KR100547967B1 - Fault Locating System of Lightning for Overhead Transmission Line - Google Patents

Abstract

 The present invention is one of the four main materials of each transmission tower when a surge current due to lightning strikes and a fault current due to a ground fault in the steel tower flows through the overhead line and the transmission tower among various accidents occurring in the overhead transmission line. Relayed transmission of the short-range wireless communication module (a radio station that can be opened without reporting under Article 30 of the Radio Wave Act Enforcement Decree) installed by detecting the information through a current transformer installed in the main body It is a system that collects one center device by a communication program and compares the collected data of individual pylons with a computer program to accurately determine a lightning point or a failure point.

Fault Detection Transmitter, Near Field Communication, Overhead Line, Steel Tower Host, Overhead Transmission Line, Transmission Line Path, Ground Fault, Surge, Brain Standard Waveform, Level Detector, Maximum Value Detector, Surge / Failure Current Discriminator, Synchronous, Flashover, Reverse flashover, air gap, transient grounding resistance

Description

Fault Locating System of Lightning for Overhead Transmission Line             

1 is an exemplary view illustrating the flow of a lightning current or a fault current when a lightning strike occurs on a processing line of a transmission line or a ground fault occurs in a transmission tower.

Figure 2a is a diagram showing the IEC brain standard waveform.

FIG. 2B illustrates an example of the lightning current waveforms flowing through one main material in the 30, 29, 28, and 27 transmission towers when the lightning current of 100KA is applied to the 30 transmission tower in FIG. 1. It is also.

FIG. 3 is a diagram illustrating a time chart of square waves output from a level detector of a fault detection transmitter and receiver installed in transmission towers 30, 29, 28, and 27 when a lightning current flows as illustrated in FIG. 2B. to be.

Figure 4 is an exemplary embodiment showing the magnitude of the lightning discharge current value detected by each of the towers between the 24 to 36 transmission tower when there is a lightning strike in the transmission tower of No. 30 as shown in FIG. to be.

5 is an electronic circuit block diagram of a fault detection transmitter and receiver.

6 is an exemplary diagram showing an installation state of a current transformer and a fault detection transmitter.

The present invention relates to a lightning point and a failure point detection system of a overhead transmission line for quickly providing real-time fault information of the overhead transmission line to a related party.

 Transmission line is a line that acts as a passage for transporting the power produced by the power plant to the user, and is located between the distribution substation and the power station, so the amount of transmission power is always large. Therefore, even if one breakdown occurs, the ripple effect is very large. To make matters worse, the vast majority of power transmission equipment is passing through mountainous areas, and when a breakdown occurs, a lot of manpower and time is required to find the breakdown, but no quick action is taken. In some cases, it takes more time and manpower to locate and identify the cause of an accident than the time and manpower required to recover from it.

Against this background, there was a need for a system for collecting fault information on overhead transmission line, which can monitor various abnormalities in transmission line in real time.

 To this need, the state of the art to date has almost escaped from the primitive method. In other words, by investigating the operation status according to the percentage of correction of zone-1, zone-2, zone-3 elements of short circuit or ground fault protection distance relay installed in substation and whether Carrier Trip of the switch is operated, It is necessary to determine whether it is within 15% of the transmission line, within 15% of the opposite substation, or 70% of the middle part of both substations, and conduct line inspection and inspection in the area. This determination is based on the assumption that the error of the protective relay is within the valid value and the forward operation of the protective relay.

 In recent years, it has been possible to estimate more advanced failure points on transmission lines employing digital distance relays, and to estimate the lightning points by operating the lightning system installed at the local power supply station of the power company. . However, even though these expensive facilities are installed, the exact point is not known.

 Accordingly, the present invention is a case in which a surge current or a fault current flows through a transmission tower and a processing ground line or a surge voltage is applied to the transmission tower and the processing ground line by a lightning strike and an accident in a steel tower among various accidents occurring in the overhead transmission line. Measure the magnitude of the current value or the abnormal voltage flowing through each transmission tower through the detectors installed in each transmission tower, and report the detected data to the short-range wireless communication module installed in each detection terminal (Article 30 of the Radio Wave Enforcement Decree). It is a system that collects data into a single center device by relay transmission of a radio station that can be established, and compares and analyzes the collected data with a computer program to accurately identify lightning points and failure points.

 According to the patent publication data, there is a “lightning indicator” of utility model registration No. 20-0201727, which means that when a failure occurs due to a lightning strike, the display cloth is unfolded so that a lightning tower can be easily found from a distant place. It is identical with the standard set in “Lightning Indicator for Overhead Transmission Line” of KEPCO purchase specification (specification: PS112). However, the practical application of this technique is to extend the scope of the inspection by operating simultaneously on five to six pylons in a single lightning strike, and the line-inspector must make a field tour in outline.

 Among foreign technologies, JOSLYN, FISHER PIERCE, POWER DELIVERY PRODUCT INC, EDISON CONTROLS FCI INC. Similar technology products were being released on the back. However, when the information is collected remotely, the telecommunication carrier's telecommunication means must be used, and when the short-range wireless communication is used, the data must be collected by the handheld receiver while traveling around the field.

 In addition, Nippon Kouatsu Electric Co., Ltd.'s Fault Locating System was the most advanced technology, but this system also received the clock through the GPS antenna to synchronize the fault detection, and used as a means of transmitting data. In case of using phone module or short range wireless communication, it was too uneconomical for actual application in the field because it uses a method of collecting data by moving a car or helicopter equipped with a handheld receiver to the accident area. .

The present invention has been made to solve the above-mentioned problems, and installs a fault detection transmitter and receiver for detecting lightning current and fault current for each transmission tower which is a support of a overhead transmission line, and transmitting the detected data to the center apparatus. However, in order to accurately determine the lightning point and the failure point, the detection terminals of each transmission tower should be compared and analyzed with the data measured at the same time. In order to do this, there should be a clock function that allows the detection terminals to share each other. At the same time, there should be a transformer to measure the magnitude of the large current. And there is a need for a communication system that can collect and collect the measured results.

 Therefore, the technical problem of the present invention

First, how to synchronize the synchronization between each terminal?

Second, how do you measure large currents?

Third, how will the data of the entire transmission tower be collected in real time at the substations at both ends of the transmission line? I'm in solving problems that are.

Therefore, the present invention is unconditional display of the steel tower in which the lightning current occurs, while the lightning point and failure point detection system of the overhead transmission line according to the present invention is not only insulated damage as well as failure of the insulator, The display unit is operated against all permanent failures occurring in transmission towers due to flashover caused by deterioration, salt, fouling, flashover caused by floating material, and reverse flashover caused by guided lightning. In addition, it is possible to accurately display a lightning strike that has been attacked by guided lightning but is not connected to a failure.

Lightning point and failure point detection system of the overhead transmission line according to the present invention for achieving the above object, it is possible to accurately determine the lightning point or failure point by comparing and analyzing the data of the individual towers collected through the detection terminal with a computer program In the lightning and fault detection system of overhead transmission line, set the reference value directly below the saturation point of the current transformer, and then increase the peak value from the point when the instantaneous value of the input surge waveform reaches the reference value and then rise again to the crest value. A level detector for measuring a duration up to the time of falling below; And a maximum value detecting means for detecting the magnitude of the lightning current waveform by using the proportionality of the magnitude of the duration and the magnitude of the surge waveform, and the magnitude of the lightning current waveform passing through each steel tower detected by the maximum value detecting means. By comparing with, it is characterized in that the pylon with the largest waveform detected is determined as the pylon closest to the lightning strike point.
A surge / fault current discriminator further distinguishes a surge current due to lightning strike and a fault current due to a ground fault in the steel tower, and the surge / fault current discriminator is collected from the individual steel towers to provide the surge / fault current discriminator. Means for sampling the input waveform once every 50 [㎲] for 1 [㎳], and when the result of the sampling outputs a specific value up to 10 times, it is judged to be a surge current, and the result of the sampling determines the specific values. In the case of outputting at least 50 times, it comprises a means for determining the fault current.
Lightning point and failure point detection system of the overhead transmission line according to the present invention for achieving the above object, it is possible to accurately determine the lightning point or failure point by comparing and analyzing the data of the individual towers collected through the detection terminal with a computer program A lightning point and failure point detection system of a overhead transmission line, comprising: means for sampling waveforms collected from said individual towers once every 50 [mV] for 1 [mV]; Means for judging as a surge current when outputting a specific value that is meaningful as a result of sampling by the sampling means up to 10 times, and as a fault current when outputting at least 50 times when a specific value as a result of sampling is output; Characterized in that it comprises a.
And means for generating a correction value from the measured values for comparative analysis of the collected data of the individual towers, the correction value generating means for inputting each ground resistance value and the transient ground resistance value of each individual towers. Numerical input means; By applying Ohm's law that defines the relationship between the resistance value and the current value with respect to the numerical value inputted by the numerical input means, correction is made according to each ground resistance value in case of a ground fault, and each transient grounding in the case of lightning attack. Compensation means for correcting according to the resistance value, characterized in that to make a comparative analysis between the generated correction values through a computer program.
Before describing the lightning point and failure point detection system of the overhead transmission line of the present invention for achieving the above objects, the basics of the transmission line will be described first.

 Overhead transmission lines are installed between substations and substations, consisting of transmission towers and transmission line conductors, ranging in length from several kilometres to tens of kilometres. And, it is supported by transmission tower every 300m of standard span, and conductors are supported from the pylons by self-detachment, and processing overhead line at the top of the tower so that the overhead line is located above the track conductor for lightning protection. Support. In addition, since there is no insulation between the processing ground wire and the steel tower, the processing ground wire is directly grounded at every supporting steel tower. In addition, the power transmission system in Korea uses three-phase three-wire type regardless of voltage type, so when one conductor is used, regardless of single conductor or multi-conductor, three conductors become one transmission line. Therefore, when it is difficult to secure the construction site of transmission line as it is today, many transmission lines are naturally installed in one pylon, and four lines are multi-reflective and up to 6 lines are installed.

 And even if several lines are installed in one transmission route, this “lightning point and failure point detection system of the overhead transmission line” accurately displays the span of failure in the transmission tower path, and multiple transmission lines The indication of the transmission line having a failure in the installed transmission tower path can determine which line is broken by analyzing the operation status of relays or breakers at both substations. Here, the transmission line tower path is a term distinguished from the transmission line. In other words, when a transmission tower is used as a support for a transmission line, it is not only used for any one transmission line but also becomes a bottle of another transmission line. In addition, two or more transmission lines starting together at the beginning of a transmission line path may be divided along different paths in the middle. Therefore, a group of transmission towers connected by one overhead line is considered as one transmission tower path.

 The system configuration of the present invention is composed of the following three.

A fault detection transmitter (FDT = Fault Detector Transceiver) installed in each tower to detect abnormal current flowing through the tower and transmit the detected data to the center apparatus, or perform relay transmission between terminals;

A center unit (CCU = Central Communication Unit) for transmitting data to the fault detection transmitter or receiving data from the fault detection transmitter and receiver and transmitting the received data to a PC or a Web Server PC;

It is a PC or Web Server PC that manages data received from the center device and a management program. However, since it is generalized about PC or Web Server PC, the explanation is omitted here, and only the configuration of the management program will be described for a while.

 In addition, when the faults are detected, different towers must be detected at the same time and compared with each other, so that a valid comparison can be made. In the Fault Locating System of Japan, the synchronization is achieved by receiving a clock through a GPS antenna. Since the level detector operates within 2 [㎲] at the rising part or head of the abrupt waveform which occurs during a lightning attack or ground fault, the data detected in each pylon have an synchronized effect automatically. Therefore, the device related to synchronization is omitted.

 Now, the configuration and operation of the present invention will be described in detail with reference examples 1 to 6.

 1 is an exemplary view illustrating the flow of a lightning current or a fault current when a lightning strike occurs on a processing line of a transmission line or a ground fault occurs in a transmission tower.

  In this exemplary view, one transmission tower path is composed of 60 transmission towers, and serial numbers are assigned to Nos. 1 to 60, respectively. Among them, when the lightning strike occurred near the No. 30 pylon or the ground fault occurred in the transmission tower, the flow of the lightning current or the fault current discharged through the processing ground and each steel tower is shown in Nos. 27 to 33.

 As shown in the diagram, the most discharge current flows through No. 30 pylon, followed by No. 29 and No. 31 pylon, then No. 28 and No. 32, and then No. 27 and No. 33 pylon. The magnitude of the discharge current is reduced. In other words, as the distance from the lightning strike or ground fault occurs, the discharge current decreases.

 Figure 2a is a diagram showing the IEC brain standard waveform.

In general, the waveform of the lightning voltage or brain current is an impulse wave as shown in FIG. 2A. Shock waves are also called surges, which have a waveform that reaches a crest value in a very short time and disappears in a very short time. In the figure, the A point is called the digging point, OA is called Padu, and AB is called Pami. Shock waves are usually represented by crest values, wave lengths, and wave lengths.

 In practice, however, the wave is distorted, so as shown in the figure, a straight line between 10 [%] of the peak value (30 [%] for voltage) and 90 [%] intersects the time axis. The point of time is referred to as the reference point of time (this is called the protocol zero), and the time from this time until the upper curve passes the A point, that is, the Th of the figure is called the wave length. Fami length is the time from the reference point to half the crest value, ie the Tt in the figure is called the fam length.

 Therefore, if 100 [KV] and 1.2 × 50 [㎲] waves are used, the wave height is 100 [KV], the wave length is 1.2 [,], and the wave length is 50 [㎲].

 However, the actual value of brain waves is known to be tens of thousands to 200,000 [A], wave length is 1-10 [～], and wave length is 10-100 [㎲].

 However, the fault currents that must be dealt with here are quite different from brain waveforms. That is, it belongs to the commercial frequency, and the period of 1㎐ is 16,700 [㎲], which lasts for a very long time compared to the brain waveform. Therefore, the brain waveform and the fault current waveform can be distinguished very easily.

 FIG. 2B illustrates an example of the lightning current waveforms flowing through one main material in the 30, 29, 28, and 27 transmission towers when the lightning current of 100KA is applied to the 30 transmission tower in FIG. 1. It is also.

 Referring to the magnitude of the current discharged through each of the towers in Figure 1, it is assumed that the current discharged through the closest pylon No. 30 pylon 30 currents propagating to both sides in the 40KA, No. 30 pylon respectively. 30KA reaching the No. 29 or No. 31 pylon is discharged through the No. 29 or No. 31 pylon and the remaining 12KA flows in the direction of No. 28 or No. 32 pylon again. The classification method of is repeated.

 When the lightning discharge current of the No. 30 pylon is detected by this estimated value, it will be classified evenly into the four main subjects of the transmission tower, and 10KA will flow as one main subject.

 In the No. 29 or No. 31 tower, 4.5KA, which is 1/4 of 18KA, flows as one main body, and in the No. 28 or 32 tower, 1.8KA, which is 1/4 of 7.2KA, flows. Will be.

 In the case of using a current transformer to detect the magnitude of such a lightning discharge current, the saturation point of the current transformer should be high to several KA, and such current transformers cannot be installed as a detection device for each steel tower. Therefore, a method of inserting a void into the core of the current transformer can be used to increase the saturation point even in a small area path. It is assumed here that a current transformer at saturation point 3KA is used.

 Accordingly, FIG. 2b shows a state in which the lightning discharge current waveforms discharged through the main body of the steel towers gradually approaching the lightning tower and the lightning tower are gradually decreasing, and the lightning discharge discharged through the respective towers. The saturation point duration of the current waveform is shown.

 That is, the waveform of the lightning discharge current discharged through the closest steel tower (No. 30 steel tower in FIG. 1) at the lightning strike point is the waveform of ①, and next to the left and right steel towers (No. 29 or 31 in the case of FIG. 1). The lightning discharge current waveform discharged through a steel tower is a waveform of ②, and the lightning discharge current waveform discharged through a steel tower adjacent to the left and right (No. 28 or 32 steel tower in FIG. 1) is a waveform of ③, Next, the lightning discharge current waveform discharged through the left and right steel towers (No. 27 or 33 steel tower in FIG. 1) becomes a waveform of ④.

 The durations above which the waveforms of ① ② ③ ④ exceed the saturation point 3KA are shown in the figure as T1 (a'-a) [㎲], T2 (b'-b) [㎲], T3 (c'-c) [ I) and T4 (d'-d) [i]. By measuring this saturation duration, it is possible to invert the crest point that exists above the saturation point that cannot be measured.

 FIG. 3 is a diagram illustrating a time chart of square waves output from a level detector of a fault detection transmitter and receiver installed in transmission towers 30, 29, 28, and 27 when a lightning current flows as illustrated in FIG. 2B. to be. In FIG. 5, the level detector has a logic of turning on when the value is greater than or equal to the set value and turning off when the level is less than the set value. Therefore, in FIG. 2B, point a is 1 [㎲], point b is 2 [㎲], point c is 3 [㎲], point d is 4 [㎲], point a 'is 70 [㎲], point b' is 55 [㎲], assuming that the point c 'is 45 [d] and the point d' is 30 [,], T1 has a duration of 69 (70-1) [㎲] because the time chart is drawn as shown in the figure. Generates one square wave, T2 generates one square wave with a duration of 53 (55-2) [m], and T3 generates one square wave with a duration of 42 (45-3) [m]. T4 is to generate one square wave with a duration of 26 (30-4) [Hz].

 4 is a bar graph showing the magnitude of the discharge current value detected by each of the towers between the towers 24 to 36 when there is a lightning attack or ground fault in the transmission tower of No. 30 as shown in FIG. It is an exemplary illustration. This graph is assuming that the ground resistance and the transient grounding resistance of each transmission tower are uniform. In practice, however, there are differences in ground resistance and transient grounding resistance values depending on the soil quality and construction conditions of each transmission tower. Therefore, it may be difficult to determine the bar graph of FIG.

 Therefore, in order to output a bar graph that can induce accurate judgment, input the ground resistance and the transient grounding resistance value of each transmission tower to the management program, and the relationship of the current value inversely proportional to the resistance value (Ohm's law). ) Should be corrected in consideration of the This correction process can be inserted into the computer management program. In case of new transmission line, the ground resistance value and transient ground resistance value inputted to the program are inputted after the construction of transmission line is completed, and then the ground resistance and transient ground resistance value measured periodically are inputted. Let's do it. In the existing transmission line, the latest measurement data is always input or updated, so that a bar graph in the form of an example can be displayed so that an accurate lightning point or failure point can be determined.

 5 is an electronic circuit block diagram of a fault detection receiver. When a lightning current flows into the steel tower from the overhead processing line 22 of the overhead transmission line or a fault current flows into the steel tower from the transmission line conductor, it is discharged through the four steel tower host materials 21, where one steel tower host material ( Through the current transformer 23 installed in 21), a lightning current or a fault current is detected. However, current transformers used in general are not high enough to detect the instantaneous value of large current as they are not high. Therefore, use a current transformer to increase the saturation point by inserting a void in any part of the closed-core iron core used as a current transformer of the current transformer, and use a level detector (24) to detect the instantaneous value higher than the saturation point of the current transformer with voids. ). In other words, set a value below the saturation point of the current transformer, turn it on when the input instantaneous value reaches the set value, and turn it off when it falls below the set value. It is possible to find out the instantaneous value above the saturation point by measuring the duration of whether it lasts for a while and inverting the time. The maximum value detector 25 detects the maximum instantaneous value when the value is less than the set value of the level detector 24. In this case, high speed sampling IC or holding IC can be used.

 In addition, a surge / fault current discriminator 26 capable of distinguishing whether the detected waveform is a surge waveform or a fault current waveform is provided. This discriminator can be easily judged by a combination of a coil and a capacitor showing different impedance values for surge and commercial frequency waveforms, and for 1 [Hz] by using an IC that is sampled once every 50 [Hz]. When the waveform is sampled, the surge waveform can sample only one or two times any value except for the same value that is close to zero, and the waveform of the commercial frequency always changes, except for the same value that is close to zero. You can sample them 334 times. Using these methods, the determination is easy.

 As described above, the level detector 24 outputs a duration longer than the set value and inputs it to the CPU 27, detects the maximum value from the maximum value detector 25, inputs it to the CPU 27, and the surge / fault current. When the surgeon distinguishes the surge waveform and the commercial frequency waveform from the discriminator 26 and inputs them to the CPU 27, the CPU 27 stores these signals, calculates the data, and converts the signals into its own identification number by the dip switch 29. Together with the RF module 28 is to be transmitted to the center apparatus. In addition, the RF module 28 receives and retransmits signals transmitted from neighboring terminals, thereby enabling data transmission to a place far beyond a communication communication distance through multi-stage relay transmission. That is, communication programs of these various functions are built into this CPU 27.

 And the problem of the power to be supplied to the fault detection transceiver may be used in various ways. How to replace the battery from time to time, using the current leakage current flowing through the processing line as a current using a current transformer, a method using a solar cell, a method using a wind power generation using wind, etc. . Either way, the use of a battery that can be charged and discharged is indispensable.

6 is an exemplary diagram showing an installation state of a current transformer and a fault detection transmitter. In other words, the current transformer is installed at the main and subsidiary joints located under the lowest arm so that a quarter of the current flowing through the steel tower flows. In particular, the current transformer should be structurally manufactured to be split type core and assembled in the field, so that it can be installed without disassembling, modifying, or damaging the main parts of the tower. In addition, high current strength, good characteristics, and uniformity can be used as data to compare data obtained from individual current transformers. The fault detection transmitter and receiver should be installed close to the current transformer and at the position where RF communication with the fault detection transmitters of nearby steel towers can be best done.

 As described above, when the fault detection transmitter / receiver transmits data of a lightning current or a fault current, the center apparatus receives the data through the RF module, inputs the received data to the CPU, performs calculation and storage, and transmits the data to the PC or the server PC. It is. In addition, the CPU of this center device also incorporates a communication program to send a command signal to the slave terminals and to receive data from the slave terminals.

 The present invention collects fault information generated from overhead transmission lines passing through hilly or rugged mountain areas in real time to a management computer or Internet Web Server, and utilizes the collected data to accurately determine and display the fault location, In addition, it is possible to search from the PC, PDA, Mobile Phone, etc. of the department concerned, so that the stakeholders can immediately recognize the point of failure when the transmission line breaks down, thereby implementing stable transmission system operation through rapid recovery of the transmission system.

Therefore, it contributes to high-quality electricity supply by reducing transmission line management manpower and minimizing transmission line outage time, and enables economic and efficient transmission line management.

Claims (4)

It is a lightning point and failure point detection system of overhead transmission line that can accurately identify the lightning point or failure point by comparing and analyzing the data of individual towers collected through the detection terminals with computer program.  A level detector for setting a reference value just below the saturation point of the detection current transformer, and measuring a duration from the time when the instantaneous value of the input surge waveform reaches the reference value to the crest value and then falls back below the reference value; , And a maximum value detecting means for detecting the magnitude of the lightning current waveform by using the proportional magnitude of the duration and the magnitude of the surge waveform. Lightning point of the overhead transmission line, characterized in that to compare the magnitude of the lightning current waveform passing through each of the towers detected by the maximum value detection means, to determine the pylon detected the largest waveform as the steel tower closest to the lightning-damping point. And fault detection system. The surge / fault current discriminator of claim 1, further comprising a surge / fault current discriminator for distinguishing a surge current due to lightning strike and a fault current due to a ground fault in the steel tower. Means for sampling the waveform collected from the individual towers and input to the surge / fault current discriminator once every 50 [mV] for 1 [mV], And means for determining a surge current when the sampling result outputs a specific value up to 10 times, and means for determining a fault current when the sampling result outputs at least 50 times a specific value. Lightning point and fault point detection system of overhead transmission line. It is a lightning point and failure point detection system of overhead transmission line that can accurately identify the lightning point or failure point by comparing and analyzing the data of individual towers collected through the detection terminals with computer program.  Means for sampling the waveform collected from the individual towers once every 50 [mV] for 1 [mV], Means for judging as a surge current when outputting a specific value that is meaningful as a result of sampling by the sampling means up to 10 times, and as a fault current when outputting at least 50 times when a specific value as a result of sampling is output; Lightning point and failure point detection system of the overhead transmission line, comprising a. The method according to any one of claims 1 to 3, further comprising means for generating a correction value from the measurements for comparative analysis of the collected data of the individual towers, the correction value generating means comprising: Numerical input means for inputting each ground resistance value and transient ground resistance value of each individual tower; By applying Ohm's law that defines the relationship between the resistance value and the current value with respect to the numerical value inputted by the numerical input means, correction is made according to each ground resistance value in case of a ground fault, and each transient grounding in the case of a lightning strike. Including correction means for correcting according to the resistance value, Lightning point and failure point detection system of the overhead transmission line, characterized in that the comparison between the generated correction values through a computer program.

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