of the DC insulation detection and switch control device provided by the embodiment of the present application when K1 is closed. Specific Embodiments

[0032] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0033] It should be noted that although functional module division is performed in the device schematic diagram and the logical sequence is shown in the flowchart, in some cases, the steps shown or described can be executed in a different module division in the device or a different sequence in the flowchart. Terms such as "first" and "second" in the specification, claims and the above-mentioned drawings are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of the present application and are not intended to limit the present application.

[0035] Next, an exemplary description will be given of the ground insulation detection device for the DC operating power supply system according to the embodiment of the present application with reference to the drawings.

[0036] The schematic installation diagram of the DC insulation detection and switch control device is as shown in Figure 1 shown, and the device composition is as shown in Figure 2 shown.

[0037] Technical solution of the DC insulation detection and switch control device: It includes an insulation detection and switch control device host, a controllable switch, a leakage current sensor, etc.

[0038] The insulation detection and switch control device host realizes the detection of the insulation resistance between the bus and the ground, including: online live insulation detection, and the DC line insulation detection below K1 when K1 is disconnected, and has the function of controlling the disconnection and closing of the K1 switch.

[0039] The leakage current sensor uses a current transformer for high-speed detection and has the function of quickly converting and measuring the DC leakage current.

[0040] Controllable switches K1, K2, K3: These refer to relays, circuit breakers, etc. that can be controlled to disconnect and close by the device host.

[0041] Implementation method (taking the figure as an example):

[0042] I. Before (when open) K1 is closed, the device host uses the off-line detection method and applies the signal injection principle. Before K1 is closed, a DC signal is injected into the branch. The voltage acquisition module monitors the voltage in real time and performs calculations in the processor to obtain the insulation status of the DC bus section below K1. When the insulation is normal, K1 can be manually closed. If the insulation is abnormal, the device issues an alarm, indicating that the insulation of the DC system equipment to be connected is abnormal.

[0043] As Figure 3 shown, the DC bus voltage is 220V, +KM and -KM are the positive and negative voltages of the bus, Rx and Ry are the bus balance bridges, and Vref is the calibration point mark known at the factory.

[0044] Before the switch K1 is closed, the 12V DC voltage injection method of V2 is adopted. At this time, K1 and K2 are open, and K3 is closed.

[0045] The bridge resistors of the positive and negative poles to the ground in the host have been calibrated at the factory. R1 and R2 are respectively the positive bridge resistor and the negative bridge resistor in the device. If there is no grounding, there is no voltage at V3 and V4.

[0046] If there is grounding, assuming the positive grounding resistance is R3 and the negative grounding resistance is R4, then there is

[0047] 1) When R3 is 0 and R4 is not 0, the negative pole is grounded. The calculation formula for the negative grounding resistance R4 is:

[0048] V2 / (R2 + R4) = V4 / R4

[0049] 2) When R3 is not 0 and R4 is 0, the positive pole is grounded. The calculation formula for the positive grounding resistance is:

[0050] V2 / (R1 + R2) = V3 / R3

[0051] 3) When both R3 and R4 are not 0, there is grounding at both the positive and negative poles. The calculation formula for the grounding resistance is: V2 / (R3 + R1) = V4 / R4 V2 / (R4 + R2) = V3 / R3

[0052] Generally speaking, based on the sampled voltages V3 and V4, the insulation situation to the ground can be judged, and further calculation of the grounding resistance is for further judging the degree of abnormality. Specifically, according to the amplitudes of the sampled voltages V3 and V4, the insulation situations of the positive and negative poles of the branch to the ground can be judged. V3 and V4 respectively represent the insulation status of the positive and negative poles. The larger the amplitude, the smaller the grounding resistance. If the voltage amplitude rises to 12V, it means the grounding resistance is 0 and the branch is completely grounded.

[0053] II. When K1 is closed, the device host converts the bus insulation detection method (the device host determines through the positive and negative voltages of the bus to the ground), K3 is open, K2 is closed, and the device host triggers an interrupt task with a fixed time limit of 5 ms through the processor to detect the bus insulation status (this insulation status is the total insulation status of the DC system). Then calculate the insulation resistance value of the bus. After confirming abnormal insulation, calculate the branch insulation value through the leakage current measured by the sensor. If the branch insulation is abnormal, the device host controls K1 to disconnect.

[0054] As shown in the figure, take R1 = R2 = R, then:

[0055]

[0056] Take R1 = R2 = R, then:

[0057]

[0058] Take R1 = R2 = R, then:

[0059]

[0060] According to the grounding situation of the DC bus, the analysis is as follows:

[0061] 1) No grounding; when there is no grounding in the system, Rx = Ry = ∞, at this time, the voltages of +KM and -KM to the ground are +110V and -110V respectively (for a 220V DC bus).

[0062] 2) Single - end grounding: when the system is single - end grounded (assuming the positive pole is grounded), at this time Ry = ∞, by detecting the voltages V3 and V4 of +KM and -KM to the ground, the following formula can be obtained:

[0063]

[0064] According to formula 3 - 6, through V1, V2 and R, the positive - pole grounding resistance value can be calculated.

[0065] 3) Balanced grounding; when the positive and negative buses are grounded simultaneously with the same resistance value, that is, Rx = Ry = R', then the calculation shows:

[0066] R + = R - = R / / R'

[0067] Since R+ = R-, their voltage divisions are the same, then V1 = 110V, V2 = -110V, and the data obtained at this time is the same as that without grounding, and the grounding resistance value R' cannot be calculated.

[0068] 4) Unbalanced grounding; when the positive and negative buses are grounded simultaneously with different resistance values, that is, Rx ≠ Ry, the following formula can be obtained:

[0069]

[0070] Since there is only one equation and it is impossible to solve two unknowns simultaneously, it cannot be solved.

[0071] In this case, the processing method is to consider the larger one of Rx and Ry as infinity and solve it according to the case of single-ended grounding. The calculated grounding resistance value is greater than the actual value, and the closer the actual values of Rx and Ry are, the greater the measurement error. When Rx = Ry, it becomes a balanced grounding situation, and the measured grounding resistance value is infinity.

[0072] After detecting the abnormal bus insulation, the resistance of this branch is judged by the branch leakage current detection method to determine whether the fault point is in this branch.

[0073] The resistance of the branch is calculated with single-pole grounding (positive pole grounding): Rx = Up / I

[0074] where Rx is the insulation resistance of the branch to the ground, Up is the voltage of the positive pole of the bus to the ground, and I is the current detected by the leakage current sensor

[0075] When K1 is disconnected, the working mode of item 1 is executed in real time.

[0076] This solution adopts contact-type bus insulation detection, and cooperates with a leakage current sensor to monitor the insulation situation in real time and quickly disconnect the switch, so that the equipment connected to the DC system is disconnected from the DC system.

[0077] Compared with the current leakage protection switch, the leakage protection switch only performs leakage protection through current. The leakage current is determined by the manufacturer at the time of factory shipment and is generally not adjustable. Moreover, the insulation state of the measured access equipment cannot be monitored after disconnection.

[0078] This solution has more automated and intelligent insulation monitoring of DC current, and can more effectively and quickly protect the stability of the DC system.

[0079] The embodiment of the present application also provides a ground insulation detection system, the system includes: the above-mentioned device arranged on a plurality of power supply branches, and a master control unit electrically connected to the device for overall control of the device, and the device reports the detected ground insulation situation to the master control unit.

[0080] The embodiment of the present application also provides a ground insulation detection method, the method is based on the above-mentioned device, and the method includes:

[0081] Detect the state of the first switch,

[0082] When the first switch state is off, control the DC injection power supply to supply power to the balanced bridge resistor unit, and judge the insulation condition to the ground according to the sampled voltage;

[0083] When the first switch state is on, judge the insulation condition to the ground according to the sampled voltage.

[0084] An embodiment of this application also provides an electronic device, including: a processor and a memory coupled to the processor. The memory is used to store a computer program; the processor is used to execute the computer program stored in the memory so that the electronic device executes the method described in any one of the above embodiments.

[0085] The electronic device can be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The electronic device may include, but is not limited to, a processor and a memory.

[0086] The so-called processor may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. The processor is the control center of the electronic device, and uses various interfaces and lines to connect all parts of the device.

[0087] The memory can be used to store the computer program. The processor realizes various functions of the electronic device by running or executing the computer program stored in the memory and calling the data stored in the memory.

[0088] The memory may mainly include a program storage area and a data storage area. Among them, the program storage area may store an operating system, application programs required for at least one function, etc.; the data storage area may store data created according to the use of the mobile phone, etc. In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, at least one magnetic disk storage device, a flash device, or other volatile solid-state storage devices.

[0089] The embodiments of the present application also provide a storage medium, which is a computer-readable storage medium. The computer program is stored in the computer-readable storage medium. When the computer program is executed by a processor, the steps of the above-mentioned various method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file or some intermediate form, etc. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disc, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electrical carrier signal, telecommunication signal, and software distribution medium, etc.

[0090] The embodiments of the present application also provide a computer program product, including: a computer program or instruction. When the computer program or instruction runs on a computer, the computer is enabled to execute the method of any of the above possible implementation manners.

[0091] The above is the preferred implementation manner of the present application. It should be noted that for those of ordinary skill in the art of the present technology, without departing from the principle of the present application, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present application.

Claims

1. A ground insulation detection device for a DC operating power supply system, characterized in that: The device comprises: The balancing bridge resistance unit is arranged on a power supply branch, the power supply bus supplies power to the load through the power supply branch, and the power supply branch is provided with a first switch for controlling the on and off of the power supply branch; DC injection power supply; a voltage sampling unit, used for sampling the voltage of the power supply branch; and The detection unit is used to detect the state of the first switch. When the first switch state is disconnected, the DC injection power supply is controlled to supply power to the balanced bridge resistance unit, and the insulation condition to the ground is determined according to the sampled voltage; when the first switch state is connected, the insulation condition to the ground is determined according to the sampled voltage.

2. The device according to claim 1, characterized in that The power supply branch is also provided with a bus balancing bridge resistor, which includes: a bus positive bridge resistor and a bus negative bridge resistor. The balancing bridge resistor unit includes a detection positive bridge resistor and a detection negative bridge resistor. The DC injection power supply outputs power to the bridge point of the detection positive bridge resistor and the detection negative bridge resistor through a second switch, and the second switch is controlled by the detection unit.

3. The device according to claim 2, characterized in that The power supply branch is also provided with a leakage current sensor, and the detection unit is also used for: When the first switch state is disconnected, the first grounding resistance is calculated according to the sampled voltage, the resistance value of the detected positive bridge resistance and the resistance value of the detected negative bridge resistance, and the degree of grounding resistance decrease is judged according to the comparison result of the first grounding resistance and a preset threshold value; When the first switch state is on, the second grounding resistance is calculated according to the sampling voltage, the resistance value of the bus positive bridge resistor or the bus negative bridge resistor, and the resistance value of the detection positive bridge resistor or the detection negative bridge resistor, or the second grounding resistance is calculated according to the sampling voltage and the current detection value of the leakage current sensor, and the degree of grounding resistance reduction is judged based on the comparison result of the second grounding resistance with a preset threshold.

4. The device according to claim 1, characterized in that The detection unit is further configured to control the first switch to be disconnected when the first switch is in the on state and the insulation condition to the ground detected is abnormal.

5. A ground insulation detection system, characterized in that: The system comprises: a device as described in any one of claims 1 to 4, which is arranged on several power supply branches, and a main control unit electrically connected to the device and used for overall control of the device, wherein the device reports the detected insulation status to the ground to the main control unit.

6. A method for detecting insulation to ground, characterized in that: The method is based on the device according to any one of claims 1 to 4, and the method comprises: detecting a state of the first switch, When the first switch state is disconnected, controlling the DC injection power supply to supply power to the balanced bridge resistance unit, and judging the insulation condition to the ground according to the sampled voltage; When the first switch state is on, the insulation condition to the ground is determined according to the sampled voltage.

7. An electronic device, characterized in that: The electronic device comprises: a processor, and a memory coupled to the processor, The memory is used to store a computer program; and The processor is used to execute the computer program stored in the memory so that the electronic device executes the method as claimed in claim 6.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a computer program or an instruction. When the computer program or the instruction is executed on a computer, the computer is caused to execute the method as claimed in claim 6 .

9. A computer program product, characterized in that The computer program product comprises: a computer program or instructions, and when the computer program or instructions are run on a computer, the computer is caused to execute the method as claimed in claim 6 .

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