JP2010273515A - Digital protective relay - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital protective relay, which even in a power failure caused by an artificial operation other than an ordinary breakdown, allows a person to make a distinction and determination, for determining whether the power failure is a result of failure with an action display or failure to reset the action display or a normal outcome due to a normal breakdown, etc. <P>SOLUTION: The digital protective relay includes a calculation circuit 16, which converts an input analog electric quantity into a digital signal and executes various calculating processes using the digital signal; an output circuit 13, which generates and outputs an action signal for putting a switch in action based on a determination result given by the calculating circuit 16; a nonvolatile memory 17 which records an action made by the output circuit 13; and a first action display 26 and a second action display 27, which display an action made by the output circuit 13. The first action display 26 displays action that is made by the output circuit 13 under operation, and the second action display 27 displays action record recorded by the nonvolatile memory 17 at the start of the operation. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a digital protective relay that performs various arithmetic processes after converting an input analog electric quantity (system electric quantity) into a digital signal.

  The digital protective relay detects an accident in the power system and a failure of the protected device in the power system (hereinafter collectively referred to as “failure etc.”) and shuts off the switch provided in the circuit breaker, It is a device that protects protected devices by opening and localizing sections such as breakdowns.

  In this type of digital protection relay, the configuration and function of a typical display unit is described in, for example, the prior art section of Patent Document 1 below. Therefore, the configuration and function of a typical display unit will be described below using the digital protection relay disclosed in Patent Document 1 as an example.

  The digital protective relay shown in Patent Document 1 (hereinafter referred to as “conventional protective relay”) has a relay circuit housed in the main body case, and a cover is attached to the front operation panel from the viewpoint of erroneous operation and dust-proof structure. It has been.

  The operation panel on the front side is provided with a display signal such as a measurement value and a display unit such as a 7-segment LED for displaying an abnormality, and a changeover switch. This change-over switch is provided for switching and displaying a specific signal to be displayed, for example, a real-time measurement value of current and voltage and its maximum value. However, since the number of selection of the changeover switch is limited, there is a limit to the number of items of signal information to be specified for display selection.

  In particular, protective relays for consumers are often single-element type for low cost and compactness, and the switching method is often used for measurement display etc., so the number of display items is limited. In many cases, the display items also have a minimum necessary configuration to display only when they are operated.

  That is, the conventional protective relay does not provide a display for each display signal for a plurality of specific signal information to be displayed, but provides a display changeover switch and designates a specific display signal as desired. The display contents can be displayed. The switching operation of the display changeover switch is performed manually with the front cover removed.

  In addition, when a conventional protective relay detects a fault in the power system, it outputs a cut-off signal to a switch such as a circuit breaker to open and localize the section of the fault, etc. The phase information to be displayed is displayed on the operation display. At this time, the maintenance / operator confirms the operation state by the operation indicator of the protective relay when a failure or the like occurs or during maintenance / inspection.

  In addition, among conventional protective relays, for example, if a voltage element protective relay, when configuring a control power supply circuit that operates an arithmetic processing unit, an output circuit, etc., an instrument transformer for introducing a voltage for fault detection ( Some of them share the (VT) and use the output of the VT to generate an internal power supply.

  In the case of a digital protective relay for consumers, a voltage that detects a failure or the like and a power source that generates a control power supply circuit from the same VT can be used other than an operation due to a failure or the like, for example, if it is an insufficient voltage element During maintenance / inspection, breakers and other switches may be opened by human operation, resulting in a power failure. In this case, the digital protective relay detects an undervoltage after the switch is opened, and outputs an interruption signal to operate the operation indicator.

Japanese Patent Laid-Open No. 10-341523

  However, in the above-described conventional digital protective relay, if a power failure occurs due to an artificial operation other than a failure, etc., the digital protective relay is erroneously set despite the fact that the digital protective relay has not failed. It was judged that there was a failure, and unnecessary cause investigation and soundness confirmation tests were sometimes required.

  This event will be explained in detail. First, the digital protective relay is operated by opening the breaker and other switches by human operation, etc., but forgetting to return the switch and leaving it alone. Is assumed. In this case, when the switch is turned on again and the main circuit is restored, the digital protection relay is restarted and the operation is resumed, but the operation indicator remains in the operating state. Next, consider the case where the maintenance / operator inspected the power distribution facilities during the subsequent operation (when no failure occurred). In this case, the maintenance / operator recognizes the erroneous display on the operation indicator because the display on the operation indicator is in an operating state even though the digital protection relay is restarted.

  Therefore, in the conventional digital type protective relay, it cannot be determined whether the operation indicator of the digital type protective relay has failed, whether the operation indicator has been forgotten to be restored, or whether a malfunction has occurred. In some cases, there is a problem that unnecessary cause investigation and soundness confirmation test may be required.

  The present invention has been made to solve the above-described problem, and even if a power failure caused by an artificial operation other than a failure or the like is caused, whether the operation indicator has failed or the operation indicator It is an object of the present invention to provide a digital protective relay that makes it possible to distinguish and judge whether the device has forgotten to be restored or whether it is a normal operation due to a failure or the like.

  In order to solve the above-described problems and achieve the object, the digital protection relay according to the present invention converts an input analog electric quantity into a digital signal, and performs various arithmetic processes using the digital signal. A circuit, an output circuit that generates and outputs an operation signal for operating the switch based on a determination result of the arithmetic circuit, a non-volatile memory that records the operation of the output circuit, and the output circuit operates An operation indicator for displaying the operation, the operation indicator including a first operation indicator for displaying an operation during operation of the output circuit, and an operation record recorded in the nonvolatile memory at the start of operation. And a second operation indicator for displaying the above.

  According to the digital type protective relay according to the present invention, even if a power failure caused by an artificial operation other than a failure or the like is caused, the operation indicator may be forgotten to be restored due to the power failure or the operation due to the failure or the like. There is an effect that it is possible to distinguish and judge whether there is any.

FIG. 1 is a block diagram showing a schematic configuration of a digital protection relay according to an embodiment of the present invention. FIG. 2 is an external perspective view showing an example of a display unit in the digital protection relay according to the present embodiment. FIG. 3 is a flowchart showing the processing of the operation indicator in the protective relay of the present embodiment.

  Hereinafter, a digital protection relay according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below.

<Embodiment>
FIG. 1 is a block diagram showing a schematic configuration of a digital protection relay according to an embodiment of the present invention. As shown in FIG. 1, the digital protection relay in the present embodiment includes an input circuit 11, an arithmetic processing unit 12, an output circuit 13, a control power circuit 14, a relay (Ry) 15, a first operation indicator 26, and The second operation indicator 27 is provided. The arithmetic processing unit 12 includes an arithmetic circuit 16 and a nonvolatile memory 17. Note that the first operation indicator 26 and the second operation indicator 27 are in a normal operation due to the above-described problem of the present application, that is, whether the operation indicator has failed, whether the operation indicator has been forgotten to be restored, or has failed. It is a display that makes it possible to distinguish and judge whether there is any.

  The digital protection relay according to the present embodiment is a type of protection relay that uses a system voltage introduced as a monitoring target as a power source, and the control power generated by the control power circuit 14 includes the arithmetic processing unit 12, The output circuit 13, the relay 15, the first operation indicator 26 and the second operation indicator 27 are supplied.

  In FIG. 1, an input circuit 11 converts an analog signal (system electrical quantity) such as current and voltage in a power system input from a transformer (not shown) into a digital signal. The arithmetic circuit 16 performs various arithmetic processes using the digital signal from the input circuit 11, detects a failure of a protected device (not shown) in the power system, and operates a circuit breaker (not shown). The determination (operation determination) is performed. The output circuit 13 outputs an operation signal for operating the switch provided in the circuit breaker or the like to the relay 15 based on the operation determination result of the arithmetic circuit 16, and also includes the first operation indicator 26 and the second operation indicator 26. A display signal to the operation indicator 27 is generated and output.

  Further, when the operation circuit 16 outputs an operation signal to the relay 15, the operation circuit 16 records the operation record in the nonvolatile memory 17. By storing the operation record in the nonvolatile memory 17, the operation record is stored even when the power supply function by the control power supply circuit 14 is lost. With this function, when the power supply function by the control power supply circuit 14 is restored, the operation record recorded in the nonvolatile memory 17 can be confirmed.

  Specifically, when the power supply function by the control power supply circuit 14 is restored, the operation record of the nonvolatile memory 17 is read, and when there is an operation record, the second operation is performed instead of the first operation indicator 26. Display on the display 27. By this processing, it can be distinguished that the display is an operation display before the power supply function by the control power supply circuit 14 is lost.

  FIG. 2 is a perspective view showing the appearance of the display unit in the digital protective relay of the present embodiment. 2, the operation panel unit 20 on the front of the display unit includes a numerical display unit 21, a forced operation switch 22, a display changeover switch 23, an operation value set switch 24, an operation time set switch 25, and also shown in FIG. A first operation indicator 26 and a second operation indicator 27 are provided. The return switch 28 is an operation switch for returning the display of the first operation indicator 26 and the second operation indicator 27 collectively or arbitrarily.

  FIG. 3 is a flowchart showing the processing of the operation indicator in the protective relay of the present embodiment. In this processing flow, the operation indicator A corresponds to the first operation indicator 26, and the operation indicator B corresponds to the second operation indicator 27.

  First, in step SS31, it is determined whether the operating state of the digital protection relay (hereinafter simply referred to as “relay”) is “starting operation” or “in operation”. When the relay is “in operation”, a normal processing flow for detecting a failure of the protected device runs. That is, when a failure or the like is detected, the relay operates (step S36), outputs a circuit breaker signal for operating the circuit breaker and the like, and indicates that the circuit breaker or the like has been operated (hereinafter referred to as “normal operation display”). Is displayed on the operation display A (step S37). Further, after the display on the operation indicator A, the fact that the digital type protective relay has normally operated is recorded in the nonvolatile memory 17 (step S38).

  That is, the operation indicator A is an indicator that operates when the digital protection relay normally operates. The maintenance / operator checks the display of the operation indicator A so that the digital protection relay operates normally. It is possible to determine whether or not.

  In step S39, it is determined whether or not a return operation using a display return switch (see FIG. 2) has been performed. Here, when a return operation is performed, after the return of the motion indicator A and the motion indicator B is arbitrarily or collectively processed (step S40), the motion record recorded in the nonvolatile memory is reset (erased). (Step S41).

  On the other hand, if the return operation is not performed in step S39, the display process is terminated. At this time, the display of the operation indicator A and the operation record recorded in the nonvolatile memory 17 maintain the state until the return operation is performed.

  Returning to step S31, when the relay is "starting operation" (for example, it means that the control power supply is restored from a power-off state due to a power failure or the like), the digital protection relay is started up. When a failure of the protected device is detected immediately after the start of operation, the presence / absence of a failure is determined from the viewpoint of performing the operation determination with priority (step S32).

  Here, when the determination result in step S32 is “None”, the process proceeds to step S34 for determining whether or not there is an operation record reading process because no failure or the like has been detected in a transition period such as power recovery and start of relay operation. On the other hand, if the determination result in step S32 is “Yes”, it is determined whether or not the relay has actually been operated since a failure or the like has been detected during a transition period such as power recovery and start of relay operation (step S33). ).

  Next, when it is determined in step S33 that the relay is “operation”, the process proceeds to step S37 to perform display processing of the operation indicator A, and thereafter, the processing after step S38 described above is executed. On the other hand, when the determination result in step S33 is “return”, it is considered that the abnormality of the protected device is temporary, so that the operation record reading process is performed as in the case where the determination result in step S32 is “none”. The process proceeds to step S34 for determining whether or not there is any.

  In step S34, the presence / absence of the operation record is read from the non-volatile memory. However, if the operation record is “present”, it means that the digital protective relay operates before stopping and the return operation is not performed. A display process of the operation indicator B different from the operation indicator A that displays the normal operation is performed (step S35). If the read result is “none”, it means that there is no record to be displayed, and the display process is terminated.

  In the determination process of step S33, the process of step S37 is performed when the relay determines “operation” in order to prevent confusion due to the operation / display confirmation of the maintenance / operator. If the relay is determined to be “operation” in step S33, it means that the relay has been operated due to a new failure or the like. Therefore, even if the operation record is recorded in the non-volatile memory, the operation record reading process is performed. The maintenance / operator does not make a mistake by performing the display process of the normal operation without performing the process.

  In FIG. 2, the operation panel unit 20 is provided with a forcible operation switch 22 that is operated during a test or the like. However, when the forcible operation switch 22 is operated, the relay also “operates”. . For this reason, the operation recording to the non-volatile memory by operating the forced operation switch 22 is not performed.

  As described above, according to the protective relay of the present embodiment, the display that indicates that the output circuit has been operated is divided into the first operation indicator and the second operation indicator, and the first The operation indicator displays the operation during operation of the output circuit, and the second operation indicator displays the operation record recorded in the nonvolatile memory at the start of operation. It is possible to determine whether the type protective relay has been operated before or after stopping. As a result, even when a power failure caused by an artificial operation other than a failure occurs, it is possible to distinguish and judge whether the operation indicator has been forgotten to be restored due to a power failure or whether the operation is due to a failure. Thus, it is possible to save the trouble of performing unnecessary cause investigation and soundness confirmation test.

  In this embodiment, a digital type protective relay using a system voltage introduced as a monitoring target as a power source has been described as an example. However, the present invention is not limited to this type of digital protective relay. For example, the present invention can be applied to a digital protective relay that operates by detecting an undervoltage and records the operation in a nonvolatile memory.

DESCRIPTION OF SYMBOLS 11 Input circuit 12 Arithmetic processing part 13 Output circuit 14 Control power supply circuit 15 Relay 16 Arithmetic circuit 17 Non-volatile memory 20 Operation panel part 21 Numerical display part 22 Forced operation switch 23 Display change switch 24 Operation value set switch 25 Operation time set switch 26 First operation indicator 27 Second operation indicator 28 Return switch

Claims (3)

An arithmetic circuit that converts an input analog electric quantity into a digital signal and executes various arithmetic processes using the digital signal;
An output circuit for generating and outputting an operation signal for operating the switch based on the determination result of the arithmetic circuit;
A non-volatile memory that records that the output circuit has been operated;
An operation indicator for indicating that the output circuit has been operated;
With
The operation indicator is
A first operation indicator for displaying an operation during operation of the output circuit;
A second operation indicator for displaying an operation record recorded in the nonvolatile memory at the start of operation;
A digital protective relay characterized by comprising:   2. The display according to claim 1, wherein when the output circuit operates at the start of operation and the operation of the output circuit does not return, the display of the operation is performed using the first operation indicator. Digital type protective relay.   3. The digital protective relay according to claim 1, wherein the operation record of the non-volatile memory is erased in response to a return operation for returning the display of the first and second operation indicators.

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