A kind of improvement both-end Method of Traveling Wave Fault Ranging
阅读说明：本技术 一种改进双端行波故障测距方法 (A kind of improvement both-end Method of Traveling Wave Fault Ranging ) 是由 孙广 乐健 王阳 薛枫 董金星 冯晓伟 梁伟 王新伟 杨义勇 岳洪国 于 2019-09-05 设计创作，主要内容包括：本发明属于直流输电线路技术领域,尤其涉及一种改进双端行波故障测距方法,包括获取直流线路电流的采样数据,根据电流采样数据计算电流导数,在电流导数大于设定阈值时确定故障行波到达第一、第二测量端时间的范围；在确定时间范围内采用小波模极大值分析,计算故障行波到达第一、第二测量端的时刻；根据故障行波第一次到达第一、第二测量端的两个时刻以及故障行波第二次到达第一、第二测量端的相对较短的一个时刻计算出故障距离。该方法提高了故障行波到达测量端时刻计算的准确性并减小了数据计算量；同时提高了直流输电线路故障定位精度,不受行波波速的影响,也提高了直流输电系统线路故障的排查效率。(The invention belongs to DC power transmission line technical fields, more particularly to a kind of improvement both-end Method of Traveling Wave Fault Ranging, sampled data including obtaining DC line electric current, according to current sampling data calculating current derivative, determine that fault traveling wave reaches the range of the first, second measurement end time when derivative of current is greater than given threshold；It is analyzed determining in time range using Wavelet Modulus Maxima, at the time of calculating fault traveling wave the first, second measurement end of arrival；Second of the relatively short moment for reaching the first, second measurement end of two moment and fault traveling wave for reaching the first, second measurement end for the first time according to fault traveling wave calculates fault distance.The accuracy of measurement end moment calculating is reached the method increase fault traveling wave and reduces data calculation amount；Direct current transmission line fault positioning accuracy is improved simultaneously, is not influenced by traveling wave speed, also improves the investigation efficiency of DC transmission system line fault.)
1. a kind of improvement both-end Method of Traveling Wave Fault Ranging, characterized in that the following steps are included:
S1. the sampled data for obtaining DC line electric current is greater than according to current sampling data calculating current derivative in derivative of current Determine that fault traveling wave reaches the range of the first, second measurement end time when given threshold；
S2. it is determining in time range using Wavelet Modulus Maxima analysis, is calculating fault traveling wave and reach the first, second measurement end Moment；
S3. second of the arrival of two moment and fault traveling wave of the first, second measurement end is reached for the first time according to fault traveling wave A relatively short moment for first, second measurement end calculates fault distance.
2. improving both-end Method of Traveling Wave Fault Ranging as described in claim 1, characterized in that the specific implementation packet of step S1 It includes:
S1.1. fault recorder data line current sampled value y (i) is obtained first, i=1,2 ..., M, M are the current sample obtained The total number of value；Calculate the derivative of line current:
In formula, y (i+n) and y (i) are that respectively the i-th+n and i-th of current sampling data, n are selected constant, and T is data sampling week Phase, KthFor given threshold；
S1.2. work as KiIt is greater than preset threshold K for the first timethWhen, it records i and determines sampled data section [i-H, i+H], the calculating side of H Method are as follows:
In formula, L is transmission line of electricity overall length, and v is fault traveling wave spread speed.
3. improving both-end Method of Traveling Wave Fault Ranging as claimed in claim 2, characterized in that the specific implementation packet of step S2 It includes: Wavelet Modulus Maxima analysis is carried out to the sampled data in determination section [i-H, i+H], determine fault traveling wave for the first time and the T at the time of the first measurement end of secondary arrival1And t3And at the time of fault traveling wave first time and second of the second measurement end of arrival t2And t4。
4. improving both-end Method of Traveling Wave Fault Ranging as claimed in claim 3, characterized in that the specific implementation packet of step S3 It includes:
S3.1. compare t3And t4If t3≤t4, then the distance X of fault point to the first measurement endRF≤ L/2 carries out event using formula (3) Barrier distance calculates；
If S3.2. t3>t4, then fault distance XRF> L/2 carries out fault distance calculating using formula (4)；
S3.3. fault localization result X is exportedRF。
Technical field
The invention belongs to DC power transmission line technical field more particularly to a kind of improvement both-end Method of Traveling Wave Fault Ranging.
Background technique
DC transmission system because its transmission line capability is big, control response speed is fast, without synchronous operation stability problem, in great Rong With the obvious advantage when amount long distance power transmission, oneself becomes one of the transmission of China's electric energy and the most important mode of area networking.Direct current transportation Route route is long, across with a varied topography, when line failure carry out fault point artificial investigation difficulty is big and low efficiency.Quickly It is accurately realized line fault positioning, and then corresponding measure is taken to remove failure, the operation for improving DC transmission system can By property, reduces economic loss caused by system shutdown etc. and all have important realistic meaning.
Currently, direct current transmission line fault localization method is broadly divided into two major classes: Travelling Wave Fault Location method and accident analysis Method.Traveling wave positioning mode can be measured by the time that transient state travelling wave on detection faulty line is propagated between measurement end and fault point Fault distance.Fault analytical method is affected by system parameter, to side system and fault point transition resistance, and positioning accuracy is opposite It is larger in traveling wave positioning mode error.Traveling wave positioning mode is not influenced by circuit types, fault resstance and two side systems, and transient state row Fault message is abundant in wave, and wave head is readily identified, but this method usually requires measurement traveling wave speed, and traveling wave speed is being propagated It will change in the process, error will be brought by carrying out fault localization using fixed traveling wave speed.
Summary of the invention
The object of the present invention is to provide can accurately count at the time of a kind of only need using three fault traveling waves arrival measurement ends The method for calculating fault distance.
To achieve the above object, the technical solution adopted by the present invention is that: a kind of improvement both-end Method of Traveling Wave Fault Ranging, packet Include following steps:
S1. the sampled data for obtaining DC line electric current, according to current sampling data calculating current derivative, in derivative of current Determine that fault traveling wave reaches the range of the first, second measurement end time when greater than given threshold；
S2. it is determining in time range using Wavelet Modulus Maxima analysis, is calculating fault traveling wave and reach the first, second measurement At the time of end；
S3. two moment for reaching the first, second measurement end for the first time according to fault traveling wave and fault traveling wave are for the second time The relatively short moment for reaching the first, second measurement end calculates fault distance.
In above-mentioned improvement both-end Method of Traveling Wave Fault Ranging, the specific implementation of step S1 includes:
S1.1. fault recorder data line current sampled value y (i) is obtained first, i=1,2 ..., M, M are the electric current obtained The total number of sampled value；Calculate the derivative of line current:
In formula, y (i+n) and y (i) are that respectively the i-th+n and i-th of current sampling data, n are selected constant, and T adopts for data Sample period, KthFor given threshold；
S1.2. work as KiIt is greater than preset threshold K for the first timethWhen, it records i and determines sampled data section [i-H, i+H], the meter of H Calculation method are as follows:
In formula, L is transmission line of electricity overall length, and v is fault traveling wave spread speed.
In above-mentioned improvement both-end Method of Traveling Wave Fault Ranging, the specific implementation of step S2 includes: to determination section [i- H, i+H] in sampled data carry out Wavelet Modulus Maxima analysis, determine fault traveling wave for the first time and second reach the first measurement T at the time of end1And t3And t at the time of fault traveling wave first time and second of the second measurement end of arrival2And t4。
In above-mentioned improvement both-end Method of Traveling Wave Fault Ranging, the specific implementation of step S3 includes:
S3.1. compare t3And t4If t3≤t4, then the distance X of fault point to the first measurement endRF≤ L/2, using formula (3) into Row fault distance calculates；
If S3.2. t3>t4, then fault distance XRF> L/2 carries out fault distance calculating using formula (4)；
S3.3. fault localization result X is exportedRF。
Beneficial effects of the present invention: the present invention can effectively avoid normal current fluctuation to failure arrival time by derivative method The influence of analysis, calculation method is simple and avoids influence of the velocity of wave fluctuation to distance measurement result, improves DC power transmission line event The precision and fault location precision for hindering ranging, reduce data calculation amount, while also improving line fault investigation efficiency.For DC transmission system reliability of operation is improved, economic loss caused by transmission line malfunction etc. is reduced and all has important practical valence Value.
Detailed description of the invention
Fig. 1 (a) is 0≤X of one embodiment of the inventionRFBoth-end Method of Traveling Wave Fault Ranging schematic diagram is improved when≤L/2；
Fig. 1 (b) is one embodiment of the invention L/2≤XRFBoth-end Method of Traveling Wave Fault Ranging schematic diagram is improved when≤L；
Fig. 2 is that one embodiment of the invention improves both-end Method of Traveling Wave Fault Ranging flow chart.
Specific embodiment
Embodiments of the present invention are described in detail with reference to the accompanying drawing.
What the present embodiment was achieved through the following technical solutions, a kind of improvement both-end Method of Traveling Wave Fault Ranging, including with Lower step, the sampled data for obtaining DC line electric current are greater than according to current sampling data calculating current derivative in derivative of current Determine that fault traveling wave reaches the range of measurement end R and measurement end I time when given threshold；It is determining in time range using small echo Modulus maximum analysis calculates the exact time that fault traveling wave reaches measurement end R and measurement end I；It is arrived for the first time according to fault traveling wave The relatively short of measurement end R and measurement end I is reached up to two moment of measurement end R and measurement end I and second of fault traveling wave A moment calculate fault distance.
As shown in Figure 1, a kind of improvement both-end traveling wave fault location schematic diagram of the present embodiment.When point F occurs on transmission line of electricity When failure, the fault traveling wave propagated to route both ends can be generated from fault point F.XRFAnd XIFRespectively fault point F to measurement end R With the distance of measurement end I, L is transmission line of electricity overall length.t0Moment, t occurs for failure1And t3Respectively traveling wave first time and second At the time of secondary arrival measurement end R, t2And t4At the time of respectively traveling wave is for the first time and second reaches measurement end I.
As 0≤XRFWhen≤L/2, as shown in attached drawing 1 (a), the first two fault traveling wave that measurement end R is received is respectively first The secondary failed row to measurement end R involves the traveling wave that the fault traveling wave arrives again at measurement end R after fault point F reflection.Two events Hinder traveling wave reach measurement end R at the time of with fault distance XRFRelationship are as follows:
In formula, v is the speed that fault traveling wave is propagated；
Eliminating velocity of wave v can obtain:
As L/2≤XRFWhen≤L, as shown in Fig. 1 (b), the first two fault traveling wave of measurement end R received is respectively first The secondary failed row to measurement end R involves fault traveling wave after measurement end I reflection, and measurement end R is reached after F is reflected in fault point Fault traveling wave.It can similarly obtain:
For theoretically, in t1、t2And t3In accurate situation, fault point can be obtained according to formula (2 ') or formula (3 ') To the accurate distance of measurement end R.But in L/2≤XRFWhen, due to t3It is that fault traveling wave is reflected through measurement end I and reflected in fault point At the time of reaching measurement end R afterwards, traveling wave energy attenuation is larger, leads to t3Moment, there are relatively large errors.It at this time should be with event Hinder two moment progress fault distance calculating that traveling wave reaches measurement end I, it may be assumed that
Therefore, as 0≤XRFWhen≤L/2, Ying Xuanyong formula (2 ') carries out fault distance calculating；And work as L/2≤XRFWhen≤L, answer Selection formula (4 ') carries out fault distance calculating.
As shown in Fig. 2, being a kind of improvement both-end Method of Traveling Wave Fault Ranging flow chart of the present embodiment.Specific steps are as follows:
1) fault recorder data is obtained first, and fault recorder data is usually the line current sampled value y of series of discrete (i), i=1,2 ..., M, M are the total number of the current sampling data obtained.Calculate the derivative of line current:
In formula, y (i+n) and y (i) are that respectively the i-th+n and i-th of current sampling data, n are selected constant, and T adopts for data Sample period, KthFor given threshold.
2) work as KiIt is greater than preset threshold K for the first timethWhen, it records i and determines sampled data section [i-H, i+H], the calculating side of H Method are as follows:
In formula, L is transmission line of electricity overall length, and v is fault traveling wave spread speed.
3) Wavelet Modulus Maxima analysis, Wavelet Modulus Maxima point are carried out to the sampled data in determination section [i-H, i+H] Analysis is mature technology, especially suitable for the detection to waveform catastrophe point, therefore can determine that traveling wave reaches two of measurement end R Moment t1And t3And traveling wave reaches two moment t of measurement end I2And t4；
4) compare t3And t4.If t3≤t4, show fault distance XRF≤ L/2 carries out fault distance calculating using formula (2 ')； If t3>t4Then show fault distance XRF> L/2 carries out fault distance calculating using formula (4 ')；
5) by fault localization result XRFOutput.
A kind of improvement both-end Method of Traveling Wave Fault Ranging of the present embodiment determines that fault traveling wave reaches measurement end using derivative method The range at moment carries out wavelet analysis to sampled data within the scope of this, improves fault traveling wave and reaches what the measurement end moment calculated Accuracy simultaneously reduces data calculation amount；Fault distance can be obtained according to each moment that traveling wave reaches measurement end.This implementation Example improves direct current transmission line fault positioning accuracy, is not influenced by traveling wave speed, also improves DC transmission system route The investigation efficiency of failure.
It should be understood that the part that this specification does not elaborate belongs to the prior art.
Although being described in conjunction with the accompanying a specific embodiment of the invention above, those of ordinary skill in the art should Understand, these are merely examples, various deformation or modification can be made to these embodiments, without departing from original of the invention Reason and essence.The scope of the present invention is only limited by the claims that follow.
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