JP2011188589A - Portable ground fault protection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a portable ground fault protection device which can surely interrupt a ground fault line within a predetermined time limit even in operation by two lines. <P>SOLUTION: The portable ground fault protection device includes an OVG detection circuit 10 having a ground fault overvoltage relay, a trip output circuit 50 for letting circuit breakers 130, 140 provided on the ground fault line execute breaking operation based on an interruption command by the operation of an existing ground fault overvoltage relay, a trip memory circuit 30 which memorizes the interruption command when either one of the two lines is interrupted, and a hand carriable portable case 2 in which at least the OVG detection circuit 10, the trip memory circuit 30, and the trip output circuit 50 are incorporated. The trip output circuit 50 forms a circuit for letting the circuit breaker on the other line execute the breaking operation based on the operation of the ground fault overvoltage relay of the OVG detection circuit 10, when the ground fault overvoltage relay provided at the distribution line side fails to operate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a ground fault protection device for a distribution line, and more particularly to a portable ground fault protection device capable of ground fault protection during operation with two lines.

  In recent years, inspections of circuit breakers and the like of distribution lines with a voltage of 6 kV at power substations have been carried out from a power failure in units of banks to a power failure in units of feeders, taking into account the particularity of each distribution line device. In other words, the inspection of the circuit breaker, etc. in the distribution line is based on the distribution line extending from the distribution circuit breaker from the bank-level power outage where all customers who supply power from the transformer (bank) are subject to the power outage. It corresponds with the power failure of the feeder unit. Customers who are subject to a power outage are asked to the related departments to supply electricity from the distribution lines of other substations and adjacent transformers (banks) to the substation exit of the distribution lines. In power outage work in units of distribution lines, one to several lines may be interrupted and power may be supplied through the remaining two lines or less. In this case, countermeasures against ground faults during work are required.

  Therefore, as an example of a technique relating to ground fault protection, a device that shuts off the circuit breaker in order when a fine ground fault occurs is known (see, for example, Patent Documents 1 and 2).

JP 50-74149 A JP-A-51-79243

  However, in the case where the power supply in the distribution line is performed by only two lines, if a ground fault occurs, the ground capacitance of the entire bank is reduced, causing the following problems. In other words, when one line is being interrupted due to a ground fault or a short-circuit accident during operation with two lines, or if the remaining one line causes a ground fault, the ground fault direction relay There arises a problem that the (67F relay) does not operate.

FIG. 8 shows a distribution line composed of three phases and three lines. The terminal (*) from which the ground fault voltage V ₀ is detected in the ground voltage transformer F in FIG. 8 is connected to the terminals (*) of the ground fault direction relays (67F relays) D1 to D3 provided in each line. ing. The power failure work range S in the distribution line shown in FIG. No. 1 distribution line, for example, No. 1 When a ground fault occurs in the distribution line 3, the ground fault current Ig decreases due to the influence of the ground capacitance of the entire bank, and the ground voltage transformer F and the signals of the zero-phase current transformers Z1 to Z3 The operating ground fault relays (67F relays) D1 to D3 do not operate normally. Here, in order to operate the ground fault direction relays D1 to D3 with certainty, the ground capacitance of the entire bank can be ensured by inserting a busbar breaker at a place where there are two or more banks, or in units of feeders. Switching from a power outage to a bank-by-bank power outage. Since such measures are taken by requesting the relevant departments of the electric power company, a great deal of labor is required.

  In the case of operation with two lines, if the line lengths of both lines are equal, even if a ground fault occurs on either line, a ground fault current can be secured in the first line ground fault. Protection is possible. However, when one line continues to be tripped (shut off) or becomes partly distributed, the ground fault current decreases when a ground fault occurs on the remaining lines. For this reason, the ground fault direction relay does not operate, and the line cannot be disconnected unless waiting for 3 to 9 seconds until the ground fault protective relay is operated. Therefore, in the case of such a ground fault, there is a problem that it does not satisfy the electrical equipment technical standard that is required to disconnect the line within one second from the occurrence of the ground fault.

  When the length of the line is long and short in the operation of two lines, it is possible to secure a sufficient ground fault current for a short line, but a long line cannot ensure a sufficient ground fault current. Similarly, the line cannot be disconnected unless waiting for 3 to 9 seconds until the ground fault retrofit protection relay operates. In addition, when the distribution line is designed with two lines from the beginning, the power station is equipped with a ground fault countermeasure device for the two lines. There is a problem that ground fault protection cannot be performed with this ground fault protection device. Therefore, it is desired to develop a ground fault protection device capable of interrupting a line within a time limit defined in the electrical equipment technical standards from the occurrence of a ground fault even in a power outage work on two lines accompanying an inspection work or the like.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a portable ground fault protection device capable of reliably shutting off a line where a ground fault has occurred within a predetermined time period even when operating with two lines.

  In order to achieve the above object, the invention described in claim 1 is a portable ground fault protection device used for ground fault protection of a distribution line to which power is supplied by only two lines, and is connected to the distribution line side. An OVG detection circuit having a ground fault overvoltage relay that operates with a ground fault voltage that is greater than or equal to a set value, and an existing ground fault overvoltage provided on the distribution line side that is formed based on a ground fault generation signal from the OVG detection circuit A trip output circuit for operating a circuit breaker provided in a circuit in which a ground fault has occurred due to an operation command of the relay, and a circuit for shutting off one of the two circuits is stored. A trip memory circuit; the OVG detection circuit; the trip memory circuit; and a portable portable case in which the trip output circuit is at least incorporated. The output circuit forms a circuit for interrupting the circuit breaker in the other line based on the operation of the ground fault overvoltage relay of the OVG detection circuit when the ground fault direction relay provided on the distribution line side is inoperative. This is a portable ground fault protection device.

  According to the present invention, when one of the two lines supplying power is shut off due to an accident or the like, the cutoff command is stored in the trip memory circuit. When a ground fault occurs in the other line in this state and the ground fault direction relay on the distribution line side becomes inoperative, the trip output circuit for the other line is formed by the operation of the ground fault overvoltage relay of the OVG detection circuit. Is done. The trip output circuit shuts off the circuit breaker provided in the circuit where the ground fault has occurred on the condition of the operation of the existing ground fault overvoltage relay on the distribution line side, so that malfunction is prevented and a ground fault occurs. It is possible to securely disconnect the connected line.

  The invention according to claim 2 is the portable ground fault protection device according to claim 1, wherein the portable case has a non-operating state of the ground fault direction relay due to the length of the line length of the distribution line. The trip memory circuit is locked, and a ground fault direction relay non-operation countermeasure circuit for instructing disconnection of a line in which a ground fault has occurred after a predetermined time period is incorporated.

  According to a third aspect of the present invention, in the portable ground fault protection device according to the first or second aspect, a schematic diagram of the ground fault protection circuit and an operating state of the trip output circuit are displayed on the surface of the portable case. It is characterized in that a display lamp is provided.

  According to the first aspect of the present invention, any one of the two lines is being interrupted due to an accident or the like, or partial power distribution or the like, and the ground fault direction relay on the distribution line side does not operate due to the influence of the ground capacitance. When this happens, it is detected that a ground fault has occurred in the line operated by the ground fault overvoltage relay of the OVG detection circuit, and a trip output circuit is formed after waiting for the operating time limit of the ground fault direction relay. Therefore, even if the ground fault direction relay is inoperative, it is possible to reliably disconnect the grounded line within a predetermined time period.

  In addition, since the operation of the ground fault overvoltage relay and ground fault direction relay on the distribution line side, which is an existing protection circuit, is utilized, it is unnecessary compared to the ground fault protection device that adopts a control method completely independent of the distribution line. Malfunction can be prevented, and the reliability of ground fault protection can be ensured.

  According to the second aspect of the present invention, since the ground fault direction relay non-operation countermeasure circuit is incorporated in the portable case, the distribution line side ground fault direction relay does not operate due to the length of the distribution line. However, the circuit breaker can be operated reliably, and ground fault protection becomes possible.

  According to the invention described in claim 3, since the display lamp for displaying the schematic diagram of the ground fault protection circuit and the operation state of the trip output circuit is provided on the surface of the portable case, the circuit outline and the operation state of the trip output circuit are provided. Can be easily grasped, and erroneous operation can be prevented.

It is a block diagram which shows the outline | summary of the portable ground fault protection apparatus concerning embodiment of this invention. It is a perspective view which shows the external appearance of the case in the portable ground fault protection apparatus of FIG. It is an electric circuit diagram of the portable ground fault protection apparatus of FIG. It is a flowchart which shows the operation | movement procedure of the portable ground fault protection apparatus of FIG. It is a flowchart which shows the operation | movement procedure of the portable ground fault protection apparatus of FIG. 1, Comprising: It is a flowchart following FIG. It is a time chart which shows the interruption | blocking timing by the operation | movement of the ground fault direction relay by the side of the distribution line in the portable ground fault protection apparatus of FIG. 1, and the trip circuit formation timing of a portable ground fault protection apparatus (when an accident generate | occur | produces in A line) Is shown). It is a time chart which shows the interruption | blocking timing at the time of the non-operation of the ground-fault direction relay by the side of the distribution line in the portable ground fault protection apparatus of FIG. 1 (The case where A line operate | moves with a ground-fault direction relay is shown). It is a power distribution system figure which shows the ground fault condition at the time of the electric power supply by two lines in a power failure operation.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  1 to 7 show an embodiment of the present invention. FIG. 2 shows the outer shape of the portable case 2 in the portable ground fault protection device 1. The portable case 2 is composed of a duralumin case that is lightweight and has high strength, and has a size that is about the size of an attache case. The transportable case 2 has a handle 2a for movement, and protective rubber bushes 2b are provided on the lower surface and the back surface. As shown in FIG. 1, an OVG detection circuit 10, a ground fault relay non-operation countermeasure circuit 20, a trip memory circuit 30, and a trip output circuit 50 are incorporated in the portable case 2.

  FIG. 3 shows an electrical wiring diagram of the portable ground fault protection device 1. As shown in FIG. 3, the portable ground fault protection device 1 has a power supply circuit 5. The power supply circuit 5 has terminals 5a1 and 5a2 to which DC 100V is input. The terminals 5a1 and 5a2 can be connected to a DC power source of a substation, for example. A power switch 5b is connected to the terminals 5a1 and 5a2.

  A rectifier diode bridge 5d is connected to the power switch 5b via a fuse 5c1. The diode bridge 5d is provided to prevent an error in the polarity of the DC power supply. Control lines E1 to E4 are connected to the output side of the diode bridge 5d. The control line E3 is provided with a fuse 5f. Since the control line E3 and the fuse 5f are connected to the existing distribution line control circuit, the control line E3 and the fuse 5f reliably protect the internal circuit of the portable case 2 in the event of a short circuit or other trouble, and do not interfere with the existing circuit. It is provided to make it. A reset timer 7 constituting an initial reset circuit is provided between the control line E3 and the control line E4. The control line E2 is connected to the control line E3 via a contact point of the reset timer 7.

The OVG detection circuit 10 includes a 64V relay 11, a timer 12, and a relay 13 as a ground fault overvoltage relay. The 64V relay 11 is connected to input terminals 14 a and 14 b provided on the surface side of the portable case 2. The input terminals 14a and 14b can be connected to a PT test plug 123 on the distribution line side. That is, a signal corresponding to the ground fault voltage V ₀ can be input to the input terminals 14 a and 14 b via the PT test plug 123. The timer 12 and the relay 13 are provided between the control line E3 and the control line E4. The timer 12 is activated in accordance with the operation of the 64V relay 11, and activates the relay 13 0.7 seconds after the operation starts. The reason for setting the time limit to 0.7 seconds is that, as shown in FIG. 7, it is necessary to cooperate with 0.5 seconds of the trip command (shutoff command).

Between the control line E3 and the control line E4, a ground fault direction relay non-operation countermeasure circuit 20 is provided. When operating 2 lines in the distribution line, for example, there is an extreme difference in the length of the line due to a large load at the substation exit, and if the operation of the 67F relay cannot be expected with a long line length, This ground fault direction relay non-operation countermeasure circuit 20 is used. By using the ground fault direction relay malfunction prevention circuit 20, if the B line 128 does not trip even if the generation of the ground fault voltage V ₀ continues, it is determined that an A line fault has occurred, and the A line 127 is delayed. I try to make it trip.

  The ground fault direction relay non-operation countermeasure circuit 20 includes a changeover switch unit 21, a first keep relay 23, a confirmation lamp 24, a timer 25, and relays 26 and 27. The first keep relay 23 is connected to the control line E3 and the control line E4 via the changeover switch unit 21. The changeover switch unit 21 includes a use push button switch 21a and a non-use push button switch 21b. In the first keep relay 23, the set coil 23a is operated by operating the use push button switch 21a, and the reset coil 23b is operated by operating the non-use push button switch 21b. The timer 25 is connected to the control line E3 and the control line E4 via the contact 11b of the 64V relay 11 and the contact 23c of the first keep relay 23. The relay 26 operates in accordance with the operation of the timer 25, and starts the relay 27 0.7 seconds after the operation starts. The reason for setting the time limit to 0.7 seconds is that, as shown in FIG. 7, it is necessary to cooperate with 0.5 seconds of the trip command (shutoff command). The ground fault direction relay non-operation countermeasure circuit 20 is provided with a confirmation lamp 24 for confirming the state (mode) of the first keep relay 23. The relay 26 is provided for the purpose of delay in order to ensure the lock of the A-line trip memory circuit M1.

  A trip memory circuit 30 is provided between the control line E3 and the control line E4. The trip memory circuit 30 is an A-line trip memory circuit that stores the interruption of the A-line 127 by the voltage change of the distribution line 67F trip lock terminal in the control circuit 126a provided with the trip coil 130a for operating the A-line circuit breaker 130 of FIG. Has M1. Similarly, the trip memory circuit 30 stores the interruption of the B line 128 by the voltage change of the distribution line 67F trip lock terminal in the control circuit 126b provided with the trip coil 140a for operating the B line breaker 140 of FIG. A trip memory circuit M2 is provided. The A-line trip memory circuit M1 includes a second keep relay 33, a first confirmation lamp 34, a timer 35, and a relay 36. The B line trip memory circuit M2 includes a third keep relay 37, a second confirmation lamp 47, a timer 38, and a relay 39. The first confirmation lamp 34 displays the operation state of the second keep relay 33, and the second confirmation lamp 47 displays the operation state of the third keep relay 37.

  The trip memory circuit 30 includes operation switches 31a, 31b, and 31c including push button switches for operating the keep relays 33 and 37. The set coil 33a of the second keep relay 33 is connected to the control line E3 and the control line E4 via the first operation switch 31a and the contact point 37c of the keep relay 37. The timer 35 is connected to the control line E3 and the control line E4 via the contact 33c of the second keep relay 33. The timer 35 operates in accordance with the operation of the contact 33c of the second keep relay 33, and starts the relay 36 1.0 seconds after the operation starts. The set coil 37a of the third keep relay 37 is connected to the control line E3 and the control line E4 via the second operation switch 31b and the contact 33d of the second keep relay 33. The timer 38 is connected to the control line E3 and the control line E4 via the contact point 37d of the third keep relay 37. The timer 38 operates in accordance with the operation of the contact 37d of the third keep relay 37, and starts the relay 39 1.0 seconds after the operation starts.

  The second keep relay 33 and the third keep relay 37 are simultaneously reset by the operation of the reset coils 33b and 37b of the keep relays 33 and 37 by the operation of the third operation switch 31c. Thus, since the trip memory circuit 30 requires a test including a cable at the start of use, the operation switches 31a, 31b, and 31c for the simulation test are provided so that the trip of the distribution line can be manually simulated. Have. Further, as shown in the time chart of FIG. 6, since there is a time lag between the trip signal and the opening of the wiring line and the return of the 64V relay 11, the timers 35 and 38 have a time limit of 1.0 second.

  A trip output circuit 50 is connected to the trip memory circuit 30. The trip output circuit 50 is composed of a circuit in which contacts of a timer and a relay are combined. The trip output circuit 50 has trip signal input / output terminals 51 and 52 exposed on the outer surface of the transportable case 2. The trip signal input / output terminal 51 for the A line is connected to the set coil 33a of the second keep relay 33 via the B contact 25a of the timer 25, the diode 40a, and the contact 37c of the third keep relay 37. The trip signal input / output terminal 52 for the B line is connected to the set coil 37a of the third keep relay 37 via the diode 40b and the contact 33d of the second keep relay 33.

The B contact 25a of the timer 25 connected to the A line trip signal input / output terminal 51 is provided for the purpose of locking the A line trip memory circuit M1. A line trip memory circuit M1 is, B a trip signal A line output from the ground fault directional relay inoperative countermeasure circuit 20 by storing via the contact 27a of the relay 27, upon the occurrence of the next ground voltage V ₀ It is provided for the purpose of preventing the line from tripping.

  The trip signal input / output terminal 51 for the A line can be connected to the terminal 46 of 64VB1XB via the contact point 27a of the relay 27. The terminal 46 of 64VB1XB is exposed on the surface of the portable case 2. Further, the trip signal input / output terminal 51 for the A line can be connected to the terminal 46 of 64VB1XB via the contact 39a of the relay 39 of the B line trip memory circuit M2 and the contact 13a of the timer 13 of the OVG detection circuit 10. ing. The B line trip signal input / output terminal 52 can be connected to the 64VB1XB terminal 46 via the contact 36a of the relay 36 of the A line trip memory circuit M1 and the contact 13a of the relay 13 of the OVG detection circuit 10. . The end of the control line E1 is connected to the P1 terminal 45 exposed on the outer surface of the portable case 2. The P1 terminal 45 is provided adjacent to the terminal 46 of 64VB1XB.

  Trip signal input / output terminals 51 and 52 and 64VB1XB terminal 46 can be connected to a control circuit on the distribution line side. The trip signal input / output terminal 51 for the A line can be connected to a control circuit 126a having a contact 124a of a ground fault direction relay (67F). A trip coil 130a of the circuit breaker 130 is connected to the control circuit 126a. The trip signal input / output terminal 52 for the B line can be connected to a control circuit 126b having a contact 124b of a ground fault direction relay (67F relay). A trip coil 140a of the circuit breaker 140 is connected to the control circuit 126b. The terminal 46 of 64VB1XB can be connected to the DG test TT terminal 125 on the distribution line side to which the contacts 124a and 124b of the ground fault direction relay are connected.

  As shown in FIG. 3, an SWG (switchgear) ground fault detection circuit 120 having an existing 64V relay 121 is provided on the distribution line side. Signals K1 and K2 from the SWG ground fault detection circuit 120 are sent to the DG test TT terminal 125, and the signals sent to the control circuits 126a and 126b via the DG test TT terminal 125. Thus, the second keep relay 33 or the third keep relay 37 is operated. The SWG ground fault detection circuit 120 has a 10G relay 122 as a ground fault protective relay. The 10G relay 122 performs ground fault protection 3 to 9 seconds after the occurrence of a ground fault in the distribution line. That is, for example, if the ground fault resistance exceeds a predetermined value, the 10G relay 122 cannot operate the 67F relay as a ground fault direction relay, so that the 10G relay 122 can be used to disconnect the line. When the DG test TT terminal 125 does not exist on the distribution line side, the P1 terminal 45 provided in the transportable case 2 can be used instead.

  A circuit test terminal 60 exposed on the outer surface of the portable case 2 is connected to the end of the control line E4. The circuit test terminal 60 is used for on-site simulation tests. Display lamps 41 to 44 for displaying the operation state of the trip output circuit 50 are provided on the surface of the portable case 2. The display lamps 41 to 44 are composed of LEDs (two-color light emitting diodes). The display lamps 41 to 44 are turned on by turning on and off the red and green colors in conjunction with the operations of the contacts 13a, 27a, 36a, and 39a of the trip output circuit 50.

  As shown in FIG. 2, some of the electric components constituting the OVG detection circuit 10, the ground fault direction relay non-operation countermeasure circuit 20, the trip memory circuit 30, and the trip output circuit 50 are on the surface of the portable case 2. The time is set and the operation can be confirmed on the surface side of the portable case 2. Each of the above-described terminals provided on the surface side of the portable case 2 can be connected to a circuit on the distribution line side via a cable (not shown).

  Next, the operation and action of the portable ground fault protection device 1 will be described.

  The portable ground fault protection device 1 is transported to a predetermined place during power outage work of a distribution line accompanying inspection of a circuit breaker or the like, and protects each circuit stored in the portable case 2 with existing ground fault protection. Used by connecting to a circuit. When the portable ground fault protection device 1 is used, it is necessary to first perform a simulation test to check whether the device operates normally.

  When starting the simulation test, a voltage regulator (not shown) is connected to the OVG detection circuit 10 and the set value of the simulated voltage applied to the 64 V relay 11 and the set time limit of the timer 12 are confirmed. Next, both the second keep relay 33 corresponding to “A line off” and the third keep relay 37 corresponding to “B line off” are reset by the third operation switch 31c, and the DG test TT is performed. It is confirmed whether the terminal 125 and the control circuit 126a of A line and the control circuit 126b of B line are short-circuited.

  Next, the first operation switch 31a is pressed to confirm that the DG test TT terminal 125 and the B line control circuit 126b are short-circuited. Then, each of the keep relays 33 and 37 is reset by the operation of the third operation switch 31c, and the second operation switch 31b is pressed to short-circuit between the DG test TT terminal 125 and the A-line control circuit 126a. Make sure. Next, the keep relays 33 and 37 are reset by the third operation switch 31c, the use push button switch 21a of the ground fault direction relay non-operation countermeasure circuit 20 is pressed, the TT terminal 125 for DG test and the control circuit for the A line It confirms that it is short-circuited with 126a.

  When the power switch 5b is turned off and then turned on again, the circuit shown in FIG. 3 is reset to the initial state. Here, when there is no DG test TT terminal 125 on the distribution line side, the terminal 46 of 64VB1XB is connected to the P1 terminal 45 of the transportable case 2 and the voltage is checked with the N1 terminal 60.

4 and 5 show the procedure of the operation of the portable ground fault protection device 1. In step S61 of FIG. 4, the power switch 5b of the portable case 2 is turned on, and the circuit of FIG. 3 is reset to the initial state by the reset timer 7 in step S62. Then, in step S63, whether ground voltage V ₀ generated is equal to or greater than a set value is determined. Here, when it is determined that the ground fault voltage V ₀ is equal to or higher than the set value, that is, when a ground fault occurs in the distribution line, the process proceeds to step S64, and the ground fault direction relay (67F relay) malfunction prevention circuit Whether or not 20 is used is determined. No ground fault in distribution line, if the ground voltage V ₀ is determined to not occurred, repeating the process of step S63, maintains the standby state.

  If it is determined in step S64 that the ground fault direction relay (67F relay) non-operation countermeasure circuit 20 is not used, the process proceeds to step S73 in FIG. 5 to determine whether or not the A line 127 is tripped (cut off). Is judged. If it is determined that the A line 127 is interrupted, the process proceeds to step S74, and the trip memory circuit 30 stores the A line 127 interrupt command. If it is determined in step S73 that the trip is not for the A line 127, the process proceeds to step S75, and it is determined whether or not the trip is for the B line 128. Here, when it is determined that the trip of the B line 128 is not detected, the process proceeds to step S77, and the ground fault protection by the 10G relay 122 is performed. In step S75, when it is determined that the trip of the B line 128 is detected, the trip memory circuit 30 stores the cutoff command of the B line 128. When the processes of step S74 and step S76 are completed, the process proceeds to step S78, and the A-line 127 or the B-line 128 is closed again.

Next, the process proceeds to step S79, where it is determined whether the re-closing / re-closing failure or the occurrence of the ground fault voltage V ₀ in a new ground fault is generated. Here, when the ground fault voltage V ₀ is generated and it is determined that the ground fault voltage V ₀ is equal to or higher than the set value, the process proceeds to step S80, and the existing 67F relay of either the A line 127 or the B line 128 is used. It is determined whether or not it is a trip. If it is determined in step S80 that the trip is either the A line 127 or the B line 128, the process proceeds to step S84, where the A line 127 or the B line 128 is reclosed, the A line or the B line is reclosed, One of the final interruptions is performed.

In step S79, ground fault of the power distribution line ground voltage V ₀ no If it is determined not to have occurred, the process proceeds to step S82, the whether is always systematic distribution line is judged. Here, when it is determined that the distribution line is not always connected, that is, when distribution is being performed with one line or during partial distribution, the process returns to step S79. If it is determined in step S82 that the distribution line is always connected to the power distribution system (system before the occurrence of a series of accidents), the process proceeds to step S83, and the third operation switch 31c manually resets the keep relays 33 and 37. After that, the process returns to step S63 again.

  In step S80, when neither the A line 127 or the B line 128 trips due to the existing 67F relay not operating, the process proceeds to step S81, and the memory content of the cutoff command is determined. Here, when the memory content of the cutoff command is the A line 127, the process proceeds to step S85, and the cutoff command for the remaining line (B line 128) is issued. In step S80, when the memory content of the cutoff command is B line 128, the process proceeds to step S86, where a cutoff command for the remaining line (A line 127) is issued. When the processes of steps S85 and 86 are completed, the process proceeds to step S87, and the number of reclosing operations for the remaining lines is determined.

  If it is determined in step S87 that the number of reclosing operations for the remaining line is 1 or less, the process proceeds to step S88, where the remaining line is reclosed or reclosed again. If it is determined in step S87 that the number of reclosing operations for the remaining line is two, the process proceeds to step S89, where the remaining line is finally blocked.

  If it is determined in step S64 in FIG. 4 that the ground fault direction relay non-operation countermeasure circuit 20 is used, the process proceeds to step S65, where either the A line 127 or the B line 128 is tripped by the existing 67F relay. It is determined whether or not. Here, when it is determined that the trip of either the A line 127 or the B line 128 is made by the existing 67F relay, the process proceeds to step S66, and the cutoff command for the A line 127 or the B line 128 is sent to the trip memory circuit 30. After that, the process proceeds to step S78 in FIG.

  If it is determined in step S65 that neither the A-line 127 nor the B-line 128 trips due to the existing 67F relay, that is, if the 67F relay on the distribution line side does not operate, the process proceeds to step S67, and the A-line 127 The trip memory circuit 30 is locked for the shut-off command. Then, it progresses to step S68 and the interruption | blocking command of the A line 127 is performed. Next, the process proceeds to step S69, where the number of reclosing operations for the A line 127 is determined. Here, if it is determined that the number of times of reclosing of the A line 127 is one or less, the process proceeds to step S70, where the reclosing or reclosing of the A line 127 is performed, and the process returns to step S63. In step S69, when it is determined that the number of reclosing operations of the A line 127 is two, the process proceeds to step S71, and the final shutoff of the A line is performed. That is, in this state, power distribution is performed on one line. Then, the process proceeds to step S72, and the line A “cut” is manually performed through the first operation switch 31a.

FIG. 6 shows a time chart of each operation in steps S63 and S65 to S66 in FIG. 4 and steps S63 and S73 to 76 in FIG. 5, and in particular, the 67F relay when the A line 127 causes a ground fault. The time chart until B line trip output circuit formation by operation | movement is shown. As shown in FIG. 6, ground fault occurred A line 127 in step S91, 64V relay 11 and the existing 64V relay 121 is operated by the occurrence of a ground fault the voltage _{V 0} at step S92, existing at step S93 Blocking of the A line 127 by the 67F relay on the distribution line side is started. When the A line 127 break command is issued, the A line 127 breaker 130 operates and the A line 127 break command is stored in the trip memory circuit 30. Here, the time from when the existing 64V relay 121 is operated until the shut-off command is issued is 0.5 seconds. After the 64V relay 121 existing operates, to cut off the operation of the A line 127 in step S95, the return of the ground voltage _{V 0} which step S96, 64V relay 11 and the existing 64V relay 121 in step S97 is restored The time is set within 0.7 seconds. The time from the storage of the cutoff command for the A line 127 in step S98 to the trip memory circuit 30 to the formation of the circuit for the trip output of the B line 128 in step S99 is set to 1.0 second.

  Each operation timing is set as shown in FIG. 6 because the trip is made only by the operation of the 64V relay 11, so that the trip output circuit for the B line 128 in step S99 is formed during the return of the 64V relay 11. This is to prevent the B line 128 from being erroneously cut off.

FIG. 7 shows time charts of operations in steps S63, S65 to S68 of FIG. 4 and steps S79 to 81 and steps S84 to 86 of FIG. 5, and in particular, the 67F relay cutoff of the A line 127 and the B line 128 of FIG. The time chart which shows cooperation with the interruption | blocking instruction | command is shown (in the case of FIG. 4, A line is read as B line). Ground fault occurs in step S101, 64V relay 11 and the existing 64V relay 121 by the occurrence of a ground fault the voltage _{V 0} at step S102 is operated. Here, when the 67F relay on the distribution line side operates, the A line 127 is cut off, the 64V relay 11 and the existing 64V relay 121 are restored within 0.7 seconds, and the B line 128 is not cut off. If the 67F relay 124a on the A-line distribution line side does not operate, it is determined that a ground fault has occurred on the B-line 128, and a command to shut off the B-line 128 is issued in step S108 after 0.7 seconds. That is, when the 67F relay is shut off, the time from the operation of the 67F relay in step S103 to the return of the 64V relay 11 in step S107 is set to 0.7 seconds or less, so that the 64V relay 11 returns. As a result, the B-line cutoff command in step S108 is not output.

  The reason why each operation timing is set as shown in FIG. 7 is to give priority to selective blocking by the existing 67F relay operation. That is, here, in order to coordinate with the operation time limit of 0.5 seconds of the 67F protection circuit and prevent malfunction during protection by the existing 67F relay, the time until the 64V relay 11 is restored is 0.7 seconds or less. It is set.

  In this way, it is detected that a ground fault has occurred in the line operated by the 64V relay 11 of the OVG detection circuit 10 and thereby the trip output circuit 50 is formed, so that it is provided on the distribution line side. By using a signal from the 67F relay (contacts 124a and 124b) as a ground fault direction relay, it is possible to reliably disconnect a ground fault line within a predetermined time limit. The trip output circuit 50 forms a circuit for breaking the circuit breaker in the other line after the 64V relay 11 returns to operation, so that it is possible to reliably prevent malfunction and to connect the line where the ground fault has occurred. It becomes possible to shut off reliably.

  In addition, by utilizing the operation of the DG test terminal 125 and the 67F relay (contacts 124a and 124b) on the distribution line side, which are the operation results of the 64V relay 121 that is an existing protection circuit, it is possible to prevent malfunction when a ground fault occurs. And the reliability of ground fault protection can be ensured. In other words, this portable ground fault protection device 1 is manufactured based on the existing ground fault protection concept of adopting the existing 64V relay 121 and 67F relay, so that malfunction can be avoided, and The reliability can be improved compared to a ground fault protection device that employs a completely independent control method.

  Furthermore, since the ground fault direction relay non-operation countermeasure circuit 20 is incorporated in the portable case 2, even if the 67F relay (contacts 124a, 124b) on the distribution line side does not operate due to the length of the distribution line, The circuit breakers 130 and 140 can be operated reliably, and ground fault protection becomes possible. And since the display lamps 41-44 which display the operation state of the schematic 2c of a ground fault protection circuit and the trip output circuit 50 are provided in the surface of the portable case 2, the structure of a circuit and operation | movement of the trip output circuit 50 are provided. Can be easily grasped, and erroneous operation can be prevented.

  In this embodiment, it is possible to manually reset the keep relays 33 and 37 by the third operation switch 31c regardless of the operation of the reset timer 7, so when the power distribution system returns to the normal state, The apparatus can be easily reset while the mode configuration of the ground fault direction relay non-operation countermeasure circuit 20 is continued.

  The portable ground fault protection device 1 operates the use push button switch 21 a of the changeover switch unit 21 to use the ground fault direction relay non-operation countermeasure circuit 20 or the second operation switch 31 b of the trip memory circuit 30. If operated, it can be utilized when supplying power for only one line.

  In addition to normal ground fault protection, a signal from a pallet switch (not shown) of the circuit breakers 130 and 140 is captured when all circuit breaks such as a short circuit accident and manual disconnection occur. However, in this embodiment, the voltage of the control circuit 126a for the A line or the voltage of the control circuit 126b for the B line is checked, so that the circuit of the portable ground fault protection device 1 is used. Configuration and on-site wiring work can be simplified and reliability can be improved.

  In this embodiment, a large current for reliably interrupting the circuit breakers 130 and 140 is applied to the wires and relay contacts between the power supply circuit 5 and the control line E1 and the 64VB1XB terminal 46 to the trip signal output terminals 51 and 52. Since it is necessary to flow through the trip coils 130a and 140a, the trip output circuit 50 that handles a large current has a circuit configuration separated from other control circuits. The relays 13, 27, 36, and 45 have circuit configurations that amplify the relay contacts in the previous stage in order to secure more energization capacity than the contacts of other timers and keep relays.

  The embodiment of the present invention has been described in detail above, but the specific configuration is not limited to the above-described embodiment, and even if there is a design change or the like without departing from the gist of the present invention, It is included in this invention. For example, although the operation state of the trip output circuit 50 is grasped by the display lamps 41 to 44, the operation state of the trip output circuit 50 may be displayed by, for example, a liquid crystal screen.

DESCRIPTION OF SYMBOLS 1 Portable type ground fault protective device 2 Carrying case 10 OVG detection circuit 11 64V relay (ground fault overvoltage relay)
20 ground fault direction relay non-operation countermeasure circuit 23 first keep relay 30 trip memory circuit 33 second keep relay 37 third keep relay 50 trip output circuit 121 existing 64V relay 122 10G relay 130 circuit breaker 140 circuit breaker V ₀ Ground fault voltage

Claims (3)

A portable ground fault protection device used for ground fault protection of distribution lines to which power is supplied by only two lines,
An OVG detection circuit having a ground fault overvoltage relay that can be connected to the distribution line side and operates with a ground fault voltage equal to or higher than a set value;
The circuit breaker provided on the line in which the ground fault has occurred is cut off by the cutoff command generated by the operation of the existing ground fault overvoltage relay provided on the distribution line side, which is formed based on the ground fault generation signal from the OVG detection circuit. A trip output circuit for
A trip memory circuit that stores the shut-off command when any of the two lines is shut off;
A portable portable case in which the OVG detection circuit, the trip memory circuit, and the trip output circuit are at least incorporated;
With
The trip output circuit is a circuit for interrupting the circuit breaker in the other line based on the operation of the ground fault overvoltage relay of the OVG detection circuit when the ground fault direction relay provided on the distribution line side is inoperative. A portable ground fault protection device characterized by forming   The portable case locks the trip memory circuit when the ground fault direction relay is inoperative due to the length of the line length of the distribution line, and also provides a command to shut off the line where the ground fault has occurred after a predetermined time limit. The portable ground fault protection device according to claim 1, wherein a ground fault direction relay non-operation countermeasure circuit is incorporated. The portable earth fault according to claim 1 or 2, wherein a display lamp for displaying a schematic diagram of a ground fault protection circuit and an operation state of the trip output circuit is provided on a surface of the portable case. Protective device.

Images