Disclosure of Invention
In order to solve the problem that the existing traveling wave ranging switch is not considered to have fast attenuation of the voltage traveling wave and poor traveling wave ranging effect, the invention provides a distribution network voltage type traveling wave ranging switch and an independent device ranging method, wherein the method comprises the following steps:
s1, presetting a point distribution rule and a maximum equivalent branch number N, wherein N is an integer greater than or equal to 1;
s2, obtaining a topological graph of a target area, and determining the point distribution position of the first traveling wave ranging equipment based on the topological graph;
S3, obtaining a plurality of first nodes based on the point distribution positions and the topological graph, calculating a first equivalent branch number M of each first node based on the point distribution positions, obtaining a plurality of second nodes based on the first equivalent branch number M and the maximum equivalent branch number N, and obtaining an initial position based on the maximum values of the second nodes and the first equivalent branch number M, wherein M is a positive number;
S4, judging whether the initial position meets the point distribution rule, if so, updating the point distribution position into the initial position, returning to the S3 until the point distribution position covers the target area, and executing the S5;
And S5, distributing the traveling wave ranging equipment based on the point distribution position.
The method creates equivalent branches, characterizes each scene in the voltage traveling wave transmission process, utilizes the equivalent branches to select the distribution point positions, can uniformly characterize attenuation factors affecting various voltage traveling waves by the equivalent branches, ensures that the attenuation condition of the voltage traveling waves can be simply quantitatively characterized, is convenient for accurately distributing voltage traveling wave ranging switches and independent devices, and improves the traveling wave ranging effect.
Further, in the step S1, the point distribution rule includes:
A. The first distance between the point distribution position and the connection point of the cable and the overhead line is larger than or equal to a first threshold value;
B. the second spacing between adjacent placement locations is less than a second threshold.
Since the voltage traveling wave is severely attenuated when too close to the connection point of the cable and the overhead line, the point should be located at least a distance from the connection point of the cable and the overhead line (including cable branching and cable crossing scenarios) in order to minimize attenuation. And in order to ensure that the pairing can be successfully performed once according to the millisecond time scale of the wave recording file under the vast majority of conditions when double-end ranging is performed, and meanwhile, in order to leave a certain margin for branching the line, the maximum interval between the distributed point positions cannot exceed a certain distance.
Further, in the step S1, the maximum equivalent branch number N is obtained by:
The method comprises the steps of presetting a ground fault with a maximum threshold ohm, wherein the ground fault occurs in a traveling wave ranging switch, and obtaining a voltage measured value and a minimum voltage value of the traveling wave ranging switch;
The calculation formula of the maximum equivalent branch number N is as follows:
;
wherein, the Represents the margin coefficient and,The value of the minimum voltage is indicated,Representing a voltage measurement.
Because a complete T-branch can attenuate the voltage traveling wave to 67%, the method converts all the situations into the complete T-branch, and meanwhile, when the most far end of a protection zone fails after the point distribution, the device can still acquire and have a certain margin, so that the calculation of the maximum equivalent branch number N of the method is simple and clear and is convenient for field application.
Further, in the step S2, the specific step of determining the point location of the first traveling wave ranging device includes:
if the transformer substation is externally connected with a cable outlet and a traveling wave ranging switch is preset and installed at the cable outlet, acquiring the point distribution position of a first traveling wave ranging device based on the cable outlet;
and if the transformer station is not externally connected with the cable outlet, acquiring the point distribution position of the first traveling wave distance measuring equipment based on the point distribution rule.
If the transformer substation is externally connected with a cable outlet and a traveling wave ranging switch is required to be installed at the outlet, the position is distributed, otherwise, the first distribution point is as close to the outlet side of the transformer substation as possible on the premise of meeting the distribution point rule A in order to ensure that the ranging effect covers the whole network.
Further, in the step S3, the first equivalent branch number M is obtained by:
Acquiring node areas from the point distribution positions to each first node based on the topological graph, dividing node lines of the node areas, and acquiring a plurality of topological structures, wherein each topological structure corresponds to different equivalent branch conversion modes;
acquiring the line length of each topological structure, and acquiring a second equivalent branch number of each topological structure based on the line length and the equivalent branch conversion mode;
and superposing the second equivalent branch numbers to obtain the first equivalent branch number M of each first node.
Because the attenuation effects of different topological structures on the voltage traveling wave are different, different topological structures adopt different equivalent branch conversion modes, complex attenuation calculation work can be converted into simple branch conversion work, the method is convenient for reliable field application, and different topological structures are subjected to different conversion strategies from distribution point to downstream conversion.
Further, in the step S3, the specific step of obtaining the initial position further includes:
s301, acquiring the second node adjacent to the initial position based on the downlink direction of the power distribution network line, and acquiring a node position;
s302, calculating a third equivalent branch number M1 of the node position based on the node position, the point distribution position and the acquisition mode of the first equivalent branch number M;
s303, if the maximum value of the first equivalent branch number M is smaller than the maximum equivalent branch number N and the third equivalent branch number M1 is larger than the maximum equivalent branch number N, determining the initial position as a point distribution position, and if the condition is not met, returning to S301, updating the initial position as the node position and updating the maximum value of the first equivalent branch number M as the third equivalent branch number M1.
Further, in S4, the determining manner of covering the target area by the setpoint position is as follows:
And if the point distribution positions are distributed to the tail end of the trunk line and the branch tail end of the fault locating section, judging that the point distribution positions cover the target area.
Further, in S4, the specific step of obtaining the adjustment position includes:
S401, acquiring the second node adjacent to the initial position based on the uplink direction of the power distribution network line, and acquiring an adjacent position;
and S402, judging whether the adjacent position meets the point distribution rule, if so, acquiring an adjustment position based on the adjacent position, and if not, returning to the S401, and updating the initial position to the adjacent position.
Considering that the traveling wave ranging switch is an upgrade of a pole switch, namely the traveling wave ranging switch has the function of the pole switch, and the pole switch in the power distribution network mainly plays a role of protecting a section of line, and the tail end of the pole switch has no line, so that the pole switch is not generally installed at the tail end of the line except for a special switch for bearing the functions of a tie switch and a network source switch, and the existing mode for arranging the traveling wave ranging switch cannot realize fault positioning of all lines.
Further, in the step S5, the traveling wave ranging device includes a traveling wave ranging switch and an independent device, and the specific steps of laying the traveling wave ranging device based on the setpoint position include:
Judging whether the distribution point positions meet the following conditions at the same time:
the condition 1 is that the point distribution position has the installation condition of the traveling wave ranging switch;
the point distribution position has a point distribution principle of a power distribution network switch;
the point distribution position is not the line end;
If the conditions are met, the traveling wave ranging switch is arranged at the point distribution position, and if the conditions are not met, the independent device is arranged at the point distribution position.
The method provides a voltage type traveling wave ranging switch of a power distribution network and an independent device, the independent device is arranged at the tail end of a line, fault traveling wave signals are collected by the independent device, and fault positioning of the whole line is achieved.
The invention also provides a distribution network voltage type traveling wave distance measuring switch and an independent device point distribution system, wherein the system comprises:
The data unit is used for presetting a point distribution rule and a maximum equivalent branch number N, and acquiring a topological graph of a target area, wherein N is an integer greater than or equal to 1;
The starting point unit is used for determining the point distribution position of the first traveling wave ranging equipment based on the topological graph;
The initial unit is used for obtaining a plurality of first nodes based on the point distribution positions and the topological graph, calculating a first equivalent branch number M of each first node based on the point distribution positions, obtaining a plurality of second nodes based on the first equivalent branch number M and the maximum equivalent branch number N, and obtaining initial positions based on the second nodes and the maximum value of the first equivalent branch number M, wherein M is a positive number;
The analysis unit is used for judging whether the initial position meets the point distribution rule, if so, updating the point distribution position into the initial position, returning to the initial unit until the point distribution position covers the target area, and executing S5;
And the point distribution unit is used for distributing the traveling wave ranging equipment based on the point distribution position.
The principle and effect of the system are similar to those of the method, and corresponding redundant description is not carried out on the system.
The one or more technical schemes provided by the invention have at least the following technical effects or advantages:
The method creates equivalent branches, characterizes each scene in the voltage traveling wave transmission process, utilizes the equivalent branches to select a point distribution position, considers the voltage traveling wave attenuation and improves the traveling wave ranging effect, provides a voltage type traveling wave ranging switch of the power distribution network and an independent device, installs the independent device at the tail end of a line, and utilizes the independent device to collect fault traveling wave signals so as to realize fault positioning of the whole line.
Detailed Description
In order that the above-recited objects, features and advantages of the present invention will be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description. In addition, the embodiments of the present invention and the features in the embodiments may be combined with each other without collision.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than within the scope of the description, and therefore the scope of the invention is not limited to the specific embodiments disclosed below.
Example 1
Referring to fig. 1-2, the present embodiment provides a distribution network voltage type traveling wave ranging switch and a point setting method of an independent device, where the method includes:
s1, presetting a point distribution rule and a maximum equivalent branch number N, wherein N is an integer greater than or equal to 1;
wherein, the distribution rule includes:
A. In this embodiment, the first threshold is at least 300 meters, and is optimally 500 meters, and 300 meters can ensure that the voltage traveling wave is not affected by the connection point basically, and 500 meters can ensure that the voltage traveling wave is not affected by the connection point completely.
B. The second spacing between adjacent placement locations is less than a second threshold. In this embodiment, the second threshold is optimally 6km. Considering that the traveling wave propagation speed is 3×10 8 m/s, the maximum interval between control points is not more than 6km, the maximum time difference of double-end ranging can be ensured to be 0.02ms, a millisecond-level time scale is arranged on a wave recording file generated by a pole switch, and in most cases, the ranging can be performed by directly pairing the time scales. The method is controlled within 6km, so that even if the extreme condition of boundary ranging occurs, the extremely high probability can still be ensured to be successfully paired once through the file name time scale, and only a few cases need secondary check pairing, so that the traveling wave ranging speed can be improved. Meanwhile, 6km is approximately 100-level towers in the field, and if the span between two points exceeds 100-level towers, the line is modified and branched, and the margin is insufficient, so that the ranging effect after branching is poor.
The maximum equivalent branch number N is obtained by the following steps:
The method comprises the steps of presetting a ground fault with a maximum threshold ohm, wherein the ground fault occurs in a traveling wave ranging switch, obtaining a voltage measured value and a minimum voltage value of the traveling wave ranging switch, obtaining the maximum equivalent branch number N based on the voltage measured value and the minimum voltage value, determining the magnitude of the voltage measured value according to the maximum threshold ohm in the embodiment, and generally determining the relation between the maximum threshold ohm and the voltage measured value through simulation and experiments.
The calculation formula of the maximum equivalent branch number N is as follows:
;
wherein, the The margin coefficient is represented, which can be selected according to the stability and accuracy of the actual device, and can be 1.2 in common cases,The value of the minimum voltage is indicated,Representing the voltage measurement, i.e., the magnitude of the voltage traveling wave measured by the sensor when a maximum threshold ohmic ground occurs on the traveling wave range switch (or at the equivalent node).
S2, obtaining a topological graph of a target area, and determining the point distribution position of the first traveling wave ranging equipment based on the topological graph;
The specific steps of determining the point distribution position of the first traveling wave distance measuring equipment include:
If the transformer substation is externally connected with a cable outlet and a traveling wave ranging switch is preset at the cable outlet, acquiring a point distribution position of a first traveling wave ranging device based on the cable outlet, and considering that a cable branch with the length being the length of the externally connected cable exists at the point distribution position, and converting the branch when the cable branch is distributed later (the conversion method is S3);
and if the transformer station is not externally connected with the cable outlet, acquiring the point distribution position of the first traveling wave distance measuring equipment based on the point distribution rule. On the premise of meeting the distribution rule A, in order to ensure that the ranging effect covers the whole network, the first distribution point should be as close to the outlet side of the transformer substation as possible.
S3, obtaining a plurality of first nodes based on the point distribution positions and the topological graph, calculating first equivalent branch numbers M of each first node based on the point distribution positions, obtaining a plurality of second nodes based on the first equivalent branch numbers M and the maximum equivalent branch numbers N, namely selecting first nodes with the first equivalent branch numbers M < the maximum equivalent branch numbers N, and obtaining the second nodes;
Based on the maximum values of the second node and the first equivalent branch number M, an initial position is obtained, the first equivalent branch number M is selected to be smaller than the maximum equivalent branch number N, the first equivalent branch number M is the largest node, the initial position is obtained, the point position can be ensured to be as few as possible, the cost and the live working installation quantity are as small as possible, and M is a positive number;
the first equivalent branch number M is obtained by:
based on the topological graph, acquiring node areas from the point distribution positions to each first node, dividing node lines of the node areas, and acquiring a plurality of topological structures, wherein each topological structure corresponds to different equivalent branch conversion modes, and in the embodiment, the equivalent branch conversion modes of different topological structures are shown in table 1:
table 1 equivalent branch conversion modes of different topologies
Acquiring the line length of each topological structure, and acquiring a second equivalent branch number of each topological structure based on the line length and the equivalent branch conversion mode;
and superposing the second equivalent branch numbers to obtain the first equivalent branch number M of each first node.
Wherein, the specific step of obtaining the initial position further comprises:
s301, acquiring the second node adjacent to the initial position based on the downlink direction of the power distribution network line, and acquiring a node position;
s302, calculating a third equivalent branch number M1 of the node position by adopting the same equivalent branch conversion mode based on the node position, the point distribution position and the acquisition mode of the first equivalent branch number M as shown in the table 1;
s303, if the maximum value of the first equivalent branch number M is smaller than the maximum equivalent branch number N and the third equivalent branch number M1 is larger than the maximum equivalent branch number N, determining the initial position as a point distribution position, and if the condition is not met, returning to S301, updating the initial position as the node position and updating the maximum value of the first equivalent branch number M as the third equivalent branch number M1.
S4, judging whether the initial position meets the point distribution rule, if so, updating the point distribution position into the initial position, returning to the S3 until the point distribution position covers the target area, and executing the S5;
The judgment mode of covering the target area by the point distribution position is as follows:
and if the point distribution positions are distributed to the tail end of the trunk line and the branch tail end of the fault locating section, judging that the point distribution positions cover the target area. If all points have been placed at the end of the trunk and the end of the fault locating branch is to be achieved, stopping.
The specific steps for obtaining the adjustment position comprise:
S401, acquiring the second node adjacent to the initial position based on the uplink direction of the power distribution network line, and acquiring an adjacent position;
and S402, judging whether the adjacent position meets the point distribution rule, if so, acquiring an adjustment position based on the adjacent position, and if not, returning to the S401, and updating the initial position to the adjacent position.
And S5, distributing the traveling wave ranging equipment based on the point distribution position.
The traveling wave ranging equipment comprises a traveling wave ranging switch and an independent device, and the specific steps of arranging the traveling wave ranging equipment based on the point distribution position comprise the following steps:
Judging whether the distribution point positions meet the following conditions at the same time:
the condition 1, the point location has the installation condition of the traveling wave ranging switch, for example, the installation condition of the traveling wave ranging switch may include a main segment point and a branch point;
The condition 2 that the distribution position is provided with a distribution principle of a distribution network switch, for example, the distribution principle of the distribution network switch can comprise that the distribution position has the requirement of separating and combining large loads;
The point distribution position is not the line end, namely all end point positions are provided with independent devices;
If the conditions are met, the traveling wave ranging switch is arranged at the point distribution position, and if the conditions are not met, the independent device is arranged at the point distribution position.
The independent device is a device which has no switching-on/off function and only has a voltage traveling wave detection function.
Example two
Referring to fig. 2 to 4, in fig. 3 to 4, black nodes in the drawings represent towers, numerals with # represent tower numbers, connection lines between the nodes represent transmission lines, numerals on the connection lines represent transmission line lengths (units: meters), solid lines represent transmission lines as overhead lines, broken lines represent transmission lines as cables, and sections where it is desired to achieve fault location are branches of 1# to 43# and 33 #.
On the basis of the first embodiment, this embodiment exemplifies a flow of laying out the traveling wave ranging apparatus:
s1, presetting a point distribution rule and a maximum equivalent branch number N, wherein N is an integer greater than or equal to 1;
wherein, the distribution rule includes:
A. the point of placement is at least 300 meters (preferably 500 meters) from the connection point of the cable and the overhead line (including cable branches and cable crossing scenarios);
B. the maximum spacing between adjacent setpoint positions is less than 6km.
The maximum equivalent branch number N is obtained by the following steps:
In this embodiment, in order to achieve positioning of a ground fault with a maximum threshold of 5000 ohms, the ground fault with a maximum threshold of 5000 ohms is preset, and occurs in a traveling wave ranging switch, a voltage measurement value and a minimum voltage value of the traveling wave ranging switch are obtained, the maximum equivalent branch number N is obtained based on the voltage measurement value and the minimum voltage value, and =893mV,=150mV,=1.2, According to the calculation formula of the maximum equivalent branch number N, N。
S2, obtaining a topological graph of the target area, and determining the point distribution position of the first traveling wave ranging equipment based on the topological graph;
The specific steps of determining the point distribution position of the first traveling wave distance measuring equipment include:
If the transformer substation is externally connected with a cable outlet and a traveling wave ranging switch is preset at the cable outlet, acquiring a point distribution position of a first traveling wave ranging device based on the cable outlet, and considering that a cable branch with the length being the length of the externally connected cable exists at the point distribution position, and converting the branch when the cable branch is distributed later (the conversion method is S3);
And if the transformer station is not externally connected with the cable outlet, acquiring the point distribution position of the first traveling wave distance measuring equipment based on the point distribution rule. On the premise of meeting the distribution rule A, in order to ensure that the ranging effect covers the whole network, the first distribution point should be as close to the outlet side of the transformer substation as possible. Assume that the first deployment site is deployed at tower G 0 as described above.
In this embodiment, the tower 1# is closest to the outlet side of the substation, and therefore the first point is located on the tower 1#.
S3, calculating equivalent branch number M backwards by taking the first point distribution position as a starting point, and taking the position where M is smaller than N and as large as possible as a preliminary point distribution position. Obtaining a plurality of first nodes based on a point distribution position and a topological graph, calculating a first equivalent branch number M of each first node based on the point distribution position, obtaining a plurality of second nodes based on the first equivalent branch number M and a maximum equivalent branch number N, and selecting nodes M < N in the first nodes to obtain the second nodes;
and obtaining an initial position based on the maximum value of the second node and the first equivalent branch number M, namely M < N, wherein M is the maximum node and is defined as the initial position.
The first equivalent branch number M is obtained by:
obtaining node areas from the distribution positions to each first node based on the topological graph, dividing node lines of the node areas, and obtaining a plurality of topological structures, wherein each topological structure corresponds to different equivalent branch conversion modes;
acquiring the line length of each topological structure, and acquiring a second equivalent branch number of each topological structure based on the line length and an equivalent branch conversion mode;
and superposing the second equivalent branch number to obtain the first equivalent branch number M of each first node.
Downstream from G 0 (1 #), different modes of conversion are adopted when different topologies are encountered, and the specific modes of conversion are shown in Table 1.
In this embodiment, the branches at 11#, 21#, 22#, 25#, 33# are equivalent to 1, 0.3, 1 equivalent branches, 1# to 25# are about 4km, equivalent to 0.8 equivalent branches, 25# to 33# are 1257.32m, equivalent to 0.25 equivalent branches, 33# to 42# are 1330.73m, equivalent to 0.27 equivalent branches, 60.05m cable traversal, equivalent to 3 equivalent branches, and 60.05m cable itself is equivalent to 0.025 branches.
1# To 25# with a total equivalent branch number of 1+1+0.3+0.3+0.8=3.4 <4;
1# to 33# and the total equivalent branch number is 1+1+0.3+0.3+1+0.8+0.25=4.65 >4, and therefore, one point should be arranged between 25# to 33 #.
And similarly, calculating the total equivalent branch number of other nodes.
Wherein, the specific step of obtaining the initial position further comprises:
s301, acquiring a second node adjacent to the initial position based on the downlink direction of the power distribution network line, and acquiring a node position;
s302, calculating a third equivalent branch number M1 of the node position by adopting the same equivalent branch conversion mode based on the node position, the distribution position and the acquisition mode of the first equivalent branch number M as shown in the table 1;
S303, if the maximum value of the first equivalent branch number M is smaller than the maximum equivalent branch number N and the third equivalent branch number M1 is larger than the maximum equivalent branch number N, determining the initial position as the point distribution position, and if the condition is not met, returning to S301, updating the initial position as the node position and updating the maximum value of the first equivalent branch number M as the third equivalent branch number M1.
If the next setpoint position is placed at tower G 1, m=m 1, and the next setpoint position is placed adjacent to tower G 2(G2 and G 1), m=m 2, and satisfies:
;
And arranging the next point-setting position at the tower G 1, if not, moving G 1 to G 2, and repeating the steps until the condition is met.
S4, judging whether the initial position meets the point distribution rule, if so, updating the point distribution position into the initial position, returning to S3 until the point distribution position covers the target area, and executing S5;
The judgment mode of covering the target area by the point distribution position is as follows:
and if the point distribution positions are distributed to the tail end of the trunk line and the branch tail end of the fault locating section, judging that the point distribution positions cover the target area. If all points have been placed at the end of the trunk and the end of the fault locating branch is to be achieved, stopping.
The specific steps for obtaining the adjustment position comprise:
S401, acquiring a second node adjacent to the initial position based on the uplink direction of the power distribution network line, and acquiring an adjacent position;
and S402, judging whether the adjacent positions meet the point distribution rule, if so, acquiring the adjustment positions based on the adjacent positions, and if not, returning to S401, and updating the initial positions to the adjacent positions.
If G 1 violates the rule of distribution, a tower is moved to G 0, G 11(G11 is moved to be adjacent to G 1, whether the rule of distribution is still violated is checked, if so, the tower is continuously moved to G 0, and the check is repeated until a tower G 111 which does not violate the rule of distribution is found, and the next position of distribution is finally determined to be distributed at the tower G 111.
In this embodiment, the points 25# to 33# do not violate the dot placement principle, and it is finally determined that one point is placed between 25# to 33# and 25# from the economical point of view.
Repeating S3-S4, and finally obtaining the point distribution scheme shown in figure 4.
And S5, distributing the traveling wave ranging equipment based on the point distribution position.
The traveling wave ranging equipment comprises a traveling wave ranging switch and an independent device, and the specific steps of arranging the traveling wave ranging equipment based on the point distribution position comprise the following steps:
Judging whether the distribution point positions meet the following conditions at the same time:
the condition 1 is that the point distribution position has the installation condition of the traveling wave ranging switch;
the point distribution position has a point distribution principle of a power distribution network switch;
The point distribution position is not the line end, namely all end point positions are provided with independent devices;
If the conditions are met, the traveling wave ranging switch is arranged at the point distribution position, and if the conditions are not met, the independent device is arranged at the point distribution position.
In this embodiment, traveling wave ranging switches are uniformly distributed on the points 1,2,3 and 5, and independent devices are uniformly distributed on the points 4,6, 7 and 8.
Example III
On the basis of the above embodiment, this embodiment also provides a distribution network voltage type traveling wave ranging switch and an independent device point distribution system, where the system includes:
The data unit is used for presetting a point distribution rule and a maximum equivalent branch number N, and acquiring a topological graph of a target area, wherein N is an integer greater than or equal to 1;
The starting point unit is used for determining the point distribution position of the first traveling wave ranging equipment based on the topological graph;
The initial unit is used for obtaining a plurality of first nodes based on the point distribution positions and the topological graph, calculating a first equivalent branch number M of each first node based on the point distribution positions, obtaining a plurality of second nodes based on the first equivalent branch number M and the maximum equivalent branch number N, and obtaining initial positions based on the second nodes and the maximum value of the first equivalent branch number M, wherein M is a positive number;
The analysis unit is used for judging whether the initial position meets the point distribution rule, if so, updating the point distribution position into the initial position, returning to the initial unit until the point distribution position covers the target area, and executing S5;
And the point distribution unit is used for distributing the traveling wave ranging equipment based on the point distribution position.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.