CN106207987B - A kind of differential protection method for bus based on the initial traveling wave phasor of fault current - Google Patents
A kind of differential protection method for bus based on the initial traveling wave phasor of fault current Download PDFInfo
- Publication number
- CN106207987B CN106207987B CN201610833686.1A CN201610833686A CN106207987B CN 106207987 B CN106207987 B CN 106207987B CN 201610833686 A CN201610833686 A CN 201610833686A CN 106207987 B CN106207987 B CN 106207987B
- Authority
- CN
- China
- Prior art keywords
- traveling wave
- mould
- current
- phasor
- moulds
- 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.)
- Expired - Fee Related
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/22—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for distribution gear, e.g. bus-bar systems; for switching devices
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/265—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured making use of travelling wave theory
Abstract
The present invention provides a kind of differential protection method for bus based on the initial traveling wave phasor of fault current, the method includes each element three-phase current signal that synchronous acquisition couples with busbar, obtain each element α moulds electric current,βThe step of mould electric current；According to the α moulds electric current of each element, β mould electric currents, the step of calculating its corresponding fault component；Extraction corresponds toαMould current traveling wave,βThe step of mould current traveling wave；Determine each elementαThe initial traveling wave phasor of mould,βThe step of mould initial traveling wave phasor；Calculate each elementαThe sum of initial traveling wave phasor amplitude of mould,βThe sum of initial traveling wave phasor amplitude of mould, the step of bus differential amount and braking amount are calculated according to the two size comparison result；The step of whether busbar breaks down judged.Amplitude and phase identification fault zone of the present invention using the initial traveling wave of electric current avoid and drain out electric current, TA ratio errors influence the reliability and sensitivity of protection.
Description
Technical field
The present invention relates to electric system median generatrix relay protecting methods, specially a kind of to be based on the initial traveling wave phase of fault current
The differential protection method for bus of amount.
Background technology
Electric system median generatrix breaks down, and bus protection must quickly and reliably cut off all members coupled with busbar
Part.The widely used bus differential protecting based on power frequency amount of electric system, actuation time are 1 cycle or so, and anti-current is mutual
The ability of sensor (TA) saturation is poor.In fact, there is the time being saturated usually after 1/4 period that failure occurs in TA,
Bus protection based on theory of travelling wave can act before TA is saturated, so as to avoid the influence of TA saturations.
According to the difference of structure, the bus protection based on traveling wave can be divided into centralized bus protection and distributed busbar is protected
Shield.Wherein, the centralized bus protection based on traveling wave be utilized on each circuit being connected with busbar the polarity of current traveling wave or
Amplitude Characteristics establishing protective criterion, the reliability and sensitivity of this kind of protection can by drain out electric current, TA ratio errors are influenced.Base
Identify that fault zone, this kind of protection philosophy are drawn dependent on the traveling wave directional element of each circuit in the decentralized bus protection of traveling wave
Voltage traveling wave signal is entered, since capacitance type potential transformer (CVT) can only effectively low frequency electrification of the progress of disease including power frequency
Press signal, cannot high frequency transient voltage signal effectively after progress of disease failure, cause the guard method based on transient state travelling wave to be difficult to be utilized
The transient voltage signal obtained by CVT.
Invention content
To solve the above problems, the present invention provides a kind of bus differential protectings based on the initial traveling wave phasor of fault current
Method includes the following steps：
Step 1：Each element three-phase current signal that synchronous acquisition couples with busbar obtains α moulds electric current, the β moulds of each element
Electric current.
Step 2：According to the α moulds electric current of each element, β mould electric currents, its corresponding fault component is calculated.
Step 3：Discrete S-transformation is carried out respectively to the fault component of each element, extracts corresponding α moulds current traveling wave, β
Mould current traveling wave.
Step 4：The initial traveling wave of α moulds of each element is determined according to the α moulds current traveling wave of each element, β mould current traveling waves
The initial traveling wave phasor of phasor, β moulds.
Step 5：The sum of the sum of initial traveling wave phasor amplitude of α moulds of each element, the initial traveling wave phasor amplitude of β moulds are calculated,
Bus differential amount and braking amount are calculated according to the two size comparison result.
Step 6：It is set in advance when bus differential amount is more than more than the ratio of preset threshold value and differential amount and braking amount
When fixed restraint coefficient, show that busbar breaks down, otherwise busbar does not break down.
Further, in step 1 using Clarke variation respectively to m (m=1,2,3 ... K, K be element it is total
Number) a element three-phase current signal coupling, obtain m-th element α moulds electric current, β mould electric currents, specific formula for calculation is：
In formula：ima、imb、imcThe a phases of m-th of the element respectively coupled with busbar, b phases, c phase currents.imα、imβRespectively
For m-th of element α mould, the β mould electric currents coupled with busbar.
Further, the differential filtering method extraction fault component subtracted each other using week in step 2, i.e., will be under malfunction
The electric current that subtracts under the corresponding non-faulting states of a Zhou Boqian of electric current fault component just can be obtained, specific formula for calculation is：
Δimα(t)、Δimβ(t) it is respectively m-th of element α moulds electric current, the β mould failure of the current components coupled with busbar,
T1 is the period of ac current signal.
Further, it is using discrete S-transformation extraction α moulds current traveling wave, β mould current traveling waves, specific method in step 3：
If Δ imα(t) discrete-time series are Δ imα[kT] (k=0,1,2 ..., N-1), T are sampling interval, Δ imα
The discrete Fourier transform of [kT] is Imα[m/NT] (N is discrete signal number).Using discrete S-transformation extraction signal delta imα
Fault traveling wave in [kT] is expressed as：
In formula：K=0,1 ..., N-1.N=1 ..., N-1.
It is assumed that the centre frequency of the α mould current traveling waves of extraction is f1, from Δ imα(t) the α mould current traveling waves extracted are：
In formula：Amα(k,f1)、Respectively Smα(k,f1) amplitude, phase.
If Δ imβDiscrete-time series be Δ imβ[kT] (k=0,1,2 ..., N-1), T are sampling interval, Δ imβ[kT]
Discrete Fourier transform be Imβ[m/NT].Using discrete S-transformation extraction signal delta imβFault traveling wave in [kT] is expressed as：
In formula：K=0,1 ..., N-1.N=1 ..., N-1.
It is assumed that the centre frequency of the β mould current traveling waves of extraction is f1, from Δ imβ(t) the β mould current traveling waves extracted are：
In formula：Amβ(k,f1)、For Smβ(k,f1) amplitude, phase.
Further, step 4 takes corresponding initial row respectively to the α mould current traveling waves phase of each element, β moulds current traveling wave
The specific method of wave phasor is：
Step 4.1：Amplitude is taken, all extreme values of amplitude is searched for, all extreme values is sequenced sequentially in time.
Step 4.2：Determine the maximum extreme value in all extreme values.
Step 4.3：The extreme value for determining in time sequencing the half that first is more than maximum extreme value, using the extreme value as
Initial traveling wave phasor.
Further, step 5 is specially：
If
Otherwise
Wherein M is component population, Amα(k1,f1)、Amβ(k1,f1) be respectively m-th of element the initial traveling wave phase of α mould electric currents
The amplitude of the initial traveling wave phasor of the amplitude of amount, β mould electric currents.Smα(k1,f1)、Smβ(k1,f1) respectively m-th of element α mould electric currents at the beginning of
Begin the initial traveling wave phasor of wave phasor, β mould electric currents.SdFor differential amount, SrFor braking amount.
Beneficial effects of the present invention are：
The present invention extracts the amplitude of the initial traveling wave of special frequency band electric current and phase forms the initial traveling wave phasor of electric current.With busbar
The mould of the sum of the initial traveling wave phasor of each element current of connection is the action current of differential protection, each member coupled with busbar
The sum of mould of the initial traveling wave phasor of part electric current is the stalling current of differential protection, to constitute the busbar with ratio-restrained characteristic
Differential protection criterion.Amplitude and phase identification fault zone of this method using the initial traveling wave of electric current, avoid and drain out electric current, TA
Ratio error influences the reliability and sensitivity of protection.
Description of the drawings
The flow chart of Fig. 1 this method.
Fig. 2 is bus-bar system structure chart.
Fig. 3 is ratio-restrained characteristic figure.
Fig. 4 is bus-bar fault schematic diagram.
Fig. 5 is line fault schematic diagram.
Specific implementation mode
As shown in Figure 1, originally including the following steps：
Step 1：Each element three-phase current signal that synchronous acquisition couples with busbar obtains α moulds electric current, the β moulds of each element
Electric current.
Can be used in this step Clarke variation respectively to m (m=1,2,3 ... K, K are component population) a element
Three-phase current signal it is decoupling, obtain m-th element α moulds electric current, β mould electric currents, specific formula for calculation is：
In formula：ima、imb、imcThe a phases of m-th of the element respectively coupled with busbar, b phases, c phase currents；imα、imβRespectively
For m-th of element α mould, the β mould electric currents coupled with busbar.
Step 2：According to the α moulds electric current of each element, β mould electric currents, its corresponding fault component is calculated.
The differential filtering method extraction fault component subtracted each other using week in this step, i.e., subtract the electric current under malfunction
Fault component just can be obtained in electric current under the corresponding non-faulting states of one Zhou Boqian, and specific formula for calculation is：
Δimα(t)、Δimβ(t) it is respectively m-th of element α moulds electric current, the β mould failure of the current components coupled with busbar,
T1 is the period of ac current signal.
Step 3：Discrete S-transformation is carried out respectively to the fault component of each element, extracts corresponding α moulds current traveling wave, β
Mould current traveling wave.
It is using discrete S-transformation extraction α moulds current traveling wave, β mould current traveling waves, specific method in this step：
If Δ imα(t) discrete-time series are Δ imα[kT] (k=0,1,2 ..., N-1), T are sampling interval, Δ imα
The discrete Fourier transform of [kT] is Imα[m/NT] (N is discrete signal number)；Using discrete S-transformation extraction signal delta imα
Fault traveling wave in [kT] is expressed as：
In formula：K=0,1 ..., N-1；N=1 ..., N-1.
It is assumed that the centre frequency of the α mould current traveling waves of extraction is f1, from Δ imα(t) the α mould current traveling waves extracted are：
In formula：Amα(k,f1)、Respectively Smα(k,f1) amplitude, phase.
If Δ imβ(t) discrete-time series are Δ imβ[kT] (k=0,1,2 ..., N-1), T are sampling interval, Δ imβ
The discrete Fourier transform of [kT] is Imβ[m/NT].Using discrete S-transformation extraction signal delta imβFault traveling wave expression in [kT]
For：
In formula：K=0,1 ..., N-1；N=1 ..., N-1；
It is assumed that the centre frequency of the β mould current traveling waves of extraction is f1, from Δ imβ(t) the β mould current traveling waves extracted are：
In formula：Amβ(k,f1)、For Smβ(k,f1) amplitude, phase.
Step 4：The initial traveling wave of α moulds of each element is determined according to the α moulds current traveling wave of each element, β mould current traveling waves
The initial traveling wave phasor of phasor, β moulds.
This step is from Smα(k,f1)、Smβ(k,f1) in determine initial traveling wave phasor Smα(k1,f1)、Smβ(k1,f1).With Smα
(k,f1) for illustrate determine initial traveling wave phasor Smα(k1,f1) specific steps：
1) S is takenmα(k,f1) amplitude Amα(k,f1), search for Amα(k,f1) all extreme values.
2) from Amα(k,f1) all extreme values in search maximum extreme value.
3) A is positionedmα(k,f1) all extreme values in first half for being more than maximum extreme value extreme value Amα(k1,
f1), Amα(k1,f1) corresponding to Smα(k1,f1) it is initial traveling wave phasor.
With Smβ(k,f1) determine initial traveling wave phasor Smβ(k1,f1) specific steps it is also as above.
Step 5：Calculate the sum of initial traveling wave phasor amplitude of α moulds of each element, the initial initial traveling wave of traveling wave phasor of β moulds
The sum of phasor amplitude calculates bus differential amount and braking amount according to the two size comparison result.
If
Otherwise
Wherein M is component population, Amα(k1,f1)、Amβ(k1,f1) be respectively m-th of element the initial traveling wave phase of α mould electric currents
The amplitude of the initial traveling wave phasor of the amplitude of amount, β mould electric currents；Smα(k1,f1)、Smβ(k1,f1) respectively m-th of element α mould electric currents at the beginning of
Begin the initial traveling wave phasor of wave phasor, β mould electric currents；SdFor differential amount, SrFor braking amount.
Step 6：It is set in advance when bus differential amount is more than more than the ratio of preset threshold value and differential amount and braking amount
When fixed restraint coefficient, show that busbar breaks down, otherwise busbar does not break down.
The ratio criterion of the initial traveling wave phasor bus differential of electric current is as follows：
Sd＞ STHAnd Sd/Sr＞ Kd；
STHFor preset threshold value, KdFor preset restraint coefficient, if differential amount SdWith braking amount SrOn so that
Formula is set up, and shows that busbar breaks down.
Confirmation explanation is carried out to beneficial effects of the present invention with a concrete example below.
Fig. 2 is certain substation 500kV bus-bar system structure charts, and it is line current direction, figure that electric current flows to circuit from busbar
Center line road electric current indicates three-phase current, such as i1=[i1a,i1b,i1c].The long 90m of busbar, busbar distribution capacity C over the groundMFor 50nF,
Busbar specific capacitance Matrix C (pF/m) and inductance matrix L (μ H/m) are respectively：
Preset coefficient STHFor 0.2IN(INLine current rated value), preset restraint coefficient KdIt is 0.85,
The braking characteristic of the initial traveling wave phasor bus differential of electric current is as shown in Figure 3.
The electro-magnetic transient of analogue simulation failure failure, sample frequency 100kHz, the row that extraction center frequency-band is 10kHz
Wave, data window 2ms.
In Fig. 4, busbar d1Place breaks down, examination different faults type, the protection of different faults initial angle operating mode Down Highway
Performance, table 1 be protection judging result, initial angle therein be instant of failure voltage phase angle.
1 busbar of table occurs to protect judging result when different types of faults
√：Protection judges that busbar breaks down.
In table, ABC indicates that three-phase shortcircuit, AB, BC, CA indicate that phase fault, AB-G, BC-G, CA-G indicate alternate
Short circuit grounding failure, A-G, B-G, C-G indicate singlephase earth fault.
The judging result of table 1 shows that the present invention has very high reliability, judging result consistent with fault condition.
In Fig. 5, circuit d2Place breaks down, examination different faults type, the protection of different faults initial angle operating mode Down Highway
Performance, table 2 be protection judging result.
2 circuit of table occurs to protect judging result when different types of faults
×：Indicate that busbar does not break down.
When the judging result of table 2 shows bus protection external area error, the present invention can reliably be failure to actuate.
Claims (6)
1. a kind of differential protection method for bus based on the initial traveling wave phasor of fault current, which is characterized in that include the following steps：
Step 1：Each element three-phase current signal that synchronous acquisition couples with busbar obtains α moulds electric current, the β mould electricity of each element
Stream；
Step 2：According to the α moulds electric current of each element, β mould electric currents, its corresponding fault component is calculated；
Step 3：Discrete S-transformation is carried out respectively to the fault component of each element, extracts corresponding α moulds current traveling wave, β mould electricity
Popular wave；
Step 4：The initial traveling wave phase of the α moulds of each element is determined according to the α moulds current traveling wave of each element, β mould current traveling waves
Amount, the initial traveling wave phasor of β moulds；
Step 5：The sum of the sum of initial traveling wave phasor amplitude of α moulds of each element, the initial traveling wave phasor amplitude of β moulds are calculated, according to
The two size comparison result calculates bus differential amount and braking amount；
Step 6：When bus differential amount is more than the ratio of preset threshold value and differential amount and braking amount more than preset
When restraint coefficient, show that busbar breaks down, otherwise busbar does not break down.
2. the differential protection method for bus as described in claim 1 based on the initial traveling wave phasor of fault current, which is characterized in that
It is decoupling to the three-phase current signal of m-th of element respectively using Clarke transform in step 1, obtain m-th of element α mould electricity
Stream, β mould electric currents, specific formula for calculation are：
In formula：ima、imb、imcThe a phases of m-th of the element respectively coupled with busbar, b phases, c phase currents；imα、imβRespectively with
Busbar connection m-th of element α mould, β mould electric currents, m=1,2,3 ... K, K are component population.
3. the differential protection method for bus as claimed in claim 2 based on the initial traveling wave phasor of fault current, which is characterized in that
The differential filtering method extraction fault component subtracted each other using week in step 2, i.e., subtract a cycle by the electric current under malfunction
Fault component just can be obtained in electric current under preceding corresponding non-faulting state, and specific formula for calculation is：
Δimα(t)、Δimβ(t) m-th of element α moulds electric current, the β mould failure of the current components respectively coupled with busbar, T1 are
The period of ac current signal, imα、imβM-th of element α mould, the β mould electric currents respectively coupled with busbar.
4. the differential protection method for bus as claimed in claim 3 based on the initial traveling wave phasor of fault current, which is characterized in that
It is using discrete S-transformation extraction α moulds current traveling wave, β mould current traveling waves, specific method in step 3：
If Δ imα(t) discrete-time series are Δ imα[kT], T are sampling interval, Δ imαThe discrete Fourier transform of [kT] is
Imα[m/NT]；Using discrete S-transformation extraction signal delta imαFault traveling wave in [kT] is expressed as：
In formula：K=0,1 ..., N-1；N=1 ..., N-1；N is discrete signal number；
It is assumed that the centre frequency of the α mould current traveling waves of extraction is f1, from Δ imα(t) the α mould current traveling waves extracted are：
In formula：Amα(k,f1)、Respectively Smα(k,f1) amplitude, phase；
If Δ imβ(t) discrete-time series are Δ imβ[kT] (k=0,1,2 ..., N-1), T are sampling interval, Δ imβ[kT]
Discrete Fourier transform be Imβ[m/NT], using discrete S-transformation extraction signal delta imβFault traveling wave in [kT] is expressed as：
In formula：K=0,1 ..., N-1；N=1 ..., N-1；
It is assumed that the centre frequency of the β mould current traveling waves of extraction is f1, from Δ imβ(t) the β mould current traveling waves extracted are：
In formula：Amβ(k,f1)、For Smβ(k,f1) amplitude, phase.
5. the differential protection method for bus as claimed in claim 4 based on the initial traveling wave phasor of fault current, which is characterized in that
Step 4 takes the specific method of corresponding initial traveling wave phasor to be the α moulds current traveling wave of each element, β moulds current traveling wave respectively：
Step 4.1：Amplitude is taken, all extreme values of amplitude is searched for, all extreme values is sequenced sequentially in time；
Step 4.2：Determine the maximum extreme value in all extreme values；
Step 4.3：The extreme value for determining first half for being more than maximum extreme value in time sequencing, using the extreme value as initial
Traveling wave phasor.
6. the differential protection method for bus as claimed in claim 5 based on the initial traveling wave phasor of fault current, which is characterized in that
Step 5 is specially：
If
Otherwise
Wherein M is component population, Amα(k1,f1)、Amβ(k1,f1) be respectively m-th of element the initial traveling wave phasor of α mould electric currents
The amplitude of the initial traveling wave phasor of amplitude, β mould electric currents；Smα(k1,f1)、Smβ(k1,f1) be respectively m-th of element α mould electric currents it is initial
The initial traveling wave phasor of traveling wave phasor, β mould electric currents；SdFor differential amount, SrFor braking amount.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610833686.1A CN106207987B (en) | 2016-09-20 | 2016-09-20 | A kind of differential protection method for bus based on the initial traveling wave phasor of fault current |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610833686.1A CN106207987B (en) | 2016-09-20 | 2016-09-20 | A kind of differential protection method for bus based on the initial traveling wave phasor of fault current |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106207987A CN106207987A (en) | 2016-12-07 |
| CN106207987B true CN106207987B (en) | 2018-08-21 |
Family
ID=58067310
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610833686.1A Expired - Fee Related CN106207987B (en) | 2016-09-20 | 2016-09-20 | A kind of differential protection method for bus based on the initial traveling wave phasor of fault current |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106207987B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108318783B (en) * | 2018-02-06 | 2023-11-28 | 国网四川省电力公司电力科学研究院 | Current transformer traveling wave transformation model and construction method thereof |
| CN109188207B (en) * | 2018-09-18 | 2020-12-25 | 四川理工学院 | Bus fault positioning method based on initial traveling wave active power |
| CN117517755B (en) * | 2024-01-08 | 2024-03-19 | 石家庄科林电气股份有限公司 | Method for rapidly determining alternating current component in electric quantity and protection measurement and control safety device |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102694375B (en) * | 2012-06-11 | 2014-07-30 | 国家电网公司 | Ultra high-voltage alternating current transmission line protection method based on all-component differential coefficient matrix |
| CN102882193B (en) * | 2012-09-28 | 2015-03-11 | 中国南方电网有限责任公司超高压输电公司 | Method and system for traveling wave protection setting of high-voltage direct-current transmission line |
| CN105610132A (en) * | 2014-11-13 | 2016-05-25 | 郭振威 | Line and bus protection method based on initial fault angle, transition resistance and machine learning |
-
2016
- 2016-09-20 CN CN201610833686.1A patent/CN106207987B/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN106207987A (en) | 2016-12-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107064741B (en) | A kind of successive ground fault line selecting method of distribution network line different name phase two o'clock | |
| Bo et al. | Transient based protection for power transmission systems | |
| CN108254657B (en) | Power distribution network section with low-current ground faults localization method based on Study of Transient Energy | |
| CN103245879B (en) | Based on the low current grounding localization method in transient reactive power direction | |
| CN109283428B (en) | Zero-sequence component high-order differential transformation-based single-phase grounding transient protection method at feeder outlet | |
| Khodadadi et al. | A noncommunication adaptive single-pole autoreclosure scheme based on the ACUSUM algorithm | |
| Mamiş et al. | Transmission lines fault location using transient signal spectrum | |
| CN103529358B (en) | Method with current information detection intermediate distribution system persistence high resistance earthing fault | |
| CN106207987B (en) | A kind of differential protection method for bus based on the initial traveling wave phasor of fault current | |
| CN108776284A (en) | A kind of small resistance grounding system single phase earthing protection method compared based on zero-sequence current | |
| CN103197203A (en) | Fault line selection method based on time domain waveform correlation analysis of three-phase current breaking variable | |
| CN108899879B (en) | Small resistance grounding system earthing protecting method based on zero-sequence current projection coefficient | |
| CN110297154A (en) | Earth fault line selection method and device based on zero mould current temporary state energy | |
| CN104111403A (en) | Microcomputer integrated protection line-selection method for low-current earthed power system | |
| CN103683198B (en) | The excitation surge current method for quickly identifying of consecutive points distance in a kind of plane based on difference current adjacent order difference composition | |
| CN104779591A (en) | Longitudinal differential protection scheme for inverter interfaced distributed generator teed line | |
| CN107085165A (en) | A kind of distribution network line is with 2 points of successive ground fault line selecting methods of famous prime minister | |
| CN103267927A (en) | Small current grounding system fault line selection method using power frequency component wavelet coefficients to carry out linear fitting detection | |
| CN102608499A (en) | Low-current line selection device and control method for inhibiting unbalanced current by way of differential filtration | |
| CN105606955B (en) | A kind of faulty line method of discrimination based on numerical differentiation and empirical mode decomposition | |
| CN104655980B (en) | A kind of this non-side voltage class adjacent lines short trouble method for quickly identifying based on db4 wavelet decomposition | |
| CN105914718A (en) | Phase current sudden change based earth fault protection method | |
| CN102879713A (en) | Ground protection circuit selection method | |
| CN105021954A (en) | Bus protection method based on line-mode current S-transformation argument detection | |
| CN105403779A (en) | Direct current line fault recognition method based on polar line current gradient sum |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20180821 Termination date: 20210920 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |