CN105301440A - Method and system for cable hybrid power transmission line double-end traveling wave distance measurement - Google Patents

Abstract

The invention provides a method for measuring the distance of a double-terminal traveling wave of a cable hybrid transmission line. As the starting point, obtain the interval time difference formed when the fault traveling wave reaches the first and second bus end points; determine the total length of each section, and calculate the fault point on different sections according to the total length, propagation speed and interval time difference of each section , the time difference of the fault traveling wave propagating on the hybrid line; the calculated time difference is screened to obtain the time difference satisfying certain conditions and the location of the corresponding fault point on the hybrid line, and calculate the difference between the fault point and The distance between the first bus or the second bus. By implementing the present invention, there is no need to determine the time midpoint position and fault search direction of the three-segment cable hybrid line, and it is not necessary to consider the complicated fault traveling wave propagation process, and the ranging result can be given simply and reliably.

Description

Method and system for double-terminal traveling wave distance measurement of cable hybrid transmission line

technical field

The present invention relates to the technical field of cable hybrid transmission line fault location, in particular to a method and system for distance measurement of double-terminal traveling waves of a cable hybrid transmission line.

Background technique

With the continuous advancement of modern city construction projects, the application of cable mixed line structure is becoming more and more extensive. Outside the city, in order to save costs, overhead lines are used for power transmission. In cities, in order to beautify the city, save land resources and other factors, laying cables are used for power transmission. On the substation side, overhead lines are generally used for power transmission, so that power cable lines The structure is formed as an overhead line-cable-overhead line three-section cable hybrid transmission line. Three-section cable hybrid transmission lines are more and more widely used, such as crossing large waterways, straits and other complex environments. Once any fault occurs in any of the three-section cable hybrid lines, it will seriously affect the safe operation of the power network. It may even cause significant economic losses. Therefore, it is particularly important to locate the fault of the three-section cable hybrid line.

At present, relevant scholars have proposed a variety of ranging methods for the overhead line-cable two-section cable hybrid line, which are mainly divided into impedance method and traveling wave method. Among them, the impedance method mainly gives the ranging result by analyzing the voltage or current measured on the busbar side at both ends of the line, but the ranging accuracy of this method is affected by factors such as fault type, transition resistance, and uneven distribution of line parameters along the corridor. The influence of the traveling wave method is relatively large; the traveling wave method only needs to combine the time when the traveling wave arrives at the measuring end combined with the propagation speed of the traveling wave in the line to give the ranging result, which is not affected by the above factors, so fault location in the cable mixed line It has been widely used in the field. Firstly, the double-ended principle is used to select the fault section, and then the single-ended principle is used to give accurate ranging results. Although this method eliminates the line given length error and double-ended time synchronization error , but such methods are only applicable to single lines or two-segment mixed lines.

In order to solve the problem that the distance measurement method applied to the cable-overhead line two-section hybrid line is not suitable for the three-section cable hybrid line, some scholars proposed a traveling wave distance measurement method based on the time midpoint method. The shortcoming of this method is that the principle is relatively complicated and the ranging accuracy is not ideal.

Contents of the invention

The technical problem to be solved by the embodiments of the present invention is to provide a method and system for double-terminal traveling wave ranging of cable hybrid transmission lines, that is, it is not necessary to determine the time midpoint position and fault search direction of the three-segment cable hybrid line, and It does not need to consider the complex fault traveling wave propagation process, and can simply and reliably give ranging results.

In order to solve the above technical problems, the embodiment of the present invention provides a method for distance measurement of double-ended traveling waves of cable hybrid transmission lines. It is implemented on a three-section cable hybrid line with the cable between the first overhead line and the second overhead line, the first overhead line is also connected to the first busbar, and the second overhead line Also connected to the second busbar, the method includes:

The fault traveling wave is collected by the fault traveling wave tester, and the propagation speeds of the fault traveling wave on the first overhead line, the second overhead line and the cable line are respectively obtained, and a certain moment is taken as a starting point to obtain The interval time difference between the time when the fault traveling wave reaches the terminal point of the first bus and the time when it reaches the terminal point of the second bus; The speed of propagation on the second overhead line is equal;

Determining the total length of the first overhead wire, the second overhead wire, and the cable, and according to the determined total length of the first overhead wire, the second overhead wire, and the cable, the acquired fault traveling waves are respectively The speed of propagation on the first overhead line, the second overhead line and the cable line, and the obtained interval time difference, respectively calculate that the fault point is located in the first overhead line, the second overhead line and the cable line When one is on, the time difference of the fault traveling wave propagating on the three-section cable hybrid line;

Screening the calculated time difference to obtain the time difference satisfying certain conditions and the position of the corresponding fault point located on the three-section cable hybrid line, and further calculating the obtained fault point and The distance between the first busbar and/or the second busbar.

Wherein, the determination of the total length of the first overhead wire, the second overhead wire and the cable, and according to the determined total length of the first overhead wire, the second overhead wire and the cable, the obtained The speeds at which the fault traveling wave propagates on the first overhead line, the second overhead line, and the cable line, and the obtained interval time difference are calculated to calculate the fault points located at the first overhead line, the second overhead line, and the When one of the cables is on, the specific steps of the time difference of the fault traveling wave propagating on the three-section cable hybrid line include:

determining the total length L ₁ of the first overhead wire, the total length L ₃ of the second overhead wire and the total length L ₂ of the cable;

When the fault point is located on the first overhead line, according to the formula Calculate the first time difference Δt ₁ of the fault traveling wave propagating on the three-section cable hybrid line; where Δt is the interval time difference; v ₁ is the fault traveling wave in the first The speed of propagation of the overhead line and the second overhead line; v ₂ is the speed of propagation of the fault traveling wave on the cable;

When the fault point is located on the cable line, according to the formula Calculate the second time difference Δt ₂ of the fault traveling wave propagating on the three-section cable hybrid line;

When the fault point is located on the second overhead line, according to the formula A third time difference Δt ₃ for the fault traveling wave propagating on the three-section cable hybrid line is calculated.

Wherein, the said calculated time difference is screened to obtain the time difference satisfying a certain condition and the position of the corresponding fault point located on the three-section cable hybrid line, and further calculating the obtained The specific steps of the distance between the fault point and the first busbar and/or the second busbar include:

Determine the first condition formula second conditional formula and the third conditional formula $-\frac{L_3}{v_1}\≤{\mathrm{\Δt}}_3\≤\frac{L_3}{v_1};$

When the calculated first time difference Δt1 satisfies the _first conditional formula, it is determined that the obtained fault point position is located on the first overhead line, and according to the first distance calculation formula Calculate the first distance D _SF1 between the obtained fault point and the first bus bar and/or the second distance D _RF1 between the obtained fault point and the second bus bar; wherein, D _RF1 =L ₁ +L ₂ +L ₃ -D _SF1 ;

When the calculated second time difference Δt ₂ satisfies the second conditional formula, it is determined that the obtained fault point position is located on the cable, and according to the second distance calculation formula Calculate the third distance D _SF2 between the obtained fault point and the first bus bar and/or the fourth distance D _RF2 between the obtained fault point and the second bus bar; wherein, D _RF2 =L ₁ +L ₂ +L ₃ -D _SF2 ;

When the calculated third time difference Δt ₃ satisfies the third conditional formula, it is determined that the obtained fault point position is located on the second overhead line, and according to the third distance calculation formula Calculate the fifth distance D _SF3 between the obtained fault point and the first bus bar and/or the sixth distance D _RF3 between the obtained fault point and the second bus bar; wherein, D _RF3 =L ₁ +L ₂ +L ₃ -D _SF3 .

The embodiment of the present invention also provides a system for double-terminal traveling wave distance measurement of cable hybrid transmission lines, which is matched with a fault traveling wave tester, which includes the first overhead line, the second overhead line and the It is implemented on a three-section cable hybrid line between an overhead line and the second overhead line, the first overhead line is also connected to the first busbar, and the second overhead line is also connected to the second busbar connected, the system includes:

The first parameter acquisition unit is used to collect the fault traveling wave through the fault traveling wave tester, obtain the propagation speed of the fault traveling wave on the first overhead line, the second overhead line and the cable line respectively, and use A certain moment is the starting point, and the interval time difference between the time when the fault traveling wave arrives at the end point of the first bus and the time when it reaches the end point of the second bus is obtained; wherein, the fault traveling wave is at the first overhead The speed of propagation on the line is equal to the speed of propagation on said second overhead line;

The second parameter acquisition unit is configured to determine the total length of the first overhead wire, the second overhead wire and the cable, and according to the determined total length of the first overhead wire, the second overhead wire and the cable, the According to the speeds at which the obtained fault traveling waves propagate on the first overhead line, the second overhead line and the cable line respectively, and the obtained interval time difference, the fault points are calculated respectively in the first overhead line, the second overhead line When one of the two overhead lines and cable lines is on, the time difference of the fault traveling wave propagating on the three-section cable hybrid line;

The distance calculation unit is used to screen the calculated time difference to obtain the time difference that satisfies certain conditions and the position of the corresponding fault point on the three-section cable hybrid line, and further calculate the The distance between the obtained fault point and the first busbar and/or the second busbar.

Wherein, the second parameter acquisition unit includes:

An acquisition module, configured to acquire the total length L ₁ of the first overhead wire, the total length L ₃ of the second overhead wire, and the total length L ₂ of the cable;

The first time difference calculation module is used for when the fault point is located on the first overhead line, according to the formula Calculate the first time difference Δt ₁ of the fault traveling wave propagating on the three-section cable hybrid line; where Δt is the interval time difference; v ₁ is the fault traveling wave in the first The speed of propagation of the overhead line and the second overhead line; v ₂ is the speed of propagation of the fault traveling wave on the cable;

The second time difference calculation module is used for when the fault point is located on the cable line, according to the formula Calculate the second time difference Δt ₂ of the fault traveling wave propagating on the three-section cable hybrid line;

The third time difference calculation module is used for when the fault point is located on the second overhead line, according to the formula A third time difference Δt ₃ for the fault traveling wave propagating on the three-section cable hybrid line is calculated.

Wherein, the distance calculation unit includes:

Condition determination module, used to determine the first condition formula second conditional formula $-\frac{L_2}{v_2}\≤{\mathrm{\Δt}}_2\≤\frac{L_2}{v_2}$ and the third conditional formula $-\frac{L_3}{v_1}\≤{\mathrm{\Δt}}_3\≤\frac{L_3}{v_1};$

A first calculation module, configured to determine that the obtained fault point location is located on the first overhead line when the calculated first time difference Δt1 satisfies the _first conditional formula, and according to the first overhead line A distance calculation formula Calculate the first distance D _SF1 between the obtained fault point and the first bus bar and/or the second distance D _RF1 between the obtained fault point and the second bus bar; wherein, D _RF1 =L ₁ +L ₂ +L ₃ -D _SF1 ;

The second calculation module is used to determine that the obtained fault point location is located on the cable line when the calculated second time difference Δt ₂ satisfies the second conditional formula, and according to the second measurement distance calculation formula Calculate the third distance D _SF2 between the obtained fault point and the first bus bar and/or the fourth distance D _RF2 between the obtained fault point and the second bus bar; wherein, D _RF2 =L ₁ +L ₂ +L ₃ -D _SF2 ;

The third calculation module is used to determine that the obtained fault point location is located on the second overhead line when the calculated third time difference Δt ₃ satisfies the third conditional formula, and according to the first Three distance calculation formulas Calculate the fifth distance D _SF3 between the obtained fault point and the first bus bar and/or the sixth distance D _RF3 between the obtained fault point and the second bus bar; wherein, D _RF3 =L ₁ +L ₂ +L ₃ -D _SF3 .

Implementing the embodiment of the present invention has the following beneficial effects:

In the embodiment of the present invention, since the fault traveling wave is collected by the fault traveling wave tester, the propagation speed of the fault traveling wave on each section of the three-section cable hybrid line (including the first overhead line, the second overhead line and the cable line), and its The time difference between arrival at the first and second buses can calculate the time difference when the fault point is located on any section of the three-section cable hybrid line, and filter the calculated time difference to obtain the time difference that meets certain conditions value and its corresponding fault point position, so as to further obtain the distance between the screened fault point and the first bus or the second bus, so there is no need to determine the time midpoint position and fault search direction of the three-section cable hybrid line, and also It does not need to consider the complex fault traveling wave propagation process, and can simply and reliably give ranging results.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, obtaining other drawings based on these drawings still belongs to the scope of the present invention without any creative effort.

Fig. 1 is a flow chart of a method for distance measurement of double-ended traveling waves of a cable hybrid transmission line provided by an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a three-segment cable hybrid line in an application scenario of a method for double-terminal traveling wave distance measurement of a cable hybrid transmission line provided by an embodiment of the present invention;

Fig. 3 is a schematic structural diagram of another three-segment cable hybrid line in an application scenario of a method for double-terminal traveling wave distance measurement of a cable hybrid transmission line provided by an embodiment of the present invention;

Fig. 4 is a schematic structural diagram of yet another three-segment cable hybrid line in an application scenario of a method for double-terminal traveling wave distance measurement of a cable hybrid transmission line provided by an embodiment of the present invention;

Fig. 5 is a schematic structural diagram of a system for distance measurement of double-terminal traveling waves of cable hybrid transmission lines provided by an embodiment of the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings.

As shown in Figure 1, in the embodiment of the present invention, a method for distance measurement of double-ended traveling waves of cable hybrid transmission lines is provided, which cooperates with the fault traveling wave tester, which includes the first overhead line, the It is implemented on a three-section cable hybrid line of two overhead lines and cables located between the first overhead line and the second overhead line, the first overhead line is also connected to the first busbar, and the second overhead line is connected to the first busbar. The two overhead lines are also connected to the second busbar, and the method includes:

Step S1, collect the fault traveling wave through the fault traveling wave tester, obtain the propagation speed of the fault traveling wave on the first overhead line, the second overhead line and the cable line respectively, and start from a certain moment time, to obtain the interval time difference between the time when the fault traveling wave reaches the terminal point of the first bus and the time when it reaches the terminal point of the second bus; wherein, the speed at which the fault traveling wave propagates on the first overhead line is equal to the speed at which it propagates on said second trolley line;

The specific process is that the fault traveling wave is collected by the fault traveling wave tester. In order to facilitate the analysis and calculation, the propagation speeds of the fault traveling waves on the first overhead line, the second overhead line and the cable line are constant at a constant speed, and The propagation speed of the fault traveling wave on the first overhead line and the second overhead line is equal, and the time t _S1 when the fault traveling wave reaches the first bus and the time t _R1 when it reaches the second bus are both absolute moments, and the interval time difference formed is Δt=t _S1 -t _R1 ; that is, take a certain moment as the starting point to collect, measure the time when the fault traveling wave reaches the first bus at the end point, and the time when it reaches the second bus at the end point, so as to obtain the time difference between the two.

Step S2, determine the total length of the first overhead wire, the second overhead wire and the cable, and according to the determined total length of the first overhead wire, the second overhead wire and the cable, the acquired fault The speeds at which traveling waves propagate on the first overhead line, the second overhead line, and cable lines, and the acquired interval time difference, respectively calculate the point of failure in the first overhead line, the second overhead line, and the cable When one of the lines is on, the time difference of the fault traveling wave propagating on the three-section cable hybrid line;

The specific process is to determine the total length L ₁ of the first overhead wire, the total length L ₃ of the second overhead wire and the total length L ₂ of the cable;

When the fault point is located on the first overhead line, according to the formula (1), the first time difference Δt ₁ of the fault traveling wave propagating on the three-section cable hybrid line is calculated:

${\mathrm{<span\; class="notranslate">\; \&Delta;t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$

In formula (1), Δt is the interval time difference; v ₁ is the propagation speed of the fault traveling wave on the first overhead line and the second overhead line; v ₂ is the propagation speed of the fault traveling wave on the cable line;

When the fault point is located on the cable line, according to the formula (2), the second time difference Δt ₂ of the fault traveling wave propagating on the three-section cable hybrid line is calculated:

${\mathrm{<span\; class="notranslate">\; \&Delta;t</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$

When the fault point is located on the second overhead line, according to the formula (3), the third time difference Δt ₃ of the fault traveling wave propagating on the three-section cable hybrid line is calculated:

${\mathrm{<span\; class="notranslate">\; \&Delta;t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$

Step S3. Filter the calculated time difference to obtain the time difference that satisfies certain conditions and the position of the corresponding fault point on the three-section cable hybrid line, and further calculate the obtained The distance between the fault point and the first busbar and/or the second busbar.

The specific process is to determine the first conditional formula (4), the second conditional formula (4) and the third conditional formula (5):

$<span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; \&Delta;t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \&le;</span>\frac{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$

$<span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; \&Delta;t</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&le;</span>\frac{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$

$<span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; \&Delta;t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; \&le;</span>\frac{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$

When the calculated first time difference Δt ₁ satisfies the first conditional formula (4), it is determined that the fault point position is located on the first overhead line, and according to the first ranging calculation formula (7), the fault point and The first distance D _SF1 between the first busbars:

${\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Delta;t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$

And/or calculate the second distance D _RF1 between the fault point and the second busbar according to formula (8):

D _RF1 =L ₁ +L ₂ +L ₃ -D _SF1 (8);

When the second time difference Δt ₂ of the calculation satisfies the second conditional formula (5), then it is determined that the fault point position is located on the cable line, and according to the second ranging calculation formula (9), calculate the fault point and The third distance D _SF2 between the first busbars:

${\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; \&Delta;t</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 9</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$

And/or calculate the fourth distance D _RF2 between the fault point and the second busbar according to formula (10):

D _RF2 = L ₁ +L ₂ +L ₃ -D _SF2 (10);

When the calculated third time difference Δt ₃ satisfies the third conditional formula (6), it is determined that the fault point position is located on the second overhead line, and according to the third ranging calculation formula (11), calculate the fault point and The fifth distance D _SF3 between the first busbars:

${\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Delta;t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 11</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$

And/or calculate the sixth distance D _RF3 between the fault point and the second busbar according to the formula (12):

D _RF3 =L ₁ +L ₂ +L ₃ -D _SF3 (12);

As shown in Figures 2 to 4, the application scenario of a method for double-terminal traveling wave distance measurement of a cable hybrid transmission line in the embodiment of the present invention is further described:

In Figures 2 to 4, S and R represent the first bus end and the second bus end connected to the two ends of the three-section cable hybrid line, F represents the location of the fault point, and P represents the connection between the cable and the first overhead line point, O indicates the connection point between the cable and the second overhead line, L ₁ , L ₂ , and L ₃ respectively indicate the total lengths of the first overhead line SP section, the cable PO section and the second overhead line OR section, D _SF , D _RF respectively represent the distance from the fault point F to the first bus S and the second bus R, and t _S1 and t _R1 respectively represent the absolute time when the fault traveling wave reaches the bus at the S end and the R end of the line.

Assuming that L ₁ is 124.411km, L ₂ is 31.4km, and L ₃ is 13.468km, the propagation speed of the fault traveling wave on the first and second overhead lines is 294km/ms, and the propagation speed of the traveling wave on the cable line is 192km/ms, thus: L ₁ /v ₁ = 423.167μs, L ₂ /v ₂ = 163.542μs, L ₃ /v ₁ = 45.810μs; and when t = 0, a single-phase ground fault occurs at point F :

When the measured: t _S1 = 68μs, t _R1 = 566μs, it can be calculated that Δt = t _S1 -t _R1 = -497μs, substituting into the formula (1) ~ (3) can get: Δt ₁ = -287.648μs, Δt ₂ =-874.357 μs, Δt ₃ =-1083.708 μs, obviously satisfying -423.167 μs ≤ Δt ₁ ≤ 423.167 μs, that is, satisfying the first conditional formula (4), and determining that the position of the fault point F is located on the first overhead line (as shown in Figure 2 Shown), substituting into formula (7) can get: D _SF1 =19.921244km, and the actual fault point F is 25km away from the S end, and the distance measurement error is 78.756m. Similarly, D _RF1 can be obtained according to formula (8);

When the measured: t _S1 = 495μs, t _R1 = 137μs, it can be calculated that Δt = t _S1 -t _R1 = 358μs, substituting into the formula (1) ~ (3) can get: Δt ₁ = 567.351μs, Δt ₂ =- 19.357 μs, Δt ₃ =-228.708 μs, obviously satisfying -163.542 μs ≤ Δt ₂ ≤ 163.542 μs, that is, satisfying the second conditional formula (5), and determining that the position of the fault point F is located on the cable line (as shown in Figure 3), Substituting into the formula (9) can get: D _SF2 = 138.252728km, and the distance between the actual fault point F and the S terminal is 138.411km, and the distance measurement error is 158.272m. Similarly, D _RF2 can be obtained according to the formula (10);

When the measured: t _S1 = 603μs, t _R1 = 29μs, it can be calculated that Δt = t _S1 -t _R1 = 574μs, substituting into the formula (1) ~ (3) can get: Δt ₁ = 783.351μs, Δt ₂ = 196.643 μs, Δt ₃ =-12.708 μs, obviously satisfying -45.810 μs≤Δt ₃ ≤45.810 μs, that is, satisfying the third condition formula (5), and determining that the position of the fault point F is located on the second overhead line (as shown in Figure 4 ), substituting into the formula (11) can get: D _SF3 = 160.676924km, and the actual fault point F is 160.811km away from the S terminal, and the ranging error is 134.076m. Similarly, D _RF3 can be obtained according to the formula (12).

As shown in Figure 5, in the embodiment of the present invention, a double-terminal traveling wave ranging system for cable hybrid transmission lines is provided, which cooperates with the fault traveling wave tester, which includes the first overhead line, the second It is implemented on a three-section cable hybrid line of two overhead lines and cables located between the first overhead line and the second overhead line, the first overhead line is also connected to the first busbar, and the second overhead line is connected to the first busbar. The two overhead lines are also connected to the second busbar, and the system includes:

The first parameter acquisition unit 510 is configured to acquire a fault traveling wave through the fault traveling wave tester, obtain the propagation speeds of the fault traveling wave on the first overhead line, the second overhead line and the cable respectively, and Taking a certain moment as the starting time, obtaining the interval time difference between the end time of the fault traveling wave reaching the first bus and the end time of the second bus; wherein, the fault traveling wave is at the first bus The speed of propagation on the trolley line is equal to the speed of propagation on said second trolley line;

The second parameter acquisition unit 520 is configured to determine the total length of the first overhead wire, the second overhead wire and the cable, and according to the determined total length of the first overhead wire, the second overhead wire and the cable, According to the acquired fault traveling wave propagation speeds on the first overhead line, the second overhead line and the cable line respectively, and the acquired interval time difference, it is calculated that the fault point is located in the first overhead line, the second overhead line, the When one of the second overhead line and cable line is on, the time difference of the fault traveling wave propagating on the three-section cable hybrid line;

The distance calculation unit 530 is configured to screen the calculated time difference to obtain a time difference that satisfies certain conditions and the location of the corresponding fault point on the three-section cable hybrid line, and further calculate The obtained distance between the fault point and the first busbar and/or the second busbar.

Wherein, the second parameter acquisition unit 520 includes:

An acquisition module 5201, configured to acquire the total length L ₁ of the first overhead wire, the total length L ₃ of the second overhead wire, and the total length L ₂ of the cable;

The first time difference calculation module 5202 is used for when the fault point is located on the first overhead line, according to the formula Calculate the first time difference Δt ₁ of the fault traveling wave propagating on the three-section cable hybrid line; where Δt is the interval time difference; v ₁ is the fault traveling wave in the first The speed of propagation of the overhead line and the second overhead line; v ₂ is the speed of propagation of the fault traveling wave on the cable;

The second time difference calculation module 5203 is used for when the fault point is located on the cable line, according to the formula Calculate the second time difference Δt ₂ of the fault traveling wave propagating on the three-section cable hybrid line;

The third time difference calculation module 5204 is used for when the fault point is located on the second overhead line, according to the formula A third time difference Δt ₃ for the fault traveling wave propagating on the three-section cable hybrid line is calculated.

Wherein, the distance calculation unit 530 includes:

Condition determination module 5301, configured to determine the first conditional formula second conditional formula $-\frac{L_2}{v_2}\&le;{\mathrm{\&Delta;t}}_2\&le;\frac{L_2}{v_2}$ and the third conditional formula $-\frac{L_3}{v_1}\&le;{\mathrm{\&Delta;t}}_3\&le;\frac{L_3}{v_1};$

The first calculation module 5302 is configured to determine that the obtained fault point location is located on the first overhead line when the calculated first time difference Δt1 satisfies the _first conditional formula, and according to First distance calculation formula Calculate the first distance D _SF1 between the obtained fault point and the first bus bar and/or the second distance D _RF1 between the obtained fault point and the second bus bar; wherein, D _RF1 =L ₁ +L ₂ +L ₃ -D _SF1 ;

The second calculation module 5303 is configured to determine that the obtained fault point location is located on the cable line when the calculated second time difference Δt ₂ satisfies the second conditional formula, and according to the second Distance Calculation Formula Calculate the third distance D _SF2 between the obtained fault point and the first bus bar and/or the fourth distance D _RF2 between the obtained fault point and the second bus bar; wherein, D _RF2 =L ₁ +L ₂ +L ₃ -D _SF2 ;

The third calculation module 5304 is configured to determine that the obtained fault point location is located on the second overhead line when the calculated third time difference Δt3 satisfies the _third conditional formula, and according to The third distance calculation formula Calculate the fifth distance D _SF3 between the obtained fault point and the first bus bar and/or the sixth distance D _RF3 between the obtained fault point and the second bus bar; wherein, D _RF3 =L ₁ +L ₂ +L ₃ -D _SF3 .

Implementing the embodiment of the present invention has the following beneficial effects:

In the embodiment of the present invention, since the fault traveling wave is collected by the fault traveling wave tester, the propagation speed of the fault traveling wave on each section of the three-section cable hybrid line (including the first overhead line, the second overhead line and the cable line), and its The time difference between arrival at the first and second buses can calculate the time difference when the fault point is located on any section of the three-section cable hybrid line, and filter the calculated time difference to obtain the time difference that meets certain conditions value and its corresponding fault point position, so as to further obtain the distance between the screened fault point and the first bus or the second bus, so there is no need to determine the time midpoint position and fault search direction of the three-section cable hybrid line, and also It does not need to consider the complex fault traveling wave propagation process, and can simply and reliably give ranging results.

It is worth noting that in the above system embodiments, the system units included are only divided according to functional logic, but are not limited to the above division, as long as the corresponding functions can be realized; in addition, the specific functions of each functional unit The names are only for the convenience of distinguishing each other, and are not used to limit the protection scope of the present invention.

Those of ordinary skill in the art can understand that all or part of the steps in the method of the above-mentioned embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, and the storage Media such as ROM/RAM, magnetic disk, optical disk, etc.

The above disclosures are only preferred embodiments of the present invention, and certainly cannot limit the scope of rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope of the present invention.

Claims (6)

1. A method for double-terminal traveling wave ranging of a cable hybrid transmission line, which cooperates with a fault traveling wave tester, is characterized in that it includes the first overhead line, the second overhead line and the first overhead line located at the first It is implemented on a three-section cable hybrid line between the overhead line and the second overhead line, the first overhead line is also connected to the first busbar, and the second overhead line is also connected to the second busbar , the method includes: The fault traveling wave is collected by the fault traveling wave tester, and the propagation speeds of the fault traveling wave on the first overhead line, the second overhead line and the cable line are respectively obtained, and a certain moment is taken as a starting point to obtain The interval time difference between the time when the fault traveling wave reaches the terminal point of the first bus and the time when it reaches the terminal point of the second bus; The speed of propagation on the second overhead line is equal; Determining the total length of the first overhead wire, the second overhead wire, and the cable, and according to the determined total length of the first overhead wire, the second overhead wire, and the cable, the acquired fault traveling waves are respectively The speed of propagation on the first overhead line, the second overhead line and the cable line, and the obtained interval time difference, respectively calculate that the fault point is located in the first overhead line, the second overhead line and the cable line When one is on, the time difference of the fault traveling wave propagating on the three-section cable hybrid line; Screening the calculated time difference to obtain the time difference satisfying certain conditions and the position of the corresponding fault point located on the three-section cable hybrid line, and calculating the difference between the obtained fault point and the The distance between the first busbar and/or the second busbar. 2. The method according to claim 1, characterized in that, determining the total length of the first overhead wire, the second overhead wire and the cable, and according to the determined first overhead wire, the second overhead wire The total length of the line and the cable, the speeds at which the obtained fault traveling waves propagate on the first overhead line, the second overhead line and the cable line, and the obtained interval time difference are calculated respectively at the fault point When located on one of the first overhead line, the second overhead line and the cable, the specific steps of the time difference of the fault traveling wave propagating on the three-section cable hybrid line include: determining the total length L ₁ of the first overhead wire, the total length L ₃ of the second overhead wire and the total length L ₂ of the cable; When the fault point is located on the first overhead line, according to the formula Calculate the first time difference Δt ₁ of the fault traveling wave propagating on the three-section cable hybrid line; where Δt is the interval time difference; v ₁ is the fault traveling wave in the first The speed of propagation of the overhead line and the second overhead line; v ₂ is the speed of propagation of the fault traveling wave on the cable; When the fault point is located on the cable line, according to the formula Calculate the second time difference Δt ₂ of the fault traveling wave propagating on the three-section cable hybrid line; When the fault point is located on the second overhead line, according to the formula A third time difference Δt ₃ for the fault traveling wave propagating on the three-section cable hybrid line is calculated. 3. The method according to claim 2, wherein the said calculated time difference is screened to obtain a time difference satisfying certain conditions and a corresponding fault point located in said three-section cable hybrid The position on the line, and further calculating the specific steps of the distance between the obtained fault point and the first bus and/or the second bus include: Determine the first condition formula second conditional formula and the third conditional formula $-\frac{L_3}{v_1}\&le;{\mathrm{\&Delta;t}}_3\&le;\frac{L_3}{v_1};$ When the calculated first time difference Δt1 satisfies the _first conditional formula, it is determined that the obtained fault point position is located on the first overhead line, and according to the first distance calculation formula Calculate the first distance D _SF1 between the obtained fault point and the first bus bar and/or the second distance D _RF1 between the obtained fault point and the second bus bar; wherein, D _RF1 =L ₁ +L ₂ +L ₃ -D _SF1 ; When the calculated second time difference Δt ₂ satisfies the second conditional formula, it is determined that the obtained fault point position is located on the cable, and according to the second distance calculation formula Calculate the third distance D _SF2 between the obtained fault point and the first bus bar and/or the fourth distance D _RF2 between the obtained fault point and the second bus bar; wherein, D _RF2 =L ₁ +L ₂ +L ₃ -D _SF2 ; When the calculated third time difference Δt ₃ satisfies the third conditional formula, it is determined that the obtained fault point position is located on the second overhead line, and according to the third distance calculation formula Calculate the fifth distance D _SF3 between the obtained fault point and the first bus bar and/or the sixth distance D _RF3 between the obtained fault point and the second bus bar; wherein, D _RF3 =L ₁ +L ₂ +L ₃ -D _SF3 . 4. A system for double-terminal traveling wave distance measurement of a cable hybrid transmission line, which is matched with a fault traveling wave tester, is characterized in that it includes the first overhead line, the second overhead line and the first overhead line located at the first Realized on the three-section cable hybrid line of the cable between the overhead line and the second overhead line, the first overhead line is also connected to the first busbar, and the second overhead line is also connected to the second busbar , the system includes: The first parameter acquisition unit is used to collect the fault traveling wave through the fault traveling wave tester, obtain the propagation speed of the fault traveling wave on the first overhead line, the second overhead line and the cable line respectively, and use A certain moment is the starting point, and the interval time difference between the time when the fault traveling wave arrives at the end point of the first bus and the time when it reaches the end point of the second bus is obtained; wherein, the fault traveling wave is at the first overhead The speed of propagation on the wire is equal to the speed of propagation on said second overhead wire; The second parameter acquisition unit is configured to determine the total length of the first overhead wire, the second overhead wire and the cable, and according to the determined total length of the first overhead wire, the second overhead wire and the cable, the According to the speeds at which the obtained fault traveling waves propagate on the first overhead line, the second overhead line and the cable line respectively, and the obtained interval time difference, the fault points are calculated respectively in the first overhead line, the second overhead line When one of the two overhead lines and cable lines is on, the time difference of the fault traveling wave propagating on the three-section cable hybrid line; The distance calculation unit is used to screen the calculated time difference to obtain the time difference that satisfies certain conditions and the position of the corresponding fault point on the three-section cable hybrid line, and further calculate the The distance between the obtained fault point and the first busbar and/or the second busbar. 5. The system according to claim 4, wherein the second parameter acquisition unit comprises: An acquisition module, configured to acquire the total length L ₁ of the first overhead wire, the total length L ₃ of the second overhead wire, and the total length L ₂ of the cable; The first time difference calculation module is used for when the fault point is located on the first overhead line, according to the formula Calculate the first time difference Δt ₁ of the fault traveling wave propagating on the three-section cable hybrid line; where Δt is the interval time difference; v ₁ is the fault traveling wave in the first The speed of propagation of the overhead line and the second overhead line; v ₂ is the speed of propagation of the fault traveling wave on the cable; The second time difference calculation module is used for when the fault point is located on the cable line, according to the formula Calculate the second time difference Δt ₂ of the fault traveling wave propagating on the three-section cable hybrid line; The third time difference calculation module is used for when the fault point is located on the second overhead line, according to the formula A third time difference Δt ₃ for the fault traveling wave propagating on the three-section cable hybrid line is calculated. 6. The system according to claim 5, wherein the distance calculation unit comprises: Condition determination module, used to determine the first condition formula second conditional formula $-\frac{L_2}{v_2}\&le;{\mathrm{\&Delta;t}}_2\&le;\frac{L_2}{v_2};$ and the third conditional formula $-\frac{L_3}{v_1}\&le;{\mathrm{\&Delta;t}}_3\&le;\frac{L_3}{v_1};$ A first calculation module, configured to determine that the obtained fault point location is located on the first overhead line when the calculated first time difference Δt1 satisfies the _first conditional formula, and according to the first overhead line A distance calculation formula Calculate the first distance D _SF1 between the obtained fault point and the first bus bar and/or the second distance D _RF1 between the obtained fault point and the second bus bar; wherein, D _RF1 =L ₁ +L ₂ +L ₃ -D _SF1 ; The second calculation module is used to determine that the obtained fault point location is located on the cable line when the calculated second time difference Δt ₂ satisfies the second conditional formula, and according to the second measurement distance calculation formula Calculate the third distance D _SF2 between the obtained fault point and the first bus bar and/or the fourth distance D _RF2 between the obtained fault point and the second bus bar; wherein, D _RF2 =L ₁ +L ₂ +L ₃ -D _SF2 ; The third calculation module is used to determine that the obtained fault point location is located on the second overhead line when the calculated third time difference Δt ₃ satisfies the third conditional formula, and according to the first Three distance calculation formulas Calculate the fifth distance D _SF3 between the obtained fault point and the first bus bar and/or the sixth distance D _RF3 between the obtained fault point and the second bus bar; wherein, D _RF3 =L ₁ +L ₂ +L ₃ -D _SF3 .