Intelligent direct-current insulation online monitoring device with grounding positioning function
Technical Field
The invention relates to the technical field of operation and maintenance of power systems, in particular to an intelligent direct-current insulation online monitoring device with a grounding positioning function.
Background
The operation of relay protection, automation, signaling, emergency lighting and electrical equipment in power systems generally relies on a dc power supply. The output quality and reliability of the dc power supply are directly related to the safe and reliable production of each power device. Therefore, there is a need to ensure stable and reliable operation of the dc power supply in the power system. The direct current power supply in the power system consists of a storage battery, charging equipment or a direct current screen and other equipment. The most common fault of a dc power supply is a bus ground fault, and when a point of ground fault occurs in a dc system, no immediate harmful consequences are usually produced. However, if two or more points are grounded simultaneously, a malfunction of the signal device, the control circuit and the relay protection device may be caused, which may cause a circuit breaker to trip or directly cause a short circuit of the dc operating power supply, resulting in a serious power system fault. Therefore, it is necessary to periodically check the bus grounding condition of the dc system. However, the insulation monitoring function of the current direct current system is single, online monitoring and searching of the grounding position cannot be carried out simultaneously, and the working efficiency is low.
For example, chinese patent CN104535850B, published 2019, 1 month, 4 days, a dc insulation monitoring device, which comprises a balanced bridge circuit and an unbalanced bridge circuit, and also comprises an intelligent regulating circuit and a leakage current sensor, wherein the intelligent regulating circuit comprises a controlled current source and a switching device, and the switching device is used for connecting the controlled current source between a positive bus and ground or between a negative bus and ground; the leakage current sensor is connected with a detection switch in series and then connected with two ends of the controlled current source in parallel. A controlled current source in the intelligent regulating circuit can simulate an unbalanced fault, and when the unbalanced fault occurs, a leakage current sensor can detect leakage current so as to calculate the ground resistance of the positive bus and the negative bus. Although the earth insulation of the positive and negative buses can be monitored, the search of an earth insulation fault point cannot be completed.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the technical problem of single function of the insulation monitoring device of the direct current system. An intelligent direct-current insulation online monitoring device with a grounding positioning function is provided.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows: an intelligent direct current insulation online monitoring device with a grounding positioning function comprises a shell, a bus insulation online detection module, a positioning signal generation module, a positioning signal detection module, a grounding branch detection module, a controller, a grounding positioning button, an alarm indication module and an upper computer communication interface, wherein the bus insulation online detection module, the positioning signal generation module, the positioning signal detection module, the grounding branch detection module and the controller are all arranged in the shell, the alarm indication module and the upper computer communication interface are all arranged on the shell, the bus insulation online detection module is connected with a positive bus + KM and a negative bus-KM and is used for detecting the insulativity of the positive bus + KM and the negative bus-KM, the positioning signal generation module is connected with the positive bus + KM and the negative bus-KM and generates a low-frequency alternating current signal, the positioning signal detection module is connected with the positioning signal generation module, the positioning signal detection module detects voltage signals at connecting points of the positioning signal generation module and a positive bus + KM and a negative bus-KM, the grounding branch detection module detects alternating voltage signals of each branch, and the bus insulation on-line detection module, the positioning signal generation module, the positioning signal detection module, the grounding branch detection module, the grounding positioning button, the alarm indication module and the upper computer communication interface are all connected with the controller. The bus insulation online detection module monitors bus insulation on line, when a bus has an insulation fault, the fault is indicated through the alarm indication module, a patrol and inspection worker presses a grounding positioning button after finding the fault, then the bus insulation online detection module automatically cuts off connection with the bus, and the positioning signal generation module, the positioning signal detection module and the grounding branch detection module work to position a grounding fault point. Because the bus insulation on-line detection module adopts a bridge balance method, a resistor is connected between the positive and negative buses and the grounding wire DD, the grounding branch circuit is positioned by adopting an alternating current injection method, and the resistor connected between the positive and negative buses and the grounding wire DD can interfere the trend of an alternating current signal injected into the buses, so that the grounding branch circuit cannot be positioned. In the prior art, the bus insulation on-line detection module and the grounding branch positioning module have respective devices, work independently of each other, and when a grounding fault occurs, if the grounding branch positioning is needed, the bus insulation on-line detection module needs to be firstly removed, then the grounding branch positioning module is connected, after the positioning is completed, the grounding branch positioning module needs to be removed, and the bus insulation on-line detection module is connected with a bus again, so that the operation is very complicated, and the work efficiency is low.
Preferably, the positioning signal generation module includes an optical coupling switch, an oscillator, an amplifier, an electronic switch K1, an electronic switch K2, a capacitor C1 and a capacitor C2, the oscillator is connected to a power supply via the optical coupling switch, the optical coupling switch is connected to the controller, the oscillator is connected to an input end of the amplifier, an output end of the amplifier is connected to the electronic switch K1 and the electronic switch K2, the electronic switch K1 is connected to the positive bus + KM via the capacitor C1, and the electronic switch K2 is connected to the negative bus-KM via the capacitor C2.
Preferably, the positioning signal detection module includes a voltage measurement unit and a phase detection unit, the voltage measurement unit and the phase detection unit are both connected to the positioning signal generation module, the detection positioning signal generation module inputs the positive bus + KM and the negative bus-KM low-frequency alternating-current signals, and the voltage measurement unit and the phase detection unit are both connected to the controller.
Preferably, the bus insulation online detection module comprises an adjustable resistor R1, an adjustable resistor R2, a positive bus filter circuit, a positive bus voltage transmitter, a negative bus filter circuit and a negative bus voltage transmitter, wherein a first end of the adjustable resistor R1 is connected with a positive bus + KM, a second end of the adjustable resistor R is connected with a first end of the adjustable resistor R2 and a ground wire DD, a second end of the adjustable resistor R2 is connected with the negative bus-KM, the positive bus filter circuit is connected with a first end of the adjustable resistor R1, an output end of the positive bus filter circuit is connected with the positive bus voltage transmitter, the negative bus filter circuit is connected with a first end of the adjustable resistor R2, an output end of the negative bus filter circuit is connected with the negative bus voltage transmitter, and both the positive bus voltage transmitter and the negative bus voltage transmitter are connected with the controller. When the positive bus + KM or the negative bus-KM has a ground fault independently or both have ground faults but the ground fault degrees are different, the ground fault can be conveniently detected by adopting an electric bridge balance method. In the bridge balance method, the more the resistance values of a pair of equivalent resistors are close to the ground resistance, the larger the detected unbalanced current is under the same grounding degree, namely, the detection sensitivity is improved, so that when the adjustable resistor R1 and the adjustable resistor R2 are adopted to carry out on-line bus insulation monitoring, the bridge unbalanced current measurement under the condition of automatically adjusting a plurality of resistance values can be realized, and the bus insulation monitoring accuracy is improved.
Preferably, the adjustable resistor R1 includes a resistor R21 and a trimming resistor R31, the resistor R21 is connected in series with the trimming resistor R31, the adjustable resistor R2 includes a resistor R22 and a trimming resistor R32, and the resistor R22 is connected in series with the trimming resistor R32.
Preferably, the adjustable resistor detection and indication circuit is further included, and detects whether the resistance values of the adjustable resistor R1 and the adjustable resistor R2 are equal or not.
Preferably, the adjustable resistance inspection circuit comprises an electronic switch K3, an electronic switch K4, an electronic switch K5, an electronic switch K6, an equivalent resistor R11, an equivalent resistor R12 and a current meter a1, the equivalent resistor R11 and the equivalent resistor R12 have equal resistance, a first end of the resistor R21 is connected with a first end of the electronic switch K21 and the electronic switch K21, a second end of the resistor R21 is connected with a first end of a trimming resistor R21, a second end of the trimming resistor R21 is connected with a first end of the resistor R21, a second end of the trimming resistor R21 and a first end of the resistor R21 are connected with a ground line DD, a second end of the resistor R21 is connected with a first end of the trimming resistor R21, a second end of the electronic switch K21 is connected with a positive bus + KM, a second end of the electronic switch K21 is connected with a first end of the equivalent resistor R21, a second end of the equivalent resistor R21 is connected with a second end of the equivalent resistor R21 and the electronic switch K21, the second end of the electronic switch K5 is connected with the negative bus-KM, the ammeter A1 is connected between the second end of the equivalent resistor R11 and the second end of the trimming resistor R31, and the ammeter A1 is connected with the controller. When the sum of the resistances of the resistor R21 and the trimming resistor R31 is equal to the sum of the resistances of the resistor R22 and the trimming resistor R32, the current meter A1 cannot detect current, so that the bridge arm resistors of the balanced bridge are ensured to be the same.
Preferably, the resistance value automatic adjusting device further comprises a resistance value automatic adjusting device, the trimming resistor R31 and the trimming resistor R32 are knob type adjustable resistors, the trimming resistor R31 and the trimming resistor R32 are fixedly installed in the shell side by side, the resistance value automatic adjusting device comprises a driving plate, a driving spring, a pressing block, a resistance switch K8 and an electronic switch K9, knobs of the trimming resistor R31 and the trimming resistor R32 are respectively abutted to two opposite side surfaces of the driving plate, the side surface of the driving plate is provided with a rubber anti-skidding embedding layer, the driving plate is movably clamped on the shell, the pressing block is movably clamped with the shell, the stroke of the pressing block is perpendicular to the stroke direction of the driving plate, one end of the driving plate is connected with a first end of the driving spring, a second end of the driving spring is fixedly connected with the shell, the first end of the driving spring is connected with a positive pole of a power supply, and the second end of the driving spring is connected with a negative pole of the power supply through the electronic switch K9, one end of the pressing block is connected with a first end of a pressing spring, a second end of the pressing spring is fixedly connected with the shell, the first end of the pressing spring is connected with a negative electrode of a power supply, and the second end of the pressing spring is connected with a positive electrode of the power supply through an electronic switch K8. The trimming resistor R31 and the trimming resistor R32 are installed side by side, when the driving plate moves, the resistances of the trimming resistor R31 and the trimming resistor R32 are increased one by one, and the resistance of the trimming resistor R32 is decreased the other by the other, if the resistance of the bridge arm where the trimming resistor R31 is located is larger than that of the bridge arm where the trimming resistor R32 is located, the driving plate drives the trimming resistor R32 to be increased while the resistance of the trimming resistor R31 is decreased, and therefore the resistances of the two bridge arms can be adjusted to be consistent quickly and conveniently. The drive spring is electrified to contract, the contraction quantity of the spring can be controlled by controlling the duty ratio of the electronic switch, namely, a PMW mode is adopted, the spring is equivalent to an inductor, namely, the spring has an equivalent resistance, and the series current-limiting resistor is a known technology for avoiding overlarge current.
Preferably, the alarm indication module comprises a display, an alarm indication lamp and an alarm output interface, the display, the alarm indication lamp and the alarm output interface are all installed on the shell, and the display, the alarm indication lamp and the alarm output interface are all connected with the controller.
Preferably, the grounding branch detection module comprises a filtering amplification circuit, an AD conversion circuit and a current transformer, the current transformer is coupled with the branch line to detect the branch current, the current transformer is connected with the AD converter through the filtering amplification circuit, and the AD converter is connected with the controller.
Preferably, the current transformer is a split core current transformer.
The substantial effects of the invention are as follows: the disconnection of the bus insulation on-line detection module and the bus connection box is automatically controlled through the electronic switch, and the connection and disconnection of the positioning signal generation module, the positioning signal detection module and the grounding branch detection module and the bus are controlled, so that the one-key positioning detection that the bus insulation on-line detection is changed into the grounding branch is realized, the bus insulation detection efficiency is improved, and the safety of a direct current system is improved.
Drawings
FIG. 1 is a schematic structural diagram of an embodiment.
Fig. 2 is a schematic structural diagram of a positioning signal generating module according to an embodiment.
Fig. 3 is a schematic structural diagram of a positioning signal detecting module according to an embodiment.
Fig. 4 is a schematic structural diagram of a bus bar insulation online detection module according to an embodiment.
Fig. 5 is a schematic structural diagram of a ground branch detection module according to an embodiment.
Fig. 6 is a schematic structural diagram of a second bus insulation online detection module according to the embodiment.
Wherein: 100. the bus insulation online detection device comprises a bus insulation online detection module, 101, a positive bus filter circuit, 102, a positive bus voltage transmitter, 103, a negative bus filter circuit, 104, a negative bus voltage transmitter, 105, a drive plate, 106, a compression spring, 107, a compression block, 108, a drive spring, 200, a positioning signal generation module, 201, an optical coupling switch, 202, an oscillator, 203, an amplifier, 300, a positioning signal detection module, 301, a voltage measurement unit, 302, a phase detection unit, 400, a controller, 500, a grounding positioning button, 600, a grounding branch detection module, 601, a filtering amplification circuit, 602, an AD converter, 603, a current transformer, 700, an alarm indication module, 800 and an upper computer communication interface.
Detailed Description
The following provides a more detailed description of the present invention, with reference to the accompanying drawings.
The first embodiment is as follows:
an intelligent dc insulation on-line monitoring device with a grounding positioning function, as shown in fig. 1, the embodiment includes a housing, a bus insulation on-line detection module 100, a positioning signal generation module 200, a positioning signal detection module 300, a grounding branch detection module 600, a controller 400, a grounding positioning button 500, an alarm indication module 700 and an upper computer communication interface 800, wherein the bus insulation on-line detection module 100, the positioning signal generation module 200, the positioning signal detection module 300, the grounding branch detection module 600 and the controller 400 are all installed in the housing, the alarm indication module 700 and the upper computer communication interface 800 are all installed on the housing, the bus insulation on-line detection module 100 is connected with a positive bus + KM and a negative bus-KM to detect the insulation of the positive bus + KM and the negative bus-KM, the positioning signal generation module 200 is connected with the positive bus + KM and the negative bus-KM, the positioning signal generating module 200 generates a low-frequency alternating current signal, the positioning signal detecting module 300 is connected with the positioning signal generating module 200, the positioning signal detecting module 300 detects voltage signals at connecting points of the positioning signal generating module 200 and a positive bus + KM and a negative bus-KM, the grounding branch detecting module 600 detects alternating voltage signals of each branch, and the bus insulation on-line detecting module 100, the positioning signal generating module 200, the positioning signal detecting module 300, the grounding branch detecting module 600, the grounding positioning button 500, the alarm indicating module 700 and the upper computer communication interface 800 are connected with the controller 400. The bus insulation online detection module 100 monitors the bus insulation on line, when the bus has an insulation fault, the fault is indicated through the alarm indication module 700, after a patrol inspection worker finds the fault, the grounding positioning button 500 is pressed, then the bus insulation online detection module 100 automatically cuts off the connection with the bus, and the positioning signal generation module 200, the positioning signal detection module 300 and the grounding branch detection module 600 work to position a grounding fault point. Because the bus insulation on-line detection module 100 adopts a bridge balance method, a resistor is connected between the positive and negative buses and the grounding wire DD, the grounding branch is positioned by adopting an alternating current injection method, and the resistor connected between the positive and negative buses and the grounding wire DD can interfere with the trend of an alternating current signal injected into the buses, so that the grounding branch cannot be positioned. In the prior art, the bus insulation on-line detection module 100 and the grounding branch positioning module have respective devices, which work independently of each other, when a grounding fault occurs, if the grounding branch positioning is needed, the bus insulation on-line detection module 100 needs to be removed at first, then the grounding branch positioning module is connected, after the positioning is completed, the grounding branch positioning module needs to be removed, and the bus insulation on-line detection module 100 is connected with a bus again, which is very tedious and low in working efficiency.
As shown in fig. 2, the positioning signal generating module 200 includes an optical coupling switch 201, an oscillator 202, an amplifier 203, an electronic switch K1, an electronic switch K2, a capacitor C1 and a capacitor C2, the oscillator 202 is connected to a power supply through the optical coupling switch 201, the optical coupling switch 201 is connected to the controller 400, the oscillator 202 is connected to an input end of the amplifier 203, an output end of the amplifier 203 is connected to the electronic switch K1 and the electronic switch K2, the electronic switch K1 is connected to a positive bus + KM through the capacitor C1, and the electronic switch K2 is connected to a negative bus-KM through the capacitor C2.
As shown in fig. 3, the positioning signal detection module 300 includes a voltage measurement unit 301 and a phase detection unit 302, the voltage measurement unit 301 and the phase detection unit 302 are both connected to the positioning signal generation module 200, the positioning signal generation module 200 is detected to input a positive bus + KM and a negative bus-KM low-frequency ac signal, and the voltage measurement unit 301 and the phase detection unit 302 are both connected to the controller 400.
As shown in fig. 4, the bus insulation online detection module 100 includes an adjustable resistor R1, an adjustable resistor R2, a positive bus filter circuit 101, a positive bus voltage transmitter 102, a negative bus filter circuit 103, and a negative bus voltage transmitter 104, wherein a first end of the adjustable resistor R1 is connected to a positive bus + KM, a second end of the adjustable resistor R is connected to a first end of the adjustable resistor R2 and a ground line DD, a second end of the adjustable resistor R2 is connected to the negative bus-KM, the positive bus filter circuit 101 is connected to a first end of the adjustable resistor R1, an output end of the positive bus filter circuit 101 is connected to the positive bus voltage transmitter 102, the negative bus filter circuit 103 is connected to a first end of the adjustable resistor R2, an output end of the negative bus filter circuit 103 is connected to the negative bus voltage transmitter 104, and both the positive bus voltage transmitter 102 and the negative bus voltage transmitter 104 are connected to the controller 400. When the positive bus + KM or the negative bus-KM has a ground fault independently or both have ground faults but the ground fault degrees are different, the ground fault can be conveniently detected by adopting an electric bridge balance method. In the bridge balance method, the more the resistance values of a pair of equivalent resistors are close to the ground resistance, the larger the detected unbalanced current is under the same grounding degree, namely, the detection sensitivity is improved, so that when the adjustable resistor R1 and the adjustable resistor R2 are adopted to carry out on-line bus insulation monitoring, the bridge unbalanced current measurement under the condition of automatically adjusting a plurality of resistance values can be realized, and the bus insulation monitoring accuracy is improved.
The adjustable resistor R1 comprises a resistor R21 and a trimming resistor R31, the resistor R21 is connected with the trimming resistor R31 in series, the adjustable resistor R2 comprises a resistor R22 and a trimming resistor R32, and the resistor R22 is connected with the trimming resistor R32 in series.
The adjustable resistor detection and indication circuit detects whether the resistance values of the adjustable resistor R1 and the adjustable resistor R2 are equal or not.
The adjustable resistance inspection circuit comprises an electronic switch K3, an electronic switch K4, an electronic switch K5, an electronic switch K6, an equivalent resistor R11, an equivalent resistor R12 and a current meter A1, wherein the equivalent resistor R11 and the equivalent resistor R12 have equal resistance values, a first end of a resistor R21 is connected with a first end of the electronic switch K21 and a first end of the electronic switch K21, a second end of the resistor R21 is connected with a first end of a trimming resistor R21, a second end of the trimming resistor R21 is connected with a first end of the resistor R21, the second end of the resistor R21 and the first end of the resistor R21 are connected with a ground line DD, a second end of the resistor R21 is connected with the first end of the trimming resistor R21, a second end of the electronic switch K21 is connected with a positive bus + KM, a second end of the electronic switch K21 is connected with the equivalent resistor R21, a second end of the equivalent resistor R21 is connected with a second end of the equivalent resistor R21 and the equivalent resistor R21, the second end of the electronic switch K5 is connected with the negative bus-KM, the ammeter A1 is connected between the second end of the equivalent resistor R11 and the second end of the trimming resistor R31, and the ammeter A1 is connected with the controller 400. When the sum of the resistances of the resistor R21 and the trimming resistor R31 is equal to the sum of the resistances of the resistor R22 and the trimming resistor R32, the current meter A1 cannot detect current, so that the bridge arm resistors of the balanced bridge are ensured to be the same.
The alarm indication module 700 includes a display, an alarm indicator light and an alarm output interface, the display, the alarm indicator light and the alarm output interface are all installed on the housing, and the display, the alarm indicator light and the alarm output interface are all connected with the controller 400.
As shown in fig. 5, the grounding branch detection module 600 includes a filtering and amplifying circuit 601, an AD conversion circuit, and a current transformer 603, where the current transformer 603 is coupled to a branch line to detect a branch current, the current transformer 603 is connected to an AD converter 602 through the filtering and amplifying circuit 601, and the AD converter 602 is connected to the controller 400. The current transformer 603 is a current transformer in the form of a current clamp 603.
Example two:
the embodiment is further improved on the basis of the first embodiment. As shown in fig. 6, the present embodiment further includes an automatic resistance value adjusting device, the trimming resistor R31 and the trimming resistor R32 are both knob type adjustable resistors, the trimming resistor R31 and the trimming resistor R32 are fixedly installed in the housing side by side, the automatic resistance value adjusting device includes a driving board 105, a driving spring 108, a pressing spring 106, a pressing block 107, a resistor switch K8 and an electronic switch K9, knobs of the trimming resistor R31 and the trimming resistor R32 are respectively abutted against two opposite side surfaces of the driving board 105, a side surface of the driving board 105 has a rubber anti-slip embedded layer, the driving board 105 is movably clamped on the housing, the pressing block 107 is movably clamped with the housing, a stroke of the pressing block 107 is perpendicular to a stroke direction of the driving board 105, one end of the driving board 105 is connected with a first end of the driving spring 108, a second end of the driving spring 108 is fixedly connected with the housing, the first end of the driving spring 108 is connected with a positive pole of a power supply, the second end of the driving spring 108 is connected with a negative pole of the power supply through the electronic switch K9, one end of the pressing block 107 is connected with a first end of the pressing spring 106, a second end of the pressing spring 106 is fixedly connected with the shell, the first end of the pressing spring 106 is connected with the negative pole of the power supply, and the second end of the pressing spring 106 is connected with the positive pole of the power supply through the electronic switch K8. The trimming resistor R31 and the trimming resistor R32 are installed side by side, when the driving board 105 moves, the resistances of the trimming resistor R31 and the trimming resistor R32 are increased one by one, and the resistance of the trimming resistor R32 is decreased the other, if the resistance of the bridge arm where the trimming resistor R31 is located is larger than that of the bridge arm where the trimming resistor R32 is located, the driving board 105 drives the trimming resistor R32 to be increased while the resistance of the trimming resistor R31 is decreased, and therefore the resistances of the two bridge arms can be adjusted to be consistent quickly and conveniently. The driving spring 108 is electrified to contract, the contraction quantity of the spring can be controlled by controlling the duty ratio of the electronic switch, namely, by adopting a PMW mode, the spring is equivalent to an inductor, namely, the spring has an equivalent resistance, and in order to avoid overlarge current, a series current-limiting resistor is a known technology.
The above-described embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention in any way, and other variations and modifications may be made without departing from the spirit of the invention as set forth in the claims.