JP5401879B2 - Ground fault sequence interrupting device - Google Patents

Description

  The present invention relates to a ground fault detection device that detects a ground fault fault line at a substation, and more particularly to a ground fault sequence interruption device.

  A protection system composed of a main protection device and a ground fault sequence interrupting device is applied to protect facilities (power transmission lines, buses, transformers) constituting the power system. The role of the ground fault sequence interrupting device is to protect the transmission line, bus, transformer, etc. when the main protection device does not function for some reason.

  FIG. 4 is a circuit diagram showing an example of a conventional general substation. 4, the transmission line 1 is connected to the main transformer Tr1 via the primary circuit breaker 52TP1, and the main transformer Tr1 is connected to the secondary circuit breaker 52TS1 (No. 1Tr secondary CB). It connects to each bus line mentioned later. The main transformer Tr1 is grounded through a grounding resistor NGR1 and includes a ground fault overcurrent relay 51NA that detects a ground fault overcurrent. Also, the power transmission lines 2 and 3 are connected to the respective buses from the power transmission line 1 with the same configuration as that of each bus. That is, the transmission line 2 and the transmission line 3 are connected to the main transformers Tr2 and Tr3 via the primary circuit breakers 52TP2 and 52TP3, and the main transformers Tr2 and Tr3 are connected to the secondary circuit breaker 52TS2 (N0.2Tr secondary CB). ) And 52TS3 (No. 3Tr tertiary CB). Similar to the main transformer Tr1, the main transformers Tr2 and Tr3 are grounded through the ground resistors NGR2 and NGR3, and are provided with ground fault overcurrent relays 51NB and 51NC that detect ground fault overcurrent.

  The secondary circuit breakers 52TS1 (No. 1Tr secondary CB), 52TS2 (No. 2Tr secondary CB), and 52TS3 (No. 3Tr secondary CB) are connected to the buses through the circuit breakers 4a, 4b, and 4c. The blocking portions 4a, 4b, and 4c are constituted by, for example, two line switches LS1 and LS2 connected in series, and the line switches LS1 and LS2 are connected to the upper bus and the second bus, respectively. Further, a plurality of blocking portions 4d, 4e, 4f, 4g,..., 4m, which are configured in the same manner as the blocking portions 4a, 4b, 4c, are provided between the upper bus and the second bus (described later). The same number as the number of distribution lines (for example, when there are 10 distribution lines, there are also 10 blocking portions) is inserted. For example, 10 distribution lines 1L to 10L are connected between the line switches LS1 and LS2 in the breakers 4d, 4e, 4f, 4g,... 4m, respectively, and the distribution line breakers 521L to 5210L are connected to each other. Connected with each customer. In addition, the bus line and the Oto bus line are connected by a bus line connection line, and a circuit breaker (hereinafter referred to as a bus line connection breaker 52CB) is inserted in the bus line connection line. It should be noted that ground fault overvoltage relays 64VA and 64VB are connected to the A bus and the B bus, respectively, via a transformer PT.

  During normal operation, the bus bar breaker 52CB is turned on, but as for the other breakers, one of the line switches LS1, LS2 is turned on and the other is opened. For example, the interrupting parts 4a, 4d, 4f,... (The interrupting parts connected to the main transformer Tr1 and the distribution lines 1L, 3L, 5L, 7L, 9L) are switched on the line switch LS1 and opened the line switch LS2. And the breaking parts 4b, 4c, 4e, 4g, ... (breaking parts connected to the main transformers Tr2, Tr3 and the distribution lines 2L, 4L, 6L, 8L, 10L) open the line switch LS1, The switch LS2 is turned on (however, the connection state of the line switches LS1 and LS2 differs depending on the operation).

  Next, the operation of the ground fault sequence interrupting device will be described in detail based on the sequence diagram of FIG. Also, the same components as those in FIG. 4 are denoted by the same reference numerals, and detailed description thereof is omitted here. The ground fault sequence interrupting device includes a main detection unit and an accident detection unit configured separately from the main detection unit.

  When the accident F1 occurs, the overvoltage relays 64VFA and 64VFB operate in the accident detection unit to output the "1" level output signal, and the relay operation confirmation timer 64VTF is started via the OR circuit 5 by this output signal. . The relay operation confirmation timer 64VTF has a predetermined time limit, and if an “1” level input signal from the OR circuit 5 continues for the predetermined time period, an accident has occurred at the substation. It is judged and an output signal of “1” level is output. This output signal is output to the main detection unit.

  In the main detection unit, the ground fault overvoltage relays 64VA and 64VB and the ground fault overcurrent relays 51NA, 51NB and 51NC operate, and are connected to the ground fault overvoltage relays 64VA and 64VB and the ground fault overcurrent relays 51NA, 51NB and 51NC, respectively. The OR circuits 6a and 6b output an output signal of “1” level. The AND circuit 7 outputs a “1” level output signal on condition that the accident detection unit has detected an accident while the OR circuits 6a and 6b are outputting “1” level output signals. . The relay operation confirmation timer 64VT is started by this output signal.

  The relay operation confirmation timer 64VT has a predetermined time limit, and when the "1" level input signal from the AND circuit 7 continues in the predetermined time period, a "1" level output signal is output, Timers 86T, 52T1 to 52T10, 52BT, 52TRA, 52TRB, and 52TRC are activated to start counting. The on-delay timer has a preset time limit (for example, 51T1 to 51T10, 52BT, 52TRA, 52TRB, 52TRC, 86T, which is set in a short order in this order) according to the priority of the line. The time is increased in order from the delay timer, and output signals of “1” level are output respectively.

  First, the on-delay timer 52T1 is timed up, and a cutoff command is output to the circuit breaker 521L via the one-shot timer 8 that operates only for a fixed time. Although the circuit breaker 521L is cut off by the cut-off command, the ground fault overcurrent relays 51NA, 51NB, 51NC and the ground fault overvoltage relays 64VA, 64VB do not return unless they correspond to the accident F1, and the accident continues. Then, every time the time set by the on-delay timer elapses in another line, the circuit breaker of that line is cut off. Thereafter, the above operation is continued until the ground fault overcurrent relays 51NA, 51NB, 51NC and the ground fault overvoltage relays 64VA, 64VB are restored.

  Here, the case where the ground fault A1 has occurred in the distribution line 3L will be described. After the time set in the on-delay timer 52T3 has elapsed and the on-delay timer 52T3 has timed up, the distribution line 3L is interrupted. The vessel 523L is cut off and the accident F1 is disconnected from the system. By disconnecting the distribution line 3L from the system in this way, the ground fault overcurrent relays 51NA, 51NB, 51NC, and the ground fault overvoltage relays 64VA, 64VB are restored. Thereby, the distribution line 3L is determined to be an accident line.

In addition, when the ground fault overcurrent relays 51NA, 51NB, 51NC, and the ground fault overvoltage relays 64VA, 64VB are restored, the relay operation confirmation timer 64VT and the on-delay timers are also restored. Then, the circuit breaker that has been cut off so far is turned on (for example, turned on by a reclosing relay (not shown)).
JP-A-9-103026 (paragraphs [0023] to [0047], FIG. 1) Japanese Patent Laid-Open No. 2-183928 (FIG. 1)

  The characteristics required for the ground fault sequence interrupting device as described above are to detect and shut down the accident line promptly, minimize the line to be interrupted, and minimize the damage caused by the ground fault. Is mentioned.

  However, in the method of judging the accident line by sequentially shutting off the line from the distribution line 1L as described above, if the line where the on-delay timer has been set for a long time is the accident line, many healthy lines are interrupted unnecessarily. In addition, there is a problem that it takes time to detect the accident line. In addition, even in substations with a large number of lines, it took time to detect and block accident lines.

  As described above, in the ground fault sequence interrupting device provided in the substation, it is required to suppress the unnecessary disconnection of the sound line and to minimize the damage caused by the ground fault.

  In addition, it is required to shorten the time required to detect and block the accident line.

The present invention has been devised in view of the conventional problems, and the invention according to claim 1 is characterized in that a plurality of buses are connected to each other via a bus bar breaker, and a line switch is connected to each bus bar. Provided in a substation connected to a plurality of lines via a ground fault , when a ground fault occurs, the lines are sequentially shut down and the ground fault is determined based on whether the ground fault is resolved or not. A ground fault sequence interrupting device that identifies a generated line, and determines whether or not the line is connected to the fault system by reading a signal indicating the connection status of the line switch, and is connected to the fault system A disconnection command is output only to the line, the order of shutting off each line and the time interval for shutting off are set in advance, the bus connection breaker is shut off first, and the bus is determined as the accident bus. Later, only the line connected to the accident bus And performing reordering process of disconnection sequence.

According to a second aspect of the present invention, in the first aspect of the present invention, the line switch is a line switch.

The invention according to claim 3 is the invention according to claim 1 or 2, wherein a zero-phase voltage due to a ground fault is detected and a ground fault overvoltage relay connected to each of the buses, and a transformer neutral point due to the ground fault An accident confirmation unit comprising a ground fault overcurrent relay connected to the main transformer for detecting current;
An AND circuit that inputs a signal indicating a connection status of the line switch and a signal indicating an operation status of the ground fault overvoltage relay, and an on-delay timer set with a time limit for disconnecting each line, and a sequence interruption And
In the accident confirmation unit, when the overcurrent relay and the overvoltage relay operate for a certain time, it is determined that a ground fault has occurred,
In the sequence cut-off unit, it is determined whether a line is connected to an accident system based on an output signal of the AND circuit, and only the line connected to the accident system is sequentially shut off by an on-delay timer.

According to a fourth aspect of the present invention, in the third aspect of the invention, the sequence interruption unit can select whether or not to interrupt the bus bar breaker when the lines are sequentially interrupted. Features.

  According to the configuration as in the first to seventh aspects of the present invention, it is possible to prevent unnecessary disconnection of a line that is not connected to a system fault.

  According to the configuration of the invention as claimed in claims 2 to 5, the accident bus and the healthy bus are separated by first opening the bus connection breaker and separating the bus when the lines are sequentially cut off. It is possible to determine which bus is the accident bus.

  According to the configuration of the fifth aspect of the invention, it is possible to easily read the connection status of the line switch.

  As is apparent from the above description, according to the inventions of claims 1 to 7, it is possible to suppress unnecessarily blocking a healthy line and to minimize damage caused by a ground fault. It becomes.

  According to invention of Claims 2-5, it can prevent unnecessarily interrupting | blocking the line | wire connected to the healthy bus-line. In addition, by shortening the settling time limit of the interruption at the accident bus by the amount that the healthy line has been disconnected, it is possible to quickly identify the accident line and to minimize damage caused by a ground fault. Become.

  According to the fifth aspect of the present invention, it is possible to easily recognize whether each line is currently connected to the Ko-bus line or the Oto-bus line.

  According to invention of Claim 7, it becomes applicable also to the system | strain which is not equipped with the bus-line connection circuit breaker.

  Hereinafter, a ground fault sequence interrupting device according to an embodiment of the present invention will be described in detail based on examples. 4 and 5 are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate.

  The ground fault sequence interrupting device in the present embodiment is provided in a substation where a plurality of lines are connected to the bus via a line switch, and when a ground fault occurs, in the ground fault sequence interrupting device, The line is sequentially cut off, and the accident line is specified based on whether or not the ground fault has been resolved. The method of sequentially shutting off the line is to determine whether the line is connected to the fault system by reading the signal indicating the connection status of the line switch, and to cut off the line not connected to the system fault The command is not output.

[Example 1]
The operation of the ground fault sequence interrupting apparatus according to the first embodiment will be described in detail based on the sequence diagram of FIG. Since the target system has the same configuration as that described in the related art (FIG. 4), detailed description is appropriately omitted using the same reference numerals. Also in the first embodiment, the ground fault sequence interrupting apparatus includes a main detection unit and an accident detection unit.

  In the accident detection unit, when the accident F1 occurs, the overvoltage relays 64VFA and 64VFB operate, an output signal of “1” level is output from the OR circuit 5a, and the relay operation confirmation timer 64VTF is started. The relay operation confirmation timer 64VTF is set with a predetermined time limit. When the predetermined time period elapses, an output signal of “1” level is output to the AND circuit 19 described later. Note that an off-delay timer 18 is inserted between the relay operation confirmation timer 64VTF and the AND circuit 19, and when the "1" level output signal from the relay operation confirmation timer 64VTF is stopped, the off-delay timer 18 is set. After the predetermined time period, the output signal of “1” level to the AND circuit 19 is stopped.

  The main detection unit is composed of an accident confirmation unit 9 and a sequence interruption unit 10, which detects a system fault in the accident confirmation unit 9, and is preset by an on-delay timer provided in each line described later in the sequence interruption unit 10. System faults are eliminated by shutting down in the order specified.

  For example, if a system fault occurs, the fault confirmation unit 9 operates on the condition that the ground fault overvoltage relays 64VA and 64VB operate and the transformer PT connected to the ground fault overvoltage relays 64VA and 64VB is not disconnected. The AND circuits 5b and 5c output an output signal of “1” level, and the OR circuit 6a outputs an output signal of “1” level. When a system fault occurs, the ground fault overcurrent relays 51NA, 51NB, and 51NC also operate, and the OR circuit 6b outputs an “1” level output signal. The AND circuit 7a outputs a “1” level signal on the condition that 43BGF is selected to be used in BGF use / lock selection while the “1” level signal is output from the OR circuits 6a and 6b. Is output to start the relay operation confirmation timer 64VT. The relay operation confirmation timer 64VT has a predetermined time limit. When the "1" level input signal from the AND circuit 7a continues for the predetermined time period, it is determined that a system fault has occurred. The output signal of “1” level is output to the AND circuit 14 (when either one of 6a and 6b becomes “0” level). The AND circuit 14 is in a state where both of the AND circuits 6a and 6b continue to output a "1" level signal (accident continuation state) after the "1" level output signal is output from the relay operation confirmation timer 64VT. , 43BGF are selected to be used, and a "1" level output signal is output to the AND circuits 13a, 13b, 13c1, ... on condition that a lockout timer 86T (to be described later) does not output a "1" level output signal. Output a signal. At this time, the AND circuits 5b and 5c also output "1" level output signals to AND circuits 11a1, 11b1, 11a2, 11b2, 11a3, 11b3,.

  The output signals from the OR circuits 6a and 6b are also output to the AND circuit 7b. When at least one of the output signals from the OR circuits 6a and 6b is a “0” level signal, the AND circuit 7b outputs “0”. ”Level output signal is output. Then, a "1" level output signal is output from the NOT circuit 15, the memory M is reset, the lockout timer 86T times up, and a "1" level output to the AND circuits 13a, 13b, 13c1,. The signal becomes an “0” level output signal.

  Next, the order blocking unit 10 will be described. First, output signals from the AND circuits 5b and 5c and signals indicating the connection status of the line switches are output to the AND circuits 11a1, 11b1,..., 11c, 11d,. The purpose of this is to determine whether each line is connected to a system fault, and when it is not connected to the fault system, the line has the purpose of preventing unnecessary disconnection by not starting a disconnection sequence. In the first embodiment, each line switch (breakers 4a to 4n, bus bar breaker 52CB, primary breakers 52TP1, 52TP2, 52TP3, secondary breaker 52TS1 of main transformers Tr1, Tr2, Tr3) , 52TS2, 52TS3), line switches are applied, and the connection status of each line switch is read.

  For example, when accident F1 occurs in FIG. 4, the accident line (distribution line 3L) is connected to the main bus, but the main bus is also connected to the Oto bus with the bus connection breaker 52CB. The fault overcurrent relays 51NA, 51NB and 51NC and the ground fault overvoltage relays 64VA and 64VB operate.

  When an accident occurs, first, the bus bar breaker 52CB is shut off (bus bar precedent shut-off) to separate the upper bus and the second bus, and to distinguish the accident bus from the healthy bus. Since each line is only connected to either the bus or the Otobus line, the sequence interruption sequence for the line connected to the Kobus line is continued, and the fault is removed from the Otobus line and the ground fault overcurrent relays 51NB, 51NC and The ground fault overcurrent relay 64VB is restored.

  In order to make the above-described movement, the on-delay timer sets the settling time limit of the bus bar breaker 52BT1 the shortest, and the other 52T1 to 52T10 and 52TRA to 52TRC set a highly important line with a long time limit. The settling time of the on-delay timers 52TRA to 52TRC is set longer than the settling time of the on-delay timers 52T1 to 52T10 of the distribution lines. As an example, 52BT1 <52T1 <52T2 <52T3 <52T4 <52T5 <52T6 <52T7 <52T8 <52T9 <52T10 <52TRA <52TRB <52TRC <52BT2 <86T. When the on-delay timer is set as described above, it operates as follows.

  When the ground fault A1 occurs in the distribution line 3L, the ground fault overcurrent relays 51NA, 51NB, 51NC, the ground fault overvoltage relays 64VA, 64VB, the overvoltage relays 64VFA, 64VFB operate, and the AND circuits 5b, 5c are set to the “1” level. The output signal is output. The AND circuits 11c and 11d include "1" level output signals from the AND circuits 5b and 5c, the secondary breaker 52TS1 (No. 1Tr secondary CB) of the main transformer Tr1, and the secondary of the main transformer Tr2. A signal indicating the connection status of the circuit breaker 52TS2 (No. 2Tr secondary CB) is input. For example, when the secondary circuit breaker 52TS1 of the main transformer Tr1 is turned on, an output signal of “1” level is output to the AND circuit 11c, and the secondary circuit breaker 52TS2 of the main transformer Tr2 is turned on , "1" level output signal is output to the AND circuit 11d. That is, the AND circuit 11c outputs an output signal of “1” level on condition that the secondary circuit breaker 52TS1 of the main transformer Tr1 is turned on while the ground fault overvoltage relay 64VA is in operation. Similarly, the AND circuit 11d also outputs an output signal of “1” level on condition that the secondary circuit breaker 52TS2 of the main transformer Tr2 is turned on while the ground fault overvoltage relay 64VB is operating. . These output signals are output to the OR circuit 12c and the AND circuit 16, and the OR circuit 12c and the AND circuit 16 output a "1" level output signal. The AND circuit 13c1 outputs a “1” level output signal on condition that both the AND circuit 16 and the AND circuit 14 output a “1” level output signal. The AND circuit 13c3 is a signal of “1” level on the condition that an output signal of “1” level is output from the AND circuit 13C1 in a state where the mother chain preceding cutoff selection unit 20 is set to “1”. Is output to start the on-delay timer 52BT1. Since the on-delay timer 52BT1 is set to the shortest time limit, the time is first up, and an “1” level output signal is output to the AND circuit 19 via the OR circuit 17 and the one-shot timer 8. In the AND circuit 19, 43 BGF is selected for use in a state in which an output signal of “1” level is input from the one-shot timer 8, and an output signal of “1” level is output from the accident detection unit. On the condition that it is output, a disconnection command is output to the bus bar breaker 52CB.

  That is, the mother-unit preceding cutoff sequence is activated on condition that the ground fault overvoltage relays 64VA and 64VB are operating and the secondary transformers 52TS1 and 52TS2 of the main transformer Tr1 and the main transformer Tr2 are turned on, After the time set by the on-delay timer 52BT1, a cut-off output is performed to the bus bar breaker 52CB.

  When the bus bar breaker 52CB is cut off, the A bus line is separated from the Oto bus line, and the accident continues on the A bus side line to which the accident line (distribution line 3L) is connected. Will return from the accident state. That is, the operation of the ground fault overcurrent relay 51NA, the ground fault overcurrent relay 64VA, and the overvoltage relay 64VFA is continued, and the ground fault overcurrent relays 51NB and 51NC, the ground fault overvoltage relay 64VB, and the overvoltage relay 64VFB are restored.

  Next, the sequence interruption sequence of the distribution line and the breaker of the main transformer will be described. In the AND circuit 11a1, the line switch LS1 on the side of the bus line of the blocking part 4d connected to the distribution line 1L is turned on in a state where the AND circuit 5b outputs an output signal of “1” level. An output signal of “1” level is output on condition of When an “1” level output signal is output from the AND circuit 11a1, the OR circuit 12a outputs a “1” level output signal. The AND circuit 13a outputs a "1" level output signal when a "1" level output signal is output from the AND circuit 14 while the "1" level output signal is output from the OR circuit 12a. The on-delay timer 52T1 is started. The on-delay timer 52T1 is set to the next short time period after the on-delay timer 52BT1. When the set time period elapses, an output signal of “1” level is output, and the AND circuit 19 is connected via the one-shot timer 8. Output an output signal of “1” level. The AND circuit 19 outputs “1” level output signal from the accident detection unit while 43BGF is selected to “use” while the “1” level output signal is output from the one-shot timer 8. On the condition that this is done, an output signal of “1” level is output, and a disconnection command is output to the circuit breaker 521L of the distribution line 1L. However, since the distribution line 1L is not an accident line, the operation of the ground fault overvoltage relay 51NA and the ground fault overcurrent relay 64VA is continued.

  Next, the interruption | blocking sequence after the distribution line 2L is demonstrated. In addition, since the interruption | blocking sequence after the distribution line 2L is the same as that of the distribution line 1L, detailed description is abbreviate | omitted using the same code | symbol.

  The AND circuit 11a2 outputs an output signal of “1” level from the AND circuit 5b, but the line switch LS1 on the upper bus side of the blocking part 4e connected to the distribution line 2L is blocked. An output signal of “0” level is output. The AND circuit 11b2 has a line switch LS2 on the side of the busbar of the blocking section 4e connected to the distribution line 2L, but after the busbar connection circuit breaker 52CB is cut off, the AND circuit 5c has a “0” level. Therefore, the output signal of “0” level is output. As a result, the “1” level input signal to the on-delay timer 52T2 is stopped before the time is up, so that no interruption command is output to the circuit breaker 522L of the distribution line 2L.

  Since the AND circuit 11a3 outputs an output signal of "1" level from the AND circuit 5b, and the line switch LS1 on the side of the bus line of the blocking portion 4f connected to the distribution line 3L is turned on, An output signal of “1” level is output. Then, similarly to the disconnection sequence of the distribution line 1L, the on-delay timer 52T3 is started, and an output signal of “1” level is output after the time set by the on-delay timer 52T3 has elapsed. Is supplied to the circuit breaker 523L of the distribution line 3L. When the distribution line 3L is cut off, the accident F1 is disconnected from the system, and the ground fault overcurrent relay 51NA, the ground fault overvoltage relay 64VA, and the overvoltage relay 64VAF are restored. Thereafter, the line is not cut off, and the line can be removed by inserting a circuit breaker other than the accident line. The charging is performed by another device such as a reclose relay.

  Since the ground fault sequence interrupting device of the first embodiment is controlled as described above, the distribution lines 2L, 4L, 6L, 8L, and 10L connected to the Otsu bus are set to “1” before the on-delay timer expires. Since the "" level input signal stops, no shutoff command is output.

  The OR circuit 12c outputs a "1" level output signal when an "1" level output signal is input from at least one of the AND circuits 11c and 11d, and the AND circuit 13c2 On the condition that the “1” level output signal is input from the AND circuit 14 in a state where the “1” level output signal is input from 12c, the “1” level output signal is output, and the on-delay is performed. The timer 52BT2 is started. That is, in the system with the bus bar breaker 52CB, when the setting of the bus advance blocker selection unit 20 is set to “0”, a cut command is output to the bus bar breaker 52CB after the time set by the on-delay timer 52BT2. The Rukoto.

  It is to be noted that the mother chain preceding cutoff selection unit 20 is set to “0” and the on-delay timers 52BT1 and 52BT2 are locked and set to secondary breakers 52TS1 (No.1Tr secondary CB), 52TS2 (No.2Tr secondary CB). By always setting the signal indicating the connection status of the terminal to “0”, the present invention can also be applied to a system that does not include the bus bar breaker 52CB.

  The lockout timer 86T is set for a predetermined time, and when the set time elapses, an output signal of “1” level is output to lock the contactor 43BGF. That is, when the lockout timer 86T has a time set longer than the time set for all lines, and the time from the occurrence of a ground fault to the removal of the accident takes longer than the time set for the lockout timer 86T. Then, 43BGF is locked by BGF use / lock selection as a device abnormality, and the process proceeds to accident removal by backup protection.

  Note that the on-delay timers other than the on-delay timers 52BT1 and 52BT2 may set the time limit for each of the buses and the buses (for example, the buses are in the order of 52T1L, 52T3L, 52T5L, 52T7L, 52T9L, 52TRA, 52TRB). Short, the maiden bus is settled in the order of 52T2L, 52T4L, 52T6L, 52T8L, 52T10L, 52TRC).

  FIG. 2 is a simplified diagram of the substation described in detail in FIG. In FIG. 2, the line switches LS1 and LS2 are omitted for easy understanding of the connection state.

  As shown in the simplified diagram of FIG. 2, in the case where the bus is used in combination with the distribution line and the transformer, the bus bar breaker 52CB is used when the lines are sequentially cut off as in the first embodiment. Is disconnected first, and each bus is separated, so that the accident bus and the healthy bus are separated. As a result, since the healthy bus has no zero-phase voltage, the ground fault overvoltage relay connected to the healthy bus is restored, and it is possible to prevent unnecessary disconnection of the line connected to the healthy bus.

  Table 1 is a table showing the number of lines and the time required for blocking the lines in the conventional example and the first embodiment. In Table 1, the time from when one breaker is cut off until the next breaker is cut off is 1 second.

  As shown in Table 1, in the ground fault sequence interrupting device in the conventional example, when the fault line is specified, the distribution line breaker is sequentially interrupted from the distribution line 1L, so the distribution line 1L to the distribution line 10L are interrupted. The time required to do this is 10 seconds. On the other hand, in the ground fault sequence interruption device according to the first embodiment, when the accident line is specified, the line connected to the healthy bus does not need to interrupt the distribution line breaker, and therefore, the distribution lines 1L to 10L are blocked. The time required for this is 5 seconds, and the time required for identifying the accident line is greatly reduced.

  Further, in the present embodiment, since the line switch is applied to the line switch, it is possible to easily recognize whether each line is connected to the bus line or the bus line.

[Example 2]
Next, another example of the ground fault sequence interrupting device in the present embodiment will be described in detail with reference to FIG. 3 (circuit diagram of a substation provided with the ground fault sequence interrupting device in the second embodiment). Since the target system has the same configuration as that described in the related art (FIG. 4) and the first embodiment, the same reference numerals are used and detailed description thereof is omitted. In the second embodiment, as shown in FIG. 3, the blocking portions 4d, 4f, 4g, 4≡, 4j, 4l (the blocking portions connected to the distribution lines 1L, 3L, 4L, 6L, 7L, 9L) The line switch LS1 is turned on, the line switch LS2 is opened, and the cut-off parts 4e, 4h, 4k, 4m (the cut-off parts connected to the distribution lines 2L, 5L, 8L, 10L) are connected to the line switch LS1. Open, line switch LS2 is turned on.

  In the second embodiment, in order to make it easier to compare the time required for detecting the accident line and breaking the accident line in the conventional example and the second embodiment, here, the operation is performed assuming that only the distribution line is cut off. Explain (originally breaks the main transformer and other circuit breakers).

  In the ground fault sequence interrupting apparatus according to the second embodiment, the order of disconnecting lines and the interval of disconnecting are set. In addition, when the lines are sequentially cut off, the bus communication breaker is first cut off, and after the accident bus and the healthy bus are separated, only the lines connected to the accident bus are rearranged.

  Table 2 below shows the time until each line is cut off in the ground fault sequence interrupting device of the conventional example and the second embodiment, assuming that the ground fault A2 occurs in the distribution line 8L. In addition, the settling value in the conventional example indicates a timed settling, and the settling value in the second embodiment and the settling value after the rearrangement process indicate the settling values in the blocking order.

  As shown in Table 2, the conventional ground fault sequencer sequentially shuts off from the distribution line 1L when specifying the accident line, so it takes 8 seconds until the distribution line 8L that is the accident line is cut off. Cost.

  The ground fault sequence interrupting device according to the second embodiment includes two parameters, that is, a set value in the interrupt sequence and a set value in the interrupt interval. That is, the interruption order from the distribution line 1L to the distribution line 10L is set in the ground fault sequence interruption device (for example, as shown in Table 2, the distribution line 1L to the distribution line 10L are set in order (however, the line number and It is not necessary to set the same value as the set value)), and the time (interval) from when one line is cut off until the next line is cut off is set (for example, 1 as shown in Table 2). Settling in seconds).

  In the operation when the ground fault A2 occurs in the distribution line 8L, first, when the line is sequentially cut off as in the first embodiment, the bus bar breaker 52CB is first cut off, and the bus line and the Oto bus line are first cut off. And are separated. When the Kou bus and the Oto bus are separated, the operation of the ground fault overcurrent relays 51NA, 51NB, 51NC and the ground fault over voltage relays 64VA, 64VB indicates that the Ko bus is a healthy line and the Oto bus is an accident bus. Determined. Based on the determination, the interruption order rearrangement process is performed only for the line connected to the accident bus (Oto bus). In the second embodiment, since the lines connected to the maiden bus are the distribution lines 2L, 5L, 8L, and 10L, for example, the blocking order is as follows: distribution line 2L, distribution line 5L, distribution line 8L. 3 and the distribution line 10L are set to 4. Since the interruption interval is set at 1 second, the distribution line 8L, which is an accident line, is interrupted 3 seconds after the accident detection operation starts.

  By configuring as in the second embodiment, it is possible to prevent unnecessarily blocking the line connected to the healthy bus, and it is not necessary to block the line connected to the healthy bus so that the accident line Can be identified quickly, and damage due to a ground fault can be minimized. In addition, by setting the shut-off order and the shut-off interval, the rearrangement process only for the lines connected to the accident bus can be facilitated. Furthermore, the interruption sequence setting is more intuitive and easier to understand than the timed setting, and it is possible to suppress erroneous setting.

  Although the present invention has been described in detail only for the specific examples described above, it is obvious to those skilled in the art that various changes and modifications are possible within the scope of the technical idea of the present invention. Such variations and modifications are naturally within the scope of the claims.

  For example, in the first and second embodiments, the ground fault sequence interrupting device provided in the substation having a specific configuration has been described in detail, but the present invention can be appropriately applied to substations having various configurations.

  In addition, it is possible to apply to a system that does not have a bus bar communication breaker by including a bus advance cutoff selection unit and setting the bus advance cutoff to be unused.

  Further, in the first embodiment, the operation of the ground fault sequence interrupting device according to the present invention has been described in detail based on the sequence diagram. However, the logic circuit, the on-delay timer, and the like in the sequence diagram can be appropriately changed and omitted.

  In the first and second embodiments, the blocking unit having two line switches is applied to one line. However, when the number of line switches is one per line, or to two lines. For example, when the number of line switches is three, a blocking unit having various configurations is applicable.

The sequence diagram which shows operation | movement of the ground fault order interruption | blocking apparatus in the present Example 1. FIG. The simplification figure of the substation with which the ground fault order interruption | blocking apparatus in the present Example 1 is provided. The circuit diagram which shows an example of the substation with which the ground fault order interruption | blocking apparatus in the present Example 2 is provided. The circuit diagram which shows an example of a general substation. The sequence diagram which shows operation | movement of the ground fault order interruption | blocking apparatus with which a general substation is equipped.

Explanation of symbols

1, 2, 3 ... Power transmission lines 4a to 4h ... Blocking unit 9 ... Accident confirmation unit 10 ... Order blocking unit LS1, LS2 ... Line switch 52CB ... Bus line breaker 64VA, 64VB ... Ground fault overvoltage relay 51NA, 51NB, 51NC ... Ground fault overcurrent relay 521L to 5210L ... Distributor breaker 52TP1 to 52TP3 ... Primary breaker 52TS1 to 52TS3 ... Secondary breaker

Claims (4)

A plurality of busbars are connected to each other via a busbar breaker, and are provided in a substation in which a plurality of lines are connected to the respective busbars via a line switch,
When a ground fault occurs, it is a ground fault sequence interrupting device that sequentially shuts off the line and identifies the line where the ground fault has occurred based on whether the ground fault is resolved,
Determine whether or not the line is connected to the accident system by reading a signal indicating the connection status of the line switch, and output a cut-off command only to the line connected to the accident system ,
Set the order of blocking each line and the time interval for blocking in advance,
The ground fault sequence is characterized in that after disconnecting the bus contact breaker first and determining the accident bus by shutting off the bus contact breaker, only the lines connected to the accident bus are rearranged. Shut-off device. The ground fault sequence interrupting device according to claim 1, wherein the line switch is a line switch. A ground fault overvoltage relay connected to each of the buses for detecting a zero-phase voltage due to a ground fault, and a ground fault over current relay connected to the main transformer for detecting a transformer neutral point current due to a ground fault. A prepared accident confirmation department,
An AND circuit that inputs a signal indicating a connection status of the line switch and a signal indicating an operation status of the ground fault overvoltage relay, and an on-delay timer set with a time limit for disconnecting each line, and a sequence interruption And
In the accident confirmation unit, when the overcurrent relay and the overvoltage relay operate for a certain time, it is determined that a ground fault has occurred,
In the order blocking portion, wherein the line by the output signal of the AND circuit determines whether it is connected to the accident system, characterized by interrupting sequentially connected to the accident line the line only by the ON delay timer Item 3. A ground fault sequence interrupting device according to item 1 or 2 . 4. The ground fault sequence interrupting device according to claim 3 , wherein the sequence interrupting unit can select whether or not to interrupt the bus bar communication circuit breaker when the lines are sequentially interrupted. 5.

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