CN101951010B - Ground protection method for small-current ground system - Google Patents
Ground protection method for small-current ground system Download PDFInfo
- Publication number
- CN101951010B CN101951010B CN2010102606145A CN201010260614A CN101951010B CN 101951010 B CN101951010 B CN 101951010B CN 2010102606145 A CN2010102606145 A CN 2010102606145A CN 201010260614 A CN201010260614 A CN 201010260614A CN 101951010 B CN101951010 B CN 101951010B
- Authority
- CN
- China
- Prior art keywords
- admittance
- zero sequence
- line
- sequence
- null sequence
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
Abstract
The invention discloses a ground protection method for a small-current ground system, which comprises a data acquisition step, a data processing step and a data analysis step, wherein the data acquisition step comprises: calculating ground null sequence admittance Y0kd of an outgoing line by a single-phase grounding test or circuit parameters and acquiring a null sequence voltage U0 and a null sequence current I0 of protection access in real time; the data processing step comprises: calculating the null sequence admittance Y0k of the outgoing line, calculating the null sequence compensation admittance Y'0k of the outgoing line, calculating a null sequence compensation admittance angle phik of the outgoing line, and storing the sequence of the null sequence compensation admittance angles phik of N cycles; and the data analysis step comprises: judging the amplitude value of the null sequence compensation admittance Y'0k, if the amplitude of the null sequence compensation admittance Y'0k is more than a start threshold value, determining the null sequence compensation admittance angle phik, if phik is more than 100 DEG and less than or equal to 280 DEG, determining that the line is a faulty line, if phik is more than 80 DEG and less than or equal to 100 DEG, executing step (4), inspecting the sequence of the null sequence compensation admittance angles phik of N cycles, if phik of more than 170 DEG and less than or equal to 280 DEG appeared once, determining that the line is a faulty line, and returning to the judgment of the step.
Description
Technical field
The present invention relates to a kind of earthing protecting method of small current neutral grounding system.
Background technology
One adopts isolated neutral mode, low resistance grounding mode or through the grounding through arc mode mesolow electrical network of China; When system's generation earth fault; Characteristic quantities such as the zero-sequence current size of ground path and direction are influenced greatly by system operation mode; Bring difficulty for the judgement of ground protection, seriously influenced the reliability of power supply.
Therefore, when small current neutral grounding system generation earth fault, how to select faulty line fast and accurately, great Practical significance is arranged.
Traditional earthing protecting method has following several kinds:
1, residual voltage (electric current) method
Principle: when earth fault took place, fault was met and is produced residual voltage and zero-sequence current.The amplitude size of this method judgement residual voltage or zero-sequence current is distinguished faulty line and non-fault line.
Shortcoming: in small current neutral grounding system generation earth fault, non-fault line also has residual voltage and zero-sequence current; In the system of grounding through arc, because fault current is compensated, the zero-sequence current of faulty line maybe be also littler than the zero-sequence current of non-fault line.So this method can't realize selectivity.
2, zero-sequence current power direction method
Principle: when earth fault takes place, 90 ° of the leading residual voltages of the zero-sequence current of non-fault line, 90 ° of faulty line zero-sequence current hysteresis residual voltages.
Shortcoming: this method only is applicable to the high pressure long transmission line of isolated neutral system; For arc suppression coil earthing system; Because the compensating action of arc suppression coil; No longer lag behind 90 ° of residual voltages of the zero-sequence current of faulty line, along with the difference of taking off humorous degree, the angle of hysteresis changes between 90 ° and 270 °; For low resistance grounding system and low pressure short-term road, the angle of faulty line zero-sequence current and residual voltage changes between 90 ° and 180 °.The criterion of this method is all inapplicable.
3, zero sequence real component method
Principle: through the circuit of arc suppression coil string and resistance, when earth fault takes place, to faulty line the zero-sequence current active component is provided, non-fault line does not have active current.
Shortcoming: this method only is applicable to through the high-tension line of arc suppression coil string and resistance (insulation resistance is very big, and direct-to-ground capacitance plays a leading role).For isolated neutral system, faulty line, non-fault line all do not have the zero sequence active current; And the non-fault line of low pressure short-term road also has active current, and this method can't realize selectivity.
Summary of the invention
The objective of the invention is provides a kind of earthing protecting method that is applicable to small current neutral grounding system in order to overcome the defective of prior art.
Technical scheme of the present invention is: a kind of earthing protecting method of small current neutral grounding system, comprise image data, deal with data and analysis data step, wherein,
Said image data step comprises:
1. calculate the admittance of the zero sequence over the ground Y of circuit through single-phase earthing test or line parameter circuit value
0kd
2. gather the residual voltage U that protection inserts in real time
0, zero-sequence current I
0
Said deal with data step comprises:
1. calculate circuit zero sequence admittance Y
0k
2. calculate circuit zero sequence compensation admittance Y '
0k
3. calculate circuit zero sequence compensation admittance angle φ
k
4. preserve the zero sequence compensation admittance angle φ of N cycle
kSequence;
Said analysis data step comprises:
1. judge zero sequence compensation admittance Y '
0kAmplitude, if surpass to start threshold value, judge zero sequence compensation admittance angle φ
k
If 2. 100 °＜φ
k≤280 °, then be judged to be faulty line;
If 3. 80 °＜φ
k≤100 °, then carry out the following step 4.;
4. investigate the zero sequence compensation admittance angle φ of the N cycle of storage
kSequence was if 170 °＜φ once occurred
k≤280 °, then be judged to be faulty line;
5. the involution of whole group is judged.
Principle of the present invention is:
In the small current neutral grounding system, under normal operation, the three-phase ground capacitance of every circuit is identical, and under the effect of phase voltage, every phase all has one to be ahead of in the capacitance current inflow place of 90 ° of phase voltages, and the three-phase current sum is zero.In certain bar circuit generation metallicity or behind the resistance single phase ground fault, residual voltage will appear in total system; Zero-sequence current on non-fault line, occurs, its numerical value equals this line mutual-ground capacitor electric current sum, and the direction of capacitive character reactive power is that bus flows to circuit; Zero-sequence current on faulty line, also occurs, its numerical value equals the non-fault element zero-sequence current of total system sum, and the direction of capacitive character reactive power is that line flows is to bus.
Can find out by Fig. 1, suppose L
kBe non-fault line, L
1Be faulty line; g
k, b
kBe respectively circuit L
kElectricity over the ground lead and hold; g
sAnd b
sThe electricity that is respectively arc suppression coil is led and is held.
Among the present invention, for non-fault line: zero sequence admittance Y
0k=g
k+ jb
k, the algorithm of zero sequence compensation admittance is Y '
0k=Y
0k-Y
0kd, under one situation, zero sequence admittance Y
0kWith line-to-ground zero sequence admittance Y
0kdEquate that Y ' is arranged
0k=0; Insulation level descends after system's operation is long-time, and admittance increases over the ground, and 0≤φ is arranged this moment
k≤90 °.
For arc suppression coil: zero sequence admittance Y
0s=g
s-jb
s
For faulty line: zero sequence compensation admittance Y
01=-(Y
0s+ ∑ Y
0k(the g of)=-
s+ ∑ g
k)-j (b
s+ ∑ b
k), so 90 °≤φ is arranged
1≤270 °.
Can find out that during line single phase grounding failure, the zero sequence admittance offset angle of faulty line satisfies 90 °≤φ
k≤270 °, the zero sequence admittance offset angle of non-fault line satisfies 0≤φ
k≤90 °, can distinguish faulty line and non-fault line according to the phase place of zero sequence admittance offset angle.But in actual applications, because the influence of the sampling precision and the error of calculation has the confusion region near 90 °.
In the confusion region, for non-fault line, zero sequence admittance offset angle is by the decision of capacity current over the ground of circuit; And for faulty line, system entails is through arc suppression coil earthing system, and is operated in the overcompensation state.Because the electric current of inductance can not suddenly change, and is initial in fault according to first half-wave principle, inductive current can not be at once with the capacitive earth current full remuneration of fault point.It is a transient process that earth current becomes inductance current by capacity current, and in this process, because the character of residual voltage does not change, initial in fault, zero sequence compensation admittance angle is at third quadrant; After getting into steady-state process, because the compensating action of inductive current, zero sequence compensation admittance angle gets into second quadrant.
So 80 °＜φ in the confusion region
k≤100 °, can utilize first half-wave principle to do further judgement.If before zero sequence admittance offset angle gets into the confusion region, once be in third quadrant, and then be the fault circuit, otherwise be exactly non-fault line.Consider the influence of sampling error and system accuracy, the criterion that we will once be in third quadrant is made as in the confusion region N cycle before, 170 °＜φ once occurs
k≤280 °.
According to above-mentioned analysis; The present invention is provided with the zero sequence admittance criterion, can when system's generation single phase ground fault, select faulty line fast and accurately; And do not receive the influence of system operation mode, we define this kind ground protection scheme and are " self adaptation zero sequence node-pair method ".
This method is implemented simple, and physical significance is clear, can realize the ground protection in the small current neutral grounding system accurately and rapidly.
Description of drawings
Fig. 1 is system model figure of the present invention
Fig. 2 is the flow chart of the embodiment of the invention 1
Fig. 3 is and the embodiment of the invention 1 small current neutral grounding system ground protection logical flow chart
Embodiment
The present invention is used to realize the ground protection of small current neutral grounding system, is that example is described further below with the ground protection:
A kind of earthing protecting method of small current neutral grounding system comprises image data, deal with data and analysis data step, wherein,
The image data step comprises:
1. calculate the admittance of the zero sequence over the ground Y of circuit through single-phase earthing test or line parameter circuit value
0kd
2. gather the residual voltage U that protection inserts in real time
0, zero-sequence current I
0
The deal with data step comprises:
1. calculate circuit zero sequence admittance Y
0k
2. calculate circuit zero sequence compensation admittance Y '
0k
3. calculate circuit zero sequence compensation admittance angle φ
k
4. preserve the zero sequence compensation admittance angle φ of 10 cycles
kSequence;
The analysis data step comprises:
1. judge zero sequence compensation admittance Y '
0kAmplitude, if surpass to start threshold value, judge zero sequence compensation admittance angle φ
k
If 2. 100 °＜φ
k≤280 °, then be judged to be faulty line;
If 3. 80 °＜φ
k≤100 °, then carry out the following step 4.;
4. investigate the zero sequence compensation admittance angle φ of 10 cycles of storage
kSequence was if 170 °＜φ once occurred
k≤280 °, then be judged to be faulty line;
5. the involution of whole group is judged.
Above-mentioned steps, we are defined as " self adaptation zero sequence node-pair method ".
Small current neutral grounding system ground protection logic is seen Fig. 3 in the present embodiment, comprising:
1. the initialization of ground(preference) relay;
2. the ground protection entry condition is judged: be to guarantee that protection is reliable to start, any one satisfies condition in greater than threshold value greater than threshold value, residual voltage when zero-sequence current, and then protection starts;
3. judge " self adaptation zero sequence node-pair method " element state, like this element action, then ground protection action;
4. the involution of the whole group of ground protection is judged.
Can know according to top description; According to " self adaptation zero sequence node-pair method ", can realize the ground protection function of small current neutral grounding system accurately and rapidly, reliably accomplish the correct quick acting of faulty line; Not malfunction of non-fault line, and do not receive the influence of system operation mode.
Claims (2)
1. the earthing protecting method of a small current neutral grounding system comprises image data, deal with data and analysis data step, it is characterized in that,
Said image data step comprises:
1. calculate the admittance of the zero sequence over the ground Y of circuit through single-phase earthing test or line parameter circuit value
0kd
2. gather the residual voltage U that protection inserts in real time
0, zero-sequence current I
0
Said deal with data step comprises:
1. calculate circuit zero sequence admittance Y
0k
2. calculate circuit zero sequence compensation admittance Y '
0k, the algorithm of circuit zero sequence compensation admittance is: Y '
0k=Y
0k-Y
0kd
3. calculate circuit zero sequence compensation admittance angle φ
k
4. preserve the zero sequence compensation admittance angle φ of N cycle
kSequence;
Said analysis data step comprises:
1. judge zero sequence compensation admittance Y '
0kAmplitude, if surpass to start threshold value, judge zero sequence compensation admittance angle φ
k
If 2. 100 °＜φ
k≤280 °, then be judged to be faulty line, the involution of whole group is judged;
If 3. 80 °＜φ
k≤100 °, then carry out the following step 4. with step 5.;
4. investigate the zero sequence compensation admittance angle φ of the N cycle of storage
kSequence was if 170 °＜φ once occurred
k≤280 °, then be judged to be faulty line;
5. the involution of whole group is judged.
2. the earthing protecting method of a kind of small current neutral grounding system according to claim 1 is characterized in that, the N cycle in the said deal with data step is 10 cycles.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010102606145A CN101951010B (en) | 2010-08-23 | 2010-08-23 | Ground protection method for small-current ground system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010102606145A CN101951010B (en) | 2010-08-23 | 2010-08-23 | Ground protection method for small-current ground system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101951010A CN101951010A (en) | 2011-01-19 |
| CN101951010B true CN101951010B (en) | 2012-07-25 |
Family
ID=43454401
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010102606145A Active CN101951010B (en) | 2010-08-23 | 2010-08-23 | Ground protection method for small-current ground system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101951010B (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2487766B1 (en) * | 2011-02-11 | 2015-08-26 | ABB Technology AG | Method and apparatus for detecting earth fault |
| CN102353873A (en) * | 2011-07-14 | 2012-02-15 | 珠海威瀚科技发展有限公司 | Line selection method realized by using single criterion for low-current ground system during single-phase ground fault |
| CN103368166B (en) * | 2012-03-29 | 2016-04-06 | 徐州润泽电气有限公司 | A kind of zero sequence total current power direction realizes the method for coalmine high-voltage power network selective earth leakage protection |
| CN104280663B (en) * | 2013-07-03 | 2017-07-25 | 刘宝稳 | A kind of single-phase grounded malfunction in grounded system of low current in-service monitoring and selection method |
| CN104111403A (en) * | 2014-04-24 | 2014-10-22 | 杨庆申 | Microcomputer integrated protection line-selection method for low-current earthed power system |
| CN109406953A (en) * | 2018-12-29 | 2019-03-01 | 山东科汇电力自动化股份有限公司 | One kind is suitable for containing with bus loop power distribution network earth fault line selection method |
| CN110632441A (en) * | 2019-09-30 | 2019-12-31 | 攀钢集团西昌钢钒有限公司 | Method, device and equipment for judging ground fault |
| CN116169651B (en) * | 2023-04-25 | 2023-09-12 | 南方电网数字电网研究院有限公司 | Zero sequence admittance protection nano relay |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100345351C (en) * | 2005-01-20 | 2007-10-24 | 长沙理工大学 | Grounded fault selecting and protecting method for grouded system with small current |
| EP1870717B1 (en) * | 2006-06-20 | 2014-01-08 | ABB Technology AG | System and method for determining phase-to-earth admittances of a three-phase electric line |
| EP2051085A1 (en) * | 2007-10-19 | 2009-04-22 | ABB Research Ltd. | Method for fault location on series compensated power transmission lines with two-end unsychronized measurement |
| CN101499650A (en) * | 2009-03-10 | 2009-08-05 | 南京因泰莱配电自动化设备有限公司 | Small current earthing wire selection protection apparatus and protection method based on GPRS |
-
2010
- 2010-08-23 CN CN2010102606145A patent/CN101951010B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN101951010A (en) | 2011-01-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101951010B (en) | Ground protection method for small-current ground system | |
| CN109557422B (en) | Intelligent power distribution network short-circuit fault positioning method and system | |
| He et al. | Integrated impedance-based pilot protection scheme for the TCSC-compensated EHV/UHV transmission lines | |
| CN109444640A (en) | A kind of power distribution network single-phase high-impedance detection method, system and storage medium | |
| CN105044543B (en) | Reactor Fault method of discrimination after a kind of PT broken string | |
| CN109507516A (en) | Earth-fault detecting method, system and storage medium based on steady state fault amount | |
| SE519964C2 (en) | Systems and methods for locating faults on a single load transmission line connected to outlets | |
| CN113970685B (en) | Power distribution network fault detection method and system based on differential analysis and positioning method | |
| CN105914718B (en) | A kind of earth-fault protection method based on difference of phase currents | |
| CN103532113A (en) | Rapid distance protection method for power transmission line containing micro-grid system | |
| CN101581751B (en) | Locating method of voltage transformer disconnection | |
| CN102879713A (en) | Ground protection circuit selection method | |
| CN102082421B (en) | Implementation method of break variable current differential relay based on differential impedance principle | |
| CN102768325B (en) | Fault location method for low-current grounding system | |
| Zhang et al. | A segmented network method based faulted line selection strategy for single-phase earth fault in small current grounding distribution network | |
| Liu et al. | Insulation fault detection circuit for ungrounded DC power supply systems | |
| CN104795792B (en) | A kind of fault distinguishing method of generator negative sequence component | |
| Shilong et al. | Fault line selection of single phase grounding fault in small-current ground system based on reactive current | |
| CN109633357A (en) | More busbar grounding insulated monitoring methods and monitoring device in triple bus-bar | |
| CN100362718C (en) | Fault-tolerant complex judging self adaption high voltage parallel reactor turn-to-turn protection | |
| CN111812452B (en) | CT polarity self-correction method and system for low-current grounding line selection device | |
| CN104578008B (en) | A kind of zero-sequence direction component faulty action preventing method | |
| Suonan et al. | Study on single-phase adaptive reclosure scheme based on parameter identification | |
| Muddebihalkar et al. | Analysis of fault location algorithm for transmission line protection based on synchronized phasor measurement | |
| CN107436392B (en) | Cable single-phase earth fault detection method and system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| PE01 | Entry into force of the registration of the contract for pledge of patent right |
Denomination of invention: Ground protection method for small-current ground system Effective date of registration: 20190717 Granted publication date: 20120725 Pledgee: Nanjing Bank Co., Ltd. Nanjing North Branch Pledgor: Nanjing Hongyi Electric Automation Co., Ltd. Registration number: 2019320000333 |
|
| PE01 | Entry into force of the registration of the contract for pledge of patent right | ||
| PC01 | Cancellation of the registration of the contract for pledge of patent right |
Date of cancellation: 20200813 Granted publication date: 20120725 Pledgee: Nanjing Bank Co.,Ltd. Nanjing North Branch Pledgor: NANJING HONGYI ELECTRICAL AUTOMATION Co.,Ltd. Registration number: 2019320000333 |
|
| PC01 | Cancellation of the registration of the contract for pledge of patent right |