CN106959402A - A kind of Little Current Ground Connection System and determination methods - Google Patents
A kind of Little Current Ground Connection System and determination methods Download PDFInfo
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- CN106959402A CN106959402A CN201710302857.2A CN201710302857A CN106959402A CN 106959402 A CN106959402 A CN 106959402A CN 201710302857 A CN201710302857 A CN 201710302857A CN 106959402 A CN106959402 A CN 106959402A
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Classifications
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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
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/086—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution networks, i.e. with interconnected conductors
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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
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Abstract
A kind of Little Current Ground Connection System and determination methods, including high-frenquency current blocking device, bandpass filter, high-frequency signal source, high-frequency signal protective relaying device, the wire selection system is arranged in the outlet being electrically connected with three phase mains bus, the outlet includes three-phase outlet, respectively A phases outlet, B phase outlets, C phase outlets, the high-frenquency current blocking device is arranged in every phase outlet between three phase mains bus, and set one per phase outlet head and the tail are each, between two high-frenquency current blocking devices, it is connected per phase outlet by bandpass filter with high-frequency signal protective relaying device, and, also it is connected per phase outlet by bandpass filter with high-frequency signal source.The system and advantage using the determination methods of the system are：Which bar ground connection in the outlet between three phase mains bus can be rapidly judged.
Description
Technical field
The present invention relates to electric power network technique field, more particularly to a kind of Little Current Ground Connection System and determination methods.
Background technology
When occurring single-phase earthing in neutral nondirect earthing network (also known as small current neutral grounding system), due to trouble point
Electric current very little, and line voltage between three-phase remains in that symmetrically, the power supply on load does not influence, therefore, general
In the case of all allow to be further continued for operation 1 to 2 hour, without tripping immediately, this is also using neutral point indirect earthing operation
Major advantage.But after single-phase earthing, the voltage-to-ground of other two-phases will be raisedTimes.In order to prevent that failure from entering one
Step is expanded into or multipoint earthing short circuit at 2 points, signal should be just sent in time, so that operations staff takes measures to be eliminated.
Therefore, in single-phase earthing, typically only require that relay protection can selectively send signal, without tripping.
But when single-phase earthing is dangerous to the safety of the person and equipment, then should act in tripping operation.
Regrettably, when occurring single-phase earthing in neutral point non-direct grounding system, zero-sequence current is very small, accurately selects
Failure outlet is always a problem of scientific research personnel's exploratory development.
The content of the invention
The invention aims to solve in the prior art not judging in the outlet between three phase mains bus
The problem of which bar outlet is grounded, provides a kind of Little Current Ground Connection System and determination methods herein.
To achieve the above object, the technical solution adopted by the present invention is as follows：
A kind of Little Current Ground Connection System, including high-frenquency current blocking device, bandpass filter, high-frequency signal source, high-frequency signal
Protective relaying device, the wire selection system is arranged in the outlet being electrically connected with three phase mains bus, and the outlet includes three
Phase outlet, the respectively outlet of A phases, the outlet of B phases, C phase outlets, the high-frenquency current blocking device are arranged on every between three phase mains bus
In phase outlet, and per phase outlet, head and the tail are each sets between one, two high-frenquency current blocking devices, per phase outlet by bandpass filter with
High-frequency signal protective relaying device is connected, also, is also connected per phase outlet by bandpass filter with high-frequency signal source.
Further, the neutral ground connection of the high-frequency signal source.
Further, the high-frequency signal protective relaying device is microcomputer type high-frequency signal protective relaying device.
Further, also including time lagged type protective relaying device, the time lagged type protective relaying device is arranged on band logical filter
Between ripple device and high-frequency signal source.
Further, when outlet is a plurality of, multiple wire selection systems share a high-frequency signal protective relaying device.
Further, every group of high-frequency signal source produces symmetrical, three-phase high-frequency signal, and each high-frequency signal source production
The frequency of raw high-frequency signal is differed, and the high-frenquency current blocking device in every outlet produces this outlet high frequency signal source
Raw high frequency electric is limited in the outlet between two high-frenquency current blocking devices.
Further, the bandpass filter filters power current.
Using the determination methods of above-mentioned Little Current Ground Connection System, step is as follows：
(1) system is connected first and completed；
(2) system is worked, and the HF signal generator produces high frequency electric, and the high-frequency signal protective relaying device is born
Duty receives the high frequency electric passed back from transmission of electricity outlet；Among high-frequency signal protective relaying device during non-zero-sequence current, judge
Line is normally run；When high-frequency signal protective relaying device detects high frequency zero-sequence current, comprehensive analysis each group high-frequency signal
Which bar outlet ground connection high-frequency signal frequency and the frequency and amplitude of the zero-sequence current that source is produced, judge.
The beneficial effect of the invention is：
(1) present invention can accurately judge which bar outlet ground connection in the outlet between three phase mains bus.
(2) very big impedance is presented to the high frequency electric in this outlet for the high-frenquency current blocking device in the present invention, to power current
Low ESR is presented, the position of high-frenquency current blocking device and the setting of number are limited in high frequency electric in this outlet, and power current
It can pass through, from without influenceing the transmission of electric energy.
(3) present invention in bandpass filter setting to needed for this outlet high frequency electric present Low ESR, from without
High frequency electric is influenceed from high-frequency signal source is output to outlet and high frequency electric enters microcomputer type high-frequency signal protective relaying device,
High impedance is presented to power current, prevents that power current from entering high-frequency signal source and microcomputer type high-frequency signal protective relaying device
In, and damage high-frequency signal source and microcomputer type high-frequency signal protective relaying device.
(4) time lagged type protective relaying device is responsible for protecting high-frequency signal source in the present invention, when outlet high-frequency current is more than
During setting value, the action of protection high-frequency signal source is played in the delay tripping of time lagged type protective relaying device.
Brief description of the drawings
Fig. 1 is a kind of Little Current Ground Connection System of the present invention and the basic circuit diagram of determination methods；
Fig. 2 for the present invention a kind of Little Current Ground Connection System and determination methods specific embodiment circuit diagram.
Embodiment
As shown in figure 1, a kind of Little Current Ground Connection System, including high-frenquency current blocking device 1, bandpass filter 2, high-frequency signal
Source 3, high-frequency signal protective relaying device 4, time lagged type protective relaying device 5, the neutral-point solid ground of high-frequency signal source 3.It is high
Frequency signal protective relaying device 4 is microcomputer type high-frequency signal protective relaying device 4.Bandpass filter 2 prevents power current from entering
In high-frequency signal source and microcomputer type high frequency protective relaying device.
The wire selection system is arranged in the outlet being electrically connected with three phase mains bus, and the outlet goes out including three-phase
Line, the respectively outlet of A phases, the outlet of B phases, C phase outlets, the high-frenquency current blocking device 1 are arranged on every phase between three phase mains bus
In outlet, and one is set per phase outlet head and the tail are each, between two high-frenquency current blocking devices 1, bandpass filter is passed through per phase outlet
2 are connected with microcomputer type high-frequency signal protective relaying device 4, also, also pass through bandpass filter 2 and high-frequency signal source per phase outlet
3 connections, time lagged type protective relaying device 5 is arranged between bandpass filter 2 and high-frequency signal source 3.1 pair of high-frenquency current blocking device originally goes out
Very big impedance is presented in high frequency electric in line, and Low ESR, the position of high-frenquency current blocking device 1 and setting for number is presented to power current
Put and high frequency electric is limited in this group of outlet, and power current can be passed through, from without influenceing the transmission of electric energy.
When outlet is a plurality of, multiple wire selection systems share a high-frequency signal protective relaying device 4 or each
High-frequency signal protective relaying device 4 in wire selection system transmits mutually signal in a communication manner.
Determination methods are as follows：
(1) system is connected first and completed；
(2) system works, and the HF signal generator 3 produces high frequency electric, the high-frequency signal protective relaying device 4
It is responsible for receiving the high frequency electric passed back from transmission of electricity outlet；Among high-frequency signal protective relaying device 4 during non-zero-sequence current, judge
Outlet is normally run；When high-frequency signal protective relaying device 4 detects high frequency zero-sequence current, comprehensive analysis each group high frequency letter
Which bar outlet ground connection high-frequency signal frequency and the frequency and amplitude of the zero-sequence current that number source 4 is produced, judge.
Specific implementation is as follows：
Assuming that outlet is three, the wire selection system of three outlets shares a high-frequency signal protective relaying device 4.Every group
High-frequency signal source 3 produces the frequency for the high-frequency signal that symmetrical, three-phase high-frequency signal and three groups of high-frequency signal sources 3 are produced not
Identical, the high frequency electric that this outlet high frequency signal source is produced is limited in two by the high-frenquency current blocking device in every outlet
In outlet between high-frenquency current blocking device.
It is specific as follows：
As shown in Fig. 2 three outlets are respectively L1, L2, L3, three outlets are produced by respective high-frequency signal source 3
The high-frequency signal of symmetrical, three-phase, and the high-frequency signal frequency of three outlets differs, it is assumed that outlet L1 in this system
The frequency for the high-frequency signal that high-frequency signal source 3 is produced is 10MHz, the frequency of the high-frequency signal of the outlet L2 generation of high-frequency signal source 3
Rate is 11MHz, and the frequency of the high-frequency signal of the outlet L3 generation of high-frequency signal source 3 is 12MHz, the three-phase high-frequency electrical of three outlets
Stream is linked into microcomputer type high-frequency signal protective relaying device 4.Due to the presence of each bar outlet medium-high frequency trap 1 so that
High frequency electric produced by each group outlet high frequency signal source 3 can not flow into other outlets, that is to say, that be flowed through in outlet L1
Electric current only has the electric current flowed through in the electric current of two kinds of frequencies of 50Hz and 10MHz, outlet L2 there was only two kinds of frequencies of 50Hz and 11MHz
The electric current flowed through in electric current, outlet L3 only has the electric current of two kinds of frequencies of 50Hz and 12MHz.Meanwhile, and due to bandpass filter 2
In the presence of so that power current cannot be introduced into microcomputer type high-frequency signal protective relaying device 4, then, outlet L1 flows into microcomputer type
The power frequency of high-frequency signal protective relaying device 4 can only be 10MHz, and outlet L2 flows into microcomputer type high-frequency signal relay protection dress
The power frequency for putting 4 can only be 11MHz, and the power frequency that outlet L3 flows into microcomputer type high-frequency signal protective relaying device 4 can only
It is 12MHz.
Usually each outlet is in normal operation, because earth fault does not occur for outlet L1, outlet L2 and outlet L3, institute
There is no zero-sequence current in microcomputer type high-frequency signal protective relaying device 4.It is assumed that single-phase earthing occurs for the C phases that some time carves line L3
Failure, now, will produce the zero-sequence current of power frequency in outlet L3, this electric current is the small electricity in isolated neutral system
Stream, numerical value very little will not damage transmission of electricity outlet；Also the zero-sequence current that frequency is 12MHz can be produced in outlet L3, this electric current is
Produced by outlet L3 high-frequency signal source 3, because this high-frequency signal source 3 is neutral ground, so current values are very
Greatly (" very big " be for former high frequency electric, for the power current in outlet L3, this high frequency electric
Numerical value or very little, transmission of electricity outlet will not be damaged)；Power frequency zero-sequence current can flow into other outlets, still, and frequency is 12MHz
Zero-sequence current can only be flowed through on outlet L3.If that is, microcomputer type high-frequency signal protective relaying device 4 detects and is
The zero-sequence current for having frequency to be 12MHz in system flows through, and is only likely to be and occurs what earth fault was produced on outlet L3.And this
When, the high frequency electric for flowing into microcomputer type high-frequency signal protective relaying device 4 is：Outlet L3 flows into the three-phase electricity that frequency is 12MHz
Stream, by the calculating of microcomputer type high-frequency signal protective relaying device 4, there is the zero-sequence current that frequency is 12MHz, numerical value is very big；Go out
Line L1 flows into the three-phase current that frequency is 10MHz, by the calculating of microcomputer type high-frequency signal protective relaying device 4, has the frequency to be
10MHz zero-sequence current, but numerical value is much smaller than the high frequency electric that frequency is 12MHz；Outlet L2 flows into three that frequency is 11MHz
Phase current, by the calculating of microcomputer type high-frequency signal protective relaying device 4, there is a zero-sequence current that frequency is 11MHz, but numerical value
Much smaller than the high frequency electric that frequency is 12MHz.So, microcomputer type high-frequency signal protective relaying device 4 just can be according to zero sequence electricity
The frequency and numerical values recited of stream, it is that outlet L3 there occurs earth fault to determine.
Specifically, if outlet L3 generations are not singlephase earth faults, but line to line fault is grounded, now, microcomputer type
High-frequency signal protective relaying device 4 also has the inflow of high frequency zero-sequence current, but line to line fault ground connection belongs to phase fault,
It can easily judge that such as three-step charging can so be distinguished with device by other Principles of Relay Protections
Whether singlephase earth fault is belonged to.
Further, time lagged type protective relaying device 5 is arranged between high-frequency signal source 3 and bandpass filter 2, when this
When outlet high-frequency current is more than setting value, time lagged type protective relaying device 5 is delayed t ability trippings after default duration, plays guarantor
The effect of high-frequency signal source 3 is protected, delay t is set greater than 4 pairs of generation single-phase earthings of microcomputer type high-frequency signal protective relaying device
Time for making a choice of outlet, so in default duration, microcomputer type high-frequency signal protective relaying device 4 has been collected
The electric current of each bar outlet different frequency, calculates the size of each frequency zero-sequence current, so not influenceing the work of line selection apparatus.
Determination methods are as follows：
(1) system is connected first and completed；
(2) system works, and the HF signal generator 3 produces high frequency electric, the high-frequency signal protective relaying device
It is responsible for receiving the high frequency electric passed back from transmission of electricity outlet；Among high-frequency signal protective relaying device during non-zero-sequence current, judge
Outlet is normally run；When high-frequency signal protective relaying device detects high frequency zero-sequence current, comprehensive analysis each group high frequency letter
Which bar outlet ground connection high-frequency signal frequency and the frequency and amplitude of the zero-sequence current that number source is produced, judge.
The preferred embodiment of the invention is these are only, creation is not intended to limit the invention, it is all in the present invention
Any modification, equivalent and improvement made within the spirit and principle of creation etc., should be included in the guarantor of the invention
Within the scope of shield.
Claims (8)
1. a kind of Little Current Ground Connection System, it is characterised in that including high-frenquency current blocking device, bandpass filter, high-frequency signal source,
High-frequency signal protective relaying device, the wire selection system be arranged on three phase mains bus be electrically connected with outlet on, it is described go out
Line includes three-phase outlet, and the respectively outlet of A phases, the outlet of B phases, C phase outlets, the high-frenquency current blocking device is arranged on three phase mains bus
Between every phase outlet on, and per phase outlet, head and the tail are each sets between one, two high-frenquency current blocking devices, and band logical is passed through per phase outlet
Wave filter is connected with high-frequency signal protective relaying device, also, is also connected per phase outlet by bandpass filter and high-frequency signal source
Connect.
2. a kind of Little Current Ground Connection System according to claim 1, it is characterised in that in the high-frequency signal source
Property point grounding connection.
3. a kind of Little Current Ground Connection System according to claim 1, it is characterised in that the high-frequency signal relay is protected
Protection unit is microcomputer type high-frequency signal protective relaying device.
4. a kind of Little Current Ground Connection System according to claim 1, it is characterised in that also protected including time lagged type relay
Protection unit, the time lagged type protective relaying device is arranged between bandpass filter and high-frequency signal source.
5. a kind of Little Current Ground Connection System according to claim 1, it is characterised in that many when outlet is a plurality of
Individual wire selection system shares a high-frequency signal protective relaying device.
6. a kind of Little Current Ground Connection System according to claim 5, it is characterised in that every group of high-frequency signal source is produced
The high-frequency signal of symmetrical, three-phase, and each the frequency for the high-frequency signal that high-frequency signal source is produced is differed, it is described every
High-frenquency current blocking device in outlet by the high frequency electric that this outlet high frequency signal source is produced be limited in two high-frenquency current blocking devices it
Between outlet in.
7. a kind of Little Current Ground Connection System according to claim 1, it is characterised in that the bandpass filter is filtered
Power current.
8. a kind of determination methods of Little Current Ground Connection System using as described in claim 1-7 any one, its feature
It is that step is as follows：
(1) system is connected first and completed；
(2) system works, and the HF signal generator produces high frequency electric, and the high-frequency signal protective relaying device is responsible for connecing
Receive the high frequency electric passed back from transmission of electricity outlet；Among high-frequency signal protective relaying device during non-zero-sequence current, judge that outlet is equal
Normal operation；When high-frequency signal protective relaying device detects high frequency zero-sequence current, the production of comprehensive analysis each group high-frequency signal source
Which bar outlet ground connection raw high-frequency signal frequency and the frequency and amplitude of the zero-sequence current, judge.
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| CN201710302857.2A CN106959402A (en) | 2017-05-03 | 2017-05-03 | A kind of Little Current Ground Connection System and determination methods |
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| CN201710302857.2A CN106959402A (en) | 2017-05-03 | 2017-05-03 | A kind of Little Current Ground Connection System and determination methods |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108490311A (en) * | 2018-03-22 | 2018-09-04 | 中国南方电网有限责任公司超高压输电公司检修试验中心 | Weak impact signal extraction based on power frequency sampling and separation method |
| CN111130079A (en) * | 2020-03-01 | 2020-05-08 | 国网安徽省电力有限公司培训中心 | Three-section type current protection current setting device and method with large protection range |
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| CN206832927U (en) * | 2017-05-03 | 2018-01-02 | 国网安徽省电力公司培训中心 | A kind of Little Current Ground Connection System |
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2017
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| CN2783338Y (en) * | 2004-12-08 | 2006-05-24 | 珠海泰坦科技股份有限公司 | Small current grounding line selector |
| CN102420420A (en) * | 2011-12-05 | 2012-04-18 | 清华大学 | Single-phase grounding protection method and system |
| CN102778636A (en) * | 2012-07-26 | 2012-11-14 | 北京飞举电气有限公司 | Single-phase ground fault location method and apparatus |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108490311A (en) * | 2018-03-22 | 2018-09-04 | 中国南方电网有限责任公司超高压输电公司检修试验中心 | Weak impact signal extraction based on power frequency sampling and separation method |
| CN111130079A (en) * | 2020-03-01 | 2020-05-08 | 国网安徽省电力有限公司培训中心 | Three-section type current protection current setting device and method with large protection range |
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Address after: 230022 No. 330, Mount Huangshan Road, Hefei, Anhui Applicant after: STATE GRID ANHUI ELECTRIC POWER CO.,LTD. TRAINING CENTER Applicant after: ANHUI ELECTRICAL ENGINEERING PROFESSIONAL TECHNIQUE College Applicant after: State Grid Corporation of China Address before: 230022 Mount Huangshan Road, Anhui, China, No. 270, No. Applicant before: TRAINING CENTRE OF STATE GRID ANHUI ELECTRIC POWER CO. Applicant before: Anhui Electrical Engineering Professional Technique College Applicant before: State Grid Corporation of China |
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Application publication date: 20170718 |