CN100367043C - Fault selecting method by attenuated DC component - Google Patents
Fault selecting method by attenuated DC component Download PDFInfo
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- CN100367043C CN100367043C CNB2004100227172A CN200410022717A CN100367043C CN 100367043 C CN100367043 C CN 100367043C CN B2004100227172 A CNB2004100227172 A CN B2004100227172A CN 200410022717 A CN200410022717 A CN 200410022717A CN 100367043 C CN100367043 C CN 100367043C
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Abstract
The present invention relates to a fault line selecting method using a decaying DC component, which belongs to the technical field of relay protection of an electric power system. When a line does not have a single-phase ground fault near a maximum value of voltage, a small grounding current system grounded by arc suppression coils can generate a decaying DC component; when the fault occurs on the line, the decaying DC component of the line is large; when the fault occurs on a bus, the decaying DC component of the bus can directly flow into the arc suppression coils, and the decaying DC component of each line is small. The present invention uses a DC component of the first cycle after the fault occurs to replace the decaying DC component for calculation according to the characteristics, and realizes fault line selection of the small grounding current system according to the magnitude of the DC component. The present invention has the advantages of clear theoretical principles, and simple, practical, reliable and effective method. When fault close angle theta is less than or equal to 60 DEG, and the transition resistance is high, the present invention can accurately select the line; when the transition resistance is low, and the fault close angle is large, the present invention can also accurately select the line.
Description
The technical field is as follows:
the invention relates to a fault line selection method by using an attenuated direct current component, belonging to the technical field of relay protection of a power system.
Background art:
when a single-phase earth fault occurs, the rule allows the power distribution network to continue to operate for 1-2h because a short circuit is not formed, but two-phase earth short circuits are easily formed in long-time earth operation, and the arc grounding can also cause full-system overvoltage. Therefore, fault line selection can be realized quickly and accurately, and the method has great significance for safe and reliable operation of the power distribution network with variable operation modes and increasingly complex structure.
Through long-term research, various fault line selection methods are developed at present, and corresponding devices are developed, but the effect in practical application is not ideal. The existing single-phase earth fault line selection method of the small current earthing system can be roughly divided into three types from the used signals, namely a steady state method (references 1 to 3), a transient state method (references 4 to 5) and a signal injection method (reference 6). Typical methods in the steady state process are: amplitude comparison method, phase comparison method, zero sequence admittance method, zero sequence power method, etc. The amplitude comparison method and the phase comparison method are only suitable for a system with a neutral point not grounded, but in practice, because more outgoing lines of a transformer substation have too large single-phase grounding current, arc suppression coils are widely used, so that the two methods have small application range; the zero sequence admittance method and the zero sequence power method are easy to be interfered because the zero sequence current after the steady state is smaller, thereby influencing the application effect in practice. The transient method uses a transient component caused by a fault to perform fault line selection, but the size of the transient component is closely related to a fault closing angle, and the transient component is very small when the fault is near a voltage zero crossing and can fail under the influence of various interferences. The signal injection method requires an additional signal, and the wiring of the system PT needs to be changed during practical application, which is not favorable for practical application of the device. When single-phase earth fault occurs in a small earth current system, high-frequency transient quantity is generated, and simultaneously attenuation direct current is possibly generated. The existing transient state quantity line selection method only utilizes the former, and neglects the utilization of the latter.
For a small grounding current system with ungrounded neutral points, a fault line can be easily selected by using the existing amplitude comparison method and phase comparison method after a single-phase grounding fault. However, for a small grounding current system with a neutral point grounded through an arc suppression coil, when a single-phase grounding fault occurs, the current magnitude and the phase of a fault line and a non-fault line are both close, and reliable fault line selection is difficult to achieve, which is a key point to be paid attention to at present.
Reference documents:
[1] hao Yushan, yang Yihan, ren Yuanheng, etc. (Hao Yushan, yang Yihan, ren Yuanheng). The group-specific amplitude-to-amplitude phase selection Principle for small current grounded microcomputer (Principle of large & phase computer for micro computer based current winding system line selection). Electric Power Information (Information on Electric Power), 1994 (2): 15-19
[2] Yidong, plum blossom Zhan, huang quan (Yi Dong, li Qunzhan, huang Yanquan), zero sequence admittance earth routing protection Principle (Principle of selective ground routing on zero sequence availability), power System Automation Equipment (Power System Automation), 2002, 22 (10): 40-42
[3] Clover, xuyuqin (Du tingxing, xu Yuqin), active line selection of arc suppression coil grounding grid (failed line detection with active power in a auto-compensated distribution network), relay (Relay), 2002, 30 (5): 33-36
[4] Zhuangchun, xiao Bai (Shu Hongcun, xiao Bai), power distribution network single-phase arc ground fault line selection transient analysis (a transient-based selection for single-phase to ground fault on distribution system), power system Automation (Automation of Electric Power Systems) 2002, 26 (21): 58-61
[5] Jiaqingquan, liu liangguang, yangyhan, etc. (Jia Qingquan, liu Lianguang, yang Yihan.) the small current fault line selection protection of power distribution network (Abrupt change detection with wall for small current fault delaying) by using wavelet detection fault mutation characteristic, chinese motor engineering newspaper (Proceedings of the CSEE), 2001, 21 (10): 78-82
[6] Wang Xinchao, mulberry in China (Wang Xincao, sangg Zaizhong.) A novel fault location method based on the "S injection method" (A new approach of fault location based on "S injection signal". Relay (Relay), 2001, 29 (7): 9-12
The invention content is as follows:
the invention aims to overcome the defects of the existing ground fault line selection technology, and provides a method for accurately performing fault line selection on a small ground current system grounded by an arc suppression coil by utilizing an attenuated direct current component through a large amount of simulation after being identified on the basis of analyzing electromagnetic transient characteristics in a system grounded by the arc suppression coil at a neutral point.
1 attenuated DC component distribution characteristic
In a neutral-point crowbar grounding system as shown in fig. 1, when the line l is grounded 2 At F 1 When A phase grounding fault occurs when point voltage crosses zero (transition resistance is 100 omega), fault line (l) 2 ) And non-faulty line (l) 1 ) The zero sequence current of (2) is shown in figure. In the present invention, the horizontal axis of the waveform diagram is ms, and the vertical axis is a. As can be seen from fig. 2, there is a very significant attenuated dc component in the zero sequence current of the faulty line, while there is almost no attenuated dc component in the zero sequence current of the non-faulty line. This is because when F 1 At point of failure, it is equivalent to F on the basis of normal system 1 Point-superposed a sinusoidal voltage source e f (t)＝E m sin(w 0 t + θ), where θ represents the fault closing angle. Under the condition of neglecting the line resistance and the arc suppression coil resistance, the zero sequence current i of the fault line 02 Can be approximately written as
When θ =0,i 02 The direct current component in the fault line is maximum, but the direct current component only forms a loop through the fault line and the arc suppression coil and does not flow through the non-fault line, so that the attenuation direct current component in the fault line is larger, and the attenuation direct current component in the non-fault line is smaller. When A phase grounding fault occurs on the bus, the line l 1 And a line l 2 The zero sequence current in (2) is shown in fig. 3. In fig. 3, the attenuated dc component in the zero sequence currents of the two lines is almost zero. This is because the attenuated dc component flows directly into the arc suppression coil and does not flow through the line.
2 fault line selection method
The distribution characteristic of the attenuation direct current component is shown when the small grounding current system is in single-phase grounding fault, and the small grounding current system is grounded through the arc suppression coil: when the line fails near the maximum voltage value, there will be attenuated DC component in the system, which only flows through the failed line and the arc suppression coil, but not through the non-failed line; when a bus fails, although a damped dc component is also generated, it does not flow through any line, but flows directly into the arc suppression coil. According to the characteristic, a fault line selection method of a small grounding current system by using the attenuation direct current component can be formed. The method uses the direct current component of the first cycle after the fault to replace the calculation of the attenuated direct current component, and realizes the fault line selection of the small grounding current system according to the size of the direct current component; the method comprises the following specific steps:
(1) When the bus zero sequence voltage instantaneous value u of the small grounding current system 0 (t) is greater than K u U n The fault line selection device is started immediately, and the zero sequence current and the bus zero sequence voltage of each outgoing line of 2 cycles before the fault and 3 cycles after the fault are recorded; wherein, K u The value is 0.35U n Rated voltage for the bus;
(2) Tracing the route forward from the starting time of the route selection device, and searching for the zero sequence voltage of the bus less than 0.01U n The corresponding time is determined as the time t of the single-phase earth fault f ；
(3) From t f Starting to select a sampling point of a cycle, using
Calculating a direct current component D in the zero sequence current of each line, wherein: x is the number of k Representing discrete sampling points, wherein N is the number of sampling points of each cycle;
(4) Finding the line with the largest DC component m Let its DC component be D m ；
(5) Judging whether the bus fault occurs or not or whether the bus fault occurs near the maximum voltage value; the concrete way is from t f Starting to selectTaking a sampling point of a cycle of the bus zero sequence voltage, and calculating a phase angle theta of the sampling point u0 Let zero-sequence voltage be a sine function, and θ u0 ∈[-180°，180°]) And defining a criterion 1: d m ＜D zd And | θ u0 -90 ° | > 20 ° and | θ u0 +90 ° | > 20 °; when the criterion 1 is met, the fault is not near the maximum value of the fault phase voltage, but the fault of the bus is indicated;
(6) In the removing line l m Finding the line with the largest DC component s Let its DC component be D s Calculating the ratio K D ＝D m /D s . Defining a criterion 2: k D ＞K Dzd When criterion 2 is satisfied, it is line l m The fault line is the fault line, and the bus fault is the opposite.
Compared with the prior art, the invention has the following advantages:
1. the theoretical basis of the invention is more visual, and the method is simple, practical, reliable and effective.
2. A large number of simulations show that: the method can correctly select the line when the fault closing angle theta is less than or equal to 60 degrees and the transition resistance is large; when the transition resistance is small, the line can be correctly selected when the fault closing angle is large;
3. the method can be combined with a transient state line selection method to form a perfect fault line selection technology of the small grounding current system.
Description of the drawings:
fig. 1 is a schematic diagram of a system in which a neutral point is grounded through an arc suppression coil. In the figure: line l 1 A length of 30km, line l 2 Line l with a length of 25km 3 A line length of 12km, l 4 A length of 15km, a line l 5 The length is 16km.
Fig. 2 shows the zero sequence currents of the faulted line and the non-faulted line when the line has a fault.
Fig. 3 shows the line zero sequence current in case of a bus fault.
The specific implementation mode is as follows:
the method comprises the following specific steps:
(1) When bus zero sequence voltage instantaneous value u of small grounding current system 0 (t) is greater than K u U n And starting the fault line selection device immediately, and recording the zero sequence current and the bus zero sequence voltage of each outgoing line of 2 cycles before the fault and 3 cycles after the fault. Wherein, K u The value is generally 0.35U n Represents the rated voltage of the bus;
(2) Tracing the route forward from the starting time of the route selection device, and searching for the zero sequence voltage of the bus less than 0.01U n The corresponding time is regarded as the time t of the single-phase earth fault f ；
(3) From t f Starting to select a sampling point of a cycle, using
Calculating a direct current component D in the zero sequence current of each line, wherein: x is the number of k Representing discrete sampling points, wherein N is the number of sampling points of each cycle;
(4) Finding the line with the largest DC component m Let its DC component be D m ；
(5) And judging whether the bus fault occurs or the fault occurs near the maximum voltage value.
When D is present m ＜D zd When (D) zd The size is related to the system parameters, for system D shown in FIG. 1 zd 0.4A) indicating a small attenuated dc component on the line. This may be caused by two reasons: (1) bus fault, (2) fault phase voltage is in fault near the maximum value; and therefore needs to be identified. The specific method comprises the following steps: from t f Starting to select a sampling point of a cycle of the bus zero sequence voltage, and calculating the phase angle theta u0 (zero sequence voltage is set as sine function, and theta u0 ∈[-180°，180°]) And defining criterion 1: d m ＜D zd And | θ u0 -90 ° | > 20 ° and|θ u0 +90 ° | > 20 °. When criterion 1 is met, it is indicated that the fault does not occur near the maximum value of the faulty phase voltage, but rather a fault of the bus.
(6) In the removing line l m Finding the line with the largest DC component s Let its DC component be D s Calculating the ratio K D ＝D m /D s . Defining criterion 2: k D ＞K Dzd When criterion 2 is satisfied, line l is considered m And the fault line is a fault line, otherwise, the fault line is considered as a bus fault. K Dzd The whole was set to 3.
Claims (1)
1. A fault line selection method using attenuation direct current component is carried out by using the measurement of the attenuation direct current component, and is characterized in that the calculation of the attenuation direct current component is replaced by the direct current component of the first cycle after the fault, and the fault line selection of a low-current grounding system is realized according to the size of the direct current component; the method comprises the following specific steps:
(1) When the bus zero sequence voltage instantaneous value u of the small current grounding system 0 (t) is greater than K u U n The fault line selection device is started immediately, and the zero sequence current and the bus zero sequence voltage of each outgoing line of 2 cycles before the fault and 3 cycles after the fault are recorded; wherein, K u The value is 0.35U n Rated voltage for the bus;
(2) Tracing the route forward from the starting time of the route selection device, and searching for the zero sequence voltage of the bus less than 0.01U n The corresponding time of the sampling point is determined as the time t of the occurrence of the single-phase earth fault f ；
(3) From t f Starting to select a sampling point of a cycle, using
Calculating a direct current component D in the zero sequence current of each line, wherein: x is a radical of a fluorine atom k Representing discrete sampling points, wherein N is the number of sampling points of each cycle;
(4) Finding the line with the largest DC component m Let its DC component be D m ；
(5) Judging whether the bus fault occurs or the fault occurs near the maximum voltage value; the concrete way is from t f Starting to select a sampling point of a cycle of the zero sequence voltage of the bus and calculating the phase angle theta u0 Let zero-sequence voltage be a sine function, and θ u0 ∈[-180°，180°]And defining criterion 1: d m ＜D zd And | θ u0 -90 ° | > 20 ° and | θ u0 +90°|＞20°，D zd Taking 0.4A; when the criterion 1 is met, the fault is not near the maximum value of the fault phase voltage, but the fault of the bus is shown;
(6) In the removing line l m Finding the line with the largest DC component s Let its DC component be D s Calculating the ratio K D ＝D m /D s Defining criterion 2: k D ＞K Dzd ，K Dzd Is set to 3, and when criterion 2 is satisfied, is line l m A faulty line, and conversely a bus fault.
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Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101227086B (en) * | 2008-01-22 | 2010-06-02 | 昆明理工大学 | Power distribution network cable-line commingle line fault route selection anastomosing method using extension theory |
| CN103163425B (en) * | 2013-02-22 | 2015-12-02 | 山东电力工程咨询院有限公司 | A kind of work criterion method of power frequency variation amplitude com parison line selection apparatus |
| CN105911414A (en) * | 2016-04-27 | 2016-08-31 | 福州大学 | Fuzzy theory based power distribution network multi-criteria integrated fault line selection method |
| CN108919045B (en) * | 2018-05-14 | 2020-05-26 | 三峡大学 | Fault line selection method based on direct current component-main frequency component ratio and amplitude-phase measurement |
| CN110441641B (en) * | 2019-07-24 | 2022-02-15 | 南京国电南自电网自动化有限公司 | Low-current grounding line selection method and system based on zero-sequence direct-current component |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06109784A (en) * | 1992-09-28 | 1994-04-22 | Tohoku Electric Power Co Inc | Measurement device for ground capacitance of electric power system |
| JPH10112929A (en) * | 1996-10-07 | 1998-04-28 | Showa Shell Sekiyu Kk | Line-to-ground fault detector for low-voltage activating panel circuit |
| JP2000333359A (en) * | 1999-05-21 | 2000-11-30 | Meidensha Corp | Grounding fault-detecting device for mechanically/ electrically integrated system |
| CN1388382A (en) * | 2001-05-25 | 2003-01-01 | 北京合纵科技有限公司 | One-phase earthing failure searching method and monitor |
| JP2003134659A (en) * | 2001-10-17 | 2003-05-09 | Kansai Electric Power Co Inc:The | Amplifier for ground-fault current on power distribution line |
-
2004
- 2004-06-03 CN CNB2004100227172A patent/CN100367043C/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06109784A (en) * | 1992-09-28 | 1994-04-22 | Tohoku Electric Power Co Inc | Measurement device for ground capacitance of electric power system |
| JPH10112929A (en) * | 1996-10-07 | 1998-04-28 | Showa Shell Sekiyu Kk | Line-to-ground fault detector for low-voltage activating panel circuit |
| JP2000333359A (en) * | 1999-05-21 | 2000-11-30 | Meidensha Corp | Grounding fault-detecting device for mechanically/ electrically integrated system |
| CN1388382A (en) * | 2001-05-25 | 2003-01-01 | 北京合纵科技有限公司 | One-phase earthing failure searching method and monitor |
| JP2003134659A (en) * | 2001-10-17 | 2003-05-09 | Kansai Electric Power Co Inc:The | Amplifier for ground-fault current on power distribution line |
Non-Patent Citations (2)
| Title |
|---|
| 小电流接地系统单相接地暂态保护判据研究. 张兰等.湖南大学学报，第31卷第2期. 2004 * |
| 提取衰减直流分量参数的改进算法. 侯有韬等.华北电力大学学报，第31卷第3期. 2004 * |
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