CN109188205A - A kind of distance measuring method of the distance protection based on petal type power grid - Google Patents
A kind of distance measuring method of the distance protection based on petal type power grid Download PDFInfo
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- CN109188205A CN109188205A CN201811054682.9A CN201811054682A CN109188205A CN 109188205 A CN109188205 A CN 109188205A CN 201811054682 A CN201811054682 A CN 201811054682A CN 109188205 A CN109188205 A CN 109188205A
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- fault
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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
- G01R31/088—Aspects of digital computing
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
- Y04S10/52—Outage or fault management, e.g. fault detection or location
Abstract
The invention belongs to power grid distance protection technical field more particularly to a kind of distance measuring methods of the distance protection based on petal type power grid.Present invention obviates excessive resistances, the ability of tolerance load current with higher, fault distance can accurately be obtained in order to which localization of fault is rapidly completed, method of the invention is easy to implement, it can be positioned for fault detection and accurate distance measurement result is provided, the efficiency for improving electric network fault detection and excluding, and then further increase the stability and safety of petal power grid.
Description
Technical field
The invention belongs to power grid distance protection technical field more particularly to a kind of distance protections based on petal type power grid
Distance measuring method.
Background technique
" petal-shaped " wiring refers in power distribution network, and a closed network is by the outlet of two-way substation, between closed network
Also there is contact, form petal type network.Mutual is got in touch between " petal ", can be supported each other when breaking down, be restored electricity rapidly.
" petal " has two-way power supply power supply under normal operating mode, once " petal " interior any appliance or line failure, therefore
Barrier section will be automatically isolated in " zero second ", the power supply of non-faulting section normal continuous.If substation bus bar or transformer fault, can also
It is powered by interconnection by adjacent petal, in this manner it is possible to reduce fault zone and power off time.Meanwhile " petal " is got in touch with
More, power supply reliability is higher.Petal power grid can effectively improve the stability inside power grid as a novel power grid, but
It is limited to cost and technical problem, current petal power grid only carries out pilot application in zonule, huge relative to China
Power grid framework for, widespread adoption popularization, therefore petal power grid and other types cannot be still carried out in the short time
Power grid and major network nesting exist and the situation used can gradually increase.And with the increase of power grid complexity, all kinds of phase lines
Between and phase ground between short trouble it is more and more frequent.In order to guarantee highly effective and safe when petal operation of power networks, need
Timely carry out the work such as fault location, ranging.
In the ranging process of traditional distance protection, the distance between fault point and protection point are usually calculated according to impedance
To realize ranging, since real process middle impedance will receive the influence of excessive resistance, biggish mistake can be caused in calculating process
Difference can also bring huge cost input although can reduce error by way of hardware and information processing accordingly,
New uncertain factor is introduced simultaneously, for petal power grid, in order to guarantee its stability and safety, is occurred in failure
After positioning distance measuring and failure recovery time can be reduced rapidly, more more efficient fault localization scheme should be taken.
Summary of the invention
The purpose of the invention is, provides a kind of distance measuring method of distance protection based on petal type power grid, no
Dependent on the demand in traditional distance measuring method to impedance, it can be avoided influence of the distance measurement result by excessive impedance, can be realized
In high precision, the ranging task of efficient distance protection.
To achieve the above object, the invention adopts the following technical scheme that.
Its basic step includes:
Step 1. installs voltage and line current detection device at each protection, is occurred at the protection of front and back with obtaining failure
Electric current and voltage data；
Step 2. determines fault type
The distance measuring method of fault distance under step 3. singlephase earth fault
Measuring obtained data includes power frequency phase voltage, line current and the line current zero-sequence component that front and back occurs for failure；
When singlephase earth fault, fault point voltage
Fault point voltage variable before and after failure
Wherein,Phase voltage, line current and the line current zero-sequence component of installation place are protected respectively after failure；The variable quantity of front and back protection installation place phase voltage and phase current occurs for failure；K=(Z0-Z1)/3Z1For zero sequence electricity
Flow penalty coefficient, Z1For route positive sequence impedance, x is distance of the fault point to protection installation place；
The short circuit current of fault point is
Wherein Uf|0|For fault point voltage, the Z before failure∑(1)、Z∑(2)、Z∑(0)That respectively inwardly sees from fault point is positive and negative
The equivalent impedance of zero-sequence network；Z∑=Z∑(1)+Z∑(2)+Z∑(0)/ 3 are considered as from fault point to the external equivalent network as viewed from system
The equivalent impedance of network；It is hereby achieved that fault component equivalent structure circuit；
Voltage jump amount Δ U before and after fault pointf=Uf-Uf|0|=-IfZ∑；
And fault point voltage
Obtain UfWith Δ UfAngle relationship formula
Wherein offset angle α=90 °-ω, ω are external network equivalent impedance Z∑Impedance angle；Arg (X) indicates vector X
Phase angle；By Uf、ΔUf、The form for being write as real and imaginary parts addition obtains:
It is obtained after formula abbreviation before above-mentioned form is substituted into:
It enables
Obtain the quadratic equation with one unknown about fault distance x:
(bh+df)x2+ (ah-bg-cf-de) x+ce-ag=0
Offset angle ω is adjusted；
It solves
An invalid value is rejected, fault distance x is obtained；
The ranging of fault distance under step 4. phase fault:
After phase fault after failure
The short circuit current of fault point
Similarly fault point line voltage after available failureWith its Sudden Changing RateBetween relationship:
Z at this time∑=Z∑(1)+Z∑(2)；
Fault point line voltageWith its Sudden Changing RateBetween angle relationship:
Fault point voltage and its Sudden Changing Rate and fault distance x after failure1Relational expression can be expressed as:
It is obtained after being handled according to above-mentioned steps:
It enables
It obtains about fault distance x1Equation:
(b1h1+d1f1)x1 2+(a1h1-b1g1-c1f1-d1e1)x1+c1e1-a1g1=0
Offset angle ω is adjusted；
It solves
An invalid value is rejected, fault distance x is obtained1；
Particularly, for offset angle ω；Since I section of distance protection in power grid of range is 400km, in reality
It is main during test verification to need to guarantee for 50~380km apart from detection accuracy, the especially position 340km；Therefore, compared with
Excellent method is that offset angle ω=8.27 ° for using fault distance for 340km when are used as setting valve.
The beneficial effect is that:
Present invention obviates excessive resistance, the ability of tolerance load current with higher can accurately obtain failure
In order to which localization of fault is rapidly completed, method of the invention is easy to implement distance, can be positioned and be provided accurately for fault detection
Distance measurement result, improve electric network fault detection and the efficiency excluded, and then further increase the stability and peace of petal power grid
Quan Xing.
Detailed description of the invention
Fig. 1 is the schematic network structure of singlephase earth fault；
Fig. 2 is fault component equivalent circuit figure structure schematic representation；
Fig. 3 is power transmission line phase-to phase fault structural schematic diagram；
The relational graph of offset angle and fault point distance when Fig. 4 is singlephase earth fault；
Using the range error figure of fault distance after the present invention when Fig. 5 is alternate metallicity failure.
Specific embodiment
It elaborates below in conjunction with specific embodiment to the invention.
In the ranging process of traditional distance protection, the distance between fault point and protection point are usually calculated according to impedance
To realize ranging, since real process middle impedance will receive the influence of excessive resistance, biggish mistake can be caused in calculating process
Difference can also bring huge cost input although can reduce error by way of hardware and information processing accordingly,
New uncertain factor is introduced simultaneously, for petal power grid, in order to guarantee its stability and safety, is occurred in failure
After positioning distance measuring and failure recovery time can be reduced rapidly, more more efficient fault localization scheme should be taken.
Based on the demand, the present invention provide it is a kind of for petal power grid, can quickly to short circuit and ground connection therefore
Fault point after barrier occurs carries out ranging localization, and to determine fault point rapidly, process is simple, the small distance measuring method of error rate.
Its basic step includes:
Step 1. installs voltage and line current detection device at each protection, is occurred at the protection of front and back with obtaining failure
Electric current and electricity
Press data；
Step 2. determines fault type；
The present invention is not used in the type of determining failure, is only used for occurring in failure and after determining fault type to fault point
It is determined, the determination for fault type, it can be according to existing Bayes's Fault Model, power grid expert analyzing system
(ES) etc. mature method for diagnosing faults determines；
Present invention is generally directed to phase lines to be shorted the ranging that class failure carries out fault distance, including
The distance measuring method of fault distance under step 3. singlephase earth fault
The principle of distance measuring method and process are described in detail below:
As shown in Figure 1, when singlephase earth fault occurs, for the power transmission line in electric system, excessive resistance with
Based on resistive, the phase of fault point power-frequency voltage is identical as the phase of failure path electric current；
Electrical quantity in route can include before failure occurs by measuring obtained data by protecting installation place measurement to obtain
Power frequency phase voltage, line current and line current zero-sequence component afterwards；
When singlephase earth fault, fault point voltage
Fault point voltage variable before and after failure
Phase voltage, line current and the line current zero-sequence component of installation place are protected respectively after failure；The variable quantity of front and back protection installation place phase voltage and phase current occurs for failure；K=(Z0-Z1)/3Z1For zero sequence electricity
Flow penalty coefficient, Z1For route positive sequence impedance, x is distance of the fault point to protection installation place；
The short circuit current of fault point is
Wherein Uf|0|For fault point voltage, the Z before failure∑(1)、Z∑(2)、Z∑(0)That respectively inwardly sees from fault point is positive and negative
The equivalent impedance of zero-sequence network；Z∑=Z∑(1)+Z∑(2)+Z∑(0)/ 3 are considered as from fault point to the external equivalent network as viewed from system
The equivalent impedance of network；It is hereby achieved that fault component equivalent structure circuit；
Fault component equivalent circuit diagram Fig. 2 is obtained after simplification, is obtained by Fig. 2:
Voltage jump amount Δ U before and after fault pointf=Uf-Uf|0|=-IfZ∑；
And fault point voltage
Obtain UfWith Δ UfAngle relationship formula
Wherein offset angle α=90 °-ω, ω are external network equivalent impedance Z∑Impedance angle；Arg (X) indicates vector X
Phase angle；By Uf、ΔUf、The form for being write as real and imaginary parts addition obtains:
It is obtained after formula abbreviation before above-mentioned form is substituted into:
It enables
Obtain the quadratic equation with one unknown about fault distance x:
(bh+df)x2+ (ah-bg-cf-de) x+ce-ag=0
Offset angle ω is adjusted；
It solves
An invalid value is rejected, fault distance x is obtained；Measure impedance
The distance measuring method of fault distance under step 4. phase fault:
The schematic network structure of phase fault is as shown in Figure 3；
After phase fault after failure, the short circuit current of fault point
Similarly fault point line voltage after available failureWith its Sudden Changing RateBetween relationship:
Z at this time∑=Z∑(1)+Z∑(2)；
Fault point line voltageWith its Sudden Changing RateBetween angle relationship:
Fault point voltage and its Sudden Changing Rate and fault distance x after failure1Relational expression can be expressed as:
It is obtained after being handled according to above-mentioned steps:
It enables
It obtains about fault distance x1Equation:
(b1h1+d1f1)x1 2+(a1h1-b1g1-c1f1-d1e1)x1+c1e1-a1g1=0
Offset angle ω is adjusted；
It solves
An invalid value is rejected, fault distance x is obtained1；
Particularly, for offset angle ω；
Based on the detection scheme in the present invention, in singlephase earth fault, ω is (Z∑(1)+Z∑(2)+Z∑(0)The resistance of)/3
The complementary angle at anti-angle, during actual test, the offset angle relationship of fault point distance is as shown in Figure 4 when singlephase earth fault
Since I section of distance protection in power grid of range is 400km, mainly need to protect in actual test checkout procedure
Card is for 50~380km apart from detection accuracy, the especially position 340km；Therefore, preferably method be use fault distance for
Offset angle ω=8.27 ° when 340km are used as setting valve；
By actual experiment, the measurement data based on above-mentioned setting valve is as shown in table 1 (with single phase metal ground fault M
It holds for the measurement result of 30 ° of generator rotor angles of unloaded 0 ° of generator rotor angle and heavy load)；
1 metallic earthing fault measuring result of table
Maximum error of measuring in gamut fully meets the required precision of petal power grid within 5%.
Similarly, for phase fault, ω Z∑(1)+Z∑(2)+Z∑(0)Impedance angle complementary angle, corresponding measurement misses
Shown in difference data result such as table 2 (by taking alternate metallic short circuit failure as an example)；
The 2 alternate end metallic short circuit failure M measurement result of table
Its measurement error as shown in figure 5, the maximum error of measuring within the scope of its all fronts less than 5%.
Finally it should be noted that above embodiments are only to illustrate the technical solution of the invention, rather than to this hair
It is bright create protection scope limitation, although being explained in detail referring to preferred embodiment to the invention, this field it is general
Lead to it will be appreciated by the skilled person that can be modified or replaced equivalently to the technical solution of the invention, without departing from this
The spirit and scope of innovation and creation technical solution.
Finally it should be noted that above embodiments are only to illustrate the technical solution of the invention, rather than to this hair
It is bright create protection scope limitation, although being explained in detail referring to preferred embodiment to the invention, this field it is general
Lead to it will be appreciated by the skilled person that can be modified or replaced equivalently to the technical solution of the invention, without departing from this
The spirit and scope of innovation and creation technical solution.
Claims (2)
1. a kind of distance measuring method of the distance protection based on petal type power grid, which comprises the steps of:
Step 1. installs voltage and line current detection device at each protection, and electric current at the protection of front and back occurs to obtain failure
And voltage data；
Step 2. determines fault type；
The distance measuring method of fault distance under step 3. singlephase earth fault
Measure front and back occurs for failure power frequency phase voltage, line current and line current zero-sequence component；
When singlephase earth fault, fault point voltage
Fault point voltage variable before and after failure
Wherein,Phase voltage, line current and the line current zero-sequence component of installation place are protected respectively after failure；The variable quantity of front and back protection installation place phase voltage and phase current occurs for failure；K=(Z0-Z1)/3Z1For zero sequence electricity
Flow penalty coefficient, Z1For route positive sequence impedance, x is distance of the fault point to protection installation place；
The short circuit current of fault point is
Wherein Uf|0|For fault point voltage, the Z before failure∑(1)、Z∑(2)、Z∑(0)The positive and negative zero sequence respectively inwardly seen from fault point
The equivalent impedance of network；Z∑=Z∑(1)+Z∑(2)+Z∑(0)/ 3 are considered as from fault point to the external equivalent network as viewed from system
Equivalent impedance；It is hereby achieved that fault component equivalent structure circuit；
Voltage jump amount Δ U before and after fault pointf=Uf-Uf|0|=-IfZ∑；
And fault point voltage
Obtain UfWith Δ UfAngle relationship formulaArg(Uf)=Arg (Δ Ufej(90°+α))；
Wherein offset angle α=90 °-ω, ω are external network equivalent impedance Z∑Impedance angle；The phase of Arg (X) expression vector X
Angle；By Uf、ΔUf、ΔUfej(90°+ω)The form for being write as real and imaginary parts addition obtains:
ΔUfej(90°+ω)=j Δ Ufejω=-Im (Δ Ufejω)+jRe(ΔUfejω)
It is obtained after formula abbreviation before above-mentioned form is substituted into:
It enables
Obtain the quadratic equation with one unknown about fault distance x:
(bh+df)x2+ (ah-bg-cf-de) x+ce-ag=0
Offset angle ω is adjusted；
It solves
An invalid value is rejected, fault distance x is obtained；
The distance measuring method of fault distance under step 4. phase fault
The schematic network structure of phase fault is as shown in Figure 2；
After phase fault after failure
The short circuit current of fault point
Similarly fault point line voltage after available failureWith its Sudden Changing RateBetween relationship:
Z at this time∑=Z∑(1)+Z∑(2)；
Fault point line voltageWith its Sudden Changing RateBetween angle relationship:
Fault point voltage and its Sudden Changing Rate and fault distance x after failure1Relational expression can be expressed as:
It is obtained after being handled according to above-mentioned steps:
It enables
It obtains about fault distance x1Equation:
(b1h1+d1f1)x1 2+(a1h1-b1g1-c1f1-d1e1)x1+c1e1-a1g1=0
Offset angle ω is adjusted；
It solves
An invalid value is rejected, fault distance value x is obtained1。
2. a kind of distance measuring method of the distance protection based on petal type power grid according to claim 1, which is characterized in that mend
Angle ω=8.27 ° are repaid as setting valve.
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Cited By (4)
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| CN110988598A (en) * | 2019-12-17 | 2020-04-10 | 国网河北省电力有限公司 | Petal type urban power grid ground fault positioning method based on zero sequence current association |
| CN111076872A (en) * | 2019-12-17 | 2020-04-28 | 天津大学 | Petal type urban power grid ground fault accurate positioning method based on multi-line zero-sequence current information |
| CN112595930A (en) * | 2020-12-18 | 2021-04-02 | 国网河北省电力有限公司 | Backup protection method for petal type urban power grid area containing distributed power supply |
| CN113346462A (en) * | 2021-06-02 | 2021-09-03 | 国网河北省电力有限公司电力科学研究院 | Petal type power distribution network contact line protection method based on predicted voltage amplitude |
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| CN110988598A (en) * | 2019-12-17 | 2020-04-10 | 国网河北省电力有限公司 | Petal type urban power grid ground fault positioning method based on zero sequence current association |
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| CN113346462A (en) * | 2021-06-02 | 2021-09-03 | 国网河北省电力有限公司电力科学研究院 | Petal type power distribution network contact line protection method based on predicted voltage amplitude |
| CN113346462B (en) * | 2021-06-02 | 2022-06-24 | 国网河北省电力有限公司电力科学研究院 | Petal type power distribution network contact line protection method based on predicted voltage amplitude |
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Application publication date: 20190111 |