CN103592563A - Direct current system insulation on-line monitoring device - Google Patents

Direct current system insulation on-line monitoring device Download PDF

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Publication number
CN103592563A
CN103592563A CN201310597921.6A CN201310597921A CN103592563A CN 103592563 A CN103592563 A CN 103592563A CN 201310597921 A CN201310597921 A CN 201310597921A CN 103592563 A CN103592563 A CN 103592563A
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CN
China
Prior art keywords
bus
voltage
unit
feeder line
central processing
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CN201310597921.6A
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Chinese (zh)
Inventor
于培永
王立欣
侯玉江
蔡南
阳薇
景伟
杨会民
Original Assignee
国家电网公司
国网黑龙江省电力有限公司检修公司
于培永
王立欣
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Application filed by 国家电网公司, 国网黑龙江省电力有限公司检修公司, 于培永, 王立欣 filed Critical 国家电网公司
Priority to CN201310597921.6A priority Critical patent/CN103592563A/en
Publication of CN103592563A publication Critical patent/CN103592563A/en

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Abstract

The invention provides a direct current system insulation on-line monitoring device, belongs to the field of electric systems, and aims to solve the problems of the existing direct current system insulation on-line monitoring technology. The direct current system insulation on-line monitoring device comprises a central processing unit, a bus detection unit, an alarm display unit and m feeder leakage current acquisition units. The bus detection unit acquires bus voltages, wherein the bus voltages include voltages between direct current buses, positive and negative bus voltages to ground and alternate current interfusion voltages; a bus voltage signal transmission side of the bus detection unit is connected with a bus voltage signal transmission side of the central processing unit. All the feeder leakage current acquisition units acquire grounded leakage currents of n feeders, wherein feeder grounded leakage current signal transmission sides of the m feeder leakage current acquisition units are connected with a feeder grounded leakage current signal transmission side of the central processing unit through an RS485 bus. An alarm display signal transmission side of the central processing unit is connected with an alarm display signal transmission side of the display and alarm unit.

Description

Straight-flow system insulation line monitoring device
Technical field
The present invention relates to straight-flow system insulation line monitoring device, belong to field of power.
Background technology
Being applied to the straight-flow system of generating plant, transformer station, current conversion station, is the power-supply system that ensures the normal operation of supervising device in electric system.Straight-flow system is mainly the DC load such as telltale, control device and protective relaying device uninterruption power source is provided, so the safe, reliable, efficient operation of electric system is directly limited by the quality of straight-flow system working condition.DC earthing is the most common failure of straight-flow system, and DC earthing may cause the maloperation of load device, and then causes even more serious accident, so the malfunction of on-line monitoring straight-flow system has great importance.Simultaneously complete DC system fault monitoring mechanism has reduced by 25~50% year maintenance cost, the time decreased having a power failure because of DC system fault 75%.As can be seen here, DC system fault is carried out to on-line monitoring and can bring huge Social benefit and economic benefit.
Shown in Fig. 1 is that electric pressure is the illustraton of model of the DC220V straight-flow system in the transformer station of 500kV, under normal operating conditions, by HF switch charging device, 380V three-phase alternating current is rectified into 220V direct current, directly to each feeder line branch road on DC bus, provide working power, battery pack in floating charge state is carried out to boost charge simultaneously, make up battery pack because the electric energy of floating charge state loss.But if during HF switch charging device generation power supply trouble, battery pack is converted to regular picture state, to DC load power supply, to ensure the uninterrupted power supply of straight-flow system.
In this straight-flow system, bus is comprised of two sections of buses, and two sections of buses can connect into one section of bus by bus joint control.On every section of bus all carry a charging set, a battery pack and an insulation line monitoring device, standby charging set can be connected and power with two sections of buses by latch switch.Battery pack adopts the valve controlled sealed lead-acid accumulator (VRLA) that cell nominal voltage is 2V, because the busbar voltage of straight-flow system is 1.05 times of straight-flow system nominal voltage 220V, need 102~108 cells that the DC bus-bar voltage of 231V is provided [8].Every section of bus can tens feeder line branch roads of carry, and on every feeder line branch road, sensor installation (CT) is measured the earth leakage stream of this feeder line, and insulation line monitoring device is collected the leakage current information of each sensor, monitors the state of insulation of each feeder line.
The method that straight-flow system insulated on-line monitoring is conventional, balanced bridge method, switching bridge method, low frequency small-signal detection method and DC leakage current detection method.But all there is problem separately in above four kinds of monitoring methods, makes a concrete analysis of as follows:
Balanced bridge method is a kind of traditional busbar grounding detection method, but exist, detects dead band.
Switch bridge method and need to find out the reasonable criterion of switching electric bridge, can not be in order to find out also nonevent earth fault, and ceaselessly remove to switch electric bridge, therefore need to find out the reasonable criterion of switching electric bridge.This has increased use difficulty.
In use, the low frequency small-signal of injection can form loop through the stray capacitance over the ground of feeder line to low frequency small-signal detection method, and that causes device fails to report or report by mistake DC system earth fault.
The DC leakage current sensor that DC leakage current detection method is used, the temperature that this sensor comes out under complex electromagnetic environment has been floated with drift problems affect the accurate measurement of feeder line insulation against ground resistance.
Summary of the invention
The present invention seeks to the problem existing in order to solve existing straight-flow system insulated on-line monitoring technology, a kind of straight-flow system insulation line monitoring device is provided.
Straight-flow system insulation line monitoring device of the present invention, it comprises CPU (central processing unit), bus detecting unit, display alarm unit and m feeder line leakage current collecting unit,
Bus detecting unit gathers busbar voltage, described busbar voltage comprises voltage between DC bus, positive and negative busbar voltage-to-ground and exchanges sneaks into voltage, and the bus voltage signal transmission ends of bus detecting unit is connected with the bus voltage signal transmission ends of CPU (central processing unit);
Each feeder line leakage current collecting unit gathers the earth leakage stream of n bar feeder line, and the feeder line earth leakage stream signal transmission ends of m feeder line leakage current collecting unit is connected with the feeder line earth leakage stream signal transmission ends of CPU (central processing unit) by RS485 bus;
The alarm indication transmission ends of CPU (central processing unit) is connected with the alarm indication transmission ends of display alarm unit.
Advantage of the present invention: the analysis of the present invention to existing insulation line monitoring device and principle, proposed a kind of bus and grounding and detected and combine, balanced bridge supplements mutually with switching electric bridge, takes into account the modified insulated on-line monitoring scheme that detection is sneaked in interchange.Utilize bus detecting unit and feeder line leakage current collecting unit to detect busbar voltage and each feeder line leakage current, by master controller overall treatment, analyzed, calculate the insulation against ground resistance of bus and each feeder line, locate fast earth fault, and report to the police and show.
Accompanying drawing explanation
Fig. 1 is that electric pressure is the illustraton of model of the DC220V straight-flow system in the transformer station of 500kV; In figure, a represents feeder line;
Fig. 2 is the structural representation of straight-flow system insulation line monitoring device of the present invention;
Fig. 3 is bridge diagram figure;
Fig. 4 is the circuit diagram of π shape low-pass filter;
Fig. 5 is direct current positive and negative busbar voltage-to-ground sample circuit figure;
Fig. 6 is the theory diagram of feeder line leakage current collecting unit;
Fig. 7 is signal processing circuit.
Embodiment
Embodiment one: present embodiment is described below in conjunction with Fig. 1 to Fig. 7, straight-flow system insulation line monitoring device described in present embodiment, as shown in Figure 2, it comprises CPU (central processing unit) 1, bus detecting unit 2, display alarm unit 4 and m feeder line leakage current collecting unit 5
Bus detecting unit 2 gathers busbar voltage, described busbar voltage comprises voltage between DC bus, positive and negative busbar voltage-to-ground and exchanges sneaks into voltage, and the bus voltage signal transmission ends of bus detecting unit 2 is connected with the bus voltage signal transmission ends of CPU (central processing unit) 1;
Each feeder line leakage current collecting unit 5 gathers the earth leakage stream of n bar feeder line, and the feeder line earth leakage stream signal transmission ends of m feeder line leakage current collecting unit 5 is connected with the feeder line earth leakage stream signal transmission ends of CPU (central processing unit) 1 by RS485 bus;
The alarm indication transmission ends of CPU (central processing unit) 1 is connected with the alarm indication transmission ends of display alarm unit 4.
CT in Fig. 2 1, CT 2... CT nrefer to n DC leakage current sensor,
The master controller of CPU (central processing unit) 1 adopts the arm processor that model is STM32F103VET6 to realize.
Bus detecting unit 2 comprises bridge diagram, DC-bus voltage sampling circuit and exchanges sneaks into tension measuring circuit;
Bridge diagram is for detection of voltage between DC bus;
DC-bus voltage sampling circuit is for detection of positive and negative busbar voltage-to-ground;
Interchange is sneaked into tension measuring circuit and is sneaked into voltage for detection of interchange.
Present embodiment provides a kind of bridge diagram as shown in Figure 3, successively change-over switch S 1, S 2, obtain bus and the two states that ground is connected, measure the Bus Voltage under this two states, can calculate bus insulation against ground resistance.Obviously switch bridge method and can complete the not detection of Grounding of the same race of bus, but ceaselessly switching electric bridge is drawn partially Bus Voltage, when Bus Voltage skew is larger, protective relay tripping operation, causes DC system fault.Electric bridge gauge tap is used AQW214 light-coupled isolation switch, and its isolation voltage reaches 400V, utilizes N channel field-effect pipe BSP297 to drive it.
DC-bus voltage sampling circuit comprises symmetrical π shape low-pass filter, voltage treatment circuit, prime RC low-pass filter, isolated amplifier, rear class voltage follower, rear class RC low-pass filter.Straight-flow system distribution cable is longer, and the noise of introducing during protective relaying device action can affect the precision of DC bus-bar voltage sampling, therefore uses symmetrical π shape low-pass filter filtering normal mode noise wherein, as shown in Figure 4.
Present embodiment has provided DC-bus voltage sampling circuit as shown in Figure 5, positive bus-bar voltage-to-ground U zsampling is used resistance pressure-dividing network that 0~330V input voltage is dwindled to 101 times; And negative busbar voltage-to-ground U fsampling is used anti-phase scale operation amplifying circuit that-330~0 input voltage has been dwindled to-100 times.
It is generally that AC power cord directly overlaps with DC bus that interchange is sneaked into, with formation loop, ground, so positive bus-bar and ground, and negative busbar between and order cross streams voltage transmitter HAV-T2,0~450V alternating voltage of isolation measurement 25Hz~5kHz, accuracy of measurement is ± 0.2%, be output as the current signal of 4-20mA, current signal is converted into after the voltage signal of 0~3V, sends into AD sample through voltage follower and RC low-pass filter.The insulation resistance of HAV-T2 is greater than 100M Ω, can be on any impact of bridge diagram parameter generating.According to straight-flow system design specifications, exchange and sneak into voltage over 10V, should report to exchange and sneak into fault.
Feeder line leakage current collecting unit 5 comprises signal processing circuit 5-1, A/D sample circuit 5-2 and sampling controller 5-3, signal processing circuit 5-1 receives the feeder line earth leakage stream signal that n DC leakage current sensor detects, the feeder line earth leakage stream signal output part of signal processing circuit 5-1 is connected with the input end of analog signal of A/D sample circuit 5-2, the digital signal output end of A/D sample circuit 5-2 is connected with the feeder line earth leakage of sampling controller 5-3 stream signal input part, and sampling controller 5-3 connects RS485 bus.
Sampling controller 5-3 adopts the controller that model is F103RBT6 to realize.
Each feeder line leakage current collecting unit 5 is accepted the output voltage signal of n platform DC leakage current sensor, by signal processing circuit 5-1, by A/D sample circuit, 5-2 carries out AD sampling, filtering prestores, receive after the reading order of CPU (central processing unit) 1, feeder line earth leakage stream information is uploaded to CPU (central processing unit) 1 by RS485.Wherein signal processing circuit as shown in Figure 7.
Embodiment two: present embodiment is described further embodiment one, it also comprises communication unit 3, CPU (central processing unit) 1 is carried out communication by communication unit 3.
Straight-flow system bus is that segmentation split screen is arranged, every section of bus is responsible for the power supply of zones of different, and every section of bus all must arrange an insulation line monitoring device.When the straight-flow system method of operation changes, two sections of buses are by the synthetic one section of bus of bus joint control, and interconnected communication between insulation line monitoring device, changes monitoring strategies.Meanwhile, each table apparatus also needs Monitoring Data to be uploaded to the host computer of central station of floating dock, and the transmission of these data all needs communication unit to complete.Consider the interconnected demand of insulation line monitoring device, and the simplification of the interconnected operation of user, communication unit arranges CAN bus, RS485 and tri-kinds of communication modes of RS232.

Claims (6)

1. straight-flow system insulation line monitoring device, is characterized in that, it comprises CPU (central processing unit) (1), bus detecting unit (2), display alarm unit (4) and m feeder line leakage current collecting unit (5),
Bus detecting unit (2) gathers busbar voltage, described busbar voltage comprises voltage between DC bus, positive and negative busbar voltage-to-ground and exchanges sneaks into voltage, and the bus voltage signal transmission ends of bus detecting unit (2) is connected with the bus voltage signal transmission ends of CPU (central processing unit) (1);
Each feeder line leakage current collecting unit (5) gathers the earth leakage stream of n bar feeder line, and the feeder line earth leakage stream signal transmission ends of m feeder line leakage current collecting unit (5) is connected with the feeder line earth leakage stream signal transmission ends of CPU (central processing unit) (1) by RS485 bus;
The alarm indication transmission ends of CPU (central processing unit) (1) is connected with the alarm indication transmission ends of display alarm unit (4).
2. straight-flow system insulation line monitoring device according to claim 1, is characterized in that, it also comprises communication unit (3), and CPU (central processing unit) (1) is carried out communication by communication unit (3).
3. straight-flow system insulation line monitoring device according to claim 1, is characterized in that, the master controller of CPU (central processing unit) (1) adopts the arm processor that model is STM32F103VET6 to realize.
4. straight-flow system insulation line monitoring device according to claim 1, is characterized in that, bus detecting unit (2) comprises bridge diagram, DC-bus voltage sampling circuit and exchanges sneaks into tension measuring circuit;
Bridge diagram is for detection of voltage between DC bus;
DC-bus voltage sampling circuit is for detection of positive and negative busbar voltage-to-ground;
Interchange is sneaked into tension measuring circuit and is sneaked into voltage for detection of interchange.
5. straight-flow system insulation line monitoring device according to claim 1, it is characterized in that, feeder line leakage current collecting unit (5) comprises signal processing circuit (5-1), A/D sample circuit (5-2) and sampling controller (5-3), signal processing circuit (5-1) receives the feeder line earth leakage stream signal that n DC leakage current sensor detects, the feeder line earth leakage stream signal output part of signal processing circuit (5-1) is connected with the input end of analog signal of A/D sample circuit (5-2), the digital signal output end of A/D sample circuit (5-2) is connected with the feeder line earth leakage stream signal input part of sampling controller (5-3), sampling controller (5-3) connects RS485 bus.
6. straight-flow system insulation line monitoring device according to claim 5, is characterized in that, sampling controller (5-3) adopts the controller that model is F103RBT6 to realize.
CN201310597921.6A 2013-11-22 2013-11-22 Direct current system insulation on-line monitoring device CN103592563A (en)

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Cited By (16)

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CN104007396A (en) * 2014-05-19 2014-08-27 广西电网公司电力科学研究院 Device and method for searching for loop channeling electric fault in direct current systems
CN105242170A (en) * 2015-11-23 2016-01-13 武汉工程大学 Automatic aerial socket signal line number recognition method and device
CN105954660A (en) * 2016-07-22 2016-09-21 安徽亚辉电气自动化有限公司 Online insulation monitoring device for high-low voltage equipment
CN106093657A (en) * 2016-07-19 2016-11-09 兰州海红技术股份有限公司 Condition monitoring system for high-voltage direct current
CN106353657A (en) * 2016-11-28 2017-01-25 国网福建省电力有限公司 High-voltage direct current cable partial discharge intelligent monitoring device and monitoring method
CN106645976A (en) * 2016-09-30 2017-05-10 阳光电源股份有限公司 Ground insulation impedance detection circuit for photovoltaic cell panel
CN108387800A (en) * 2018-03-13 2018-08-10 深圳市安特智能控制有限公司 A kind of accumulator group major loop state multidimensional judgment method
CN108398644A (en) * 2018-01-30 2018-08-14 南京理工大学 A kind of power battery of pure electric automobile Insulation Inspection System and method
CN108693442A (en) * 2018-05-17 2018-10-23 辽宁石油化工大学 The detection method and system of electric network fault
CN108761293A (en) * 2018-08-09 2018-11-06 安徽亚辉电气自动化有限公司 A kind of bus insulation condition checkout gear
CN108828393A (en) * 2018-09-17 2018-11-16 中车青岛四方车辆研究所有限公司 DC110V on-line insulation monitoring system and method
CN109782106A (en) * 2019-01-07 2019-05-21 邯郸钢铁集团有限责任公司 A kind of DC system earth fault lookup device and method
CN109782137A (en) * 2018-12-06 2019-05-21 安徽凯川电力保护设备有限公司 A kind of insulation line monitoring device and method
CN110412418A (en) * 2019-07-22 2019-11-05 国网湖北省电力有限公司电力科学研究院 Insulating tube type busbar insulation diagnosis and localization method based on earth current measurement
CN110488146A (en) * 2019-04-02 2019-11-22 许继电气股份有限公司 A kind of DC distribution net type insulation monitoring system and D.C. isolation monitoring device
CN110726952A (en) * 2019-11-18 2020-01-24 哈尔滨工业大学(深圳) Load fault detection method based on grounding insulation

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Cited By (22)

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Publication number Priority date Publication date Assignee Title
CN104007396B (en) * 2014-05-19 2017-01-25 广西电网公司电力科学研究院 Device and method for searching for loop channeling electric fault in direct current systems
CN104007396A (en) * 2014-05-19 2014-08-27 广西电网公司电力科学研究院 Device and method for searching for loop channeling electric fault in direct current systems
CN105242170A (en) * 2015-11-23 2016-01-13 武汉工程大学 Automatic aerial socket signal line number recognition method and device
CN105242170B (en) * 2015-11-23 2017-12-12 武汉工程大学 The automatic identifying method and device of aviation socket signal wire numbering
CN106093657A (en) * 2016-07-19 2016-11-09 兰州海红技术股份有限公司 Condition monitoring system for high-voltage direct current
CN106093657B (en) * 2016-07-19 2019-04-23 兰州海红技术股份有限公司 Condition monitoring system for high-voltage direct current
CN105954660A (en) * 2016-07-22 2016-09-21 安徽亚辉电气自动化有限公司 Online insulation monitoring device for high-low voltage equipment
CN106645976A (en) * 2016-09-30 2017-05-10 阳光电源股份有限公司 Ground insulation impedance detection circuit for photovoltaic cell panel
CN106353657A (en) * 2016-11-28 2017-01-25 国网福建省电力有限公司 High-voltage direct current cable partial discharge intelligent monitoring device and monitoring method
CN108398644A (en) * 2018-01-30 2018-08-14 南京理工大学 A kind of power battery of pure electric automobile Insulation Inspection System and method
CN108387800A (en) * 2018-03-13 2018-08-10 深圳市安特智能控制有限公司 A kind of accumulator group major loop state multidimensional judgment method
CN108387800B (en) * 2018-03-13 2020-04-10 深圳市安特智能控制有限公司 Multi-dimensional judgment method for main loop state of storage battery pack
CN108693442A (en) * 2018-05-17 2018-10-23 辽宁石油化工大学 The detection method and system of electric network fault
CN108761293B (en) * 2018-08-09 2021-01-05 安徽亚辉电气自动化有限公司 Bus insulation state detection device
CN108761293A (en) * 2018-08-09 2018-11-06 安徽亚辉电气自动化有限公司 A kind of bus insulation condition checkout gear
CN108828393A (en) * 2018-09-17 2018-11-16 中车青岛四方车辆研究所有限公司 DC110V on-line insulation monitoring system and method
CN109782137A (en) * 2018-12-06 2019-05-21 安徽凯川电力保护设备有限公司 A kind of insulation line monitoring device and method
CN109782106A (en) * 2019-01-07 2019-05-21 邯郸钢铁集团有限责任公司 A kind of DC system earth fault lookup device and method
CN109782106B (en) * 2019-01-07 2021-03-09 邯郸钢铁集团有限责任公司 Direct current system ground fault searching device and method
CN110488146A (en) * 2019-04-02 2019-11-22 许继电气股份有限公司 A kind of DC distribution net type insulation monitoring system and D.C. isolation monitoring device
CN110412418A (en) * 2019-07-22 2019-11-05 国网湖北省电力有限公司电力科学研究院 Insulating tube type busbar insulation diagnosis and localization method based on earth current measurement
CN110726952A (en) * 2019-11-18 2020-01-24 哈尔滨工业大学(深圳) Load fault detection method based on grounding insulation

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Application publication date: 20140219