CN203858322U - Self-adapting end-grounding line-selection device - Google Patents

Self-adapting end-grounding line-selection device Download PDF

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Publication number
CN203858322U
CN203858322U CN201420253278.5U CN201420253278U CN203858322U CN 203858322 U CN203858322 U CN 203858322U CN 201420253278 U CN201420253278 U CN 201420253278U CN 203858322 U CN203858322 U CN 203858322U
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self
control module
communication interface
main control
positive
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刘芳
蓝利民
南寅
赵志群
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Beijing Peoples Electric Plant Co Ltd
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Beijing Peoples Electric Plant Co Ltd
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Abstract

The utility model discloses an on-line insulating monitoring method for low-voltage direct-current power distribution, and a self-adapting end-grounding line-selection device. The device comprises a master control module and a leakage current measurement module. The master control module is provided with an external communication interface, an internal communication interface, and a self-adapting detection circuit. The self-adapting detection circuit detects the voltages to earth of positive and negative buses in real time, and judges whether a self-balancing resistor is switched to the positive and negative buses or not. The leakage current measurement module is provided with a zero-sequence mutual inductor, a signal conditioning unit, and a communication circuit, wherein the zero-sequence mutual inductor detects a signal of electric leakage of a branch circuit, and interacts with the internal communication interface of the master control module through the communication circuit. The device provided by the utility model can monitor the insulating conditions of a plurality of power generation branch circuits in real time. The self-balancing resistor automatically quits when there is another grounding balancing resistor in a system, or else the self-balancing resistor is automatically switched. Meanwhile, the number of a branch circuit where the insulation property decreases is uploaded through a centralized monitor, thereby bringing convenience to the monitoring and maintenance.

Description

A kind of adaptive end line-selected earthing device
Technical field
The utility model relates to low-voltage direct power transmission and distribution on-line insulation monitoring technical field, is particularly useful for the self-adaptation end line-selected earthing device that photovoltaic generation plate in photovoltaic generating system and the on-line insulation monitoring method between Intelligent photovoltaic combiner box are used.
Background technology
The world today, the fossil energies such as coal, oil signal for help repeatedly, and problem of environmental pollution is increasingly serious.And sun power is as the regenerative resource of tool potentiality, because of the unlimitedness of its reserves, the spatter property of the ubiquity of existence, utilization and practical economy more and more by people, favored.Greatly develop photovoltaic industry, active development sun power, obtained in the world unprecedented attention, become the important component part of various countries' strategy of sustainable development.Photovoltaic industry also claims solar cell industry, utilizes sun power and semi-conductor electronic device to absorb solar radiation energy, and makes it to be converted to the industry of electric energy.In large-sized photovoltaic grid-connected system, in order to reduce the wiring quantity between photovoltaic module and inverter, be convenient to safeguard, improve reliability, reduce costs simultaneously, generally need between photovoltaic module and inverter, increase direct current collector-shoe gear.By using photovoltaic array conflux box, user can be according to the DC voltage scope of inverter input, the photovoltaic module of the same size of some is connected into a photovoltaic module tandem, again by several tandem access photovoltaic array conflux boxes, by exporting after lightning protection device and isolating switch, thereby facilitated the access of rear class inverter.
Photovoltaic combiner box is a kind of smart machine being applied in Intelligent photovoltaic electricity generation system for photoelectric cell tandem and peripheral auxiliary element are protected and monitored, and is to be accompanied by the large-scale application of photovoltaic generation and a novel product producing.Fast development along with photovoltaic industry, security for photovoltaic combiner box, miniaturization, intelligent and low-power consumption has proposed more and more higher requirement, conventional Intelligent photovoltaic combiner box can only be realized branch current measurement at present, SPD and on off state monitoring, the functions such as communication, cannot to wire insulation situation, carry out on-line monitoring in real time, and because branch road in photovoltaic generating system is more, at branch road, occur that the situations such as insulation damages can affect the normal operation of generating set while causing insulation to decline, field maintemance personnel are difficult to detect in time, investigate out insulation decline branch road, when the personal safety of giving field maintemance personnel brings hidden danger, also increased on-the-spot O&M personnel's workload.
Shown in Fig. 1, be " a kind of on-line insulation monitoring system that is applicable to grid-connected photovoltaic system ", utility application numbers 201220708530.8.Wherein grid-connected photovoltaic system comprises one group of many groups photovoltaic electrification component connecting, DC cabinet and inverter, described in every group, photovoltaic electrification component comprises the header box of solar panels and connection solar panels and DC cabinet, DC cabinet is connected with described inverter via positive and negative busbar, inverter is connected with external power grid, it is characterized in that, on-line insulation monitoring system for grid-connected photovoltaic system comprises insulation Intelligent electric leakage sensor, insulation balance resistance, insulation voltage transmitter, insulating monitor and host computer, wherein, insulation Intelligent electric leakage flow sensor is as between header box and DC cabinet, and communicate by letter with insulating monitor by RS485 communication interface, insulation balance resistance one end ground connection, the other end is connected with positive and negative busbar, insulation balance resistance is connected with insulating monitor via insulation voltage transmitter with positive and negative busbar, insulating monitor comprises data reception module, data processing module, IO port and communication module, the data that wherein data reception module transmits in order to receive leakage current sensor and insulating transformer, data processing module is for adding up the data of data reception module aggregation process, alarm module is connected with data processing module, when the data of data processing module surpass corresponding setting value, described alarm module is opened and is reported to the police, between IO port, be connected with external alarming execution device, when each equipment in the on-line insulation monitoring system of grid-connected photovoltaic system or circuit break down, IO port driver alarming execution device is reported to the police, communication module communicates described data processing module and host computer by RS485 or tcp/ip communication interface.
Subject matter and the shortcoming of prior art scheme are as follows:
Can not locate the fault branch of concrete photovoltaic string, in the situation that photovoltaic string is more, investigate workload larger, if each header box needs to increase a set of insulation monitoring and warning device, purchase with later maintenance cost higher;
Conventionally insulation monitoring and warning device is to measure both positive and negative polarity voltage-to-ground value by balance resistance and switching unbalanced resistance, utilizes the magnitude of voltage of the both positive and negative polarity of measuring to calculate insulating resistance value, as shown in Figure 2.If there is other insulation monitoring and warning device in system, will certainly cause in system and exist a plurality of balance resistances to earth, balance resistance resistance is diminished, cause measured deviation, the alerting signal of output error.
Summary of the invention
The purpose of this utility model is to realize on-line real time monitoring branch road insulation status, for the abort situation of photovoltaic string, can accurately locate; Main control module can detect positive and negative busbar voltage-to-ground value in real time, judges whether that switching Equilibrium resistance is to positive and negative busbar, realizes the self-adaptation detection of insulating online.
The technical solution adopted in the utility model is:
An adaptive end line-selected earthing device, described adaptive end line-selected earthing device comprises main control module and leakage current measurement module, wherein,
An external communication interface, an intercommunication interface and a self-adapting detecting circuit are set on described main control module, and described self-adapting detecting circuit detects positive and negative busbar voltage-to-ground value in real time, judges whether that switching Equilibrium resistance is to positive and negative busbar; Described intercommunication interface is connected to the communication interface of electric leakage measurement module, and external communication interface is connected to centralized monitor;
At least one road zero-sequence transformer, signal processing unit and telecommunication circuit are set in described leakage current measurement module, described zero-sequence transformer detection branch electric leakage signal, described signal processing unit is converted to leakage current value by electric leakage signal, and is undertaken alternately by the intercommunication interface of telecommunication circuit and main control module.
Described self-adapting detecting circuit comprises 2 balance resistances and 2 relay switch K switch 1 and K2, and described relay switch K switch 1 one end is connected to bus positive pole, and the other end is connected to a described balance resistance, and this balance resistance is connected to ground; Described change-over switch K2 one end is connected to bus negative pole, and the other end is connected to another balance resistance, and this balance resistance is connected to ground.
Described adaptive end line-selected earthing device also comprises centralized monitor, and described centralized monitor is connected with the external communication interface of main control module, and described main control module communicates by external communication interface and centralized monitor.
The utility model provides a kind of online insulation measuring apparatus using in photovoltaic combiner box, this device can a plurality of generating branch road of Real-Time Monitoring insulation status, while having other earth balance resistance in system, automatically exit the balance resistance of self, otherwise the balance resistance of automatic switching self, equipment passes to main control module by bus mode by data, main control module implementing monitoring positive and negative busbar voltage-to-ground, if positive and negative busbar voltage-to-ground is poor surpass setting value (D.C. isolation monitoring device technical conditions require pressure reduction setting valve be not more than rated voltage 10%), main control module communicates by communication interface and centralized monitor, the branch road number that branch road state of insulation is declined is uploaded by centralized monitor, facilitated monitoring and safeguarded.
Accompanying drawing explanation
Fig. 1 is the on-line insulation monitoring system schematic of existing grid-connected photovoltaic system;
Fig. 2 is that a plurality of balance resistances of existing insulation monitoring and warning device are to earth circuit diagram;
Fig. 3 is measurement module structural representation;
Fig. 4 is the adaptive end line-selected earthing device of the utility model structural representation.
Embodiment
For making the purpose of this utility model, technical scheme and advantage clearer, below in conjunction with the drawings and specific embodiments, the utility model is further described.
An adaptive end line-selected earthing device, comprises measurement module and main control module.
At least one road zero-sequence transformer, signal processing unit, telecommunication circuit and a power circuit are set, as shown in Figure 3 on measurement module.Zero-sequence transformer detection branch electric leakage signal, is converted to leakage current value by signal processing unit, and is undertaken alternately by the intercommunication interface of telecommunication circuit and main control module; The wire of same branch road is through zero-sequence transformer coil, in the iron core of alternation symmetrical voltage or Impetus of Current Source, if there is direct current stationary magnetic field simultaneously, the symmetry of the alternating flux in iron core will be destroyed, positive and negative half wave phase of flux waveforms will change, to there is relative displacement in the positive and negative half-wave correspondingly, detecting in winding output voltage.The direction of positive and negative half-wave variable quantity and size can reflect direction and the size of DC bias current, and the dutycycle of the input capture port analysis square wave by MCU can calculate the numerical value of branch road leakage current.
Main control module comprises an external communication interface, an intercommunication interface and a self-adapting detecting circuit, as shown in Figure 4.Main control module regularly disconnects relay K 1/K2, self-adapting detecting circuit measuring busbar voltage U, positive and negative busbar voltage-to-ground value U+/U-, when positive and negative busbar voltage U is greater than 0V, positive and negative busbar voltage-to-ground value U+/U-is 0V, and this state continuance is after 5 minutes, can judge in system without other balance resistances, main control module is closing relay K1, K2, drops into the balance resistance of self to bus; When positive and negative busbar voltage U is greater than 0V, positive and negative busbar voltage-to-ground value U+/U-and is all greater than 0V, and this state continuance judges after 5 minutes in system and has other equipment to drop into balance resistance, and main control module keeps Equilibrium resistance off-state.In deterministic process, may there are other insulation detection devices and cut bridge route selection operation, cause positive and negative busbar magnitude of voltage to change, according to field operation experiences, insulation detection device fault location time can be over 3 minutes, the delay time that main control module detects change in voltage is designed to 5 minutes, can effectively hide other device switching electric bridges in system and bring the judgement of voltage fluctuation countermeasure set.
In main control module, intercommunication interface is connected with detection of electrical leakage module communication interface, detection of electrical leakage module is uploaded branch road electrical leakage to main control module by communication interface, the poor setting value that surpasses of positive and negative busbar voltage-to-ground that main control module is measured, and the duration was over 5 minutes, detection of electrical leakage module is uploaded the leakage current of each branch road sequence number and corresponding branch road, master control is sorted to branch road sequence number according to branch road leakage current order from big to small, fault branch numbered transmission, to main control module external communication interface, is grounded to route selection.
Above-described specific embodiment; the purpose of this utility model, technical scheme and beneficial effect have been carried out to further detailed description; institute is understood that; the foregoing is only specific embodiment of the utility model; be not limited to the utility model; all within spirit of the present utility model and principle, any modification of making, be equal to replacement, improvement etc., within all should being included in protection domain of the present utility model.

Claims (3)

1. an adaptive end line-selected earthing device, is characterized in that: described adaptive end line-selected earthing device comprises main control module and leakage current measurement module, wherein,
An external communication interface, an intercommunication interface and a self-adapting detecting circuit are set on described main control module, and described self-adapting detecting circuit detects positive and negative busbar voltage-to-ground value in real time, judges whether that switching Equilibrium resistance is to positive and negative busbar; Described intercommunication interface is connected to the communication interface of electric leakage measurement module, and external communication interface is connected to centralized monitor;
At least one road zero-sequence transformer, signal processing unit and telecommunication circuit are set in described leakage current measurement module, described zero-sequence transformer detection branch electric leakage signal, described signal processing unit is converted to leakage current value by electric leakage signal, and is undertaken alternately by the intercommunication interface of telecommunication circuit and main control module.
2. adaptive end line-selected earthing device according to claim 1, it is characterized in that: described self-adapting detecting circuit comprises 2 balance resistances and 2 relay switch K switch 1 and K2, described relay switch K switch 1 one end is connected to bus positive pole, the other end is connected to a described balance resistance, and this balance resistance is connected to ground; Described change-over switch K2 one end is connected to bus negative pole, and the other end is connected to another balance resistance, and this balance resistance is connected to ground.
3. adaptive end line-selected earthing device according to claim 2, it is characterized in that: described adaptive end line-selected earthing device also comprises centralized monitor, described centralized monitor is connected with the external communication interface of main control module, and described main control module communicates by external communication interface and centralized monitor.
CN201420253278.5U 2014-05-19 2014-05-19 Self-adapting end-grounding line-selection device Active CN203858322U (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105093060A (en) * 2014-05-19 2015-11-25 北京人民电器厂有限公司 Low-voltage DC power transmission and distribution on-line insulation monitoring method, and adaptive end grounding line selection device
CN107783070A (en) * 2017-10-19 2018-03-09 广西电网有限责任公司电力科学研究院 Small Electric Current Earthing And Routing Device round cut function automatic detection method
CN112327121A (en) * 2020-11-13 2021-02-05 深圳市永联科技股份有限公司 DC system insulation diagnosis self-coordination circuit and method

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105093060A (en) * 2014-05-19 2015-11-25 北京人民电器厂有限公司 Low-voltage DC power transmission and distribution on-line insulation monitoring method, and adaptive end grounding line selection device
CN107783070A (en) * 2017-10-19 2018-03-09 广西电网有限责任公司电力科学研究院 Small Electric Current Earthing And Routing Device round cut function automatic detection method
CN107783070B (en) * 2017-10-19 2019-11-19 广西电网有限责任公司电力科学研究院 Small Electric Current Earthing And Routing Device round cut function automatic detection method
CN112327121A (en) * 2020-11-13 2021-02-05 深圳市永联科技股份有限公司 DC system insulation diagnosis self-coordination circuit and method
CN112327121B (en) * 2020-11-13 2022-05-27 深圳市永联科技股份有限公司 DC system insulation diagnosis self-coordination circuit and method

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