CN101435843B - Method for recognizing short circuit fault of power distribution network by dynamically regulating over current fixed value - Google Patents
Method for recognizing short circuit fault of power distribution network by dynamically regulating over current fixed value Download PDFInfo
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- CN101435843B CN101435843B CN2008101321235A CN200810132123A CN101435843B CN 101435843 B CN101435843 B CN 101435843B CN 2008101321235 A CN2008101321235 A CN 2008101321235A CN 200810132123 A CN200810132123 A CN 200810132123A CN 101435843 B CN101435843 B CN 101435843B
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Abstract
The invention is mainly used to detect short trouble of a power line. The judging conditions mainly include: 1, a power line works normally; 2, current is over k times of the maximum load current in 24 hours; 3, fault current at least keeps 40 minutes, and the change of current amplitude values is larger than omega during the period of time; and 4, a transformer substation is tripped, and the power line is powered off. The invention mainly solves the problems of the self detection of the short trouble and unwanted operations caused by preventing reverse electric transmission of the power line existing in the distribution network, is applicable to various circuits, does not need to set a fixed value of the short circuit current and has the function of adaptability.
Description
Technical field:
The invention belongs to the distribution network failure detection technique
Background technology:
It is one of main task of relay protection and distribution automation system that short trouble in the circuit detects, and equipment judges that short trouble exists following problem at present:
1. the definite value of route protection need be calculated according to the characteristic of length, impedance operator and the transformer of circuit; different circuits has different protection definite values; cause the checkout equipment on the circuit to use than difficulty; and because the ring network power supply circuit; behind feeder reconfiguration; the protection definite value also might change, and also causes using very inconvenient.
2. increasing of power cable and high capacity motor makes that the distributed capacitance of cable changed into electric energy to the mechanical energy that the trouble spot produces capacitor discharge pulse and motor when short trouble took place on the circuit, send electricity to the trouble spot, makes checkout equipment produce the misoperation phenomenon.
Therefore also there is the perfect place of many needs in the method that detects short trouble at present, and the present invention is exactly the solution that proposes at these problems.
Summary of the invention:
The objective of the invention is to develop a kind of new technology, rely on the fixing short circuit definite value of setting when detecting short trouble and make checkout equipment use very difficult present situation to solve, solve the malfunction problem of sending electricity to cause owing to circuit when detecting short trouble at present simultaneously, and in a kind of brand-new fault test set, realize.
Principle of work of the present invention is as follows:
(1) load current by continuous detection line, with load current as the basis, calculate the overcurrent definite value, Ig=k1And if quick-break definite value Is=k2If, wherein If is the maximal value of load current within 24 hours, Ig is the overcurrent definite value of this moment, and k1 and k2 can be constants, also can be the functions of load current;
(2) more than the lasting 40mS of fault current, transformer station's tripping operation, line outage is then thought short trouble may have been taken place;
It is characterized in that when the load current of circuit changes that (3) overcurrent definite value and quick-break definite value also and then change, and need not calculate the protection definite value thereby make in the deterministic process;
(4) judge by waveforms amplitude short-circuit current, the size of the peak value of more adjacent two waveforms is if the ratio of the amplitude of a back waveform and the amplitude of previous waveform is then thought real short trouble greater than setting value ω, otherwise not the short circuit waveform, but send.
The load and the short-circuit current detection circuit that constitute by circuit such as rectification, low-pass filtering, A/D samplings, rectification and low-pass filtering are eliminated high frequency interference, the A/D sample circuit converts current signal to numeral and calculates load current by CPU, and then calculate overcurrent and quick-break definite value threshold value as short trouble, if short trouble greater than this threshold value, then may take place again in the current value that measures later.When detecting short-circuit current, short circuit waveform and frequency identification circuit begin one by one the relatively size of the adjacent peak value of this fault current, if the size of adjacent peak value relatively near or increasing, the waveform frequency that utilizes zero cross detection circuit to measure simultaneously is work frequency (50/60Hz), then think real fault current, thereby confirmed short trouble, the central control logic unit provides the indication warning message, if the size of adjacent peak value is reducing gradually, or the frequency departure work frequency is very big, then think the short circuit pulse electric current that send electricity to cause, the central control logic unit can not provide the indication warning message.
Description of drawings:
Fig. 1 is a structure of the present invention
Fig. 2 is a theory diagram of the present invention
Fig. 3 is short trouble testing circuit figure of the present invention
Fig. 4 is short circuit waveform of the present invention and frequency identification schematic diagram
Embodiment:
Current signal of the present invention is taken from the open C T that is stuck on the lead, as 1 of Fig. 1, constitutes by permeability magnetic material with around thereon coil, and it can being converted to voltage signal and handling for following logical circuit the current signal linear on the line of electric force.Among Fig. 12 is signal-processing board, and current signal is handled judgement, converts thereof into corresponding logical signal and gives the core logic control module and handle.Among Fig. 13 is stepper motor, it is made of the rotor of two groups of coils and a permanent magnet, the failure identification board is installed on the rotor of permanent magnet, and two groups of coils are respectively and show coil and involution coil, when pointer detection when the fault generation is arranged, drive to show coil with the poles attract of permanent magnet near self, cause it to be in alarm condition, when timing time then, drive the involution coil motion, to near the involution coil, make indicator be in the involution state poles attract of permanent magnet.
The short trouble pulse detection mainly is made of circuit such as bridge rectifier, low-pass filtering, A/D samplings, as shown in Figure 2.Bridge rectifier is finished by the B1 among Fig. 3, it becomes the simple sinusoidal alternating current signal direct current signal of pulsation, through some high frequency interference on the low-pass filtering loop filtering circuit of R1 and C1 composition, giving 12 A/D converters with signal changes, the result of conversion is calculated by CPU, thereby calculate present load current, calculate overcurrent and quick-break definite value according to load current again, surpassed overcurrent or the quick-break value that calculates if collect the current value in a certain moment suddenly, judge that then short trouble might take place circuit, whether putting short circuit may indicate, be real short trouble, also will see current waveform after this.R6 among Fig. 4～10, C7～9 and A7, A8 have constituted bandwidth-limited circuit jointly, with the radio-frequency component filtering in the circuit, giving the A/D change-over circuit with signal one tunnel then changes, thereby the peak value that identifies each waveform compares, while another road of signal behind bandpass filtering is fed to zero passage detection and the shaping circuit be made up of R4, D2, A5 and U6 and handles, and the counter mouth that the signal after the processing is fed to CPU carries out frequency measurement.If the size of adjacent peak value relatively near or increasing, if promptly the peak value of n-1 the half-wave of peakedness ratio of n half-wave is big, also be P
n/ P
N-1＞ω, P
n, P
N-1Be respectively n and n-1 peak value, and the frequency of this signal and work frequency are approaching, then this signal is a short-circuit current, send otherwise be judged as.
Claims (1)
1. dynamically adjust the method that the overcurrent definite value is discerned short circuit fault of power distribution network for one kind, comprise: the circuit operate as normal, electric current surpasses k times of maximum load current within 24 hours, this fault current continues 40mS at least, and in the variation of this section current amplitude in the time greater than ω, transformer station's tripping operation, line outage, said method is specifically further comprising the steps of:
(1) load current by continuous detection line, with load current as the basis, calculate the overcurrent definite value, Ig=k1And if quick-break definite value Is=k2If, wherein If is the maximal value of load current within 24 hours, Ig is the overcurrent definite value of this moment, and k1 and k2 can be constants, also can be the functions of load current;
(2) more than the lasting 40mS of fault current, transformer station's tripping operation, line outage is then thought short trouble may have been taken place;
It is characterized in that when the load current of circuit changes that (3) overcurrent definite value and quick-break definite value also and then change, and need not calculate the protection definite value thereby make in the deterministic process;
(4) judge by waveforms amplitude short-circuit current, the size of the peak value of more adjacent two waveforms is if the ratio of the amplitude of a back waveform and the amplitude of previous waveform is then thought real short trouble greater than setting value ω, otherwise not the short circuit waveform, but send.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2008101321235A CN101435843B (en) | 2008-07-18 | 2008-07-18 | Method for recognizing short circuit fault of power distribution network by dynamically regulating over current fixed value |
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| Application Number | Priority Date | Filing Date | Title |
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| CN2008101321235A CN101435843B (en) | 2008-07-18 | 2008-07-18 | Method for recognizing short circuit fault of power distribution network by dynamically regulating over current fixed value |
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| CN101435843A CN101435843A (en) | 2009-05-20 |
| CN101435843B true CN101435843B (en) | 2011-06-01 |
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| CN2008101321235A Active CN101435843B (en) | 2008-07-18 | 2008-07-18 | Method for recognizing short circuit fault of power distribution network by dynamically regulating over current fixed value |
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Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105738751B (en) * | 2016-02-25 | 2018-02-16 | 国网山西省电力公司电力科学研究院 | A kind of synchronizing calculation method of bus differential protecting current loop broken string alarm definite value |
| CN106159876B (en) * | 2016-07-10 | 2018-07-13 | 珠海派诺科技股份有限公司 | Electric fireproof current-limiting type protector and fault current detection method |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1529178A (en) * | 2003-10-09 | 2004-09-15 | 武汉大学 | Electric-power system transmitting-line fault diagnosis and phase selecting method |
| CN101106270A (en) * | 2007-02-13 | 2008-01-16 | 傅桂兴 | Remote short circuit failure detection method for low voltage power grid and sensitivity protection module |
-
2008
- 2008-07-18 CN CN2008101321235A patent/CN101435843B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1529178A (en) * | 2003-10-09 | 2004-09-15 | 武汉大学 | Electric-power system transmitting-line fault diagnosis and phase selecting method |
| CN101106270A (en) * | 2007-02-13 | 2008-01-16 | 傅桂兴 | Remote short circuit failure detection method for low voltage power grid and sensitivity protection module |
Non-Patent Citations (1)
| Title |
|---|
| 朱志平等.一种实用的配电网短路故障定位方法.《电网技术》.2008,第32卷(第4期),101-104. * |
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Effective date of registration: 20170417 Address after: 301800 Baodi Baodi energy saving and environmental protection industrial CUSTOMS BUILDING 110-18 room Patentee after: TIANJIN HAOYUAN HUINENG TECHNOLOGY Co.,Ltd. Address before: 100102 Beijing, Wangjing Nanhu Park, building, floor 317, 1-301 Patentee before: Jia Xian |
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Address after: 301800 No. 5 Tiantong Road, economic development zone, Baodi District, Tianjin Patentee after: Tianjin Haoyuan Huineng Co.,Ltd. Address before: Room 110-18, Baodi Energy Conservation and Environmental Protection Industrial Customs Building, Baodi District, Tianjin City, 301800 Patentee before: TIANJIN HAOYUAN HUINENG TECHNOLOGY Co.,Ltd. |
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