CN114062963A - Direct current system insulation monitoring device capable of finding specific grounding point - Google Patents
Direct current system insulation monitoring device capable of finding specific grounding point Download PDFInfo
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- CN114062963A CN114062963A CN202111213553.1A CN202111213553A CN114062963A CN 114062963 A CN114062963 A CN 114062963A CN 202111213553 A CN202111213553 A CN 202111213553A CN 114062963 A CN114062963 A CN 114062963A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
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Abstract
The invention discloses a direct current system insulation monitoring device capable of finding out a specific grounding point, which mainly comprises a host, a line selection module, a fixed CT and a movable CT; the fixed CT and the movable CT are respectively connected with the host through the line selection module, and the movable CT and the line selection module are connected in a wireless ZigBee communication mode. The invention utilizes the combination of the wireless communication technology and the CT to enable the CT to have the wireless communication function, and improves the accuracy of finding the grounding point of the insulating device under the condition of not needing a searching instrument.
Description
Technical Field
The invention belongs to the technical field of equipment grounding detection, and particularly relates to a direct current system insulation monitoring device capable of finding out a specific grounding point.
Background
The DC power supply system for the station is used as a secondary device, a communication device and an emergency lighting power supply, and has very high requirements on stability and reliability. In order to ensure the safe and controllable operation of the protection equipment, the direct-current power supply system is designed into an ungrounded system, and in order to monitor the ground fault of the direct-current system, an insulation monitoring device is arranged in the direct-current system complete equipment. The insulation monitoring device is only limited to monitoring the direct current fault state of each direct current feeder screen, and the direct current system ground fault also depends on a direct current ground finder. The number of direct current grounding seeking instruments equipped in a power supply station is limited, and in severe weather such as thunderstorm and the like, grounding faults of multiple power stations can occur in local areas, and the grounding seeking instruments are not enough to be used, so that the existence time of partial grounding faults is prolonged, and the protective operation threat is brought.
Disclosure of Invention
The invention aims to provide a direct current system insulation monitoring device capable of finding out a specific grounding point, which can shorten the grounding fault finding time, improve the grounding fault finding efficiency and better guarantee the power safety production.
In order to achieve the purpose, the invention adopts the following technical scheme:
a direct current system insulation monitoring device capable of finding out a specific grounding point mainly comprises a host, a line selection module, a fixed CT and a movable CT; the fixed CT and the movable CT are respectively connected with the host through the line selection module, and the movable CT and the line selection module are connected in a wireless ZigBee communication mode; the host comprises a power supply I, an acquisition unit I, a line selection unit, a main control unit I, a man-machine exchange unit, an alarm unit and a communication unit I; the power supply I, the acquisition unit I, the line selection unit, the man-machine exchange unit, the alarm unit and the communication unit I are respectively connected with the main control unit I; the line selection module is responsible for collecting CT current signals, calculating the CT current signals into digital signals and transmitting the digital signals to the host, and comprises a power supply II, a collection unit II, a main control unit II and a communication unit II, wherein the power supply II, the collection unit II and the communication unit II are respectively connected with the main control unit II.
The host, the line selection module and the fixed CT are online running equipment, the functions of the online running equipment are basically the same as those of the existing insulation monitoring device, the difference is that the line selection module is added with a ZigBee communication technology, and the movable CT is provided with a ZigBee communication function, can communicate with the line selection module and can communicate among the CTs; after the insulation monitoring device selects the line, the movable CT is started to the lower-level line for monitoring, the line selection is continued, and the accurate positioning of the ground fault is realized through the movable CT.
The invention further discloses that a communication unit I of the host is provided with 4 paths of 485 communication interfaces, 1 group of CAN communication interfaces, 1 group of 232 communication interfaces and 1 path of RJ45 communication interfaces; and the communication unit II of the line selection module is provided with 1 path of 485 communication circuit to communicate with the host, and 1 path of ZigBee communication circuit II communicates with the mobile CT.
The invention further discloses that the mobile CT is provided with a battery as a power supply; the mobile CT is also provided with a magnetic core, a current induction voltage amplifying circuit and a ZigBee communication circuit III; and the ZigBee communication circuit II and the ZigBee communication circuit III are designed by adopting CC2420 chips.
The invention further discloses that a power supply I of the host machine adopts a 75W switching power supply module as a main body and outputs 12V, 5V and 3.3V power supply voltages; the main control unit I of the host adopts STM32F407VET6 as a main control chip; the man-machine exchange unit of the host machine adopts a 7-inch industrial serial port touch screen; the alarm unit of the host uses 4 sets of alarm outputs of a conventional relay design.
The invention further discloses that the acquisition unit I of the host comprises a voltage input voltage division circuit, a direct current voltage acquisition circuit and an alternating current voltage acquisition circuit.
The invention further explains that the line selection unit of the host drives the variable resistor to generate a variable leakage current signal for the use of ground line selection after the direct current system has ground fault.
The invention further describes that a power supply II of the line selection module adopts a 12V power supply output by the host, and outputs 5V and 3.3V power supply voltage; the acquisition unit II of the line selection module is provided with an RC low-pass filter for filtering the signal of the CT and then acquiring the signal; and the STM32F103 is adopted as a main control chip by the main control unit II of the line selection module.
The invention further discloses that the fixed CT is directly connected with the line selection module by adopting a 4-core line, and comprises a magnetic core and a current induction voltage amplification circuit. The 4-core wire comprises a power supply and an amplified voltage signal.
The invention has the advantages that:
1. the invention combines the wireless communication technology, still keeps the original grounding searching function, and solves the original complicated and tedious grounding searching process in different places. The original insulating device can only find out the branch circuit and then find out the specific grounding point through other grounding seeking instruments, and at present, a CT with wireless communication is arranged on each small power utilization branch circuit card, and the CT can feed back the real-time situation to a host computer, so that people do not need to detect the labor-consuming and time-consuming process by other grounding seeking instruments one by one.
2. The invention solves the problem of limitation of material resources, namely saving cost, because the grounding point is found in the same time, the material resource cost of the searching instrument is increased, and the number of the searching instruments equipped at each site is limited, therefore, the movable CT adopted by the invention and the real-time reporting of the CT are far lower than the cost of the searching instrument and are not limited by the number.
3. The invention utilizes the combination of the wireless communication technology and the CT to enable the CT to have the wireless communication function, and improves the accuracy of finding the grounding point of the insulating device under the condition of not needing a searching instrument.
Drawings
Fig. 1 is a schematic structural composition diagram of an embodiment of the present invention.
Fig. 2 is a schematic structural diagram of a host according to an embodiment of the present invention.
Fig. 3 is a schematic structural diagram of a line selection module according to an embodiment of the present invention.
Fig. 4 is a schematic diagram of a voltage input divider circuit of the acquisition unit i of the host according to an embodiment of the present invention.
Fig. 5 is a schematic diagram of a dc voltage acquisition circuit of the acquisition unit i of the host in an embodiment of the invention.
Fig. 6 is a schematic diagram of an ac voltage acquisition circuit of the acquisition unit i of the host in an embodiment of the present invention.
FIG. 7 is a schematic circuit diagram of a line selection unit of a host according to an embodiment of the present invention.
Fig. 8 is a schematic diagram of a ZigBee communication circuit designed based on a CC2420 chip in an embodiment of the present invention.
Detailed Description
The invention is further described below with reference to the accompanying drawings.
Example (b):
as shown in fig. 1, a dc system insulation monitoring device capable of finding a specific grounding point mainly comprises a host, a line selection module, a fixed CT and a movable CT; the fixed CT and the movable CT are respectively connected with the host through the line selection module, and the movable CT and the line selection module are connected in a wireless ZigBee communication mode.
As shown in fig. 2, the host comprises a power supply i, an acquisition unit i, a line selection unit, a main control unit i, a man-machine exchange unit, an alarm unit and a communication unit i; the power supply I, the acquisition unit I, the line selection unit, the man-machine exchange unit, the alarm unit and the communication unit I are respectively connected with the main control unit I.
As shown in fig. 3, the line selection module is responsible for acquiring a CT current signal, calculating the CT current signal into a digital signal, and transmitting the digital signal to the host, and includes a power supply ii, an acquisition unit ii, a main control unit ii, and a communication unit ii, where the power supply ii, the acquisition unit ii, and the communication unit ii are respectively connected with the main control unit ii.
The host, the line selection module and the fixed CT are online running equipment, the functions of the online running equipment are basically the same as those of the existing insulation monitoring device, the difference is that the line selection module is added with a ZigBee communication technology, and the movable CT is designed with a ZigBee communication function, can communicate with the line selection module and can communicate among the CTs; after the insulation monitoring device selects the line, the movable CT is started to the lower-level line for monitoring, the line selection is continued, and the accurate positioning of the ground fault is realized through the movable CT.
In this embodiment, the communication unit i of the host is provided with 4 channels of 485 communication interfaces, 1 group of CAN communication interfaces, 1 group of 232 communication interfaces, and 1 channel of RJ45 communication interfaces; and the communication unit II of the line selection module is provided with 1 path of 485 communication circuit to communicate with the host, and 1 path of ZigBee communication circuit II communicates with the mobile CT. The mobile CT is provided with a battery as a power supply; the mobile CT is also provided with a magnetic core, a current induction voltage amplifying circuit and a ZigBee communication circuit III; the ZigBee communication circuit II and the ZigBee communication circuit III are designed by adopting CC2420 chips (as shown in figure 8). The power supply I of the host machine adopts a 75W switching power supply module as a main body and outputs 12V, 5V and 3.3V power supply voltages; the main control unit I of the host adopts STM32F407VET6 as a main control chip; the man-machine exchange unit of the host machine adopts a 7-inch industrial serial port touch screen; the alarm unit of the host uses 4 sets of alarm outputs of a conventional relay design. The power supply II of the line selection module adopts a 12V power supply output by the host, and outputs 5V and 3.3V power supply voltages; the acquisition unit II of the line selection module is provided with an RC low-pass filter for filtering the signal of the CT and then acquiring the signal; and the STM32F103 is adopted as a main control chip by the main control unit II of the line selection module. The fixed CT is directly connected with the line selection module by adopting a 4-core line, and comprises a magnetic core and a current induction voltage amplification circuit. The 4-core wire comprises a power supply and an amplified voltage signal.
In this embodiment, the acquisition unit i of the host includes a voltage input voltage dividing circuit, a direct-current voltage acquisition circuit, and an alternating-current voltage acquisition circuit.
The voltage input divider circuit, as shown in fig. 4: the voltage input of the direct current bus realizes overcurrent protection through insurance, overvoltage protection is carried out through two RV piezoresistors, and then common mode inductance filtering is carried out; and voltage passing through protection and filtering is divided through a resistor and voltage, and a weak voltage signal after voltage division is sampled.
A dc voltage acquisition circuit, as shown in fig. 5: after voltage division processing is carried out on the direct current bus voltage-to-ground voltage sampling circuit through the voltage division processing shown in fig. 4, operation amplification processing is carried out on weak voltage, and then AD sampling is carried out.
An alternating voltage collection circuit, as shown in fig. 6: after the voltage division processing of the alternating current channeling voltage sampling circuit shown in fig. 4, the weak voltage is subjected to operation amplification processing, and then AD sampling is performed.
In this embodiment, the line selection unit of the host drives the variable resistor to generate a variable leakage current signal for the ground line selection after the dc system has a ground fault. As shown in fig. 7, the line selection characteristic signal generates an analog signal through a DA chip, the resistor divides the voltage of the signal, the optical coupler isolates and amplifies the signal, and then the signal is amplified by current and connected between a bus of the dc system and the ground. And changing the voltage to ground of the bus to enable the grounding direct current to generate variable leakage current, detecting the characteristic current and searching for the grounding fault.
It should be understood that the above-described embodiments are merely examples for clearly illustrating the present invention and are not intended to limit the practice of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description; this is not necessary, nor exhaustive, of all embodiments; and obvious variations or modifications of the invention may be made without departing from the scope of the invention.
Claims (8)
1. The utility model provides a can find out insulating monitoring devices of direct current system of concrete ground point which characterized in that: mainly comprises a host, a line selection module, a fixed CT and a movable CT; the fixed CT and the movable CT are respectively connected with the host through the line selection module, and the movable CT and the line selection module are connected in a wireless ZigBee communication mode;
the host comprises a power supply I, an acquisition unit I, a line selection unit, a main control unit I, a man-machine exchange unit, an alarm unit and a communication unit I; the power supply I, the acquisition unit I, the line selection unit, the man-machine exchange unit, the alarm unit and the communication unit I are respectively connected with the main control unit I;
the line selection module is responsible for collecting CT current signals, calculating the CT current signals into digital signals and transmitting the digital signals to the host, and comprises a power supply II, a collection unit II, a main control unit II and a communication unit II, wherein the power supply II, the collection unit II and the communication unit II are respectively connected with the main control unit II.
2. The dc system insulation monitoring device for finding specific grounding points as claimed in claim 1, wherein: the communication unit I of the host is provided with 4 paths of 485 communication interfaces, 1 group of CAN communication interfaces, 1 group of 232 communication interfaces and 1 path of RJ45 communication interfaces; and the communication unit II of the line selection module is provided with 1 path of 485 communication circuit to communicate with the host, and 1 path of ZigBee communication circuit II communicates with the mobile CT.
3. The dc system insulation monitoring device for finding specific grounding points as claimed in claim 2, wherein: the mobile CT is provided with a battery as a power supply; the mobile CT is also provided with a magnetic core, a current induction voltage amplifying circuit and a ZigBee communication circuit III; and the ZigBee communication circuit II and the ZigBee communication circuit III are designed by adopting CC2420 chips.
4. The dc system insulation monitoring device for finding specific grounding points as claimed in claim 1, wherein: the power supply I of the host machine adopts a 75W switching power supply module as a main body and outputs 12V, 5V and 3.3V power supply voltages; the main control unit I of the host adopts STM32F407VET6 as a main control chip; the man-machine exchange unit of the host machine adopts a 7-inch industrial serial port touch screen; the alarm unit of the host uses 4 sets of alarm outputs of a conventional relay design.
5. The dc system insulation monitoring device for finding specific grounding points as claimed in claim 1, wherein: the acquisition unit I of the host comprises a voltage input voltage division circuit, a direct current voltage acquisition circuit and an alternating current voltage acquisition circuit.
6. The dc system insulation monitoring device for finding specific grounding points as claimed in claim 1, wherein: the line selection unit of the host drives the variable resistor to generate a variable leakage current signal for the use of grounding line selection after the direct current system has a grounding fault.
7. The dc system insulation monitoring device for finding specific grounding points as claimed in claim 1, wherein: the power supply II of the line selection module adopts a 12V power supply output by the host, and outputs 5V and 3.3V power supply voltages; the acquisition unit II of the line selection module is provided with an RC low-pass filter for filtering the signal of the CT and then acquiring the signal; and the STM32F103 is adopted as a main control chip by the main control unit II of the line selection module.
8. The dc system insulation monitoring device for finding specific grounding points as claimed in claim 1, wherein: the fixed CT is directly connected with the line selection module by adopting a 4-core line, and comprises a magnetic core and a current induction voltage amplification circuit.
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| CN202111213553.1A CN114062963A (en) | 2021-10-19 | 2021-10-19 | Direct current system insulation monitoring device capable of finding specific grounding point |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202111213553.1A CN114062963A (en) | 2021-10-19 | 2021-10-19 | Direct current system insulation monitoring device capable of finding specific grounding point |
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