Patent Publication Number: US-2011077866-A1

Title: Distance relay using real time lightning data

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of Korean Patent Application No. 10-2009-0092383, filed with the Korean Intellectual Property Office on Sep. 29, 2009, the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present invention relates to a distance relay apparatus, more specifically to a distance relay apparatus, a distance relay processing system and a method for processing a distance relay using lightning data. 
     2. Description of the Related Art 
     Recently, there has been an increased demand for power consumption due to the rapid growth of the industrial economy. During the peak summer season, the power consumption nearly approaches the maximum supply capacity of all available power plants, and thus cooperation by the citizens is sought on a national level. Due to the dramatic increase in electrical energy consumption caused by not only the densely populated cities but also the trends toward bigger size in various small-scale industries, large buildings and apartment complexes and the like, large capacity power transmission lines are supplied to the central part of a city. 
     This has increased the construction of underground power transmission lines and mixed power transmission lines, in which underground power lines and over-the-ground power lines are combined. In case an accident such as ground fault or lightning occurs in such power transmission lines, a relay apparatus, which blocks a fault zone, may be used. 
     As digital relay apparatuses using microprocessors are practically used to protect the power transmission lines with the increasingly larger and complicated power systems, today&#39;s relay apparatuses realize various and complicated technologies that could not be achieved by conventional analog protection relay apparatuses. 
     Among various transmission line protection apparatuses, a distance relay apparatus is most commonly used to control an electrical circuit by operating and opening or closing a contact according to the predetermined amount of electrical or physical quantity. That is, if a short circuit or ground fault occurs somewhere in the power transmission line or if an abnormal operation that has an adverse effect resulting in broken insulation occurs, the distance relay apparatus may quickly block the fault portion. 
     However, due to a location error, the conventional distance relay apparatus may not be able to accurately determine a fault location even though it is required to quickly determine and repair the fault location when the fault occurs by lightning. 
     SUMMARY 
     The present invention provides a distance relay apparatus, a distance relay processing system and a method for processing a distance relay that can determine a fault location in power transmission line by using lightning data. 
     The present invention also provides a distance relay apparatus, a distance relay processing system and a method for processing a distance relay that can quickly determine a fault location in power transmission line accurately. 
     Also, the present invention provides a distance relay apparatus, a distance relay processing system and a method for processing a distance relay that can minimize an error in finding a fault location in power transmission line. 
     An aspect of the present invention features a distance relay processing system that controls a distance relay. 
     In accordance with an embodiment of the present invention, a distance relay processing system, which controls a distance relay, can include a lightning managing apparatus, which generates comprehensive lightning information by using lightning detection information and in which the lightning detection information is provided by a lightning detector, and a distance relay apparatus, which generates fault occurrence information by determining a fault location in a power transmission line and generates fault analysis information by using the fault occurrence information and the comprehensive lightning information. 
     The distance relay apparatus can generate an error value by comparing the fault occurrence information and the comprehensive lightning information and generate the fault analysis information by removing the error value from the fault occurrence information. 
     The distance relay apparatus can generate the fault occurrence information by analyzing a distance value provided from at least one of a plurality of relays that has determined the fault location in the power transmission line. 
     The comprehensive lightning information can include at least one of lightning time information, lightning location information and lightning current magnitude information. 
     The fault occurrence information can include at least one of transmission fault time information and transmission fault location information. 
     The lightning managing apparatus can generate the comprehensive lightning information by analyzing the lightning detection information provided by at least one of a plurality of lightning detectors that has detected lightning. 
     The lightning managing apparatus can transfer the comprehensive lightning information to the distance relay apparatus in each transmission time, which is a period of time for transferring the comprehensive lightning information to the distance relay apparatus and set by the lightning managing apparatus. 
     Another aspect of the present invention features a distance relay apparatus connected to a lightning managing apparatus. 
     In accordance with an embodiment of the present invention, a distance relay apparatus connected to a lightning managing apparatus can include a relay, which determines a fault location in a power transmission line, a generating unit, which generates fault occurrence information by using a result that is determined by the relay, and a parser, which generates fault analysis information by using comprehensive lightning information and the fault occurrence information. Here, the comprehensive lightning information is received from the lightning managing apparatus. 
     The parser can generate an error value by comparing the fault occurrence information and the comprehensive lightning information and generate the fault analysis information by removing the error value from the fault occurrence information. 
     The generating unit can generate the fault occurrence information by analyzing a distance value provided by at least one of a plurality of relays that has determined the fault location in the power transmission line. 
     The distance relay apparatus can also include a display, which displays the fault analysis information. 
     The comprehensive lightning information can include at least one of lightning time information, lightning location information and lightning current magnitude information, and the fault occurrence information can include at least one of transmission fault time information and transmission fault location information. 
     Another aspect of the present invention features a distance relay processing method for controlling a distance relay in a distance relay processing system. 
     In accordance with an embodiment of the present invention, a distance relay processing method for controlling a distance relay in a distance relay processing system can include generating fault occurrence information by determining a fault location in a power transmission line, generating comprehensive lightning information by using lightning detection information provided by a lightning detector, and generating fault analysis information by using the fault occurrence information and the comprehensive lightning information. 
     In the generating of the fault analysis information, an error value can be generated by comparing the fault occurrence information with the comprehensive lightning information, and the fault analysis information can be generated by removing the error value from the fault occurrence information. 
     The generating of the fault occurrence information can include receiving a distance value from at least one of a plurality of relays and generating the fault occurrence information by analyzing the distance value. Here, at least one of the relays determines a fault location in the power transmission line. 
     In the generating of the comprehensive lightning information, the comprehensive lightning information can be generated by analyzing the lightning detection information provided by at least one of a plurality of lightning detectors that has detected lightning. 
     The comprehensive lightning information can include at least one of lightning time information, lightning location information and lightning current magnitude information. 
     The fault occurrence information can include at least one of transmission fault time information and transmission fault location information. 
     Additional aspects and advantages of the present invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram briefly illustrating a distance relay processing system in accordance with an embodiment of the present invention. 
         FIG. 2  is a block diagram illustrating a lightning managing apparatus of a distance relay processing system in accordance with an embodiment of the present invention. 
         FIG. 3  is a block diagram illustrating a distance relay apparatus of a distance relay processing system in accordance with an embodiment of the present invention. 
         FIG. 4  is a flowchart briefly illustrating a method for processing a distance relay in accordance with an embodiment of the present invention. 
         FIG. 5  is a flowchart illustrating, in detail, a method for processing a distance relay in accordance with an embodiment of the present invention. 
         FIG. 6  is an example illustrating a lightning detector and a relay in a distance relay processing system in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     As the invention allows for various changes and numerous embodiments, certain embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to particular modes of practice, and it is to be appreciated that all changes, equivalents, and substitutes that do not depart from the ideas and technical scope of the present invention are encompassed in the present invention. In the description of the present invention, certain detailed descriptions of related art are omitted when it is deemed that they may unnecessarily obscure the essence of the invention. 
     While such terms as “first” and “second,” etc., may be used to describe various components, such components may not be limited to the above terms. The above terms are used only to distinguish one component from another. 
     The terms used in the present specification are merely used to describe particular embodiments, and are not intended to limit the present invention. An expression used in the singular encompasses the expression of the plural, unless it has a clearly different meaning in the context. In the present specification, it is to be understood that the terms such as “including” or “having,” etc. are intended to indicate the existence of the features, numbers, steps, operations, components, parts, or combinations thereof disclosed in the specification, and are not intended to preclude the possibility that one or more other features, numbers, steps, operations, components, parts, or combinations thereof may exist or may be added. 
     A distance relay apparatus, a distance relay processing system and a method for processing distance relay according to certain embodiments of the present invention will be described below in more detail with reference to the accompanying drawings. Those components that are the same or are in correspondence are rendered the same reference numeral regardless of the figure number, and redundant descriptions are omitted. 
       FIG. 1  is a block diagram briefly illustrating a distance relay processing system in accordance with an embodiment of the present invention. 
     Referring to  FIG. 1 , if a power transmission line has a fault due to lightning, a distance relay processing system  100  detects the fault and block the section with the fault. For this, the distance relay processing system  100  includes a lightning managing apparatus  200  and a distance relay apparatus  300 . 
     The lightning managing apparatus  200  is connected to the distance relay apparatus  300  and detects a location that is struck by lightning as it occurs. Also, the lightning managing apparatus  200  generates comprehensive lightning information by using the detected information. Then, the lightning managing apparatus  200  transmits the generated lightning integrated information to the distance relay apparatus  300 . Here, the lightning managing apparatus  200  can transmit the lightning integrated information to the distance relay apparatus  300  by at least one of a wireless communication method and a wire communication method. The lightning managing apparatus  200  will be described in more detail with reference to  FIG. 2 . 
     The distance relay apparatus  300  is connected to the lightning managing apparatus  200  and determines a fault location if fault occurs in the power transmission line. The distance relay apparatus  300  generates fault occurrence information by using the determined fault location. The distance relay apparatus  300  generates fault analysis information by using the comprehensive lightning information received from the lightning managing apparatus  200  and the fault occurrence information. The distance relay apparatus  300  will be described in more detail with reference to  FIG. 3 . 
       FIG. 2  is a block diagram illustrating a lightning managing apparatus of a distance relay processing system in accordance with an embodiment of the present invention. 
     Referring to  FIG. 2 , the lightning managing apparatus  200  includes first to fourth lightning detectors  213 ,  215 ,  217  and  219 , a processor  220 , a lightning detection storage  230  and a transmission unit  240 . 
     Each of the first to fourth lightning detectors  213 ,  215 ,  217  and  219  is located in a different place and detects lightning when it occurs. Hereinafter, the first to fourth lightning detectors  213 ,  215 ,  217  and  219  will be referred to as a lightning detector  210 . The lightning detector  210  generates lightning detection information by detecting lightning when the lightning occurs in the detection zone. Then, the lightning detector  210  provides the generated lightning detection information to the processor  220 . Here, the lightning detector  210  can provide the lightning detection information to the processor  220  by using a wireless communication method. 
     In  FIG. 2 , there are a total of 4 lightning detectors  210 . It shall be apparent, however, that the present invention is not restricted to the total of 4 lightning detectors and can be implemented regardless of the number of the lightning detectors  210  as long as lightning can be detected. 
     The processor  220  is provided with the lightning detection information, which is provided from at least one of the lightning detectors  210 , each of which detects lightning. The processor  220  generates comprehensive lightning information by analyzing and calculating the provided lightning detection information. Here, the comprehensive lightning information includes information about when lightning has struck, information about where lightning has struck and information about the magnitude of current in the lightning. The processor  220  controls the transmission unit  240  in such a way that the comprehensive lightning information is transferred to the distance relay apparatus  300 . 
     Meanwhile, the processor  220  can set a transmission time for transferring information to the distance relay apparatus  300 . The processor  220  can transfer the comprehensive lightning information to the distance relay apparatus  300  in each transmission time by controlling the transmission unit  240 . 
     If lightning does not strike, the processor  220  can also generate lightning confirmation information regarding whether lightning has struck and transfer this information to the distance relay apparatus  300  through the transmission unit  240  in each transmission time. 
     The lightning detection storage  230  stores data that is required when detecting lightning or data that is generated by detecting the lightning. That is, the lightning detection storage  230  can store the lightning detection information, which is generated by the lightning detectors  210 , and store the comprehensive lightning information, which is generated by the processor  220 . Also, the lightning detection storage  230  can provide information that is required by the processor  220  and the transmission unit  240 . 
     The transmission unit  240  is connected to a receiver  330  of the distance relay apparatus  300 . The transmission unit  240  transfers the comprehensive lightning information, which is generated by the processor  220 , to the receiver  330 . Here, the transmission unit  240  can transfer the comprehensive lightning information to the receiver  330  either through a wireless communication method by being connected to the receiver  330  wirelessly or through a wire communication method by being connected to the receiver  330  with a wired connection. Meanwhile, the transmission unit  240  can transfer the lightning confirmation information to the receiver  330  of the distance relay apparatus  300 . 
       FIG. 3  is a block diagram illustrating a distance relay apparatus of a distance relay processing system in accordance with an embodiment of the present invention. 
     Referring to  FIG. 3 , the distance relay apparatus  300  includes first to fourth relays  313 ,  315 ,  317  and  319 , a generating unit  320 , a receiver  330 , a parser  340 , a display  350  and a distance relay storage  360 . 
     The first to fourth relays  313 ,  315 ,  317  and  319  determine whether a power transmission line that is connected to each of the first to fourth relays has a fault. Hereinafter, the first to fourth relays  313 ,  315 ,  317  and  319  will be referred to as a relay  310 . The relay  310  generates a distance value by determining a fault location when the fault occurs in the power transmission line due to lightning. Then, the relay  310  provides the distance value to the generating unit  320 . The relay  310  can provide the distance value to the generating unit  320  by a wireless communication method. 
     In  FIG. 3 , there are a total of 4 relays  310 . It shall be apparent, however, that the present invention is not restricted to the total of 4 relays and can be implemented regardless of the number of the relays  310  as long as the fault in the power transmission line can be determined. 
     The generating unit  320  is provided with a distance value, which is provided from each of a plurality of relays  310  that has detected a fault in the power transmission line. The generating unit  320  analyzes and calculates the distance value and generates fault occurrence information. Here, the fault occurrence information includes time information on the fault in the power transmission line and location information on the fault in the power transmission line. 
     The receiver  330  is connected to the transmission unit  240  of the lightning managing apparatus  200  and receives the comprehensive lightning information. Here, the receiver  330  can receive the comprehensive lightning information from the transmission unit  240  either through a wire communication method by being connected to the transmission unit  240  with a wired connection or through a wireless communication method by being connected to the transmission unit  240  wirelessly. Meanwhile, the receiver  330  can receive the lightning confirmation information from the transmission unit  240 . 
     The parser  340  generates fault analysis information by using the fault occurrence information and the comprehensive lightning information. That is, the parser  340  generates an error value by comparing the fault occurrence information with the comprehensive lightning information. The parser  340  generates the fault analysis information by removing the error value from the fault occurrence information. As such, since the fault occurrence information is generated by using the comprehensive lightning information, this can determine a more accurate location than a conventional method of determining a fault location in a power transmission line. 
     Once the fault occurrence information, which is generated using the distance value provided from the relay  310 , is provided from the generating unit  320  and the lightning confirmation information is provided from the receiver  330 , the parser  340  can generate the fault analysis information by using the fault occurrence information only, without using the comprehensive lightning information, since no fault has occurred in the power transmission line by lightning. 
     The display  350  displays the fault analysis information including information about when and where a fault occurred by lightning in the power transmission line. Here, a user can check when and where the fault occurred by viewing the display  350  and deal with the fault occurred in the power transmission line by using this. 
     The distance relay storage  360  stores data that is required for a distance relay and data that is generated for the distance relay. That is, the distance relay storage  360  can store the distance value, which is determined by the relay  310 , and store the fault occurrence information, which is generated by the generating unit  320 . The distance relay storage  360  can store the comprehensive lightning information, which is received from the receiver  330 , and the error value and the fault analysis information, which are generated by the parser  340 . Moreover, the distance relay storage  360  provides data that is needed according to the requests by the generating unit  320 , the parser  340  and the display  350 . 
     A method for processing a distance relay according to an embodiment of the present invention will be briefly described with reference to  FIG. 4 , which is a flowchart briefly illustrating a method for processing a distance relay in accordance with an embodiment of the present invention. 
     Referring to  FIG. 4 , a fault occurs in a power transmission line by lightning (S 410 ). 
     Once the fault occurs in the power transmission line, the distance relay processing system  100  determines a fault location in the power transmission line (S 430 ). That is, the distance relay apparatus  300  of the distance relay processing system  100  determines the fault location in the power transmission line by using the relay  310  and generates fault occurrence information. 
     If lightning strikes, the distance relay processing system  100  detects the lightning (S 450 ). In other words, the lightning managing apparatus  200  in the distance relay processing system  100  detects the lightning by using the lightning detector  210  and generates comprehensive lightning information. Then, the lightning managing apparatus  200  transfers the comprehensive lightning information to the distance relay apparatus  300 . 
     The distance relay processing system  100  generates fault analysis information by using the fault occurrence information and the comprehensive lightning information (S 470 ). That is, the distance relay apparatus  300  of the distance relay processing system  100  generates the fault analysis information by using the fault occurrence information, which determines a fault location in the power transmission line, and the comprehensive lightning information, which is received from the lightning managing apparatus  200 . 
     The method for processing a distance relay according to an embodiment of the present invention will be described in more detail with reference to  FIG. 5 , which is a flowchart illustrating, in detail, the method for processing a distance relay in accordance with an embodiment of the present invention. 
     Referring to  FIG. 5 , the distance relay apparatus  300  in the distance relay processing system  100  determines a fault location in the power transmission line (S 511 ). In a more detailed example, among the first to fourth relays  313 ,  315 ,  317  and  319 , which are included in the distance relay apparatus  300 , at least one relay  310  that is connected to a power transmission line where a fault occurred generates a distance value by determining the fault location in the power transmission line. 
     The distance relay apparatus  300  of the distance relay processing system  100  generates fault occurrence information by using the determined fault location (S 513 ). That is, the generating unit  320  of the distance relay apparatus  300  generates the fault occurrence information by analyzing and calculating the distance value provided from the relays  310 . Here, the fault occurrence information includes transmission fault time information and transmission fault location information. The transmission fault time information is time information about when a fault occurred in the power transmission line, and the transmission fault location information is location information about where the fault occurred in the power transmission line. 
     The lightning managing apparatus  200  in the distance relay processing system  100  generates lightning detection information by detecting lightning (S 515  and S 517 ). Among the first to fourth lightning detectors  213 ,  215 ,  217  and  219 , which are included in the lightning managing apparatus  200 , at least one lightning detector  210  that has detected lightning generates the lightning detection information. The lightning detector  210  transfers the generated lightning detection information to the processor  220  of the lightning managing apparatus  200 . 
     The lightning managing apparatus  200  in the distance relay processing system  100  generates comprehensive lightning information by using the lightning detection information (S 519 ). In other words, the processor  220  of the lightning managing apparatus  200  generates the comprehensive lightning information by analyzing and calculating the lightning detection information provided from at least one of the lightning detector  210 . In one example, the processor  220  determines when the lightning occurred by using a distance between a plurality of lightning detector  210  and the distance relay processing system  100  and time in which a plurality of lightning detection information are received and also determines where the lightning occurred by using location information included in the plurality of lightning detection information so that the processor  220  can generate the comprehensive lightning information. Here, the comprehensive lightning information includes information about when lightning has occurred, information about where lightning has occurred and information about the magnitude of current in the lightning. 
     The lightning managing apparatus  200  in the distance relay processing system  100  transfers the comprehensive lightning information (S 521 ). That is, the transmission unit  240  of the lightning managing apparatus  200  transfers the comprehensive lightning information, which is generated by the processor  220 , to the receiver  330  of the distance relay apparatus  300 . Here, the receiver  330  of the distance relay apparatus  300  receives the comprehensive lightning information from the transmission unit  240  of the lightning managing apparatus  200 . 
     The distance relay apparatus  300  of the distance relay processing system  100  compares the fault occurrence information with the comprehensive lightning information (S 523 ). The parser  340  of the distance relay apparatus  300  generates an error value by comparing the fault occurrence information, which is generated by the generating unit  320 , with the comprehensive lightning information, which is provided from the receiver  330 . The reason why the fault occurrence information is compared with the comprehensive lightning information is that a fault location in the power transmission line where a fault has occurred has to be determined accurately because an error may occur in the fault occurrence information, which is determined by the relay  310 , due to an interaction between its self-circuit and another circuit when the fault occurs in the power transmission line. 
     The distance relay apparatus  300  of the distance relay processing system  100  generates fault analysis information (S 525 ). The parser  340  of the distance relay apparatus  300  generates the fault analysis information by removing the error value from the fault occurrence information. Here, the fault analysis information includes lightning transmission fault location information and lightning transmission fault time information representing where and when a fault has occurred due to lightning in the power transmission line. 
     Then, the display  350  of the distance relay processing system  100  displays the fault analysis information, which represents where and when the fault has occurred in the power transmission line. 
     The method for processing a distance relay according to an embodiment of the present invention will be described by referring to an example shown in  FIG. 6 , which illustrates the example of a lightning detector and a relay in a distance relay processing system in accordance with an embodiment of the present invention. 
     In the following description, it shall be assumed that a fault occurs at a reference numeral  350  in a power transmission line  400  as lightning strikes, as shown in  FIG. 6 . Since the lightning has struck, the first and second lightning detectors  213  and  215  detect the lightning and generate first and second lightning detection information l 1  and l 2 , respectively. The first and second lightning detectors  213  and  215  provide the first and second lightning detection information l 1  and l 2 , respectively, to the processor  220  of the lightning managing apparatus  200 . The processor  220  generates comprehensive lightning information by determining the location  350 , which is struck by the lightning, the time when it occurred and the magnitude of the lightning by use of the first and second lightning detection information l 1  and l 2 . Here, since the comprehensive lightning information is generated by the first and second lightning detectors  213  and  215 , each of which detects the lightning, the location  350  at which the lightning has struck can be accurately determined. 
     Since a fault occurred in the power transmission line  400 , first and second relays  313  and  315  generate first and second distance values d 1  and d 2  by determining a location  370  at which the fault occurred. The first relay  313  generates the first distance value d 1  because it determines that the magnitude of impedance determined by the interaction between its self-circuit and another circuit is smaller than that of impedance to the fault location. The second relay  315  generates the second distance value d 2  because it determines that the magnitude of impedance determined by the interaction between the self-circuit and another circuit is greater than that of the impedance to the fault location. 
     The generating unit  320  generates fault occurrence information  370  by using the first and second distance values d 1  and d 2 , which are provided from the first and second relays  313  and  315 . The generated fault occurrence information  370  includes location information, instead of the actual fault location where the fault occurred, which is incorrectly determined due to the interaction between the self-circuit and another circuit. 
     Then, the parser  340  generates an error value e by comparing the comprehensive lightning information and the fault occurrence information  370 . Then, the parser  340  generates fault analysis information including the actual fault location  350  where the fault occurred, by removing the error value e from the fault occurrence information  370 . 
     Therefore, the distance relay processing system  100  according to an embodiment of the present invention can quickly determine the fault location in the power transmission line accurately by using the comprehensive lightning information provided from the lightning managing apparatus  200 . 
     The method for processing a distance relay according to an embodiment of the present invention can be tangibly implemented in a computer-readable medium that stores a program of instructions executable by a computer, etc. The computer-readable medium can include each of program instructions, data files and data structures, or a combination of the ones above. 
     The program of instructions that are written in the computer-readable medium can be specially designed and configured for the present invention, or can be those available, which are generally understood by those of ordinary skill in the field of computer software. The computer-readable medium can be, for example, a hard disk, floppy disk, magnetic media such as magnetic tape, CD-ROM, optical media such as DVD, magneto-optical media such as a floptical disk and hardware device such as a ROM, RAM and flash memory, which are configured to store and perform the program of instructions. In addition to the above, the computer-readable medium can be a program of instructions and a ray of light including a carrier wave that sends a signal specifying the data structure, or can be a transmission medium such as a metal line and waveguide. Examples of the program of instructions can include a machine code, such as those created by a compiler, as well as a high-level language code executable by the computer using an interpreter. 
     The hardware device mentioned above can be configured to work as one or more of software modules to perform operations of the present invention. 
     While the ideas of the present invention have been described in detail with reference to particular embodiments, the embodiments are for illustrative purposes only and shall not limit the present invention. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and ideas of the present invention.